HomeMy WebLinkAboutWQCS00064_Annual Report_20230109 WATER RESOURCES DEPARTMENT
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Vmn4\
y��� RECEIVED
JAN O 2023
January 6, 2023
Attn: Christyn Fertenbaugh, PE NCDEQIDWRINPDES
NC Division of Water Resources
Water Quality Permitting Section
1617 Mail Service Center
Raleigh, NC 27699-1617
Subject: Delegated Sewer Collection System Annual Report for CY2022
Program: Town of Apex
County: Wake
Dear Ms. Fertenbaugh,
As per the requirements set forth in 15A NCAC 02T.0306,the Town of Apex(Town) is required to
submit a copy of all program documents and a summary of program changes on an annual basis.
Several revisions have been made this year to the Standards Specifications and Standard Details sections
700 and 800 . Some of the revisions include that if a sewer main is located within road right-of-way or
on Town Property, there shall be no elements that would inhibit maintenance operations, all retaining
walls shall have a separation from the easement boundary of at least 1:1, and replacing the materials
table with one that has updated diameter sizes. A detailed summary of revisions for calendar year 2022
is attached to this letter.
If you have questions, of if I may be of further assistance, please do not hesitate to contact me at (919)
249-3366 or via email at lori.avent@apexnc.org.
Sincerely, i
Lori Avent
Water Resource Specialist
TOWN OF APEX
cc: Michael Deaton, PE, Water Resources Director
Matt Echols, PE, Utilities Engineer
TOWN OF APEX
The Peak of Good Living
PO Box 25o Apex, NC 27502 I (919) 249-3400 I www.apexnc.org
Town of Apex
North Carolina
Standard Specifications & Details
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April 12, 2022
Public Works & Transportation Department
Engineering Division
73 Hunter Street
Apex,NC 27502
Town of Apex
Standard Specifications & Standard Details
Summary of Revisions
April 12, 2022
Section 100 Preliminary Considerations & Instructions
101 General
Revise the last sentence of the second to read "Such deviations from the TOWNS minimum
paragraph
standards receiving such preliminary approval by the Department Director shall be clearly indicated at
one location on the construction drawings, and labeled, "Exceptions to the Standard Specifications of the
Town of Apex"."
102 Submittal Requirements
Revise last sentence to read "Submittal of the construction drawings shall be made only after the project
has received Site Plan approval."
A. Initial Submittal,
1) Final Construction Plans
Revise to read "1 electronic file submittal through IDT Plans. The plan size and content shall conform to
the requirements outlined in Section 103 hereof."
2) Storm Drainage Computations
Revise to read "1 electronic copy of complete storm drainage calculations, maps, and other supporting
material shall be submitted, addressing the following special issues as applicable:"
5) Soil Erosion and Sedimentation Control Plan
Revise to read "1 electronic copy of the "Request for Plan Approval Form" and 1 electronic copy of the
"Financial Responsibility/Ownership Form" shall be submitted."
B. Second Submittal
1) Final Construction Plans
Revise to read "1 electronic file copy submittal through IDT Plans."
2) "Water Distribution Extension Permit Application"
Revise "1 original and 2 copies for review"to "1 original for review".
3) "Gravity Sanitary Sewer Extension Permit Application"
Revise "1 original and 2 copies for review"to "1 original for review".
5) Storm Drainage Computations
Revise to read "1 electronic copy of computations, if revised after initial review as per Section 501."
6) Wastewater Pump Station & Force Main Computations
Revise to read "1 electronic copy of computations, if revised after initial review."
7) Soil Erosion and Sedimentation Control Plan
Revise to read "1 electronic copy of the Request for Plan Approval Form and 1 electronic copy of the
Financial Responsibility/Ownership Form shall be submitted, if revised after initial review."
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Revise second paragraph, first sentence to read "The Town of Apex will review the revised plans and, if
they are satisfactory, the submitter will be requested to upload final plans to IDT Plans for approval
signatures and upload final CAD design file to IDT."
106 Record Drawings
Replace with the following.
"Record drawings which reflect "AS-BUILT" conditions must be submitted electronically through
IDTPlans prior to start of warranty for roadways and/or public utilities to be maintained by the Town
of Apex. The record drawings must be labeled "RECORD DRAWINGS" and signed by the Project
Engineer of Record and/or PLS. An electronic file in AutoCAD format shall be submitted to the Town
Engineer through IDTPlans. A survey data file (.txt) denoting the coordinates and description for
each utility feature in the project scope shall be submitted to the Town Development Services
group. All applicable information listed below shall be included on all "AS-BUILT" drawings:
NOTE: Record drawings of roadways and utilities are required prior to the beginning of the one-year
warranty or acceptance by the TOWN.
All pdf sheets shall show base file (approved CD) in a transparent manner, surveyed data will be
shown in a bold/solid color.
The "Record Drawing" plans shall be the certified plans sealed by a professional land surveyor
locating the various features applicable to the project.
The "Construction Drawing" shall be the construction document designed and certified by a
professional engineer who has periodically monitored the project throughout construction and
agrees with the "Record Drawing" plan as defined above.
Record drawings are required for:
• Water and/or sanitary sewer service connections
• Doghouse manhole for service connections
• Irrigation system connections
• Water main extensions
• Fire lines (sprinkler lines)
• Fire hydrants(including relocations of existing hydrants)
• Sewer main extensions
• Sewer outfalls
• Pump stations and force mains
The following PE and PLS Certifications are required on each sheet of the Record Drawings:
I certify that these as-builts are accurate and that each of the items listed on the Town's "Record
Drawing Checklist"as contained in the Town of Apex Standard Specifications is provided on this set
of record drawings([#]total sheets in this set).
I certify that all of the information provided is field-verified record drawing information.
Name: Date:
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(Seal)
Signature Registered Land Surveyor
Name: Date:
(Seal)
Signature Professional Engineer
The following Field Survey Certification Statement is required on the cover sheet of the Record
Drawings and the Survey data file:
I, ,as a duly registered Professional Land Surveyor in the State of North
Carolina, hereby certify that the data shown on this drawing,obtained under my supervision, is an
accurate and complete representation of what was constructed in the field, that the physical
dimensions or elevations shown thus are as-built conditions and the facility was constructed
according to the approved plans, except otherwise noted hereon.
Name: Date:
(Seal)
Signature Registered Land Surveyor"
D. Water Distribution System
Revise part 3.to read"Location of valves,fire hydrants, meters, blow-off assemblies, bore and jack casings
with distance locations, provided in a survey.txt file that includes location data x,y,z."
Add part 6. to read "6. Copy of the PLS certification indicating accuracy of data."
E. Sanitary Sewer System
Revise part 4. to read "Clean-out locations with distance locations provided in a survey .txt file that
includes location data x,y,z."
Add part 12. "Copy of the PLS certification indicating accuracy of data."
Add the following paragraph to the end of the Section: "For all structures and appurtenances an
electronic coordinate survey text file(.txt)shall be submitted in the format of P,N,E,Z,D(Point Number,
Northing, Easting,Elevation, Description).The descriptions used shall be common industry abbreviated
terms (MH, CB, FH, WV, WM, CO, etc.) that are correctly labeled as they are in the CD file with any
applicable reference numbers."
Section 450 Utility Trenches
452 Pipe Laying and Backfill
A. General Requirements
Delete the last sentence of part 6. a) 1).
Replace part 6. a) 2)with "Specifications:The marking tape shall be made of polyethylene (or
approved equivalent) material,3-inches wide and a minimum of 3 millimeters thick, manufactured
specifically for identification of buried utilities.The tape color shall be in accordance with the utility
being installed:".
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Section 500 Storm Drainage
506 Stormwater Control Measures (SCMs) within the Primary and Secondary Watershed Protection
Overlay Districts
Revise the second bullet to read "The outlet structure shall be constructed of precast reinforced concrete
and the outlet pipe shall be either reinforced concrete pipe (RCP) or corrugated polypropylene pipe
(CPP)."
Delete the third bullet"All water quality drawdown devices that penetrate the dam embankment shall be
constructed of ductile iron pipe."
Section 600 Water Distribution System
601 Water Distribution Pipe
A. Design
Add the following to part 1. Location, end of the first paragraph, "All private water mains that connect to
the Town's water system shall also be designed in accordance with these specifications. Any private
commercial water connection shall be metered and protected by a reduce pressure assembly listed on
the most current Manual of Cross-Connection Control issued by the USC Foundation for Cross-
Connection Control and Hydraulic Research. See Section 620."
Add to part 1. Location,end of the seventh paragraph, "If water main is located within road right-of-way
or on Town owned property there shall be no permanent structures, equipment, retaining walls,
embankments, impoundments, landscaping, or other elements that would inhibit maintenance
operations unless approved by the Water Resources Director."
Add to the end of part 1., "All retaining walls shall have a separation from the easement boundary of at
least a 1:1 ratio,vertical to horizontal. For example,if the retaining wall is 10 feet tall, it shall be placed
no closer than 10 feet from the adjacent easement boundary."
602 Fire Protection
A. Fire Hydrants
2. Location
Revise part c), first sentence to read "In business, office and institutional, and industrial zoning the
maximum distance between hydrants, measured along street centerline, shall be in accordance with the
latest version of the NC Fire Code."
Revise part d) to read "All premises where buildings or portions of the building are located at distances
from a fire hydrant that exceed those specified by Fire Code shall be provided with approved on-site fire
hydrants and water mains capable of supplying the fire flow required by the Fire Department."
3. Specifications
Revise "Hydrants shall be furnished with a 5-inch Storz steamer" to "Hydrants shall be furnished with a
4.5-inch steamer".
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603 Valves and Appurtenances
A. Valves
1. General
Add to the end of part a) "Valves are required regardless of whether tee connection is cut-in or made by
tapping sleeve and valve. Valve requirements are not enforced unless the branch line serves more than
one parcel or has more than one connected service."
604 Water Main Taps and Services
A. Design
Revise part 11., first sentence to read "No services shall be made directly to water mains that are 18" or
larger."
Add "19.There shall be no size-on-size taps allowed. All taps must be at least one size smaller than the
main being tapped.
606 Testing and Inspections
B. Testing
5. Bacteriological and Turbidity Sampling
Revise part c)to read "Samples for laboratory analysis shall be collected by a Town Representative after
flushing is completed.The Contractor shall set up sampling stations. A Town Seal sticker shall be placed
on the sample bottle. The Town is responsible for the delivery of the sample(s)to a testing laboratory
certified by the North Carolina Department of Human Resources,Division of Health Services.The testing
lab will document the condition of the seal upon receipt. The Town shall furnish the Contractor with a
copy of the results prior to tapping any services. All costs for laboratory testing shall be borne by the
Contractor. Samples shall be taken at 2000 feet intervals, at the end of the main, at each branch
connection, and each side of all cut-in connections."
Add "m) If the Inspector or any Town representative does not approve of the sampling location,
equipment, or setup then the sample shall not be taken. Contractor shall only take samples when
approved by the Inspector or Town Representative."
6. Tracer Wire and Marker Tape Testing
Add to the end of this part "The contractor shall submit a report of all tracer wire and marker tape
testing. The Town reserves the right to require a third-party testing company at any time, at the
expense of the contractor."
607 Repair and Abandonment
Add "8.Abandonment of Existing Water Services Contractors abandoning water services shall remove
the entire service stub. When available, a mechanical plug shall be used to abandon the corporation
stop. If equipment necessary to plug the main is not available,the corporation stop shall be turned off
and capped.A%" PVC pipe shall extend a minimum of 12"above the capped corporation stop,wrapped
at least 3 times with caution tape to identify an abandoned tap. All remaining portions of the service
stub shall be removed from the main to the right of way line and shall be disposed of properly."
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1
Section 700 Wastewater Collection Systems
701 Gravity Sewer
A. Design
1. Main Location
Add to end of part h) "If sewer main is located within road right-of-way or on Town owned property
there shall be no permanent structures, equipment, retaining walls, embankments, impoundments,
landscaping, or other elements that would inhibit maintenance operations unless approved by the
Water Resources Director."
Add "x) All retaining walls shall have a separation from the easement boundary of at least 1:1,vertical
to horizontal. For example, if the retaining wall is 10 feet tall, it shall be placed no closer than 10 feet
from the adjacent easement boundary."
B. Materials
Replace materials table with the following:
Diameter(in) Depth (ft)* Material
Any <_4 DIP
8-15 4 <_ 13 PVCSDR35orC900DR18
8-20 4< D5_ 20 PVC C900 DR 18 or DIP
>20 Any DIP
Any >20 DIP
702 Manholes
A. Design
1. Manhole Location, Siting, and Design
Revise part f), first two sentences to read "In certain isolated circumstances standard free drops may be
allowed, not exceeding 24-inches. If different size pipes, the smaller diameter pipe crown shall be
positioned no higher than the larger diameter pipe crown to limit the drop."
2. Manhole Sizing
Remove "with Extended Base" from Manhole Sizing Guide table.
C. Installation
5. Epoxy Coating
Add "c) Manholes manufactured by Armorock (or approved equal) may be used as an approved
alternate to manholes that require epoxy coating."
703 Service Connection
A. Design
1. General Requirements
Revise g), second sentence to read "Service lines shall be installed so that the crown of the service line
matches the crown of the invert line(or higher) or shall be installed with a standard drop."
Add to the end of part g) "All services shall be made via a boot connection when at a manhole."
704 Testing and Inspections
B. Sewer Main and Service Connection Testing
5.Video Assessment and Cleaning
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Add to the end of part d) "Dye may be required in order to see dips in the pipe and for approval by the
Inspector."
Revise in part f) "(flash drives and CD/DVD are also acceptable)."
Section 800 Wastewater Pumping Stations & Force Mains
801 Pump Station General
A. Design Requirements
Delete the last sentence of part 5.
802 Pump Station Site and Structures
C. Structures
1. General
Add "f) Structures manufactured by Armorock (or approved equal) may be used as an approved
alternate for any structure that requires epoxy coating."
807 Wastewater Force Mains
A. Design
Add to end of part 2. "If sewer main is located within road right-of-way or on Town owned property
there shall be no permanent structures, equipment, retaining walls, embankments, impoundments, or
other elements that would inhibit maintenance operations unless approved by the Water Resources
Director."
Add "15.All retaining walls shall have a separation from the easement boundary of at least 1:1,vertical
to horizontal. For example, if the retaining wall is 10 feet tall, it shall be placed no closer than 10 feet
from the easement."
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Standard Details
Section 300 Streets
Detail 300.01 Street Typical Sections
Add 3:1 maximum slopes for grading tie-ins. Revise sidewalk cross slope to 1%to allow margin of error
while still remaining ADA compliant.
Detail 300.04 Method of Removing Existing Curb
Expand removal to include both curb and gutter.
Detail 300.07 Driveway Apron
Add to Note 1: "EXCEPT WHEN CONNECTING TO AN ALLEY WIDTH MAY BE INCREASED TO ALLOW AN
ADDITIONAL 9' WIDE PARKING PAD IF DISTANCE FROM THE ALLEY TO THE STRUCTURE IS LESS THAN 18'."
Add sheet 2 of 2, new detail for shoulder typical section.
Detail 300.08 Concrete Sidewalk
Revise sidewalk cross slope to 1%to allow margin of error while still remaining ADA compliant.
Detail 300.10 Street Cross Section Showing Utility Locations
Revise sewer depth of cover dimension to 3'from roadway subgrade,consistent with specification section
700.
Replace note with table:
VERTICAL SEPARATION
UTILITY DISTANCE (INCHES)
WATER &SEWER 18
WATER ABOVE STORM 24
WATER BELOW STORM DRAIN 18
SEWER &STORM 24
ALL OTHER UTILITIES 12
Detail 300.14 Street Geometric Standards
Add separate standards for Minor Collector Street, new row separate from Residential Street.
Detail 300.16 Pavement Widening Taper& Marking
Revise label "NCDOT W23-10 DELINEATOR"to"OBJECT MARKER OM3-R".
Detail 300.32 Bus Stop (NEW)
Section 600 Water Distribution System
Detail 600.01,34" & 1" Water Service & Meter Box, Sheet 2 of 2
Delete from note 6 "CAST IRON, ASTM A48, CLASS 25".
Detail 600.12 Air Release Manhole For Water Mains
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1
Add "OR APPROVED EQUAL"to A.R.I D-040 Combination Air Valve callout.
Detail 600.14 Multiple Branch Services
Add "AND 1" (FOR RESIDENTIAL ONLY)"to note 1 regarding multiple service connections.
Section 700 Wastewater Collection Systems
Detail 700.02 Sanitary Sewer Tap &Service
Revise sewer depth of cover to 3'from roadway subgrade, consistent with specification section 700.
Detail 700.04, Sheet 1 of 3
Remove all references to steps in the manholes. Steps are no longer required.
Detail 700.04,Sheet 2 of 3
Remove all references to steps in the manholes. Steps are no longer required.
Detail 700.04,Sheet 3 of 3
Remove all references to steps in the manholes. Steps are no longer required.
Detail 700.07
Remove all references to steps in the manholes. Steps are no longer required.
Detail 700.08
Change "NON-SHRINK GROUT" callout to "BOOT CONNECTION". Where pipe enters manhole wall, non-
shrink grout is no longer allowed.
Detail 700.09 (DELETE)
Manhole steps are no longer required.
Detail 700.20
Change minimum gate width from 12'-0"to 14"-0".
Add the following notes:
3. GATES MAY BE SINGLE OR DOUBLE PANEL AS LONG AS CENTERED ON THE PIPE.
4. FOR COMMERCIAL SITES, THE GATE WIDTH MUST BE AT LEAST 201-0".
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SECTION 700
WASTEWATER COLLECTION SYSTEMS
701 Gravity Sewers
A. Design
B. Materials
C. Sewer Main Installation
702 Manholes
A. Design
B. Materials
C. Installation
703 Service Connections
A. Design
B. Materials
C. Installation
704 Testing and Inspections
A. General
B. Sewer Main and Service Connection Testing
C. Manhole Testing
705 Aerial Crossings
A. Design
B. Pipe Materials
C. Installation
706 Repairs, Modifications, and Abandonment
A. Sewer Main Repairs
B. Installation
C. Draining Sewer Mains
D. Abandonment of Existing Sewer Mains
Section 700—Wastewater Collection Systems-Page 1 of 37
Effective Date: April 12, 2022
701 Gravity Sewer
A. Design
1. Main Location
a) All public sanitary sewer mains shall be installed in dedicated street right
of way or in dedicated utility easements. Mains within easements shall
be centered within the easement. Mains located along NCDOT roads
shall be placed outside of NCDOT right of way.
b) In preparing engineering design plans, all elevations shall be tied to
NC grid system and the benchmark shall be described on the plans. A
field survey of all waterways and waterbodies within project area must
be performed, including but not limited to: creeks, streams, rivers,
lakes, ponds, ditches, and culverts. Survey must include adequate
points to accurately represent the cross section of the
waterway/waterbody, i.e. top of bank, toe, centerline, etc.
c) Construction Drawings shall be prepared by or under the direct
supervision of a professional engineer, licensed in North Carolina.
Design shall conform to all standards and guidelines established by the
Town and NCDEQ. Any design that does not meet minimum
requirements set forth by NCDEQ and 15A NCAC 02T rules shall require
a variance approval from NCDEQ. Plans shall indicate deflection angles
at all manholes.
d) All private sewer collection mains inside the Town service area that will
connect or are planning to discharge into the Apex sewer system shall
comply with all Town of Apex design, siting and installation criteria
outlined herein. The Owner of the private sewer collection system shall
meet all State design requirements and obtain a State permit to operate
the private system.
e) Gravity mains shall be installed in dedicated public right of way (not
alleys or roundabouts) or in dedicated utility easements as follows:
Pipe Depth* Permanent Easement Width Town Road R/W
8-ft or less 20-ft Allowed
8-ft — 15-ft 30ft As Specified by the WR
Department
15-ft—20-ft 40-ft Not Allowed
Deeper than As Specified by the WR Not Allowed
20 ft Department
`Depth of the sewer main shall be measured from the top of the pipe to the final grade or road
subgrade at the deepest point between manholes.
Section 700—Wastewater Collection Systems - Page 2 of 37
Effective Date: April 12, 2022
Dedicated easements for sewer mains and appurtenances shall be
recorded as "Town of Apex Public Sanitary Sewer Easement". Town of
Apex sewer easements shall contain only Town of Apex utilities unless
otherwise approved by the site plan or an encroachment agreement.
Sewer mains shall be centered in the easement. Easements shall be
acquired by the Developer (unless utility is designed as part of a Capital
Improvement Project) prior to construction approval.
Easements must be clearly labeled as "public" or "private".
If the sewer main is located within the road right-of-way, a clear width
equal to or greater than the easement width required must be available.
If adequate width is not available within the right-of-way, additional
easement outside of the right-of-way must be maintained. For example,
if a sewer main normally requiring a 20 foot easement is installed 5 feet
inside of the right-of-way, an additional 5 feet of easement must be
obtained outside of the right-of-way to provide a clear total width of 10
feet on each side of the pipe.
f) The minimum width of a permanent easement that contains sanitary
sewer and storm sewer shall be 30 feet. There must be a separation of
10 feet between the outside of each pipe and 10 feet from the centerline
of the pipe to the easement line.
g) The minimum width of a permanent easement that contains sanitary
sewer and greenway shall be 15 feet in addition to the width required in
the table above. There must be a separation of 10 feet between the
sewer main and the edge of pavement and at least 10 feet from the
centerline of the pipe to the easement line.
h) No structures, equipment, retaining walls, embankments,
impoundments, pavement, landscaping, or other elements that
p fill,
would inhibit maintenance operations shall be constructed within a
sewer main easement as outlined in Section 200. Fences may be
allowed across easements provided that appropriate access gates or
removable panels have been installed to allow utility maintenance.
Fences shall not be installed parallel within utility easements. In all
cases, Town of Apex Operations Staff shall have access to secured
access gates. Fill or cut slopes are not allowed to extend into
easements without full development plan approval or an approved
encroachment agreement from the Town of Apex, see Section 200 for
further information. All such pre-existing or planned conditions as noted
herein that would impact operations and maintenance within the noted
sewer main easement shall be noted and disclosed during the site plan
approval process. Pre-existing conditions that are not disclosed during
Section 700—Wastewater Collection Systems - Page 3 of 37
Effective Date: April 12, 2022
the site plan review may nullify the approval and require relocating the
sewer easement where there are no existing conflicts. If sewer main is
located within road right-of-way or on Town owned property there shall
be no permanent structures, equipment, retaining walls, embankments,
impoundments, landscaping, or other elements that would inhibit
maintenance operations unless approved by the Water Resources
Director.
i) Where public sanitary sewer mains are installed within easements
crossing private property, the Town's Water Resources Department
shall have the right to enter upon the easement for purposes of
inspecting, repairing, or replacing the sewer main and appurtenances.
Where paved private streets, driveways, parking lots, etc. have been
installed over public sewer mains, the Town of Apex shall not be
responsible for the repair or replacement of pavement, curbing,
landscaping, etc. which must be removed to facilitate repairs. The
Water Resources Department shall excavate as necessary to make
the repair, and shall backfill the disturbed area to approximately the
original grade. Replacement of privately owned pavement, curbing,
walkways, etc. shall be the responsibility of the property owner and/or
Homeowner's Association.
j) Easements shall be accessible from public rights-of-ways. If easement
is not accessible perpendicular from right-of-way due to steep slope,
environmental feature, or other obstacle, additional easement may be
necessary.
k) Sewer line easements shall be graded smooth, free from rocks,
boulders, roots, stumps, and other debris, and seeded and mulched
upon the completion of construction. Easements across sloped areas
shall be graded uniformly across the slope to no steeper than a 4 to 1
ratio.
I) Mains paralleling a creek shall be of sufficient depth to allow lateral
connections below the stream bed elevation. The top of the sewer main
and laterals shall be at least three feet below the stream bed. Concrete
encasement and ductile iron pipe shall be required when the cover
between the top of the pipe and the stream bed is less than 3 feet.
m) Mains shall not be installed under any part of water impoundments or
area to be impounded. Sewer mains shall not be installed through,
above, or below any retained earth structure. Sewer main location and
depth shall not be within the theoretical 1:1 slope of any impoundment
dam or structure, or shall maintain a minimum of 10' horizontal
separation from the toe of slope, whichever is greater. The entire
Section 700—Wastewater Collection Systems - Page 4 of 37
Effective Date: April 12, 2022
easement shall be outside of the toe of slope, unless prior approval is
obtained from the Water Resources Director.
n) Sewer profile shall follow natural topography and road grade. Sewer
designed against natural grade or road grade shall only be allowed if
approved by the Water Resources Director and no practical alternative
is available.
o) The following minimum horizontal separations shall be maintained:
1. 100 feet from any private or public water supply source, including
wells, WS-1 waters or Class I or Class II impounded reservoirs
used as a source of drinking water (except as noted below)
2. 50 feet from wetlands and any waters (from normal high water)
classified WS-II, WS-III, B, SA, ORW, HQW or SB (except as
noted below)
3. 20 feet from any other stream, lake, or impoundment (except as
noted below)
4. With approval directly from PERCS, the following separations may
be acceptable when water main standards are implemented:
a. All appurtenances shall be outside the 100 foot radius
of wells.
b. 50 feet from private wells (with no exceptions)
c. 50 feet from public water wells (with no exceptions)
d. Where the required minimum separations cannot be
obtained, ductile iron pipe shall be used with joints
equivalent to water main standards.
p) Sewer mains shall always be extended along any and all natural
drainage courses/draws that are located within the property line
boundaries of the proposed development. This sewer shall be extended
to all adjacent upstream property lines.
1) Sewer design shall account for future upstream development
based on the current land use plan.
2) Project shall include evaluation of existing downstream sewer
capacity. This evaluation shall address the capacity of all
sewer collection and truck sewer systems that will be
Section 700—Wastewater Collection Systems - Page 5 of 37
Effective Date: April 12, 2022
impacted downstream of the new development and/or
redevelopment. If any downstream sewer segments exceed
50 percent full, but are less than 65% full, the Town will
evaluate and determine if upsizing is required. If any
downstream sewer segments exceed 65 percent full, the
sewer main must be upsized or re-installed at a greater slope
to allow for greater flow through the pipe. All improvements
must be made the full length, from manhole to manhole.
3) The most upstream manhole shall be designed and located
so that all upstream properties will have access to connect
with future sewer mains. Depths shall be evaluated so that
streams, roads, culverts, and any other features that must be
crossed by future upstream sewer mains can do so and still
achieve the required minimum cover on top of the sewer main.
q) Gravity sewer mains shall be deep enough to serve the adjoining
properties and allow for sufficient slope in lateral lines. Gravity sewer
pipe shall have the following minimum covers:
1) 3 feet from the top of pipe to finished subgrade in roadways.
2) 3 feet from the top of pipe to finished grade outside roadways.
r) Sewer mains that do not meet minimum cover stated above or the table
in section A.1.e) are required to be ductile iron for the entire run between
manholes. Steel casing and/or concrete may also be required for
protection, at the direction of the Water Resources Director.
s) In all cases where fill material is added above existing sewer mains, the
Engineer of Record shall prepare a structural analysis of the existing
pipeline and determine if it is capable of supporting additional loading.
If the additional fill material exceeds AWWA, DIPRA, UNIBELL and/or
manufacturer standards for loading, the pipeline shall either be
reinforced to adequately support the additional loading or replaced with
a ductile iron pipe rated to support the added loading.
t) Separation Between Sanitary Sewer and Storm Water Pipes:
Sewer mains shall have a minimum vertical separation of 24 inches
between storm pipes when the horizontal separation is 3 feet or less.
Where sanitary and storm sewers cross with a vertical separation of
less than 24 inches, the entire leg of sanitary sewer shall be made of
standard ductile iron pipe with joints rated for water main service and
the void space between the pipe crossing shall be backfilled with
3000-psi concrete or quick setting, minimum 500-psi, non-
Section 700—Wastewater Collection Systems - Page 6 of 37
Effective Date: April 12, 2022
excavatable flowable fill that meets or exceeds NCDOT
Specifications.
u) Separation Between Sanitary Sewer and Sewer Force Main:
There shall be a minimum 7 foot horizontal separation between
parallel gravity and force mains when the depth of installation is 8-ft
or less. Otherwise, the minimum horizontal separation between
pipelines shall be 10-ft up to 10-ft depth of installation.
v) Separation Between Sanitary Sewer and Water Main
1) Parallel Installations: 10-ft lateral separation (pipe edge to pipe
edge) or minimum 5-ft lateral separation, and water line at least 18-
inches above sanitary sewer line measured vertically from top of
sewer pipeline to bottom edge of water main.
Crossings (Water Main Over Sewer): All water main crossings of
sewer lines shall be constructed over the sewer line in conformance
with Town of Apex Specifications. At a minimum, 18-inches of
clearance shall be maintained between the bottom edge of the
water main and the top edge of the sewer main. If 18-inches of
clearance is not maintained, the water main and sanitary sewer
main shall:
a. Both lines shall be constructed of ductile iron pipe with
joints in conformance with water main construction
standards.
b. The sanitary sewer pipe shall be ductile iron the entire
run from manhole to manhole.
c. The void space between the pipes shall be filled with
minimum 500-psi, quick setting non-excavatable
flowable fill extending 3-ft on both sides of the crossing.
Regardless of pipe material, at least 12-inches of
vertical separation is required for sanitary sewer
crossings of potable water mains.
2) Crossings (Water Main Under Sewer Line): Allowed only as
approved by Town of Apex, when it is not possible to cross the water
main above the sewer line. At a minimum, 18-inches of separation
shall be maintained, (measured from pipe edge to pipe edge) and
the sanitary sewer shall be constructed of ductile iron in conformance
with water main construction standards the entire run from manhole
to manhole. If local conditions prevent providing 18-inches of
clearance, then at least 12-inches of clearance shall be provided and
the void space between the pipes shall be filled with minimum 500-
psi, quick setting, non-excavatable flowable fill extending at least 3-
ft on both sides of the crossing.
Section 700—Wastewater Collection Systems - Page 7 of 37
Effective Date: April 12, 2022
w) Where concentrated sources of runoff (e.g., SCM discharge, FES
discharge outlets, natural drainage ways, etc.) convey across existing
or proposed Town of Apex Sanitary Sewer Easements, the applicant
must design a rip rap lined channel across the full width of the
easement.
x) All retaining walls shall have a separation from the easement boundary
of at least 1:1, vertical to horizontal. For example, if the retaining wall
is 10 feet tall, it shall be placed no closer than 10 feet from the
adjacent easement boundary.
2. Main Size, Slope and Design Criteria
a) Public gravity mains shall be a minimum of 8 inches in diameter.
b) Major interceptors shall be sized in accordance with the "Town of Apex
Sewer Master Plan". In areas not included in the master plan,
interceptors shall be designed based on the proposed land use
(according to the Town's Comprehensive Growth Plan), using the
following flow factors. At a minimum, all gravity sewer mains shall be
designed and sized to serve the ultimate tributary buildout of the
drainage basin.
Residential flow rates:
Land Use Flow Factor
Single Family Residential 300 gpd per dwelling unit
Multi-Family Residential 250 gpd per dwelling unit
Non-residential flow rates:
Use flow factors as required by the North Carolina Department of
Environmental Quality (at the time of this Specification revision,
these flow rates are contained in 15A NCAC 02T .0114).
For all other flow rates not listed in Section ii above, use:
Land Use Flow Factor
Office and Institutional 0.09 gpd/sq.ft bldg. space
Commercial 0.12 gpd/sq.ft bldg. space
Industrial 0.20 gpd/sq.ft bldg. space
c) The ratio of peak to average daily flow shall be 2.5.
Section 700—Wastewater Collection Systems - Page 8 of 37
Effective Date: April 12, 2022
d) Sanitary sewers shall be designed to carry the projected average daily
flow at no more than 1/2 full. The minimum velocity for sanitary sewer
lines shall be 2.5-fps.
e) Sanitary sewers shall be sized based on the Manning's Equation with
Manning's roughness coefficient "n" = 0.013 or greater. Pipe diameter
sizes used in the calculation of Manning's Equation shall be nominal
pipe sizes.
f) The minimum grades for public sanitary sewers shall be as follows:
Minimum Slopes for Gravity Sewer Mains
Main Size Minimum Slope
(diameter in V=2.5ft/s, depth 1/2 full
inches) (feet per 100 feet)
(standard required velocity)
8 0.52
10 0.39
12 0.30
14 0.25
15 0.23
16 0.21
18 0.18
21 0.15
24 0.12
27 0.11
30 0.09
36 0.07
42 0.06
48 0.05
Note1: All minimum slopes based on Manning's Equation
Note2: Manning's coefficient n = 0.013 used for all computations
g) The minimum grade for the uppermost reach of a sanitary sewer line
shall be 1% regardless of sewer line size.
h) The maximum grade for sanitary sewers is 10%. The maximum velocity
in sanitary sewers is 15 ft/sec. These limits may only be exceeded with
the approval of the Director of Water Resources and the incorporation
of the following provisions, which apply to all sewers either designed or
installed at grades equal to or exceeding 10%:
1) All sewers with a grade of 10% or higher must have the downstream
run of pipe installed with ductile iron pipe.
2) High velocity manholes shall be used on all sewers with a grade of
10% or higher. High velocity lines cannot tie directly to an existing
Section 700—Wastewater Collection Systems - Page 9 of 37
Effective Date: April 12, 2022
line and must proceed 180° through the invert into the downstream
line.
3) Concrete thrust collars shall be installed on all sewers designed at
grades of 10% or higher. The anchors shall be installed at the
following spacing:
a. Not over 36' center to center on grades from 10% to 25%
b. Not over 24' center to center on grades from 25% to 40%
c. Not over 16' center to center on grades exceeding 40%
4) The Town reserves the right to require all high velocity requirements
outlined herein for sewer lines either designed or installed at grades
of 10% or greater, regardless of the flow velocity. In cases where
the design grade established on the sewer design plan is exceeded
during construction and the 10% threshold is exceeded, all high
velocity requirements shall apply without waiver.
i) Sewer extensions shall be designed for projected flows, even when the
diameter of the receiving sewer is less than the diameter of the proposed
extension.
j) All pipe diameter changes shall occur only in manholes, with the invert
of the larger pipe lowered sufficiently to maintain the same energy
gradient. An approximate method of obtaining this result is to place the
crown of the incoming pipes may be designed for an elevation at or
above the crown of the outgoing pipe.
k) All transitions of pipe material, pipe separations, grade changes, pipe
thicknesses and all angular deflection changes shall occur only at
manholes.
I) Pipe trench excavation and backfilling shall be performed in
accordance with Section 0450 of these Specifications.
m) Gravity sewer downstream from a connection point with a force main
shall be lined with 401-type ceramic epoxy for a minimum of 1,200
linear feet.
n) The minimum angle between inlet and outlet pipes in a manhole shall
be 90 degrees.
B. Materials
Materials specified herein are acceptable for sewer service as described.
Sanitary sewer mains shall conform to the following criteria:
Section 700—Wastewater Collection Systems - Page 10 of 37
Effective Date: April 12, 2022
Diameter(in) Depth (ft)* Material
Any <_4 DIP
8— 15 4—< 13 PVC SDR 35 or C900 DR 18
8—20 4 < D <_20 PVC C900 DR 18 or DIP
> 20 Any DIP
Any > 20 DIP
*Depth of the sewer main shall be measured from the top of the pipe to the final grade or road
subgrade at the deepest point between manholes.
1. Ductile Iron Pipe
Material Specifications
Ductile Iron Pipe shall be designed and manufactured in accordance
with AWWA C150 and C151 and provided in nominal 20-ft lengths. The
minimum requirements for ductile iron pipe and required laying
conditions are tabulated below. For all other installations other than
specified, the laying condition, bedding requirements or the minimum
pressure class rating and/or thickness class shall be increased in
accordance with AWWA C151. A pipe thickness design shall be
submitted for external loading in all cases where the pipe depth exceeds
the specified range of depths outlined in the following table.
Pressure Class, Max. Depth and Laying Condition for DIP
Sewer Mains
Pipe AWWA C-150, Pressure Maximum Depth
Diameter Laying Condition Class of Cover
8 -inch type 1 350 psi 3-16 feet
8-inch type 4 350 psi > 16 feet
10-12 -inch type 1 350 psi 3-16 feet
10-12 -inch type 4 350 psi 16-20 feet
10-12 -inch type 5 350 psi > 20 feet
14-20 -inch type 4 250 psi 3-20 feet
14-20 -inch type 5 250 psi > 20 feet
14-20 -inch type 5 350 psi As Directed
24-30 -inch type 4 250 psi 3-20 feet
24-30 -inch type 5 300 psi > 20 feet
24-30 -inch type 5 350 psi As Directed
36-42 -inch type 4 300 psi 3-20 feet
36-42 -inch type 5 350 psi > 20 feet
Note: For cases not specified, a ductile iron pipe and bedding design certified by a
Professional Engineer licensed in the State of North Carolina shall be required in
compliance with AWWA C150 and the Ductile Iron Pipe Research Association.
Section 700—Wastewater Collection Systems - Page 11 of 37
Effective Date: April 12, 2022
In cases where thickness class designation of ductile iron pipe is specified, the
corresponding thickness class designations are as outlined in the following table.
The following table lists approved manufacturers of DIP and DIP fittings that are allowable
for installation within the Town's system.
Product Approved Model/Series Pressure/Load Reference Requirements
Category Manufacturer Rating Standard
Ductile Iron US Pipe Tyton Joint
Pipe 8-inch
& 10-inch Cement mortar
lined with exterior
Diameter American Fastite Joint AWWA bituminous coating.
(and 4-inch (ACIPCO) 350 psi C150 and McWane pipe
and 6-inch C151 stamped "McWane
services) by Atlantic States or
Cement McWane Tyton Joint Clow" only
Mortar
Lined
Ductile Iron
US Pipe Tyton Joint 40-mils of Protecto
Pipe 12- 401 Lining (lining
inch and American AWWA must be less than 1
ACIPCO Fastite Joint
Larger (ACIPCO) 250-350 psi and DIPRA year old); McWane
Diameter Standards pipe stamped
Protecto "McWane by
401 Lined McWane Tyton Joint Atlantic States or
Clow"only
Ductile Iron Sigma Mech. Joint
Fittings 8-
inch & 10- Tyler Union Mech. Joint
inch AWWA
Diameter SIP Industries Mech. Joint C110/C111 Shall always meet
(and 4-inch 350 psi and or exceed pipe
and 6-inch Star Mech. Joint AWWA pressure rating
services) C153
Cement
Mortar American Mech. Joint
Lined
Sigma Mech. Joint Shall always
Ductile Iron receive interior
Fittings 12- Tyler Union Mech. Joint Protecto 401 Lining
inch and AWWA to
Larger SIP Industries Mech. Joint 250-350 psi and DIPRA meet or exceed
Diameter Standards main line pipe
Protecto Star Mech. Joint standards. (401
401 Lined lining must be < 1yr
American Mech. Joint old)
Section 700—Wastewater Collection Systems - Page 12 of 37
Effective Date: April 12, 2022
Ductile Iron Pipe Thickness Class
Pipe Pressure Nominal Minimum
Diameter Class Thickness Corresponding
(inches) Thickness Class
8 350 0.25 50
10 350 0.26 50
12 350 0.28 50
14 250 0.28 50
16 250 0.30 50
18 250 0.31 50
20 250 0.33 50
24 250 0.37 50
24 300 0.40 51
30 250 0.42 51
30 300 0.45 52
36 300 0.51 52
36 350 0.56 53
42 300 0.57 52
42 350 0.63 53
Pipe joints shall be of the push-on type as per AWWA C111.
For 10-inch diameter and smaller gravity sewer mains, pipe lining shall
be cement mortar with a seal coat of bituminous material, all in
accordance with AWWA C104.
For 12-inch diameter and larger gravity sewer mains, all ductile iron pipe
and fittings for sewer construction shall receive an interior ceramic epoxy
coating, consisting of an amine cured novalac epoxy containing at least
20% by volume of ceramic quartz pigment, as manufactured by Protecto
401. The interior coating shall be applied at a nominal dry film interior
thickness of 40-mils. All DIP bells and spigots shall be lined with 8-mils
of joint compound by Protecto 401 or approved equal applied by brush
to ensure full coverage. All pipe supplied with Protecto 401 interior lining
shall be provided free of holidays. Pipe installed with defects in the lining
will be rejected and required to be replaced. Patching of Protecto 401
coating defects after installation shall not be approved. Protecto 401
lined pipe must be installed within one year of the application date on
the pipe.
All buried DIP and fittings shall have bituminous coating on the exterior
surface in accordance with AWWA C151/ANSI A21.51. The seal coat
Section 700—Wastewater Collection Systems- Page 13 of 37
Effective Date: April 12, 2022
shall be a coal tar epoxy lining and shall be Indurall Coating, Inc. "Ruff-
Stuff', Kopper's Company, Inc. "Bitumastic No. 300-M" or approved
equal. Pipe shall be supplied in minimum 20-ft lengths.
All ductile iron pipes shall be marked in conformance with ASTM A-746.
Pipe material and manufacturer must have a supplier within 200 miles
of the Town of Apex.
2. Solid Wall PVC Pipe
Material Specifications
PVC Pipe shall be solid wall and made of PVC plastic having a cell
classification of 12454 or 12364 (with minimum tensile modulus of
400,000 psi) as defined in Specification D1784. PVC pipe shall have
integral wall bell and spigot joints for the conveyance of domestic
sewage and shall be supplied in 20 ft lengths. Fittings shall be made of
PVC plastic having a cell classification of 12454-B, as defined in ASTM
D1784.
All PVC gravity sewer pipe and PVC fittings up to 15-inches in diameter
shall be manufactured in accordance with the latest version of ASTM
D3034. All solid wall PVC pipe installed at diameters from 18-inches to
27-inches in diameter shall be manufactured in conformance with ASTM
F679 and provided at minimum pipe stiffness of 115-psi. Fittings must
be manufactured by pipe supplier or approved equal, and have bell
and/or spigot configurations compatible with that of the pipe. PVC pipe
shall be installed in accordance with the requirements of this
Specifications manual and ASTM D2321.
All PVC pipe up to and including 15 inches in diameter shall have a
maximum Standard Dimension Ratio (SDR) of 35 for depth of installation
no shallower than 4-ft of cover from the pipe crown and no deeper than
13-ft measured from the bottom of the pipe. All solid wall PVC pipe for
depth of installation greater than 13-ft shallbe C900 DR18. Solid wall
PVC pipe shall not be approved for depths of installation greater than
20-ft. All solid wall PVC pipe shall be marked and certified in
conformance with ASTM D3034 or ASTM F679 and all AWWA
standards.
Section 700—Wastewater Collection Systems - Page 14 of 37
Effective Date: April 12, 2022
C. Sewer Main Installation
1. General Requirements
a) Pipe trench excavation and backfilling shall be performed in
accordance with Section 0450 of these Specifications.
b) Transitions of pipe material, pipe separations, grade changes and all
angular deflection changes shall occur only at manholes. Pipe crowns
shall be matched for changes in pipe sizes.
c) All sewer mains installed with less than 4 ft of cover or deeper than 20-
ft shall be ductile iron pipe.
d) Pipe and fitting interiors shall be protected from foreign matter and shall
be inspected for damage and defects prior to installation. In the event
foreign matter is present in pipe and fittings, it shall be removed before
installation. Open ends of pipe shall be covered and protected when pipe
laying is not in progress to prevent debris from entering the pipe.
e) Pipe shall be laid on true lines as directed by the Engineer. Trenches
shall be sufficiently wide to adjust the alignment. Bell holes shall be dug
at each joint to permit proper joint assembly. The pipe shall be laid and
adjusted so that the alignment with the next succeeding joint will be
centered in the joint and the entire pipeline will be in continuous
alignment both horizontally and vertically. Pipe joints shall be fitted so
that a thoroughly watertight will result. All joints will be made in
9 Y g jointJ
conformance with the manufacturer's recommendations for the type of
joint selected.
f) Prior to beginning construction, the Contractor shall contact local utility
companies and verify the location of existing utilities. The Contractor
shall be completely and solely responsible for locating all existing buried
utilities inside the construction zone before beginning excavation. The
Contractor shall be solely responsible for scheduling and coordinating
the utility location work. When an existing utility is in conflict with
construction, it shall be exposed prior to beginning construction to
prevent damage to the existing utility.
g) No bells or connections shall be within any waterway crossing area.
h) Sewer mains shall not be installed within roundabouts.
Section 700—Wastewater Collection Systems - Page 15 of 37
Effective Date: April 12, 2022
L
702 Manholes
A. Design
1 . Manhole Location, Siting and Design
a) Manholes shall be spaced at a maximum distance of 400 feet.
b) Manholes shall be installed at each deflection of line and/or grade. The
flow channel through manholes shall have a uniform and smooth finish
free of irregularities or obstructions. The invert channel shall conform to
the shape and slope of the entering/exiting sewer line. Either pre-cast
or brick and mortar inverts may be used. Mortar shall be mixed in a
clean, tight mortar box, or in an approved mechanical mixer and used
within 45 minutes of mixing.
c) A minimum drop of 0.2 feet must be maintained between the invert into
and out of the manhole. The benches shall be sloped so as to prevent
sedimentation. The inverts from intercepted cross lines shall be tied into
the main flow line wherever possible, so as to provide a smooth
transition. Wherever such cross lines tie-in at a substantially higher
elevation than that of the downstream invert, the connecting line shall
extend into the manhole a sufficient distance to enable the flow to spill
into the flow line rather than onto the invert bench.
d) On dead-end manholes receiving service connections, the invert must
be constructed and the invert flow line shall extend through the manhole
so that all flow entering the manhole shall be readily conveyed
downstream.
e) Free falls of wastewater flow into the manhole invert from incoming
sewer mains shall not be allowed, except under limited circumstances.
f) In certain isolated circumstances standard free drops may be allowed,
not exceeding 24-inches.. If different size pipes, the smaller diameter
pipe crown shall be positioned no higher than the larger diameter pipe
crown to limit the drop. When free drops are necessary due to pipe size
changes, the Contractor shall take preventive measures to prevent free
drops into the manhole invert, such as building a flume or trough up to
the incoming invert, or piping the flow to the primary invert flow channel.
g) Drop manholes are not allowed without the written approval of the Water
Resources Department. While certain physical constraints may dictate
the need for drop manholes, they may not be used merely to decrease
trenching depth. Upstream slope changes shall be used to avoid the
need for drop manholes.
Section 700—Wastewater Collection Systems - Page 16 of 37
Effective Date: April 12, 2022
h) Manholes shall not be obstructed from view or access. It is illegal to
bury or obstruct access to manholes. Manholes shall not be installed
within roundabouts.
i) Manhole covers shall be elevated as follows:
1) Roadways: Manholes installed in roadways and road shoulders
shall be installed with the cover flush with the top of pavement.
2) Outside of Roadways: Manholes installed outside of roadways
shall be elevated at least 12 inches above the surface grade
and/or at the same elevation of the road travel lane unless
otherwise approved by the Water Resources Director.
3) Wooded Outfalls: All manholes installed in wooded, forested or
brushy areas shall be elevated at least 24 inches above the
surface elevation.
4) 100-Year Flood Zone: All manholes located within the 100-year
flood elevation shall be elevated at least 24 inches above the 100-
year flood elevation or specify watertight covers and vents that
extend at least 24 inches above the 100-year flood elevation.
5) 100-Year Culvert Headwater Depth: All manholes located within
a 100-year culvert headwater staging area shall be elevated at
least 24 inches above the 100-year flood elevation or specify
watertight covers and vents that extend at least 24 inches above
the 100-year flood elevation.
6) Well Maintained Areas: All manholes installed in well maintained
areas, such as yards, sidewalks or otherwise inside an improved
right-of-way shall be installed flush with the finished surface.
j) Manholes used in outfalls and other non-traffic bearing areas shall be
constructed with a flat top and outside steps.
k) Manholes shall be provided without interior steps.
I) When connecting a new sewer main to an existing main, the connection
shall be established with a "Doghouse" type of manhole inserted over
the existing main. Doghouse manholes shall only be installed on
existing DIP or PVC mains.
m) Grade rings shall not exceed 6 inches.
Section 700—Wastewater Collection Systems- Page 17 of 37
Effective Date: April 12, 2022
2. Manhole Sizing
Manholes shall be sized as shown in the following table. The next larger
size shall be required if the pipe size, depth, or number of main line
connections warrants a larger size. In consideration of main line
connections, all will be considered regardless of type, whether inside drop,
outside drop, force main or standard connection.
Manhole Sizing Guide
Manhole Maximum Allowable Maximum Allowable Maximum Depth
Size Pipe Size, Single In Pipe Size, Multiple In
(diameter) (diameter) (diameter) (invert to rim)
4-ft 8-12 inches 12-ft'
5-ft4 14-24 inches 8-12 inches 12-ft to 18-ft
6-ft4 30-36 inches 14-24 inches 18-ft to 24-ft
8-ft4 >_42 inches 30-36 inches 24-ft to 30-ft
10-ft4 >_42 inches >30-ft
'Depths beyond 14-ft in roadways shall require a 5-ft diameter manhole with extended base.
4Due to the limited manhole wall area that could exist between the invert in and out, some
manholes may require upsizing as directed by the Water Resources Department.
All manholes 5-ft in diameter shall be extended to surface elevation with no
further reduction in diameter until the eccentric cone section.
Manhole transitions for 6-ft and larger diameter manholes are only allowed
in the top 5-ft of the manhole. In no case shall the smallest barrel size be
less than 5-ft diameter. At least 5-ft of vertical clearance shall be maintained
above the pipe crown before transitioning to a smaller diameter riser, or
transition shall not be utilized. An eccentric flat slab reducer from 6-ft
diameter or larger manhole base sections to 5-ft diameter risers (non-paved
areas) or eccentric cones (paved areas) shall be used to make any
transition.
Manholes outside of paved areas that are 6-ft in diameter and greater and
are too shallow to maintain 5-ft of vertical clearance above the crown of the
pipe shall maintain the full manhole diameter up to the design surface
elevation and be provided with a flat top slab cover with eccentric hole.
Manholes inside of paved areas that are 6-ft in diameter and greater shall
be constructed with an eccentric, flat top reducer to 5-ft diameter and
provided with a 5-ft diameter eccentric, tapered cone at the finished grade.
When the depth of the manhole is too shallow to maintain 5-ft of vertical
Section 700—Wastewater Collection Systems - Page 18 of 37
Effective Date: April 12, 2022
clearance above the crown of the pipe a 3-ft tall eccentric, tapered cone
shall be used without any additional 5-ft diameter risers.
B. Materials
1. Concrete Manholes
a) Manholes shall be precast concrete with a minimum compressive
strength of 4000-psi and utilize minimum grade 60 rebar in compliance
with ASTM C478. All 4-ft and 5-ft diameter manholes and all 6-ft
diameter manholes in paved areas shall be provided with eccentric cone
sections. Flat top manholes are required in outfall areas and for 6-ft and
larger diameter manholes.
b) Precast concrete manholes shall meet all design and manufacturing
requirements of ASTM C478 and all H-20 loading requirements.
Minimum wall thickness shall be 5-inches and shall increase with depth
and diameter in accordance with ASTM standards. The standard joint
shall be sealed with a plastic cement putty meeting Federal Specification
SS-S-00210, such as Ram-Nek or a butyl rubber sealant. All lift holes
must be plugged with non-shrinking grout after installation.
c) All manholes greater than 5-ft diameter shall have minimum 8-inch (6-
inch for 4-ft diameter manholes), 4,000-psi concrete bottoms resting on
a minimum of 12 inches of#57 stone. Sewer mains shall enter and exit
radially through the manhole. Inverts shall be constructed with a width
equal to the effluent pipe and a height equal to 1/2 that of the effluent
pipe. Inverts shall be so finished with sufficient drop across the manhole
to compensate for all resulting energy loss across the invert. Flat invert
channels shall not be allowed. At each inlet and outlet of 8 inches or
greater, resilient connectors or manhole boots shall be provided in
conformance with ASTM C923. Rings and clamps are to meet
standards of ASTM A167 and/or ASTM C923.
d) Precast manhole components shall not be installed, transported, or
removed from the casting yard prior to reaching the minimum
compressive strength of 4,000-psi and at least 7 days have elapsed
since casting.
e) Manhole flat slab, eccentric reducers provided for 6-ft diameter and
larger manholes shall be provided with minimum slab thickness of 12-
inches. Flat slab, eccentric reducers shall not be allowed for manhole
diameters less than 6-ft.
f) Manhole flat top slab covers for outfall manholes 6-ft diameter and
greater shall be designed and manufactured for H-20 loading and
Section 700—Wastewater Collection Systems - Page 19 of 37
Effective Date: April 12, 2022
provided in minimum slab thickness of 8-inches. Manhole flat top covers
shall be provided with a minimum clear opening of 36-inches when
utilized with a 36-inch clear span manhole frame and cover.
g) Manhole benches shall slope upwards from the spring line of the pipe to
the projected level of the pipe crown at the manhole wall, or 8-inches
above the spring line, whichever is less. Bowl type inverts recessed
inside of precast benches shall not be accepted.
2. Manhole Frame and Cover Materials
a) Manhole Frames and Covers shall be Class 35 gray iron with "Sanitary
Sewer" and the Town symbol forged into the cover as indicated in the
details. Ring and cover shall be stamped with make and model. All
manhole frames and covers shall be domestically made and
manufactured in the USA from domestic iron.
b) Types
1) Manhole Frames and Covers in Paved Areas and some Unpaved
Areas: For all installations in roadways or within the right of way,
use Type 1 ring and cover, and place sufficient depth of concrete
below the pavement around the ring to ensure contact with
manhole. Type 1 covers shall be provided with 1 vent hole. Type
1 covers shall be designed for a proof load of 40,000 lbs. and be
provided in Class 35B gray iron in conformance with ASTM A48.
At a minimum, Type 1 manhole rings shall weigh 190 lbs. and the
cover shall weigh 120 lbs.
2) Manhole Frames and Covers for Outfalls: For installation in
outfall areas, with 4-ft and 5-ft diameter manholes use Type 2 ring
and covers. Type 2 covers shall not be installed in areas subject
to traffic loading. Type 2 covers shall be provided with an
integrated frame and cover assembly in which the cover rotates
away from the frame for access. The rotating assembly shall be
provided with a cast in stainless steel rod assembly. Type 2
covers shall be provided with a minimum 24-inch clear span
opening along the axis with the stainless steel rod assembly.
Security shall be provided by 3 exterior cast lugs at 3/4-inch
thickness that allow padlock installation or bolting with 3 stainless
steel bolts with stainless steel zinc plated nuts. Type 2 covers
shall be made of Class 35B iron in conformance with ASTM A48
and designed for a proof load of 12,000 lbs. The frame and cover
weight shall not be less than 60-lbs for the cover and 80-lbs for
the ring. The Type 2 frame and cover assembly shall be provided
with a gasket that makes the cover assembly watertight when
Section 700—Wastewater Collection Systems - Page 20 of 37
Effective Date: April 12, 2022
bolted at all three lugs. Type 2 covers shall be provided inside
the 100-year flood elevation or other areas subject to flooding.
c) All castings shall be machined to give even and continuous bearing on
the full length of the frame. Castings shall be free of porosity and blow
holes. All manhole frames shall be bolted to the manhole, except in
paved streets.
d) Manhole ring and cover shall be made by East Jordan Iron Works, US
Foundry, Neenah Foundry Company, or approved equal.
e) Where deemed necessary in low areas of streets, solid manhole covers
may be required to prevent surface water inflow into the sewer.
C. Installation
1. General Requirements
a) The downstream side of the last manhole(s) of a sanitary sewer line
extension under construction shall be plugged by constructing a
brick/block wall to prevent the passage of groundwater, runoff and
sediment into the sanitary sewer system. All water upstream of the wall
shall be pumped out of the sanitary sewer line and all sediment and
solids shall be removed and properly disposed of by the Contractor.
Water, sediment, and solids shall be removed every 30 days, or sooner
if necessary, for the duration of the project. The wall shall not be
removed until the line has been inspected by the Town to ensure that all
possible points of inflow or infiltration have been eliminated. Failure to
meet these requirements will be deemed a violation with fines up to
$1,000.00 per day.
b) Manholes shall not be buried or hidden, which is a violation and subject
to penalty by fines.
c) All manhole penetrations, whether sewer main or service lateral, shall
be cored with a concrete coring machine. All pipe connections must be
made with flexible watertight couplings or boots.
For new manholes, there shall be a minimum of 9-inches or the pipe
outside diameter (OD), whichever is greater, between the pipe hole
openings. (Pipe hole opening is typically 4" greater than the pipe OD.)
When the adjacent pipes are different sizes, the OD of the smaller pipe
shall be used to determine the spacing requirement, but shall never be
less than 9-inches.
Section 700—Wastewater Collection Systems - Page 21 of 37
Effective Date: April 12, 2022
For connections to existing manholes, there shall be a minimum of 9-
inches or 3.5-inches plus '/z the OD of the existing pipe, whichever is
greater, between the pipe hole openings.
d) All manhole sections shall be standard tongue and groove with rubber
"O" ring or butyl rope sealant. All external manhole joints shall be
wrapped with an approved joint seal material.
e) Each connection to a manhole shall be sealed watertight by means of a
flexible sleeve or gasket type sealing system. The flexible sleeve type
system, if used, shall be equal to Flexible Manhole Sleeve as
manufactured by the Interpace Corporation. The gasket type system, if
used, shall be equal to the PSX system as manufactured by the Press
Seal Gasket Corporation. The sealing system shall be furnished by the
manhole manufacturer.
f) Manholes shall be set on a base of 57 stone that is a minimum of eight
(8) inches thick for four (4) foot diameter manholes and twelve (12)
inches for five (5) foot diameter.
g) Backfill around manholes shall be placed uniformly in shallow layers and
thoroughly compacted with mechanical tampers and with care taken to
ensure against displacement of the structure.
h) All manhole rings shall be set in full mortar beds and bolted down. The
rings with covers shall be set to the final grade indicated on the plans or
as maybe directed bythe Town. Anyrings and covers not conforming
9
to the correct grade shall be adjusted by the Contractor as required. The
exterior surface of all manholes shall be thoroughly cleaned of all
grease, dirt, etc. All lifting lugs shall be removed and holes patched
thoroughly with non-shrink mortar, color to match that of the manhole
where such patches are exposed.
2. Manholes Subject to Inundation
a) Manholes subject to flooding shall be watertight and vented 24 inches
above the 100-YR flood elevation. In flood prone areas, the manholes
shall be vented at least every 1000-ft or every other manhole, whichever
is greater.
b) The exterior of all manholes within the 100-year flood elevation and in
wetland areas shall receive an exterior coating of an approved
bitumastic coal tar epoxy or an approved epoxy coating at 40-mils to
prevent weepage or attack by acidic soils. Individual joints shall be
wrapped with Conwrap, Conseal, or approved equal and approved by
the Town prior to backfilling.
Section 700—Wastewater Collection Systems - Page 22 of 37
Effective Date: April 12, 2022
c) Anti-flotation design measures shall be implemented as required in flood
prone areas.
3. Manholes Located on Large Collection Mains
The Town reserves the right to require all manholes located on interceptor
or outfall mains 24-inches in diameter and larger to have the manhole
interior and bench coated with an approved epoxy coating at 80-mils
thickness. The epoxy coating shall be field applied and tested as described
herein.
4. Force Main Discharge Manholes
All manholes located on gravity mains that serve or will serve as
discharge points for sanitary sewer force mains shall receive an interior
epoxy coating at 80-mils thickness. In addition to the receiver manhole,
the Town reserves the right to require epoxy coating of the next two
consecutive manholes downstream of the receiver manhole or all
downstream manholes within 1200-If of the receiver manhole, See
Section 800 for further information on force main discharge manholes.
5. Epoxy Coating
a) Surface Preparation: Concrete manholes must be well cured prior to
application of the protective epoxy coating. Generally, 28 days is
adequate cure time for standard Portland cement. If earlier application
is desired, compressive or tensile strength of the concrete can be tested
to determine if acceptable cure has occurred. (Note: Bond strength of
the coating to the concrete surface is generally limited to the tensile
strength of the concrete itself. An Elcometer pull test to determine
suitability of concrete for coating may be required).
Surface preparation shall be based on the requirements of the
manufacturer of the epoxy coating and applicable NACE International
standards.
b) Installation: A minimum 80-mils thickness shall be field applied to new
manholes (120-mils for existing manholes). During application a wet film
thickness gage, meeting ASTM D4414 - Standard Practice for
Measurement of Wet Film Thickness of Organic Coatings by Notched
Gages, shall be used to ensure a monolithic coating and uniform
thickness during application.
Temperature of the surface to be coated should be maintained between
40° F and 120° F during application. Prior to and during application,
Section 700—Wastewater Collection Systems - Page 23 of 37
Effective Date: April 12, 2022
care should be taken to avoid exposure of direct sunlight or other intense
heat source to the structure being coated. Where varying surface
temperatures do exist, care should be taken to apply the coating when
the temperature is falling versus rising or in the early morning. The
humidity should also be observed to ensure compliance with the epoxy
manufacturers' recommendations.
Manufacturer approved heated plural component spray equipment shall
be used in the application of the specified protective epoxy coating. The
spray equipment shall be specifically designed to accurately ratio and
apply the specified protective coating materials and shall be regularly
maintained and in proper working order.
If necessary, subsequent top coating or additional coats of the protective
coating should occur as soon as the basecoat becomes tack free, ideally
within 12 hours but no later than the recoat window for the specified
products. Additional surface preparation procedures will be required if
this recoat window is exceeded.
c) Manholes manufactured by Armorock (or approved equal) may be used
as an approved alternate to manholes that require epoxy coatings
6. Labeling
a) The interior of each manhole shall be labeled during construction.
Labels can be from the manufacturer (stencil, tag, etc.) or by the
contractor (tag, permanent marker, paint pen, etc.). Label must include
the manhole number according to the record drawings and must consist
of letters at least 3 inches tall and must be located approximately 12
inches above the shelf of the manhole.
703 Service Connections
A. Design
1. General Requirements
a) All residential subdivision lots shall be served by gravity unless
otherwise approved. If a pump is approved, it shall be privately
maintained and must pump into either a service connection placed on
the lot. The pump and force main (if needed) must have a note on the
recorded plat indicating the following: "Privately maintained sewer pump
and force main is required to serve this lot".
b) Service connections to the main lines shall be perpendicular to the main
line and shall extend to the edge of the right of way or easement line.
Section 700—Wastewater Collection Systems - Page 24 of 37
Effective Date: April 12, 2022
Direct taps shall be within the top quarter of the main, or within a
manhole. All single family residences and businesses shall have
individual connections to the public sewer main. Sewer services may
not cross private property if the Development is subject to UDO
requirements.
c) Multiple service connections located outside public right of way or public
easements are for private use only and will not be maintained by the
Town. A private sewer permit from NCDEQ shall be required on all
private collection systems prior to construction plan approval. A
cleanout or manhole shall be installed within each serviced lot's right of
way or easement for the Town's use, and shall extend a minimum of 6
inches above the finished grade.
d) Cleanouts are required on all services with a maximum spacing of 50
feet for four (4) inch lines and 100 feet for six (6) inch lines. The first
cleanout from the main/manhole shall be maintained by the Town and
shall be installed one (1) foot inside the right of way line or edge of
easement. All cleanouts shall extend a minimum of 6 inches above
finished grade with brass caps or meet the optional cleanout method
requirements in accordance with the Standard Details. Town
maintenance of sewer services shall terminate at the first cleanout.
e) Sewer cleanouts located in paved areas, which bear vehicle loading,
must have ductile iron risers, ductile iron fittings and a traffic rated cast
iron cover assembly.
f) All 4 inch services shall connect directly into a public sewer main or
manhole, in the fronting street or into an easement within the property.
All 6 inch service connections shall be into a manhole.
g) Service lines connected to manholes shall not be through the cone
section or manhole joints. Service lines shall be installed so that the
crown of the service line matches the crown of the invert line (or higher)
or shall be installed with a standard drop. Multiple service connections
shall not be maintained by the Town. For 6-ft diameter and larger
manholes no service is allowed in the reduced diameter riser sections
of the manhole. All services shall be made via a boot connection when
at a manhole.
h) The use of in-line wyes for service connections shall be required for all
new construction. When connecting to existing sewer mains, service
saddle taps will be allowable. Taps shall be at the 10 or 2 o'clock
position, and shall not be top taps.
Section 700—Wastewater Collection Systems- Page 25 of 37
Effective Date: April 12, 2022
i) Service connections to mains at depths of 14-ft and greater shall utilize
ductile iron pipe between the main and the cleanout, including a ductile
iron wye for the cleanout stack. Location and angle of fittings shall be
as shown in the standard detail drawings.
j) Where the flood level rims of plumbing fixtures are below the elevation
of the manhole cover of the next upstream manhole in the public sewer,
such fixtures shall be protected by a backwater valve installed in the
building drain, branch of the building drain or horizontal branch serving
such fixtures. Plumbing fixtures having flood level rims above the
elevation of the manhole cover of the next upstream manhole in the
public sewer shall not discharge through a backwater valve.
B. Materials
1. Pipe Materials
a) PVC Pipe shall be C900, schedule 40, or greater supplied in minimum
20-ft lengths. Schedule 40 PVC pipe shall be manufactured with a cell
classification of 12454 in conformance with ASTM D1784. Schedule 40
pipes shall be manufactured to dimensional tolerances as specified in
ASTM D1785 and rated for service conditions up to temperatures of 140-
degrees Fahrenheit. The pipe may be joined by solvent weld in
conformance with ASTM D2564.
Schedule 40 PVC pipe may be used for sewer services between 4 and
13 feet and shall require 4-inches of stone bedding extended to the
springline.
PVC pipe and fittings for sewer laterals shall conform to ASTM D2665
"PVC Plastic Drain, Waste & Vent Piping" and shall be NSF approved.
Laying lengths may be 10 or 20 feet with solvent weld type joints for
Schedule 40 pipe or gasketed joint for PVC C900 DR18 pipe.
PVC C900 pipe shall be used in depths between 13 and 20 feet and
shall require 6-inches of stone bedding extended 6-inches above the
pipe crown.
b) Ductile Iron Pipe may be used for any depth sewer service but must be
used for sanitary sewer services with less than 4 feet of cover or in
excess of 20 feet of cover. Ductile iron services shall also be used in all
cases where a well is located within 100-ft of the sewer service line.
Ductile iron service piping shall be provided in conformance with the
ductile iron piping standards outlined herein including cement mortar
lining.
Section 700—Wastewater Collection Systems - Page 26 of 37
Effective Date: April 12, 2022
c) Any sewer service lateral deeper than 20 feet shall be pre-approved by
the Director of Water Resources.
2. Sewer Service Fittings, New Construction
a) DIP Main with DIP Service
In-line wye fittings for ductile iron main lines joined with ductile iron
service lines shall be typical ductile iron mechanical joint fittings as
specified herein. In this case all fitting sizes shall conform to AWWA
C153. Wye fittings through 10-inches in diameter shall be provided with
cement mortar lining in accordance with AWWA C104 and provided with
exterior asphaltic coating per AWWA C151. Wye fittings for lines larger
than 10-inches in diameter shall be provided with Protecto 401 lining as
specified herein for ductile iron pipe of the same sizing.
b) DIP Main with PVC Service
For ductile iron sewer mains to be joined with PVC service lines, the in-
line wye fittings shall be slip joint ductile iron with an IPS sized branch
for PVC schedule 40 service lines. Ductile iron fittings for connecting
PVC service lines shall be deep bell, gasketed joint and air test rated.
Gasket grooves shall be machined. Bell depths shall meet the minimum
socket depth requirements of ASTM D3034 and ASTM F1336. Wall
thickness shall meet the requirements of AWWA C153. Ductile iron wye
fittings through 10-inches in diameter with IPS connections shall be
provided with cement mortar lining in accordance with AWWA C104 and
provided with exterior asphaltic coating per AWWA C151. Ductile iron
wye fittings for PVC lines larger than 10-inches in diameter shall be
provided with Protecto 401 lining as specified herein.
c) PVC Main with PVC Service
For PVC sewer mains to be joined with PVC service lines, PVC in-line
wye fittings shall be provided. Typical Schedule 40 PVC fittings shall be
provided at the cleanout wye and stack.
d) PVC Main with DIP Service
A ductile iron tee/wye shall be provided when the service line is required
to be ductile iron due to a crossing or other obstruction. The fitting shall
be specifically manufactured for ASTM 3034 PVC pipe such that a
smooth flow way exists on the main line through the fitting. The branch
shall be gasketed to receive the 4-inch DIP service line without
additional fittings. The ductile iron tee/wye fitting shall be Protecto 401
lined.
Section 700—Wastewater Collection Systems - Page 27 of 37
Effective Date: April 12, 2022
3. Service Saddle Connections, Existing Sewer Mains
a) PVC service saddles shall be of the same material as the main, 45
degree deflection, and shall be solvent welded and fastened with single
stainless steel bands. The saddle service branch shall be stubbed
slightly into the sewer main so that when installed, the saddle shall not
slip or rotate.
b) For existing DIP main lines, ductile iron service saddles shall be used.
The saddle assembly shall consist of a virgin SBR or NBR gasket
compounded for sewer service, a ductile iron saddle casting, a 304
stainless steel adjustable strap for fastening the gasket and the saddle
casting to the sewer main and a 304 stainless steel adjustable circle
clamp for securing the service line into the rubber gasket. The saddle
shall be furnished with adapters as required to properly receive the
service pipe.
C. Installation
1. General Requirements
a) Sewer laterals shall not be located in easements when gravity service
can be provided to the property frontage at the street.
b) Each separately owned structure requires a separate tap to a public
sewer.
c) Four inch lines shall have a minimum slope of inch per foot and 6 inch
lines shall have a minimum slope of 1/8 inch per foot.
d) Service connections to new mains shall include the use of wye (not tee)
connections. Saddle taps onto new lines shall not be allowed.
e) Saddle taps into existing PVC mains shall be made at the 10 o'clock or
2 o'clock position of the main with the wye saddle angled 45-degrees
towards the direction of flow in the main. Taps shall only be made by a
mechanical circular cutting saw providing a smooth and uniform cut for
the saddle installation.
f) Service connections shall be made using an approved sewer saddle
when the existing sewer line is 8", 10", or 12" in diameter. This service
connection shall not be used when the sewer main material is truss
sewer pipe. The opening in the sewer main for the sewer saddle shall
be cut with a hydraulically or pneumatically driven circular tapping saw
of the same nominal diameter as the sewer service line.
Section 700—Wastewater Collection Systems - Page 28 of 37
Effective Date: April 12, 2022
g) Service laterals to be maintained by the Town shall not be located
beneath a driveway or curb, nor shall a clean-out be located in a
sidewalk area without prior written approval from the Director of Water
Resources.
704 Testing and Inspections
A. General
The Contractor shall furnish all materials, labor, and equipment to perform
all testing. The Contractor may arrange to obtain water for testing purposes
from the Town. The Contractor shall reimburse the Town for all water used
for construction at current inside utility rates.
B. Sewer Main and Service Connection Testing
1. Visual Testing and Observation
a) All materials used must be approved by the Town prior to installation.
Rejected materials shall be immediately removed from the job site.
b) Gravity sanitary sewer lines shall be clean and free from obstructions,
and shall be visually inspected from every manhole. Lines which do
not exhibit a true line and grade or which have structural defects shall
be corrected. Sanitary sewer service connections shall be visually
inspected prior to backfilling.
The Town may re-inspect the line at any time prior to final acceptance
if any damage or displacement is suspected to have occurred
subsequent to the initial inspection
2. Air Testing
a) Low-pressure air testing in accordance with ASTM F1417 shall be
performed on all sewer mains before the laterals or stubs are installed
on the line, and after the trench has been backfilled to finished grade.
Plugs shall be installed at each manhole to seal off the test section.
Prior to testing, the sewer line shall be clear of debris and flushed with
water as necessary. The line will be pressurized with a single hose and
monitored by a separate hose connection from the plug. Air then shall
be slowly introduced into the sealed line until the internal air pressure
reaches 5.0 psig. The air pressure shall then be allowed to stabilize for
a minimum of 2 minutes. The line shall be "acceptable" if the pressure
does not drop in the time prescribed for the test in the table below.
Section 700—Wastewater Collection Systems - Page 29 of 37
Effective Date: April 12, 2022
Nominal Pipe Diameter (in)
8 12 15 16 18 21 24 30 36 42
$ 50 7:33 11:20 14:10 15:11 17:00 19:48 22:40 28:19 34:00 39:40
0 100 , 7:33 11:20 14:10 15:11 17:00 19:48 22:47 35:37 51:17 69:48
150 7:33 11:20 14:10 15:12 19:14 26:10 34:11 53:25 76:55 104:42
c n 200 7:33 11:24 17:48 20:16 25:39 34:54 45:35 71:13 102:36 139:36
' 250 7:33 14:15 22:16 25:20 32:03 43:37 56:58 89:02 128:12 174:30
H 300 7:35 17:06 26:43 30:23 38:28 52:21 68:22 106:48 153:54 209:25
0 350 8:52 19:57 31:10 35:27 44:52 61:05 79:46 124:42 179:30 244:19
400 10:07 22:48 35:37 40:31 51:17 69:48 91:10 142:30 205:06 279:13
a 450 11:23 25:39 40:04 45:35 57:42 78:31 102:36 160:18 230:48 314:07
J 500 12:39 28:30 44:31 50:39 64:06 87:15 114:00 178:06 256:24 349:02
b) If the section fails to meet these requirements, the source of leakage
shall be repaired and the pipe section re-inspected
c) The Contractor shall furnish all plugs, compressors, hoses, gauges,
and any other equipment necessary to conduct the low-pressure test.
3. Infiltration Tests
a) Portions of the sewer lines, which exhibit a higher ground water table
during construction, shall be tested for infiltration. The portions of the
line to be infiltration tested shall be determined by the Town.
b) The portion of the sewer line designated by the Town shall be tested
for infiltration by installing a V-notch measuring weir or other suitable
measuring device in the downstream end of the pipe to be tested.
When a steady flow occurs over the weir, the rate of flow (infiltration)
shall be measured. The rate thus measured shall not exceed 100
gallons per 24 hours per inch of sewer pipe diameter per mile of pipe.
The Contractor shall furnish weirs and other equipment required for
infiltration tests and the tests shall be performed in the presence of the
Town.
c) Should the infiltration tests reveal leakage in excess of the allowable,
the leaking joints shall be re-laid if necessary or other remedial
construction shall be performed by and at the expense of the
Contractor. The section of sewer thus repaired shall then be retested
to determine compliance with the Specifications.
Section 700—Wastewater Collection Systems - Page 30 of 37
Effective Date: April 12, 2022
4. Deflection Testing for Flexible Pipe
a) The mandrel (go/no-go) deflection test shall be performed on each line
prior to acceptance and no sooner than 30 days after installation. The
pipeline shall be thoroughly clean and free of debris and/or sediment
prior to testing. The Contractor shall supply the mandrel used for this
performance test. The mandrel device shall be cylindrical in shape
having 9 or 10 possible contact points with the pipe. The mandrel's
length and diameter (ID of proving ring) shall be in accordance with the
following tables, and shall be subject to the Town's approval.
b) For flexible pipes (such as PVC), the following shall apply:
Average 5% Minimum
Nominal Pi a Inside Deflection Length Fins
Diameter p Pipe Mandrel Included
(inches) Class Diameter Diameter Mandrel with
(inches) (inches) (inches) Mandrel
8 C900 7.98 7.58 10 9
8 SDR 35 7.891 7.496 10 9
10 C900 9.79 9.30 10 9
10 SDR 35 9.864 9.371 10 9
12 C900 11.65 11.07 10 9
12 SDR 35 11.737 11.150 10 9
15 SDR 35 14.374 13.655 10 9
16 C900 15.35 14.58 10 9
18 C900 17.20 16.34 24 9
24 C900 22.76 21.62 24 9
Note: Calculated 5% deflection allowance does not include additional manufacturing
tolerances provided by pipe manufacturers. For the purposes of testing, 5%deflection
shall be calculated from standard pipe inside diameter as published in ASTM D3034 and
ASTM F679.
c) The mandrel shall be advanced through the pipeline to determine if
bedding and embedment has been provided in compliance with ASTM
D2321 to assure joint deflection of less than 5%. If the mandrel
becomes obstructed for any reason while being pulled through the line
with less than 100-lbs of force, the location of the defect shall be noted
and the mandrel shall be removed from the pipeline. Under no
circumstances shall heavy equipment be utilized to force the mandrel
through the pipeline. Deflection testing may be done concurrently with
sewer televising inspections, provided the mandrel is kept within visible
range of the camera. The mandrel diameter shall have a tolerance of
+/- 0.01 inch. Contact length shall not be less than 2 inches.
Any lines not meeting this test shall be corrected by the Contractor and
the test repeated. The Town shall approve the mandrel. The Contractor
Section 700—Wastewater Collection Systems - Page 31 of 37
Effective Date: April 12, 2022
shall furnish drawings of the mandrel with complete dimensions to the
Town upon request.
5. Video Assessment and Cleaning
a) As a final measure required for acceptance, the Contractor shall clean
and televise all newly installed sewer mains prior to acceptance by the
Town. A 3rd party CCTV Contractor shall televise the sewer main and
all lateral connections installed from the upstream to downstream
manhole with no reverse setups or cutaways. This shall be done at the
Contractor's expense. Throughout shooting, the camera shall be
panned and tilted for a complete view of the main. Lighting shall be
adequate to view the entire sewer main and service connections from
beginning to end. The video inspection shall be submitted to the Town
on a CD/DVD and formatted with software compatible and readable by
the Town. The Town shall not be responsible for purchasing additional
software necessary to view the CD/DVD.
b) The camera shall be advanced at a uniform rate not to exceed 20 feet
per minute that allows a full and thorough inspection of the new sewer
main. The camera shall be a color, pan and tilt camera capable of
producing a five hundred line resolution picture. Lighting for the camera
shall be sufficient to yield a clear picture of the entire periphery of the
pipe. The picture quality shall be acceptable and sufficient to allow a
complete inspection with no lapses in coverage. The length of the sewer
main shall be measured and recorded on the video screen. The
distance counter shall be calibrated before shooting the inspection
video.
c) The Contractor shall clean the sewer mains ahead of video inspection
with a high-velocity water jet. The video inspection shall take place
within 2-hours of cleaning operations as witnessed by the Town. All
construction debris shall be collected in the downstream manhole and
shall not be released into the sewer system. No other work shall be
performed on the Sewer lines after cleaning and prior to video inspection
d) The Town shall be present throughout the cleaning and televising of the
sewer mains to verify that the video work complies with the
Specifications. The camera operator shall stop, reverse, pan, and tilt
the camera to view any area of interest during the inspection as directed
from the Town. Dye may be required in order to see dips in the pipe and
for approval by the Inspector.
e) It is recommended that all site grading and all utilities must be installed
and complete prior to final inspection to ensure that damages to the
Section 700—Wastewater Collection Systems - Page 32 of 37
Effective Date: April 12, 2022
sewer main do not occur. Damages found after final inspection would
requiring re-inspection by the Town.
f) CCTV inspection date must be acknowledged and approved by the
Water Resources Department prior to inspection. All structures must be
physically labeled by the contractor with number shown on the video.
Punch list items from the inspection must be submitted on the Town's
approved 3rd Party CCTV Report form and all vides files uploaded to
One Drive (flash drives and CD/DVDs are also acceptable).
g) The contractor may not perform CCTV inspections on any utilities that
they have installed.
6. Marker Tape Testing
Testing of the marker tape shall be performed by the Contractor at the
completion of the project to assure it is working properly and completely
detectable. It is the Contractor's responsibility to provide the necessary
equipment to test the markers. Any defective, missing, or otherwise non-
locatable segments shall be replaced.
C. Manhole Testing
1. Vacuum Testing
a) All newly installed manholes shall pass a vacuum test in accordance
with ASTM C 1244. The Contractor shall supply all equipment and
materials necessary to vacuum test the manholes.
b) Vacuum Testing shall be completed prior to any specified coating and
lining materials being installed.
c) The Town shall be present and witness all vacuum testing.
d) The following vacuum testing criteria shall apply for compliance with the
testing procedure.
1) A vacuum of 10-inches of mercury shall be drawn with an
approved vacuum testing unit.
2) The testing time shall not be measured until after the vacuum
pump has been shut off.
3) The time required for the vacuum to drop from 10-inches to 9-
inches of mercury shall meet or exceed the values listed in the
following table.
Section 700—Wastewater Collection Systems - Page 33 of 37
Effective Date: April 12, 2022
Manhole Vacuum Testing Time
Depth Manhole Diameter inches)
(feet) 48 60 I 72
Time (seconds)
8 20 26 33
10 25 33 41
12 30 39 49
14 35 48 57
16 40 52 67
18 45 59 73
20 50 65 81
22 55 72 89
24 59 78 97
26 64 85 105
28 69 91 113
30 74 98 121
2. Holiday Testing of Lined Manholes
All manholes that require an epoxy coating shall undergo discontinuity
testing. This shall be a high-voltage spark test conducted in accordance
with NACE International Standard Practice 0188. All areas of the manhole
coated shall be tested. The spark tester shall be set at a minimum of 100
volts per mil of coating thickness applied. The Contractor shall supply the
spark tester and all testing equipment and labor needed to perform this test.
All holidays identified must be repaired. The epoxy coating must be
abraded and cleaned prior to re-coating. All touch-up work shall be in
accordance with the epoxy manufacturers guidelines.
705 Aerial Crossings
A. Design
Aerial crossings shall only be utilized in cases where buried crossings are
not feasible due to stream crossings, compliance with riparian buffer
standards, minimizing impacts to wetlands, preventing excessive depth of
installation, or as otherwise directed by the Town of Apex. All aerial
crossings shall have prior approval by the Water Resources Director and
will only be considered if there are no practical alternatives available, cost
shall not be considered justification for aerial crossings
In cases where aerial crossings are utilized to cross streams, the bottom of
the pipe shall be installed above the 25-year flood elevation of the stream.
Piers shall generally be located at a uniform spacing of 20-ft or 1 pier for
every joint of pipe. Piers shall be provided in accordance with the standard
details or as otherwise designed by a licensed NC Professional Engineer.
Section 700—Wastewater Collection Systems - Page 34 of 37
Effective Date: April 12, 2022
All pier footings shall be designed by a licensed NC Professional Engineer
and the assumptions provided in the footing design shall be included on the
plans. At a minimum, the footing design shall include: 1) the allowable soil
bearing capacity, 2) design concrete compressive strength, 3) plan for
reinforcing steel with sizing and location of bars, 4) force diagram including
buoyant forces, stream velocity impacts 5) depth of installation to prevent
frost heaving, 6) bedding design to prevent differential settlement and 7)
factors of safety for unanticipated loads such as trees falling across the
aerial crossing.
At a minimum all pier foundations shall be constructed on a base of 12-
inches of washed stone. The soil conditions under the pier shall be
evaluated by a licensed NC Geotechnical Engineer to determine if the
allowable soil bearing capacity meets or exceeds the design assumptions
included in the structural design. If the soil conditions fail to meet the
specified bearing capacity requirements, a pile foundation shall be provided
or the soils shall be undercut and replaced in conformance with the
recommendations of the geotechnical engineer of record.
Piers installed in stream beds shall be avoided in lieu of spanned crossings.
Spanned pipe crossings greater than 20-ft shall be provided in accordance
with the pipe manufacturer's specifications and shall not exceed 40-ft for
ductile iron pipe. Spanned pipe crossings shall be designed such that all
flanges and exterior pipe connections are located above the 25-year flood
elevation.
Spanned crossings greater than 40-ft without piers shall be provided in a
steel encasement pipe and the entire crossing including piers, foundation,
truss and/or beam supports and pipe thickness design shall be provided by
a licensed NC Structural Engineer.
B. Pipe Materials
1. Ductile iron pipe for aerial crossings shall be interior lined with Protecto
401 at 40-mils regardless of pipe diameter from manhole to manhole. All
joints for ductile iron pipe utilized in aerial crossings shall be restrained with
a US Pipe Mech-Lok joint, American MJ Coupled joint, or other as approved
by the pipe manufacturer, the Water Resources Department and the
Engineer of Record. Ductile iron pipe utilized for spanned crossings greater
than 20-ft without a pier shall typically be provided with flanged connections.
All bolts and fasteners for flanged or bolt locking restraining systems shall
be provided in stainless steel and installed in a manner to prevent seizing.
2. PVC pipe shall not be approved for aerial crossings.
Section 700—Wastewater Collection Systems - Page 35 of 37
Effective Date: April 12, 2022
3. Steel pipe provided for aerial crossings shall be fabricated with grade B
steel that has minimum yield strength of 35 KSI in accordance with ASTM
A139. Steel pipe for aerial crossings shall be provided with minimum wall
thickness consistent with a pressure class of 200-psi or greater. Steel pipe
for aerial sewer crossings shall be provided with 40-mils of interior ceramic
coating, such as Ceramaline and provided with an exterior tape wrap
approved by the manufacturer. All steel pipe joints shall be welded in
conformance with manufacturers' specifications.
C. Installation
Aerial crossings are often utilized to span sensitive environmental areas and
installation shall be consistent with plans to preserve the sensitive areas.
Joints of bolt lock or coupled restrained pipe shall be located within 2-ft of
each pier as outlined by the detail drawings. Contractor shall ensure the
length of pipe joints allows for this spacing.
Pipe shall be secured to each pier with 1/4-inch by 2-inch width steel straps
fastened to 4; 1/2-inch stainless steel lugs anchored and adhered with epoxy
to the concrete pier. The steel straps shall receive a weather resistant
painted finish to prevent long term corrosion.
Precast piers may be submitted for approval provided the footing and
foundation designs are completed by licensed structural and geotechnical
engineers.
In cases where soil conditions cannot be sufficiently stabilized to provide an
adequate foundation for concrete piers, a pile foundation designed by a
licensed NC structural engineer and approved by the Town shall be
provided.
Reinforcing steel for concrete piers shall be grade 40 and shall be
constructed in conformance with the latest edition of the "Recommended
Practice for Placing Reinforcing Bars" or other documentation as published
by the Concrete Reinforcing Steel Institute.
In cases where rock exists at the foundation elevation, the footing shall be
drilled and connected with dowels into the rock layer.
706 Repairs, Modifications, and Abandonment
A. Sewer Main Repairs
1, Vitrified Clay Pipe - replace damaged section with DIP and install a
Fernco coupling at each end encased in concrete.
Section 700—Wastewater Collection Systems - Page 36 of 37
Effective Date: April 12, 2022
2. PVC Pipe - replace damaged section with PVC Pipe and install a
Fernco coupling at each end encased in concrete.
3. ABS/PVC Truss Pipe - replace damaged section with DIP and install
a Fernco coupling at each end encased in concrete.
4. Asbestos Cement Pipe - Replace damaged section with DIP and
couplings encased in concrete.
B. Installation
1. All repairs to damaged sanitary sewer lines in paved areas shall be
backfilled with ABC stone (crusher run) to a density of 95 percent
Standard Proctor.
2. All repairs to damaged sanitary sewer lines shall be bedded with 6-
inches of washed stone and compacted to a minimum of 95%
Standard Proctor density before installing the new joint of ductile iron
or PVC pipe.
C. Draining Sewer Mains
A detailed bypass pumping and emergency plan shall be required for any
sewer line draining event.
All sanitary sewer mains and sewer force mains 20-inches and larger,
active, inactive, or abandoned shall begin to be drained by tapping the
bottom half of the pipe. A corporation stop or other valve shall be provided
to control flow. All effluent shall be pumped to a downstream manhole
(when available) or other containment tank utilizing continuous piping. The
use of a sump pit on lines 20-inches and larger is not allowed.
In sensitive environmental areas and in other various scenarios the Water
Resources Department may require lines less than 20-inches also be
tapped in order to be drained.
D. Abandonment of Existing Sewer Mains
1. Existing sewer mains and casings located outside of road sections shall be
removed, unless otherwise directed by the Town. All materials and labor
shall be provided by the contractor.
2. Grout filling and abandoning in place may be allowed with prior approval
from the Director of Water Resources.
Section 700—Wastewater Collection Systems - Page 37 of 37
Effective Date: April 12, 2022
SECTION 800
WASTEWATER PUMPING SYSTEMS
& FORCE MAINS
801 Pump Station General
A. Design Requirements
B. Warranty
C. Submittals
802 Pump Station Site and Structures
A. General
B. Site Work
C. Structures
D. Piping and Valves
E. Electrical - General
803 Pump Station Equipment
A. Pumps
B. Pump Control Systems
C. Alarm Dialer/SCADA/Telemetry
D. Grinders
E. Generators
F. Automatic Transfer Switches
804 Odor/Chemical Facilities
805 Inspections, Testing, and Training
A. Inspections
B. Testing
C. Operator Training
806 Force Main General
807 Wastewater Force Mains
A. Design
B. Materials
C. Installation
E. Valves and Appurtenances
808 Force Main Inspections and Testing
A. Inspections
B. Testing
Section 800—Wastewater Pumping Systems& Force Mains - Page 1 of 70
Effective Date: April 12, 2022
801 Pump Station General
A. Design Requirements
1. These Specifications apply to all pump stations and associated facilities that are
to be owned, operated, and maintained by the Town of Apex. Designers of private
pump stations and force mains and associated should look for guidance from the
appropriate permitting agency (NCDEQ, NC Plumbing Code, etc.).
2. All aspects of the design of pump stations, and associated facilities shall, at a
minimum, meet the requirements of the latest version of the NCDENR "Minimum
Design Criteria for the Fast-Track Permitting of Pump Stations and Force Mains".
Requirements presented in the Town of Apex Standard Specifications hereunder
that are more restrictive or go above and beyond the requirements of the Minimum
Design Criteria are required by the Town of Apex.
3. All aspects of the design of pump stations, and associated facilities shall be
submitted for review and approval to the Town of Apex Water Resources
Department. This review may be more extensive than the typical development site
plan process. Materials necessary for the review and requiring approval include
complete plans, Specifications, design reports, and specific equipment submittals
for the specific pump station, as described hereunder.
4. Wastewater flow rates for the entire natural drainage basin must be accounted for
as outlined in Specification 700, Wastewater Collection Systems. The receiving
gravity sewer system that will accept flow from this pump station must also be
evaluated to determine if additional flow can be accepted and if any improvements
are required. All required improvements shall be incorporated as part of the pump
station/force main project and shall be installed prior to the pump station becoming
active.
5. Prior to approval of any pump station plan, a detailed economic analysis consisting
of minimum 20-year present worth evaluation shall be submitted by the Engineer-
of-Record comparing the extension of gravity sewer service with the construction
of a pump station and force main alternative. Gravity sewer systems shall always
be preferred over pump station and force main construction. The Town of Apex
reserves its right to consider economic evaluations, service area configuration,
operating costs and other external factors before approving pump station plan
submittals in lieu of gravity sewer extensions.
6. All equipment, except for the generator, included in this Specification shall be
designed for a sound rating of 55 dB(A) or less at a distance of 21 feet from the
operating equipment. The generator shall include a sound attenuating enclosure
and hospital grade silencer. The generator shall have a sound rating of less than
71 dbA for generators rated below 150KW and less than 73 dba for generators,
Section 800—Wastewater Pumping Systems & Force Mains - Page 2 of 70
Effective Date: April 12, 2022
rated between 150KW and 250KW, at a distance of 21 feet from the operating
equipment. Warning horns and sirens have no sound restrictions.
The pump station design shall incorporate ways to minimize the sound levels
leaving the site property. Factors to consider include equipment layout, cumulative
sound levels, and walls that reflect the sound. Equipment submittals that include
the sound ratings for the major equipment to be installed at the pump station shall
be supplied to and approved by the Water Resources Department prior to ordering
the equipment.
The pump station shall not be approved for routine operation until sound testing
has demonstrated that the noise levels are in accordance with the requirements of
this section. All sound testing shall be performed by reputable personnel and
testing equipment to assure accuracy. The Director reserves the right to require
certified sound engineers in cases when the accuracy of the testing equipment is
uncertain. The Director may also require sound testing to be redone prior to the
end of the corrections period to further demonstrate that the pump station,
including the generator, is performing as designed.
Generator testing and operation other than for urgent necessity in the interest of
public health and safety shall be during the time periods of Monday through Friday
between the hours of 9:00 a.m. and 4:00 p.m., not including holidays which are
observed by the state.
7. All pump station facility design plans shall evaluate surge and water hammer, and
incorporate sufficient surge suppression based on the range of flows, pressure and
other variables included in the pump station design.
8. All pump station facility designs shall include emergency by-pass pumping
capabilities and permit sufficient space to accommodate equipment staging.
9. All pumps shall perform a drawdown test to verify pump capacity flow rates. Town
representatives shall be present during the test. Documentation of the test shall
be provided to the Town for approval.
B. Warranty
1. All equipment, materials, and systems supplied under this Specification shall be
provided with a warranty from the manufacturer to the Town that the subject
equipment, materials, and systems shall be free of defects in workmanship and
material, and shall operate as intended under the known conditions, for a minimum
period of one year. The warranty shall be in printed form and made applicable to
the Town (as Warrantee) at the time of acceptance for maintenance by the Town.
Section 800—Wastewater Pumping Systems & Force Mains - Page 3 of 70
Effective Date: April 12, 2022
C. Submittals
1. Design Report
a) A design report signed and sealed by a North Carolina Professional Engineer
is required with the submittal of plans and Specifications for any facilities
covered under this section that are proposed for construction. This design
report shall contain, at a minimum, the following design criteria:
1) Total dynamic head calculations for all applicable pumping situations.
2) System curve and pump curve analysis used to determine pump
selection and operating point.
3) Pump station cycle and pump run times covering the high, low and
average flows over the entire expected operating period of the pump
station.
4) Response time available in event of an emergency (time between the
high water alarm and the first system overflow at average design flow
and peak design flow).
5) Pump station flotation/buoyancy calculations.
6) Minimum velocity within the force main, including an analysis of the
capabilities of the pumps to completely flush any depressed sections
of the force main in a single pumping cycle.
7) Maximum detention times within the pump station and force main
covering the low flows over the entire expected operating period of
the pump station.
8) An evaluation of the capability of the receiving sewer to handle the
peak flow discharge from the proposed facility in addition to the
existing or planned peak flows currently handled by the receiving
sewer or sewage facility.
9) Airflow calculations and chemical dosing calculations for the odor
control facilities (if applicable).
10)Flow capacity and headloss calculations for the grinder unit.
11)Calculations for the sizing of the backup power generator.
12)If jockey pumps are being proposed calculations much show how the
pump can meet all design criteria.
13)Total number of lots or parcels serviced, off-site drainage area and
zoning, average daily flow, and peak daily flow.
2. Project Review Submittals
a) Project Review Submittals shall be submitted to the Town of Apex Water
Resources Department for review and approval prior to application for a permit
for the pump station or force main, and prior to entering into construction
contracts or purchasing any equipment for the pump station or force main.
Obtaining permits, entering into construction contracts, or purchasing any
equipment in no way obligates the Town of Apex to accepting designs or
Section 800—Wastewater Pumping Systems& Force Mains - Page 4 of 70
Effective Date: April 12, 2022
equipment that do not meet the specified standards or other requirements the
Town may have.
b) The Project Review Submittals shall include, at a minimum, complete plans and
Specifications, a design report as described above, and manufacturer's
information on specific major equipment listed in this Specification section. The
information submitted on equipment shall include, at a minimum, the name of
the manufacturer and the specific model being supplied, fabrication and
assembly drawings, detailed specifications and data covering materials, parts,
devices, and accessories forming a part of the equipment furnished. It shall
also include any system hydraulic schematics, electrical wiring diagrams, and
control panel schematics. Additional detailed information that may be required
for submittal for specific equipment is listed in the appropriate equipment
section.
3. Pre-Approved Equal Submittals
a) Equipment and systems of equal quality and efficiency may be available from
manufacturers and suppliers other than those listed in this Section. No attempt
is made to preclude the furnishing of similar quality items by other
manufacturers. The use of alternate equipment and products will be
considered if it can be demonstrated that these items have equal or superior
construction performance, operating and maintenance costs, offer a present
worth cost equal to or less than the specified items, and do not adversely affect
other system components.
b) Equipment and systems other than those listed in this Section must receive
approval from the Director of Water Resources prior to application for a permit
for the pump station or force main, and prior to entering into construction
contracts or purchasing any equipment or systems for the pump station or force
main. Purchasing equipment in no way obligates the Town of Apex to
accepting equipment that does not meet the specified standards or other
requirements the Town may have.
c) Pre-Approved Equal packages shall include the following information as a
minimum:
1) Current catalog data sheets and complete technical data to support
Specification compliance.
2) A point-by-point list clearly stating all differences between the named
item and the proposed alternate and a separate list clearly stating all
exceptions to the Specifications. If no exceptions are listed, then no
exceptions to the Specifications will be allowed.
3) Installation list with name, address and phone number of contact
person for each of at least five (5) installations where the proposed
equipment has been in similar service and satisfactory operation for
Section 800—Wastewater Pumping Systems & Force Mains - Page 5 of 70
Effective Date: April 12, 2022
at least two (2) years. The date of placing equipment in service at
each listed installation shall be provided.
4) Three (3) copies of Pre-Approved Equal information shall be
submitted.
d) Equipment that meets the Pre-Approved Equal submittal requirements, the
technical Specification requirements, and all other requirements of the Town of
Apex, will be approved by the Director of Water Resources via letter within 14
calendar days of receipt of a complete package. Approval of Equal equipment
or systems in no way eliminates the requirement for complete submittals at a
later date.
4. Testing Results Submittals
a) The results of all testing shall be submitted to the Town of Apex Water
Resources Department for review prior to continuing progress on the particular
equipment. If shop testing is required, results shall be submitted prior to
delivery of the equipment. If installation verification is required, results shall be
submitted prior to start-up and testing of the equipment. If final start-up tests
are required, results shall be submitted prior to final acceptance of the
equipment.
b) Three printed copies of all test results are required to be submitted for review.
c) A final, compiled summary of all testing done on all equipment shall be provided
to the Town of Apex upon completion of the project prior to project closeout
and final acceptance. This final, compiled summary shall consist of a single
bound printed copy, and an electronic copy (CD).
5. Operation and Maintenance Manuals (O&M)
a) Operation and Maintenance (O&M) manuals are required for all equipment and
systems furnished under this Specification section. Three copies shall be
supplied to the Town in printed format prior to startup of the subject
equipment or systems. The O&M manuals shall contain all of the necessary
information for proper operation and maintenance of the subject equipment and
systems. At a minimum, the O&M manuals shall contain the following:
1) Final approved shop drawings.
2) Design data including certified pump curves and system curves.
3) Wiring diagrams and control schematics.
4) Detailed inventory of installed equipment, including its functional
description, and manufacturer name, address, and phone number
(and the same for a local representative of the manufacturer).
5) Operating instructions.
6) Troubleshooting techniques.
Section 800—Wastewater Pumping Systems & Force Mains- Page 6 of 70
Effective Date: April 12, 2022
7) Maintenance schedules.
8) Assembly and disassembly instructions.
9) Instructions for start-up and shutdown, as well as calibration and
adjustment.
10)Annotated hard copy and downloadable electronic copy of application
program for all field programmable equipment (eg PLCs, operator
interfaces, etc.)
b) A final, compiled Operation and Maintenance (O&M) manual covering all
equipment and systems supplied, shall be provided to the Town of Apex upon
completion of the project prior to project closeout and final acceptance. This
final, compiled summary shall consist of a single bound printed copy, and an
electronic copy (CD).
c) Any spare parts listed in the O&M manuals and/or recommended by the
manufacturer shall be provided to the Town with the O&M Manual submittal.
802 Pump Station Site and Structures
A. General
1 . Pump stations shall be designed in accordance with these standard specifications,
the Town's Standard Details, and NCDEQ's manual for the Minimum Design
Criteria for the Permitting of Pump Stations and Force Mains.
2. Pump stations shall be located on a parcel or an easement that is dedicated to the
Town of Apex. The site shall be directly connected to a dedicated public right-of-
way or have a dedicated access easement to a public right-of-way.
3. The Town requires sewage grinders, on-site backup power, and odor control
facilities at all pump stations. Sizing of these items will be based on expected flow
volumes and characteristics.
4. All stations shall have a minimum of 2 pumps of equal capacity. The pumps shall
be solids handling, submersible, centrifugal pumps each capable of pumping flows
equal to the expected peak hourly flow. The allowable peak flow can be found in
Section 0700. The Director of Water Resources may require that higher peaking
factors be used. The Director of Water Resources may require wet well/dry well
pumping systems when peak flows exceed 1-MGD. Where 3 or more pumps are
required, they should be of such capacity that with the largest unit out of service,
the remaining units shall have capacity to handle the peak hourly flows. Pumps
and force mains shall be sized to provide a minimum velocity in the force main of
2.5 fps and a maximum velocity of 10 fps.
5. Pump stations shall remain fully functional, operational, accessible and free from
physical damage during a 100-year flood.
Section 800—Wastewater Pumping Systems & Force Mains - Page 7 of 70
Effective Date: April 12, 2022
B. Site Work
1. The site shall be graded to drain and direct stormwater runoff away from the pump
station, and to remove storm water runoff from the site in a non-erosive manner.
Drainage swales shall be incorporated to direct drainage away from the site, if
necessary.
2. The site shall be stabilized by a minimum of 12" crushed stone over 98%
compacted subgrade, low maintenance vegetative ground cover or other suitable
materials. Visual screening and landscaping shall be provided in accordance with
the approved site plan.
3. The site shall be secured by an 8-ft high vinyl coated chain link fence. It shall have
3-wire vinyl coated barb arms, set at an outward facing 45 degree angle and
located at the top of each post. Each wire to be 3 strand barb wire class III
galvanized or aluminized. The outer barb wire shall hold a load of 250-lbs. The 8-
ft height does not include the barb arms. The vinyl coating shall be black and
provided with UV resistant vinyl. Fencing shall be provided around the entire
perimeter of the pump station property maintaining an offset of 10-12 feet from the
property boundary. All fence posts shall also be vinyl coated over the galvanized
steel in black color to match fencing and privacy screening. Manual slide gates for
smaller pump stations shall permit 180-degree opening and be provided in
minimum width of 14-ft. Gates at larger pump stations receiving chemical
deliveries shall be a minimum of 16-ft wide to accommodate tractor trailer
accessibility and be provided with electrically operated slide gates. All gate posts
and corner posts shall be provided with minimum 4-inch diameter fence posts. The
fence shall be screened with a row of evergreen shrubs, in accordance with the
Town's UDO and Planning requirements, that are at least 5' in height at the time
of planting. The fence gates shall be provided with black vinyl coated privacy slats
rated for a minimum life span of 12-years. If site conditions do not allow for
evergreen shrubs, then privacy slats shall be provided across the entire surface
area of the fence including gates.
4. The pump station site shall permit the loading and removal of all equipment
(pumps, grinders, generators, etc.)from the pump station site with an appropriately
sized truck and/or crane.
5. The site shall feature adequate turn around areas for a WB-40 service vehicle and
provide a minimum 16 foot wide all-weather access road to the site with grades
not to exceed 10%. If chemical feed systems are included, additional turning
radius may be required. The access road shall consist of a standard concrete curb
tie and apron through the right-of-way and transition to an asphalt-concrete section
with an 8-inch stone base and 3-inch surface course, or 12" of crushed stone over
minimum 98% compacted subgrade. Shoulders and side ditches should be
included, as applicable.
Section 800—Wastewater Pumping Systems & Force Mains - Page 8 of 70
Effective Date: April 12, 2022
6. An LED light equivalent to a high pressure sodium vapor light with a minimum 600
watt capacity in compliance with Town of Apex standards, is required. The light
shall be mounted on a suitable utility that retracts or pivots for bulb maintenance
from ground level. The light shall be at a height of 30 feet and shall be controlled
by an on/off switch mounted on the pole. All area lighting shall be provided in a
downward projecting fixture, such as shoe box type light or approved equal. Open
globe lighting shall be prohibited on all pump station sites.
7. Pump stations shall have a metered potable water supply from the Town of Apex
public water distribution system at minimum sizing of 1-inch service, but provided
with sufficient volume and pressure for operations including wash downs, etc. For
larger stations a 2-inch service shall be provided to accommodate larger wash
down and service needs. The supply shall have an approved lead free reduced
pressure principle, RPA, backflow prevention assembly. A minimum of one (1)
freeze proof yard hydrant is required within the fenced area. Emergency shower
and eye washing basin shall be provided in pump stations with chemical odor
control facilities. Separate reduced pressure principle assemblies, RPA, backflow
preventers shall be required as necessary to protect eye wash and/or emergency
shower stations from potential chemical contamination within the pump station site.
As required by ANSI Z358.1, the shower and eye wash stations shall be provided
with a tepid water system and be able to operate simultaneously. Pressure
reducing valve shall be required for any static pressure over 80 PSI.
8. A grounding electrode system shall be provided for all pump station site wiring
systems and shall be connected to the fence, generator, and electrical service.
C. Structures
1. General
a) The submersible pump station structures shall consist, at a minimum, of a
grinder manhole, a wet well, and a valve vault. Large, integrated structures
are permissible, however, there shall be walls separating the portions of the
structure listed above. Electric motor operated grinders will be required at all
stations. Pump station structures other than the wet well shall be provided
with a means to remove accumulated water and wastewater from the
structure.
b) Any portion of a pump station structure that is open and would allow
floodwater entry into the wastewater system shall be built with a top elevation
of 2 feet above the 100 year flood elevation. All structures not meeting the
elevation requirement that could allow entry of floodwater into the wastewater
system shall be sealed watertight with a vent elevated a minimum of 2 feet
above the 100 year flood elevation.
Section 800—Wastewater Pumping Systems& Force Mains - Page 9 of 70
Effective Date: April 12, 2022
c) All pump station structures shall be designed to withstand hydrostatic forces
that they will be subjected to, including uplift and shall be equipped with
buoyancy collars.
d) Refer to standard detail for stone base requirements under all structures.
e) Fall protection grating shall be installed at all access hatches. Additional
anchor posts shall be installed according to the Standard Detail.
f) Structures manufactured by Armorock (or approved equal) may be used as
an approved alternate for any structure that requires epoxy coating.
2. Wet Well
a) The wet well shall have a minimum inside dimension of 6 feet, and shall be
large enough to easily accommodate the removal of each pump and a basket
strainer. The wet well shall be designed to have an operating volume sufficient
to provide pump operating cycles to match the manufacturer's
recommendations. The pump operating cycles must be between two and eight
times per hour at design daily flow (without being excessively deep. All wet
wells must be concentric.
b) The wet well shall be constructed of precast concrete manhole sections or cast-
in-place concrete. Extended bases or another foundation shall be used to
provide adequate bearing surface and flotation protection, if needed. All
concrete shall have a minimum 28 day compressive strength of 4000 psi. The
Director of Water Resources may require a higher strength concrete.
c) Precast concrete manhole wet wells shall conform to ASTM C-478. Manhole
section joints shall be of a durable mastic sealing material and be watertight in
accordance with ASTM C-443. The exterior of manhole wet wells shall have a
factory applied bitumastic or asphaltic coating. The exterior of wetwell joints
shall be overlapped by an approved material such as Conwrap, Conseal, etc.
The interior side of the joints shall be plastered smooth with portland cement
grout.
d) Cast-in-place wet wells shall be properly designed by a NCPE and include
appropriate structural support, waterproofing, exterior coating, structure
covers, access hatches, etc.
e) At a minimum, wet wells shall have a vent made from ductile iron with flanged
joint pipe fittings. An insect screen shall be included at the exposed end of the
vent pipe. The screen shall be bronze or aluminum insect screening. Forced
air venting is also allowed and will be required on individual pump stations in
conjunction with odor control measures, depending on circumstances.
Section 800—Wastewater Pumping Systems & Force Mains -Page 10 of 70
Effective Date: April 12, 2022
f) Wet wells and wet well piping shall be coated with at least 80-mils of an
approved monolithic epoxy coating system consisting of a 100% solids,
solvent-free, two-component epoxy resin for up to 100 mils of coating with a
manufacturer approved set time of 6-hours or less. The epoxy coating system
shall be Sherwin Williams Sher-Flex, Raven Lining Systems, or approved equal
and installed in no more than 2 applications with no runs and no holidays. High
voltage holiday testing shall be utilized to verify there are no voids in the
coating. The joints of pre-cast structures shall receive three (3) coats of mortar
so as to achieve a smooth surface at each joint. Epoxy coatings shall only be
applied to adequately cured concrete structures that have been sufficiently
washed and prepared for epoxy coating installation. Properly applied coating
shall provide a smooth finish at 80-mils or greater and fill all pores in concrete
substrate.
g) Care will be taken to ensure no epoxy coating is applied to the pump coupling
face, the guide rails, or any other part that needs to allow movement or
replacement on a regular basis.
h) Cover slabs for wet well and valve vaults shall be reinforced concrete with
integral cast in place access hatch covers. Cover slabs shall be reinforced as
per ACI Code and specially reinforced around openings. Access covers shall
be double leaf or single leaf(as required) aluminum diamond pattern floor hatch
of 1/4-inch (minimum) thickness capable of withstanding 150 psf without
permanent damage. Each leaf shall open 90 degrees and be attached to the
frame by steel hinges. The door shall have a lock in the open position and vinyl
grip handle to release lock for closing.
i) Each we well shall be equipped with a removable extension ladder as specified
to enable access. The Town shall designate the location during the review
process.
j) Pre-cast structures shall have a Sherwin Williams Sher-Flex, Raven Lining
Systems, or equivalent applied to the outside of all tongue and groove joints.
Prior to backfilling the wet well structure, the entire surface shall receive 1
coat. The material used for exterior coating shall meet the requirements of
Corps of Engineers Specification C-200. The exterior coating shall be applied
as to achieve a total dry film thickness of 80-125 mils. The exterior surface
shall be clean and dry prior to application of the coating.
k) All bolted connections, including pipe flanges, inside the wet well shall be
made using stainless steel bolts, nuts, and washers.
I) An aluminum handrail shall be provided around the wet well opening of all
submersible pumping stations. The handrail shall be closed on three sides,
with the fourth side closed by a latching chain. The handrail shall be
permanently attached to the concrete cover slab. The chained side of handrail
Section 800—Wastewater Pumping Systems & Force Mains - Page 11 of 70
Effective Date: April 12, 2022
shall face the chain link fence gates for access and pump maintenance. A
minimum horizontal clearance of 10 feet between the chains and handrail is
required. Hand rails shall be grounded to the primary ground on-site.
m) A fall-through prevention system shall be provided with the wet well hatch
doors. The system shall be a grate consisting of two leafs made of 6061-T6
aluminum hinged on the same side of the hatch. The grate shall be designed
to withstand a minimum pedestrian load of 300 lbs. per square foot. The grate
openings shall be 4" x 6" to allow both visual inspection and limited
accessibility for maintenance purposes when the grate is closed. The leafs of
the grate will pivot on aluminum hinge devices with 316 SS hardware that
permit them to rotate upward 90 degrees and automatically lock in place.
Aluminum pullrods will be attached to the grate's leafs so the operator is
positioned with the grate between him and the hatch's opening whenever he
raises a leaf. Each grate leaf will have a rod made from 316 SS that
automatically engages to secure the leaf in its open position, and can be lifted
upward to permit the grate leaf to close. The hatch cover will not be able to
shut until the grate is closed, thereby insuring the grate is in position when the
next operator opens the hatch cover. The grate shall have an OSHA safety
yellow finish to increase visual awareness of the safety hazard.
3. Valve/Meter Vaults
a) The valve/meter vault shall, at a minimum, consist of a precast concrete
manhole base section at least 6 feet in diameter, or a cast in place concrete,
custom built section, or a precast concrete rectangular structure at least 6 feet
square. The valve/meter vault shall be complete with a drain that goes to the
wet well or where a gravity drain cannot be included, a sump with a minimum
1/2 hp mercury float switch activated sump pump discharging to the wet well.
The vault shall include an access ladder attached to the vault wall, and access
cover cast in the top slab with an extendable/retractable grab bar. The drain
pipe between the valve vault and the wet well shall have a back water valve at
the wet well end. The access cover for the valve vault shall be a square lockable
hatch of 1/4 inch aluminum diamond pattern plate with steel hinges on an
aluminum frame cast in place in the cover slab. All access covers shall be
centered over equipment to accommodate service and removal and includes a
removable metal grate style fall protection guards. Stainless steel or
galvanized pipe stands shall be used to support valves and other
appurtenances requiring support.
4. Manholes
a) Any manholes installed on the pump station site need to meet the standards
described in Section 0700 of the Town of Apex Standard Specifications. All
manholes installed on the pump station site shall receive an interior coating of
Section 800—Wastewater Pumping Systems & Force Mains - Page 12 of 70
Effective Date: April 12, 2022
an approved epoxy resin, as previously specified for the pump station wet well.
All manholes located within the 100 year flood elevation shall receive an
exterior coating as specified in Section 0700.
5. Buildings
a) Building systems to house chemical feed facilities shall be adequate to provide
sufficient storage, clearance, and full containment of chemicals in the event of
a chemical tank or other failure. A removable roof or roof sections shall be
required to allow sufficient access to all equipment and tanks within the
building. All supplementary or miscellaneous items, appurtenances, and
devices incidental to or necessary for a sound, secure, and complete
installation shall be designed and sealed by a NCPE. Chemical feed delivery
lines will be chemical resistant and of a flexible material routed through
oversized schedule 80 conduit
b) On a case by case basis, a building may be required to house all electrical and
control equipment. This building shall be of precast, prefabricated, or built in
place construction.
c) All buildings located on a pump station site shall have the first floor elevation a
minimum of 2 feet above the 100 year flood elevation.
d) Buildings shall be heated to avoid the freezing of chemicals.
D. Piping and Valves
1. Piping: Suction and discharge piping shall be Class 50 ductile iron flanged pipe in
accordance with AWWA C 115. Discharge piping and valves shall produce a
minimum head loss while maintaining a minimum velocity of 3 feet per second. All
exposed piping shall have adequately sized and located restraint.
2. Pump piping: The discharge connection elbow shall be a straight through fitting
with no flap valve and shall be permanently installed in the wet well along with the
discharge piping. The pumps shall be automatically connected to the discharge
connection elbow when lowered into place. The entire weight of the pump shall
bear upon the guides and base support with no part of the pump bearing directly
on the floor of the wetwell. A stainless steel chain shall be provided for lifting each
pump from the wet well. All hardware used shall be 316 stainless steel.
3. All piping, couplings, fittings, valves, etc. shall be Class 125 for flanges meeting
ANSI B16.1, unless Class 250 flanges are required for high head installations.
4. Check Valve: An external weight spring loaded or air-cushioned or hydraulic loop
check valve and a plug valve shall be provided for the discharge pipe of each
pump. A 1/4 turn plug valve shall be provided on the discharge pipe from the valve
Section 800—Wastewater Pumping Systems& Force Mains - Page 13 of 70
Effective Date: April 12, 2022
vault (the beginning of the force main). Check valves shall be ductile iron bodied,
fully bronze mounted with bronze clapper disc and bronze seat ring, and shall have
a spring loaded lever arm capable of being mounted on either side of the valve.
Check valves and plug valves shall be mounted in the horizontal position with a
minimum of 3 feet of separation between each valve body and the outside walls.
All valves shall be centered on the vault door for maintenance access and valve
removal.
5. Plug Valve: Plug valves shall be 1/4 turn, eccentric action and resilient plug facing
with heavy duty stainless steel bearings and welded-in corrosion resistant nickel
seat. Pump station plug valves shall be "full-port" cross-sectional area
perpendicular to the flow of at least 100°/0 of the adjoining pipe.
Plug valves and check valves on the discharge side of each pump shall be located
in a valve vault separate from and adjacent to the wet well. A Victaulic type
coupling shall be installed on each discharge main between the wet well and the
valve vault. An isolation plug valve shall be installed downstream approximately
50-feet from the valve/meter vault in order to isolate the force main from the vault
and equipment. Valves shall be rated for a minimum of 175 psi working pressure
and be able to pass a 3-inch solid
6. Pressure gauge: A +/- 2% accuracy pressure gauge with a 3 inch or larger liquid
filled dial, stainless steel case, and graduated to 150% of force main static
pressure shall be provided on each discharge pipe. The gauge shall be installed
between the check and plug valves. Isolation seals and cut-off ball valve shall be
provided between the gauge and force main. The gauge shall be oriented so that
it is easily visible and_legible from the valve vault hatch opening. The gauge shall
also be capable of delivering an electronic remote signal compatible with SCADA.
7. Air Release Valve: Each pump shall have an air release valve, installed on the
discharge prior to combining with other pumps and leaving the valve vault. Air
release valves shall be installed in manholes outside of the valve vault.
There shall be one additional air release valve installed in a manhole on the force
main, prior to the main leaving the pump station site.
8. Surge Valve: There shall be one surge valve installed within the valve vault.
9. Flow Meter: A full size electromagnetic flow meter shall be installed in a manhole
or vault on the discharge side of the valve vault.
10.Trash Basket:
Section 800—Wastewater Pumping Systems & Force Mains - Page 14 of 70
Effective Date: April 12, 2022
A. Each pump station shall have one aluminum trash basket with guide rails with
the following requirements:
1. Basket shall have bar screen on the front and bottom with a minimum 1-
1/4 inch to maximum 2 inch clear opening between 1/4-inch thick bars.
The sides of the basket may be solid.
2. Basket shall have a minimum of four solid aluminum wheels with stainless
steel axles for easy removal from wetwell on aluminum guide rail system.
Guide rail system shall not be provided with ladder rungs. Provide basket
stop bar for installation in field to insure proper location of basket.
3. Minimum dimensions: 2 inches wider than OD of influent pipe, 18 inches
deep, and 18 inches high. Influent pipe must be able to pass through guide
rails to influent face of basket.
11.Anchor Bolts.
a) Anchor bolts and nuts shall be furnished as required for each item of
equipment. Anchor bolts, together with templates or setting drawings, shall be
delivered sufficiently early to permit setting the anchor bolts when the structural
concrete is placed. Anchor bolts shall be at least 3/4 inch in diameter. Anchor
bolts and associated hardware shall be 316 stainless steel.
b) Anchor bolts shall be accurately located and centered in pipe sleeves having
an inside diameter approximately 2.5 times the bolt diameter and a length
approximately 8 times the bolt diameter. A square anchor plate with thickness
of approximately 0.5 the bolt diameter and side dimensions 4 times the bolt
diameter shall be welded to the bottom of each sleeve, with the anchor bolt
extended through the plate and welded thereto. Two nuts and a washer shall
be furnished with each anchor bolt.
c) Anchor bolts shall be long enough to accommodate 1.5 inches of grout beneath
the baseplate and to provide adequate anchorage into structural concrete.
Bolts shall have a "J" bend anchoring them into the concrete.
d) Anti-seize compound will be applied to the threads of all stainless steel bolts
before assembly.
E. Electrical - General
1. All electrical systems associated with any of the items covered under this section
shall meet all applicable electrical standards and code requirements, including, but
not limited to: ANSI, ASTM, NEMA, IEEE, DEMA, EEI, HEI, ISO, NFPA, SAE,
NEC, UL508, as well as any other federal, state, or local codes.
2. Electrical service to all pump stations shall be appropriately sized three phase
power, 240 VAC with automatic transfer switches to automatically starting on-site
emergency generators. The electrical power entrance shall be through a meter
Section 800—Wastewater Pumping Systems & Force Mains -Page 15 of 70
Effective Date: April 12, 2022
base, followed by a NEMA 3R heavy duty, single throw, and fusible safety switch.
This shall be followed by a heavy duty automatic transfer switch that transfers
between the utility power and the on-site generator. This shall be followed by a
NEMA 3R heavy duty, double throw, three pole safety switch which feeds the
control panel from one side and heavy duty, circuit breaking 4 wire, 4 pole male
receptacle assembly as manufactured by Crouse-Hinds or other approved equal
from the other side. There shall be a NEMA 3R heavy duty single throw fusible
safety switch between the generator and the automatic transfer switch.
3. Electrical equipment inside the wet well shall meet the requirements for Class I,
q
Division I, and Group C/D service.
4. All of these electrical components shall be suitably sized to be capable of service
with all electrically powered equipment running.
5. All electrical components, including panels, shall be sealed off from the wet well in
accordance with the N.C. Electrical Code requirements for electrical service to
class 1 division 1.
6. The use of rigid conduits is required. Generally, PVC shall be used below ground
and PVC coated galvanized steel shall be used above ground. Conduits that lead
to a control panel shall be air gapped a minimum of 3-feet from the panel or seal-
offs shall be provided.
7. Pump station electrical and control equipment shall be located in a building as
described above, or under a weatherhood. An aluminum weatherhood with a clear
height of 7 feet, an overhang of at least 4 feet and a thickness of 3/16 inch shall
be provided for control equipment exposed to the weather. The back panel and
side panel shall also be 3/16 inch thick aluminum. The support structure for the
weatherhood shall be made from structural steel members assembled to provide
individual, direct support to the control equipment panel, transfer switch, safety
switches, meter base and the weatherhood. The steel frame shall be painted with
a two component, high build epoxy polyamide paint system designed for severe
service. All weatherhoods shall be provided with a light and GFI protected 120V
outlet.
8. All electrical equipment, including non-submersible motors, electrical panels,
control panels, alarm/telemetry systems, backup generators, etc., shall be located
a minimum of 2 feet above the 100 year flood elevation. Weatherhoods shall be
installed to eliminate runoff to the front side. All electrical enclosures shall have
hinged doors/covers. The control panel shall include a concrete pad, minimum 8'
x 4' x 6" thick.
9. An intermediate terminating explosion proof junction box is to be supplied and
installed mid-way from the wet well and the pump control panel. This box shall be
NEMA type 4X suitably sized to house all pump power and control wiring. Rigid
Section 800—Wastewater Pumping Systems & Force Mains -Page 16 of 70
Effective Date: April 12, 2022
metal conduit shall be utilized with the necessary seal-off fittings. Terminal strips
shall be provided to properly split the power termination to facilitate pump removal
from the junction box and not the pump control panel.
Exposed outlet boxes for outdoor and indoor wet process areas used for lighting
fixtures, switches, and receptacles shall be aluminum provided with rubber
neoprene gasketed covers of similar metal. Junction and pull boxes shall be NEMA
4X construction and of ample size to house the required devices. Boxes shall be
provided with hasps.
The minimum size of boxes shall be according to the NEC. No box shall be filled
to more than 40% of capacity.
Where control wires must be interconnected in a junction box, terminal strips
consisting of an adequate number of screw terminals shall be installed. Current
carrying parts of the terminal blocks shall be of ample capacity to carry the full load
current of the circuits connected. Approximately 20 % of the terminals provided
shall consist of spare terminals. Terminals shall be lettered and/or numbered to
conform with the wiring diagram.
803 Pump Station Equipment
A. Pumps
1. General
a) Pumps, motors, and major accessories shall be supplied by a single
manufacturer and must be Fairbanks Morse, ABS, Hydr-o-matic, or HOMA.
b) Each pumping unit shall be complete with a close-coupled, submersible electric
motor, and all other appurtenances specified, or otherwise required for proper
operation.
c) The equipment provided under this section shall be suitable for the service
conditions and shall be capable of meeting all operating requirements of the
pumping system.
d) Each pumping unit including motor and all integral controls shall be rated and
labeled for use in a Class 1, Division 1, Group C/D area as defined by the
National Electric Code.
e) Each item of equipment and each part shipped separately shall be identified
with indelible markings for the intended service. Tag numbers shall be clearly
marked on all shipping labels and on the outside of all containers.
Section 800—Wastewater Pumping Systems& Force Mains - Page 17 of 70
Effective Date: April 12, 2022
---1
f) Abbreviations. Reference to standards and organizations herein shall be as
indicated by the following designations.
1)AFBMA Antifriction Bearing Manufacturers Association
2)AGMA American Gear Manufacturers Association
3)AISI American Iron and Steel Institute
4)ANSI American National Standards Institute
5)ASME American Society of Mechanical Engineers
6)ASTM American Society of Testing and Materials
7)NPT National Pipe Thread
8)SAE Society of Automotive Engineers
2. Submittals
a) Complete fabrication and assembly drawings, together with detailed
specifications and data covering materials, parts, devices, and accessories
forming a part of the equipment furnished, shall be submitted in accordance
with the submittals section. The data and specifications for each unit shall
include, but not be limited to, the following:
1)Pumps
1) Name of Manufacturer
2) Type and model
3) Rotating speed
4) Direction of rotation
5) Size of suction elbow inlet
6) Size of discharge elbow outlet or nozzle
7) Net weight (mass) of pump and motor only
8) Complete performance curves showing capacity versus head, bhp
(brake kW), NPSH required, and efficiency
9) Data on shop painting
2)Motors
1) Name of manufacturer
2) Type and model
3) Type of bearings and method of lubrication
4) Rated size of motor, hp (kW), and service factor
5) Insulation class and temperature rise
6) Full load rotative speed
7) Net weight
8) Efficiency at full load and rated pump condition
9) Full load current
10)Locked rotor current
b) Operation and Maintenance Manuals shall include, at a minimum, the following
information:
Section 800—Wastewater Pumping Systems & Force Mains-Page 18 of 70
Effective Date: April 12, 2022
1) Equipment function, normal operating characteristics, and limiting
conditions.
2) Assembly, installation, alignment, adjustment, and checking instructions.
3) Operating instructions for startup, routine and normal operation,
regulation and control, shutdown, and emergency conditions.
4) Lubrication and maintenance instructions.
5) Guide to troubleshooting.
6) Parts lists and predicted life of parts subject to wear.
7) Outline, cross-section, and assembly drawings; engineering data; and
wiring diagrams.
8) Test data and performance curves.
3. Quality Assurance
a) Performance and Balance Requirements
1) All specified conditions shall be at rated speed unless otherwise
indicated.
2) Overall (wire-to-water) efficiency for constant speed pumps shall include
losses in the pump and motor. Overall (wire-to-water) efficiency for
variable speed pumps shall include losses in the pump, motor, adjustable
frequency drive, and any transformers supplied as part of the adjustable
frequency drive equipment.
3) The minimum hydrostatic test pressure shall be 1.5 times shutoff head
plus max suction pressure.
4) Pump performance shall be stable and free from cavitation and noise
throughout the specified operating head range at minimum suction
submergences. The design running clearance between the impeller inlet
and the casing wearing ring (if provided) shall be not less than 0.01 inch
or 1 mil per inch of casing wearing ring diameter, whichever is greater.
5) When required, pumping units shall be designed so that maximum
reverse rotation due to reverse flow at the head as required will not cause
damage to any component. Pump supplier shall coordinate this provision
with the motor supplier.
Section 800—Wastewater Pumping Systems & Force Mains- Page 19 of 70
Effective Date: April 12, 2022
6) All rotating parts shall be accurately machined and shall be in as nearly
perfect rotational balance as practicable. Excessive vibration shall be
sufficient cause for rejection of the equipment. The mass of the unit and
its distribution shall be such that resonance at normal operation speeds
is avoided. In any case, the unfiltered vibration velocity, as measured at
any point on the machine including top of motor, shall not exceed the
maximum velocity as indicated for vertical, end suction, solids handling
pumps. At any operating speed, the ratio of rotative speed to the critical
speed of a unit or its components shall be less than 0.8 or more than 1.3.
4. Materials
a) Stator housing, oil chamber housing, impeller casing, and impeller shall be cast
iron, ASTM A48.
b) Casing wearing ring shall be bronze, ASTM B62, or rubber, or martensitic
stainless steel, Brinell 300+.
c) Bottom wearing plate shall be cast iron, ASTM A48 with spiral grooves.
d) Impeller wearing plate shall be martensitic stainless steel, Brinell 200-250.
e) Shaft shall be alloy steel, hard chrome plated, or martensitic stainless steel,
AISI type 416.
f) Mechanical seals shall be 2 tandem single type, oil lubricated with silicon or
tungsten carbide seal rings at all points, except the upper rotating seal, which
shall be carbon.
g) Discharge base shall be cast iron or fabricated steel.
h) Guiderails shall be stainless steel pipe, ASTM A312, Schedule 40S.
i) Upper guiderail bracket, cable hooks, and chain hooks shall be AISI type 304
stainless steel.
j) Pedestal base shall be cast iron or fabricated steel.
5. Pumps
a) Pumps shall be submersible, non-clog centrifugal sewage pumps capable of
passing a 3 inch sphere. Pumps shall be capable of handling raw, unscreened
sewage. Major pump components shall be of gray cast iron devoid of burrs,
pits or other irregularities.
Section 800—Wastewater Pumping Systems & Force Mains - Page 20 of 70
Effective Date: April 12, 2022
b) The impeller casing shall have well-rounded water passages and smooth
interior surfaces free from cracks, porosity, blowholes, or other irregularities.
The discharge nozzle shall be flanged, with dimensions and drilling conforming
to ANSI B16.1, Class 125. The discharge nozzle shall be flanged and
sufficiently rigid to support the pumping unit under all operating conditions.
c) The impeller shall be a semi-open and enclosed recessed one-piece casting
with not more than two nonclog passages with the impeller completely out of
h
the flow path. The interior water passages shall have uniform sections and
smooth surfaces and shall be free from cracks and porosity. The impeller shall
be dynamically balanced and securely locked to the shaft by means of a key
and self-locking bolt or nut.
d) For pumping units 20 hp and larger, renewable wearing rings shall be provided
in the casingand on the impeller. The rings shall be positivelylocked in place.
p 9
For pumping units less than 20 hp a renewable wearing ring or axially
adjustable wearing plate shall be provided in the casing. Casing wearing ring
shall be securely fastened to the impeller casing front cover to provide either
an axial or radial running clearance. Axially adjustable wearing plate shall be
arranged to permit adjustment of the axial running clearance between the
impeller and plate. The wearing plate shall have an outward spiraling groove
designed to force stringy solids outward and away from the impeller.
e) The oil chamber shall contain a drain plug and a vent plug. Food grade oil shall
be used.
f) Each pump shall be provided with two mechanical rotating shaft seals arranged
in tandem and running in an oil chamber. Each interface shall be held in contact
by an independent spring system designed to withstand maximum suction
submergence. The seals shall require neither maintenance nor adjustment and
shall be readily accessible for inspection and replacement. Shaft seals lacking
positively driven rotating members or conventional double mechanical seals
which utilize a common single or double spring acting between the upper and
lower units and requiring a pressure differential to offset external pressure and
effect sealing, will not be acceptable. The seals shall not rely upon the pumped
media for lubrication and shall not be damaged if the pumps are run
unsubmerged for extended period while pumping under load.
g) All mating surfaces of major components shall be machined and fitted with 0-
rings where watertight sealing is needed. Sealing shall be accomplished by 0-
ring contact on four surfaces and 0-ring compression in two planes, without
reliance on a specific fastener torque or tension to obtain a watertight joint. The
use of elliptical 0-rings, gaskets, or seals requiring a specific fastener torque
value to obtain and maintain compression and watertightness will not be
acceptable. The use of secondary sealing compounds, gasket cement, grease,
or other devices to obtain watertight joints will not be acceptable.
Section 800—Wastewater Pumping Systems & Force Mains- Page 21 of 70
Effective Date: April 12, 2022
6. Pump Motors
a) The pump motors shall be sealed submersible type, and shall be appropriately
sized three phase power, 60 Hertz motors with a maximum speed of 1800
RPM. The motors shall meet the U.S. requirements of Class I, Division I, and
Group D for hazardous locations, and shall be sized to non-overloading
throughout the entire operating range of the pump.
b) A heat sensor thermostat shall be attached to and embedded in the winding
and be connected in series with the motor starter contactor coil to stop motor if
temperature of winding is more than 220 degrees F. Thermostat shall reset
automatically when motor cools to safe operating temperature. The common
pump motor shaft shall be of 416 stainless steel. (See 4E)
c) The motor shall be protected by mechanical seal system as described above.
A double electrode shall be mounted in the seal chamber to detect any water
entering the chamber through the lower seal. Water in the chamber shall cause
a red light to turn on at the control panel. This signal shall not stop the motor
but shall act as a warning only.
d) Power cables to pumps shall be AWG (min) hypalon jacketed type SPC cable
a minimum of fifty (50) feet in length.
e) Motors shall be provided by the pump manufacturer and shall be air-filled,
totally submersible. Motor nameplate rating shall exceed the maximum power
required by the pump in the operating head range. Each motor shall have a
voltage, frequency, and phase rating as required and shall have a service factor
of 1.15. The stator housing shall be an air-filled, watertight casing. A cooling
jacket shall encase the motor housing for each pump where needed to maintain
adequate cooling. Cooling jacket shall require no external source of cooling
water. Motor insulation shall be moisture resistant, Class F, 180 degrees
Celcius. Each motor shall be NEMA Design B for continuous duty at 40
degrees Celcius ambient temperature, and designed for at least 10 starts per
hour.
f) Each motor housing shall be provided with a moisture detection system
provided by the motor manufacturer and per the manufacturer's requirements,
complete with all sensors, control power transformer, intrinsically safe control
modules, and relays. The moisture detection system shall be rated for a 120V
AC supply. The moisture detection system shall provide two normally open dry
output contacts rated 5 amps at 120 volts AC. The contacts shall close when
moisture is detected in the motor housing and an alarm relay energized. The
pump shall not be shut down. All moisture detection system components shall
be furnished by the pump supplier and shall be shipped loose for installation
Section 800—Wastewater Pumping Systems & Force Mains- Page 22 of 70
Effective Date: April 12, 2022
into the motor controller enclosure, or if required to be mounted separately all
components shall be mounted in a NEMA 4 stainless steel enclosure.
g) The motor bearings shall be antifriction, permanently lubricated type. The
lower bearing shall be fixed to carry the pump thrust and the upper bearing free
to move axially. The bearings shall have a calculated AFBMA L10 Live Rating
of 40,000 hours when operating at maximum operating head. Maximum shaft
runout at the mechanical seals shall not exceed 2 mils at any point in the
operating head range.
h) Thrust bearings shall be protected by bearing temperature switches. The
switches shall be normally closed automatic reset type rated 5 amps at 120V
AC.
i) Each motor shall be capable of continuous operation in air (unsubmerged) for
at least 24 hours under pump full load conditions, without exceeding the
temperature rise limits for the motor insulation system.
j) Each pump shall be equipped with one or more multiconductor cable
assemblies for power and control. Each multiconductor assembly containing
power cables shall be provided with a separate grounding conductor. Each
cable assembly shall bear a permanently embossed code or legend indicating
the cable is suitable for submerged use. Cable sizing shall conform to NEC
requirements.
k) All cables shall be of sufficient length to terminate in a junction box outside the
wetwell as indicated on the drawings, with 10 feet of slack that shall be coiled
on a cable hook at the top of the wetwell. Each cable shall be supported by
AISI Series 300 corrosion-resistant PVC Style woven Kellem Grips type woven
grips to prevent damage to the cable insulation. Mounting of cable supports in
the wetwell shall be coordinated to prevent damage to the cable.
I) The cable entry water seal shall include a strain relief and a grommet type seal
designed so that a specific fastener torque is not required to ensure a watertight
submersible seal. The cable entry junction box and motor shall be separated
by a stator lead sealing gland or a terminal board. The junction box shall isolate
the motor interior from moisture gaining access through the top of the stator
housing.
m) Motors with an adjustable frequency type speed controller shall be derated to
compensate for harmonic heating effects and reduced self-cooling capability at
low speed operation so that the motor does not exceed Class B temperature
rise when operating in the installed condition at load with power received from
the adjustable frequency drive. All motors driven by adjustable frequency
drives shall be supplied with full phase insulation on the end turns and shall
meet the requirements of NEMA MG 1, Part 31. In addition to the requirements
Section 800—Wastewater Pumping Systems & Force Mains - Page 23 of 70
Effective Date: April 12, 2022
of NEMA MG 1, Part 31, motors shall be designed to be continually pulsed at
the motor terminals with a voltage of 1600 volts ac.
n) Adjustable Speed Drives: Adjustable frequency drives shall be provided as
specified by the Director of Water Resources or if the projected flow is .5MGD
or higher.
o) Station pumps between 15-30 hp shall have a 30 hp rated RVSS. Stations with
pumps greater than 30 hp shall utilize variable frequency drives with
appropriately sized RVSS.
7. Appurtenances
a) The lift out systems shall consist of a straight elbow that bolts to the bottom of
the basin, a combination disconnect assembly with a seal flange that mounts
to the pump, rail support guides that fasten to the wall of the basin and guide
and support brackets that mount to the pump. The guide rails shall be type 316
stainless steel, 2 inch minimum diameter, schedule 40
b) Guiderail Mounted Base. A discharge base and discharge elbow shall be
furnished by the pump manufacturer. The base shall be sufficiently rigid to
firmly support the guiderails, discharge piping, and pumping unit under all
operating conditions. The base shall be provided with one or more integral
support legs or pads suitable for bolting to the floor of the wetwell. The face of
the discharge elbow inlet flange shall be perpendicular to the floor and shall
make contact with the face of the pump discharge nozzle flange. The diameter
and drilling of the elbow outlet flange shall conform to ANSI B16.1, Class 125.
The pump and motor assembly shall be automatically connected to and
supported by the discharge base and guiderails so that the unit can be removed
from the wetwell and replaced without the need for operating personnel to enter
the wetwell.
c) Sliding Bracket. Each guiderail mounted pumping unit shall be provided with
an integral, self-aligning guiderail sliding bracket. The bracket shall be
designed to obtain a wedging action between flange faces as final alignment of
the pump occurs in the connected position. The bracket shall maintain proper
contact and a suitably sealed connection between flange faces under all
operating conditions. The sliding bracket shall be non-sparking.
d) Guiderails. Each guide rail mounted pumping unit shall be equipped with one
or more guiderails. Guiderails shall be sized to fit the discharge base and the
sliding bracket and shall extend upwards from the discharge base to just below
the bottom of the access hatch. An upper guiderail bracket shall be provided
at the pump access opening. Guiderails shall be made of stainless steel.
Section 800—Wastewater Pumping Systems & Force Mains - Page 24 of 70
Effective Date: April 12, 2022
e) Lifting Chain. Each guide rail mounted pumping unit shall be provided with a
chain suitable for removing and installing. The chain shall be stainless steel
with 4x6 lifting eyes at 10ft intervals starting at the top. A suitable chain hook
shall be provided at the top of the wetwell. A stainless steel cable is not an
acceptable alternative to a lifting chain.
f) Special Tools and Accessories. Equipment requiring periodic repair and
adjustment shall be furnished complete with all special tools, instruments, and
accessories required for proper maintenance. Equipment requiring special
devices for lifting or handling shall be furnished complete with those devices.
g) A replica of the nameplate with serial number, model number, manufacturer,
operating conditions, etc. shall be provided for each pump.
8. Shop Painting
a) All iron and steel parts which will be in contact with pumped liquid or submerged
after installation, including the inside of the casing, the impeller, and the
discharge elbow, shall be shop cleaned in accordance with the coating
manufacturer's recommendations and painted with the epoxy coating system
specified. The coating shall have a dry film thickness of at least 10 mils and
shall consist of a prime coat and one or more finish coats. At least 1 quart of
the finish coat material shall be furnished with each pump for field touchup.
b) All other iron and steel surfaces, except stainless steel and machined surfaces,
shall be protected with suitable protective coatings applied in the shop.
Surfaces of the equipment that will be inaccessible after assembly shall be
protected for the life of the equipment. Exposed surfaces shall be finished,
thoroughly cleaned, and filled as necessary to provide a smooth, uniform base
for painting. Electric motors, speed reducers, starters, and other self-contained
or enclosed components shall be shop primed or finished with an oil resistant
enamel or universal type primer suitable for top coating in the filed with a
universal primer and aliphatic polyurethane system.
c) Surfaces to be coated after installation shall be prepared for painting as
recommended by the paint manufacturer for the intended service, and then
shop painted with one or more coats of the specified primer.
B. Pump Control Systems
1 . All components of the Pump Control Systems shall be properly designed and
installed to meet all NEC and other industry standards, as well as all federal, state,
and local requirements. Power service to wastewater pumping stations shall be 3-
phase.
Section 800—Wastewater Pumping Systems & Force Mains - Page 25 of 70
Effective Date: April 12, 2022
2. Submittals: Complete fabrication and assembly drawings, together with detailed
specifications and data covering materials, parts, devices, and accessories
forming a part of the equipment furnished, shall be submitted in accordance with
the submittals section. The data and specifications for the Control Panel and
Components shall include, but not be limited to, the following:
1) Name of acceptable manufacturer, Square D, Cutler Hammer, or
ABS
2) Type and model
3) Enclosure rating
4) Dimensions of complete panel
5) Electrical schematics and wiring diagram
6) Liquid level sensors with mounting details and cable lengths, and
pump controls
7) Published descriptive data on each item of equipment and all
accessories, indicating all specific characteristics and options.
3. Enclosure: The Control Equipment Enclosure shall be a NEMA type 4X fiberglass
and be of suitable size to house all components. A locking hasp shall be provided
with no screw clamp type latches. Enclosure shall be fabricated from fiberglass.
The top of the enclosure shall serve as a drip shield and the seam free sides shall
prevent rain and sleet from entering. Inner panel shall be made of fiberglass.
4. Hinged Inner Door: An inner door shall be furnished. Overload reset push buttons,
circuit breakers, switches pilot lights, and hr. meters shall be the only components
accessible with door closed. Door shall be hinged and may be opened when service
is required.
5. Line Terminal Block: A terminal block shall be furnished with properly sized line
lugs to accept the main power source entering the control panel. Load lugs shall
be adequate to accept all required load side wiring requirements. All live parts shall
be fully shielded.
6. Motor Circuit Breaker (440-480 VAC): A properly sized, molded case, thermal
hydraulic-magnetic circuit breaker or motor protector shall be provided for each
pump motor. Line and load sides shall be equipped with lugs properly sized for the
horsepower and current rating of the motor(s). The interrupting rating shall be 5,000
RMS symmetrical amps.
7. Transformer Primary Circuit Breaker: A properly sized, two pole, molded case
circuit breaker shall be furnished ahead of the control power 120-VAC power
transformer for short circuit protection and disconnecting power to the transformer.
The circuit breaker shall conform to the Specifications for the motor circuit
breaker(s).
Section 800—Wastewater Pumping Systems & Force Mains - Page 26 of 70
Effective Date: April 12, 2022
I 1
Power Transformer: An industrial qualitycontrol transformer shall be
8. Controlo
furnished to provide control voltage. The transformer shall be furnished to provide
more than adequate KVA rating to provide 120-VAC power for all items required in
the control and alarm circuits. Transformer shall be protected in its secondary by
properly sized supplemental circuit breaker(s).
9. Magnetic Contactors and Overload Relays: A magnetic contactor shall be furnished
for each motor. A separate, panel mounted, 3 leg (three phase) overload relay or
motor protector shall be supplied for each motor. Each leg of the overload relay
shall be equipped with a properly sized overload heater. Electronic overloads are
not acceptable. Contactor and overload relay shall be properly sized for the
required horsepower, voltage and phase.
10.Elapsed Time Meters: Six digit, non-resetable elapsed time meters shall be
p
mounted in the control panel enclosure inner door to record the running time of each
pump.
11.Condensation Strip Heater with Thermostat: A strip heater shall be furnished to
prevent condensation within the control panel enclosure. The heater shall be
controlled by a panel mounted, adjustable thermostat.
12.Phase & Voltage Monitor: A phase failure, reversal and under voltage monitor shall
be supplied to prevent the motors from running under low voltage, phase loss, or
phase reversal conditions. The monitor shall lock out the control circuit until the
problem is corrected and automatically reset. The phase and voltage monitor shall
be adjustable.
13.Lightning and Surge Suppressors: Suitable lightning and transient level surge
suppressors shall be provided to protect motors and control equipment from
lightning induced or other line surges. Surge suppressors shall meet current UL
standards.
14.Thru - Door Overload Reset Push Buttons: Overload reset push buttons shall be
provided for each overload relay. Push buttons shall be mounted so that with inner
door closed, overload relays may be reset without entering high voltage
compartment.
15.Switches: Heavy-duty industrial grade oil-tight 22mm switches shall be provided for
each pump for "Hand/Off/Automatic" operation selection. All switch components
shall be made of corrosion resistant metals and polyesters. Contact blocks shall be
made of see-through polycarbonate for simplified inspection of contacts. Cams and
strokers shall be Teflon impregnated for abrasion free service without lubrication.
The switches required shall be as follows:
Section 800—Wastewater Pumping Systems & Force Mains - Page 27 of 70
Effective Date: April 12, 2022
Switch Function Voltage
(Name Plate)
HOA 120 VAC
16.Pilot Lights: Full voltage, push to test, heavy-duty industrial grade oil-tight pilot
lights shall be provided. All pilot light components shall be made of corrosion
resistant metals and polyesters. An insulated socket shall be furnished to eliminate
the possibility of shock during bulb change. Bulb change shall not require removal
of the socket. Bulbs shall be "super bright" LED type. Lens shall be 22mm and
made of lexan. The pilot lights required shall be as follows:
Pilot Light Function Voltage Lens Color
(Name Plate)
PUMP 1 120 VAC GREEN
PUMP 2 120 VAC GREEN
17.Seal Fail Alarm Circuit with Test Push Button (Required for Submersible Pumps
and Motors): The control panel shall be equipped with a conductance actuated
control relay that shall respond to current from a moisture sensor in the pump seal
chamber. Relay contacts shall be rated at 10 amps minimum. All molded
structural parts shall be of high mechanical and dielectric strength, structural
dimensionally stable, arc resistant, thermosetting plastic. Base plate shall be high
strength, diecast aluminum alloy. Solid state type relays shall not be considered
acceptable for seal fail monitoring applications. An amber alarm pilot light shall
illuminate upon alarm condition. Each pilot light shall include contacts that shall
allow testing of the seal failure circuit and pilot light bulb by pushing. Bulb change
shall not require removal of the socket. Bulbs shall be "super bright" LED type.
18.Seal Failure Circuit Test Push Button (Illuminated): Heavy-duty industrial grade
oil-tight push buttons shall be provided for each submersible pump motor. All push
button components shall be made of corrosion resistant metals and polyesters. An
insulated socket shall be furnished to eliminate the possibility of shock during bulb
change. Bulb change shall not require removal of the socket. Bulbs shall be "super
bright" LED type. Lens shall be 22mm and made of lexan. The push buttons
required shall be as follows:
Push Button Function Voltage Lens Color
(Name Plate)
P1 SEAL FAIL 120 VAC AMBER
P2 SEAL FAIL 120 VAC AMBER
19.Pump Alternator Circuit (For Duplex Pump Operation): The electro-mechanical
alternator relay shall be of industrial design specifically for use in pump
applications. It shall have single-pole double-throw heavy-duty 10-amp silver
cadmium oxide contacts enclosed in a transparent cover. The snap action
Section 800—Wastewater Pumping Systems & Force Mains-Page 28 of 70
Effective Date: April 12, 2022
contacts shall transfer when the unit is de-energized. The circuit shall never be
closed or opened while current is being conducted. The alternator circuit shall
alternate the lead pump position between the pumps and shall allow the lag pump
to start in response to a rising water level in the wet well. A four position switch
shall beprovided on the exterior of the pumpcontrol panel inner door. The switch
shall have a position for: Pump 1, Pump 2, or Both.
20.Control Relay(s): Plug-in control relays with 120-VAC coils shall be provided as
required. Contact rating shall be 5-amps (minimum). Sockets shall be of the same
manufacture as the relays and hold-down clips shall be furnished to prevent relay
from sliding out of the socket. Relays shall have indicator lights showing when
they are engaged.
21.High Wet Well Level Alarm: The control panel shall be provided with a suitable
alarm circuit, activated by a separate level control. This alarm shall signal a high
water condition in the wetwell. Terminals shall be furnished in the control panel
for connection of externally mounted alarm devices. A red flashing light shall be
provided as a visual alarm of the high water in the wet well condition. A continuous
sounding alarm shall also be provided as an audible alarm of the high water in the
wet well condition.
22.Liquid Level Controls: Level control will be achieved by means of a corrosion
resistant level sensing Pressure Transducer. Float-actuated mercury level
control switches shall serve as a backup for low level alarm and high level alarm
functions. The mercury switch shall be encapsulated in polyurethane foam for
corrosion and shock resistance. Level switches shall be weighted to hold desired
position in the wetwell. The cord connection to the control shall be numbered 16-
2, rated for 13-amps, and shall be type SJTO. To ensure optimum longevity
contacts shall be rated for 20-amps at 115-VAC and shall be sealed in a heavy-
duty glass enclosure. No junction boxes or cable splices of any kind will be allowed
in the wet well. Level elevations shall be set in accordance with design drawings.
23.High Temperature Shutdown Circuit(s): The pump motor high temperature circuit
shall provide terminals for connection of the leads from the temperature sensor
provided in the pump motor windings. Upon a high temperature condition in the
pump windings, the control power to the pump motor contactor shall be
disconnected, thus stopping the pump motor. The pump shall automatically restart
when the pump motor temperature returns to an acceptable level.
24.Ground Luq(s): Equipment ground lug(s) shall be provided for grounding the
enclosure. The ground lug(s) shall be suitable for the service provided the
enclosure sized per table 250-95 of the N.E.C. In all cases, the enclosure must be
adequately grounded per article 250 of the N.E.C. except for fiberglass enclosures,
where a grounding bus shall be provided.
Section 800—Wastewater Pumping Systems & Force Mains - Page 29 of 70
Effective Date: April 12, 2022
1
25.Terminals: Terminals shall be provided for connecting mercury float switch leads,
temperature sensor and seal fail sensor leads. Terminal blocks shall be rated for
600 volt use and accept a wire range of#22-8. All live parts shall have insulating
walls on all sides of the lug. Blocks must be U.S. recognized.
26.Construction Standards: Subpanel shall be drilled and tapped to accept machine
thread bolts (self-tapping screws are not acceptable). All control wiring shall be
16-AWG machine tool wire, Carol type 76512 or equal. All control wire shall be
color coded or numbered in accordance with applicable standards. Power (motor)
shall be in accordance with the current National Electrical Code. Major groups of
wires shall be contained in plastic wiring trough equal to Panduit type E.
27.Nameplates: All indicator lights, alarms, selector switches, pushbuttons and major
control system components shall be identified with engraved phenolic plastic
nameplates, white lettering on a black background.
28.Control Panel: The control panel shall include the following elements:
a) Separate Manual Disconnect for each pump with 2-pole adjustable
overload protection for each phase;
b) Magnetic starter for each pump motor with all leg quick trip ambient
compensated overload protection for each motor. Overloads are to have
an auxiliary contact for automatic dialer;
c) Hand-Off-Auto selector switch for each pump;
d) Automatic Electric Alternator with ability to designate either Pump 1 or
Pump 2 as lead;
e) Circuit Breaker for Control Circuit;
f) Motor Thermal protection - Motor control circuit is to shut down if high
temperature occurs. Manual resets to be provided;
g) MPE LPC420-R-RM Level Control Mode;
h) MPE Level Probe-Mode-LP-10;
i) Backup float system with 3 floats shall be included as backup to the MPE
Level Control;
j) Test dial shall be provided to allow simulation of wet well level on MPE
Control;
k) >_ 40 hpw shall be 'soft start';
I) Horn signaling;
m) Control Disconnect;
n) Seal failure light for each pump and contact closure for automatic dialer
(submersible installations only);
o) High temperature light for each pump and contact closure for automatic
dialer (submersible installations only);
p) Running light for each pump;
q) Non-resettable, elapsed time meter for each pump, reading in tenths of
hours. Capacity 100,000 hours;
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Effective Date: April 12, 2022
r) High-level alarm light with Red Globe and contact closure for automatic
dialer (remote mounting for "package" pumps station where panel is inside
pump compartment);
s) All necessary internal wiring, relays, etc. to provide the operation as
described;
t) All functions and internal wiring shall be labeled accordingly;
u) Junction box shall be stainless steel and installed 4 feet above final grade
to ensure water does not damage the internal wiring;
v) Automatic Dialer/ Scada;
w) AC Voltmeter.
C. Alarm Dialer/SCADA/Telemetry
1. The pump station shall be provided with an alarm dialer in a lockable NEMA 4
enclosure. Hard line dialer units shall have a minimum of eight inputs and capable
of additional expansion with battery backup and be the ANTX Dialer Scout or
approved equal. The operating environment shall withstand from —5° Fahrenheit
to 130° Fahrenheit with a 90% relative humidity, non-condensing. The alarm dialer
shall operate on 120-VAC, and shall have a rechargeable battery backup capable
of providing 4 hours of standby power with surge protectors on the power and
telephone lines. The alarm dialer shall monitor high water conditions and grinder
jams through normally open/normally closed contacts, shall have the capability of
dialing four phone numbers, and shall work on a standard telephone service. The
dialer shall be provided by a manufacturer listed on the design drawings. Seal
failure and high temperature signals from all pumps shall be combined into a
common "pump trouble" alarm to be transmitted from the dialer.
2. The pump station telemetry units shall be compatible with the Town's current
SCADA system. The Town shall not be required to purchase additional software
to operate the telemetry unit.
D. Gr
inders
1. General
a) A wastewater grinder shall be provided at each pump station for the intended
purpose of grinding solids in the influent flow to the pump station.
b) The entire grinder unit and accessories necessary to provide a fully functional
wastewater grinder system, shall be supplied and warranted by a single
manufacturer. The list of acceptable manufacturers shall be identified on the
design drawings.
c) The wastewater grinder shall be placed in a separate manhole or other influent
structure prior to the wetwell, but still within the pump station site. The grinder
shall be able to be removed from the influent structure without entering the
Section 800—Wastewater Pumping Systems & Force Mains - Page 31 of 70
Effective Date: April 12, 2022
influent structure by means of a stainless steel guide rail and stainless steel
lifting chain with 4x6 lifting eyes at 10ft intervals starting at the top assembly.
Another means of solids removal such as a trash basket or bar rack must be
provided for installation when the grinder unit is out of service for extended
periods.
d) The wastewater grinder shall be electrically driven. The electric motor shall be
a minimum 5 hp, 60 Hz, appropriately sized immersible motor. The motor shall
be NEMA Design "B" and TEFC.
e) The wastewater grinder unit will have a complete and separate control panel
providing all settings, monitoring, and control options required, as well as the
ability to send alarm signals back to the alarm dialer and telemetry system.
f) The equipment shall be installed as recommended by the manufacturer, and in
compliance with all OSHA, local, state and federal codes and regulations.
g) The grinder unit power supply shall match the pump station power supply.
Standard pump station power supply is 3 phase AC power.
h) Identification. Each unit of equipment shall be provided with a corrosion
resistant substantial metal nameplate, securely affixed in a conspicuous place.
Nameplate information shall include equipment model number, serial number,
manufacturer's name and location, and important performance data.
2. Submittals
Submittals shall include electrical wiring diagrams complete for field wiring,
terminal identifications, and control panel schematics. Electrical and control
information shall be provided to allow coordination of field wiring to place the
system in the desired operation. Submittals shall also include complete mounting
and installation instructions, including size, length and spacing of all supports and
anchor bolts. Submittals shall include painting instructions.
3. Quality Assurance
a) All equipment shall meet the requirements of the following standards:
1) ASTM A536-84 - Standard Specifications for Ductile Iron Castings
2) ASTM A36 - Standard Specifications for Carbon Steel Plate
3) AISI 304 - Stainless Steel
4) AISI 4140 - Heat Treated Hexagon Steel
5) AISI 4130 - Heat Treated Alloy Steel
6) AISI 1018 - Carbon Steel
7) 45-50 Rockwell C
8) National Electrical Manufacturers Association (NEMA)
Section 800—Wastewater Pumping Systems & Force Mains - Page 32 of 70
Effective Date: April 12, 2022
9 National Electrical Code (NEC)
10)Underwriters Laboratory (UL and cUL)
b) Qualified manufacturers shall have a minimum of 5 years experience in the
manufacturing of grinding and controlling equipment and a minimum of 20
installations at equivalent applications. Manufacturer shall submit a listing of
names and dates of installations for verification by the Town of Apex Water
Resources Department.
c) System Controls.
1) Each grinder system shall be provided with a single control panel suitable
for mounting on an electrical rack, building wall, or as a secondary panel
located under the weathershield. The control panel shall include all power
and control circuits to provide the functional requirements specified herein.
2) A programmable controller shall be included in the panel. The
programmable logic controller shall talk directly with the SCADA PLC
without a third party communication device. Upon the grinder encountering
a jam or overload condition, the controller shall stop the grinder and screen
and reverse their direction of rotation to clear the obstruction. If the jam is
cleared, the controller shall return to normal operation. If the jam condition
persists, the controller shall repeat the reversing cycle up to eight additional
times within 45-seconds (total of nine cycles) before signaling a grinder
overload condition. Upon a grinder overload condition, the controller shall
shut down the grinder and screen and activate an overload contact.
3) If a power failure occurs while the grinder is running, the grinder shall
resume running when power is restored. A 0-60 second adjustable time
delay device shall be included in the control panel to select time delay until
restart after power restoration. If the grinder is stopped due to an overload
condition and a power failure occurs, the overload indicator shall reactivate
when power is restored.
4) The control panel shall provide overcurrent protection. The overload relay
shall be adjustable so that the range selected includes the FLA rating and
service factor. Grinder control panel shall be positioned either under the
weather shield at the electrical riser or in the control building if included. A
standalone control panel will not be accepted.
5) The control panel shall be equipped with a Hand-Off/Reset-Auto (HOA)
selector switch. In the Off/Reset position, the motor shall not run. In the
Hand position, the motor shall run continuously. In the Auto position, the
grinder shall stop and start by remote control signal. The control panel shall
include dry contacts for future addition by others of a remote maintained
contact start/stop control signal when in Auto mode. The control panel shall
Section 800—Wastewater Pumping Systems & Force Mains - Page 33 of 70
Effective Date: April 12, 2022
I 1
not allow remote resetting of overload condition. Overload reset shall be
accomplished by switching the HOA switch to the Off/Remote position.
6) The controller shall indicate each of the following statuses with an indicator
light on the panel face:
1) Power On
2) Grinder Overload
3) Motor Overload
4) Run
7) Engraved phenolic laminate plastic identification nameplates, with white
letters on black background, shall be provided for each switch, indicator
light, gauge, etc. on the control panel and in the system.
8) The controller shall be properly rated three phase power, 60 Hertz.
9) A single enclosure shall house all power and control devices, relays,
terminal blocks and motor starter. Control and indicating devices shall be
mounted in the front of the enclosure. Indicating lights shall be integral
transformer type with low voltage long life 6-volt lamps. Lamps and selector
switches shall be heavy duty type. The control panel and all control devices
shall be NEMA 4X. Enclosure shall be a NEMA 4X fiberglass reinforced
polymer equipped with full hinged door, suitable for exterior mounting as
shown on the drawings.
10)A lockable disconnect switch shall be provided on the outside of the control
panel to disconnect power to the entire grinder system.
11)One set of normally open (NO) contacts shall be provided in the control
panel for remote indication of each of grinder "fail" and grinder "run" status.
Grinder overload, motor overload, oil overtemperature, low oil level and oil
pressure alarms shall be ganged together to a common grinder "fail" alarm.
The control panel shall provide 120 VAC power to these alarm circuits for
remote indication at an existing alarm dialer system.
12)Contacts shall be provided for a future remote maintained contact
emergency stop pushbutton, to be provided by others. These contacts shall
be jumpered.
13)Motor starter shall be full voltage type with 120-volt operating coil and
captive terminal screws. Overload relay shall be mounted directly to the
contactor. The relay shall be sized to the motor full load amperage (FLA).
14)Control panel shall incorporate a manual momentary or spring return
reversing switch for grinder control.
Section 800—Wastewater Pumping Systems & Force Mains- Page 34 of 70
Effective Date: April 12, 2022
d) Spare Parts
1)The following spare parts shall be provided for each grinder as a minimum:
1) Three (3) of each type of fuse found in the system
2) Three (3) of each type of lamp bulb found in the system
2)The motor controller shall have sufficient space within its enclosure for the
storage of motor controller spare parts. Grinder spare parts shall be
packaged in suitable containers for long term storage and shall bear labels
clearly designating the contents of each package and the equipment for
which they are intended.
E. Generators
1. General
a) Backup power shall be provided by an automatically starting on-site generator
controlled by an automatic transfer switch. The generator shall be capable of
supplying all necessary electrical power for complete operation of the pump
station in the event of a failure of the electrical feed supplied by the local grid.
b) The entire generator set, switchgear, and accessories necessary to provide a
fully functional backup power system, shall be supplied and warranted by a
single manufacturer. The standby power generator set shall be Cummins,
Kohler, Caterpillar, Generac, or Blue Star.
c) Each engine-generator unit, controls, and transfer switch shall be new and a
standard product of a single manufacturer and shall be a packaged type unit,
fully shop assembled, wired and tested, requiring no field assembly of critical
moving parts.
d) The generator shall be sized to sequentially start and continuously run all
pumps, motors, and other electrical equipment at the pump station site.
Simultaneous starting of pumps is not required. The pump starting conditions
(including delay timers, VFDs, soft starts, reduced voltage starters, etc.) should
be verified for the particular site. The kW rating needed for a particular pump
station shall be calculated by a licensed professional engineer by the generator
manufacturer.
e) The voltage, amps, phase, etc., shall be coordinated with the design of the
electrical equipment for the particular site. Generators will be 3 phase, 60
hertz, and capable of multiple voltages through re-strapping.
f) The engine generator set will have a complete and separate control panel
mounted inside the generator enclosure providing all settings, monitoring, and
Section 800—Wastewater Pumping Systems& Force Mains - Page 35 of 70
Effective Date: April 12, 2022
control options required, as well as the ability to send alarm signals back to the
alarm dialer and telemetry system.
g) Each unit of equipment shall be provided with a corrosion resistant substantial
metal nameplate, securely affixed in a conspicuous place. Nameplate
information shall include equipment model number, serial number,
manufacturer's name and location, and important performance data.
h) If the generator is elevated 30 inches or greater from the existing grade, a walk
way with handrails shall be installed for access to all generator components.
i) The engine-generator set supplier shall be an authorized dealer of the engine-
generator set manufacturer and shall be fully qualified and authorized to
provide service and parts for the engine and generator 24 hours per day, 7
days per week from a location within a 100-mile radius of the installation site.
2. Submittals
a) The Contractor shall submit to the Town of Apex Water Resources Department,
complete shop drawings for assembly and installation, together with detailed
specification and data covering materials, drive unit, parts, devices and
accessories forming a part of the equipment furnished, with the submittals
section. The data and specifications for each unit shall include, but shall not
be limited to, the following:
1) Manufacturer, model, and type: engine, alternator, enclosure,
battery charger and battery, silencer, switchgear, transformer, etc.
2) Listing of standard and optional accessories.
3) Engine output horsepower and efficiency curves at specified
conditions.
4) Engine mechanical data including heat rejection, exhaust gas
emission data (maximum values at loads of 1/4, 1/2, 3/4, and full
for: carbon monoxide (CO) (lb/hr), nitrogen oxides (NOx)(Ib/hr),
temperature (F), flow (ACFM)), combustion air and ventilation air
flows, and fuel consumption at specified conditions.
5) Generator electrical data including temperature and insulation
data, winding pitch, cooling requirements, excitation ratings,
voltage regulation, voltage regulator, efficiencies, waveform
distortion and telephone influence factor.
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Effective Date: April 12, 2022
6) Ratings at specified conditions: engine (net horsepower), engine
(maximum performance horsepower bare engine), generator kW
at specified power factor, volts, amperes.
7) Overall dimensions (length, width, height) and net weight.
8) Concrete pad recommendation (including size, length, and spacing
of all necessary supports and anchor bolts) and layout/stub-up
locations for electrical conduits.
9) Wiring diagrams and schematics for the entire system, including
the engine control panel, generator breaker, automatic transfer
switch, auxiliary transformer, and remote alarm indicators.
10)Calculations or test results showing compliance with specified
motor starting and voltage dip requirements.
11)Line circuit breaker rating.
12)Control panel layout, identifying location of all instrumentation
being supplied.
13)Operation instructions.
14)Letter from the engine-generator manufacturer confirming that the
unit will provide the specified minimum kW rating at the specified
design conditions and time duration.
15)Battery sizing calculations.
16)Battery charger sizing calculations.
17)Maximum output short circuit kvA available.
18)A certificate of compliance, when required.
19)Manufacturer's and dealer's written warranty.
3. Quality Control
a) Except where modified or supplemented by these Specifications, all equipment
and materials shall be designed and constructed in accordance with the latest
applicable requirements of the standard Specifications and codes of ANSI,
ASTM, NEMA, IEEE, DEMA, EEI, HEI, ISO, NFPA, SAE, NEC, UL508, and
other such regularly published and accepted standards as well as state and
local codes.
Section 800—Wastewater Pumping Systems & Force Mains- Page 37 of 70
Effective Date: April 12, 2022
4. Generator Equipment
a) Engine.
1) Engine shall be compression ignition type diesel, propane, or natural gas
powered. Diesel fueled generators may be considered on large installations
and shall be 4 stroke, liquid cooled, American made, with a minimum of 130
HP, or equal. Propane and natural gas fueled generators shall be specified
on all small (less than 50 kW) stations. Any variance to this requirement
shall be approved by the Water Resources Director.
2) Engine shall operate at an RPM of no more than 1800.
3) The engine will be equipped with an electronic governor to maintain 4%
droop from no load to full load and +/-0.25% steady state. The electronic
governor control shall be furnished as a complete governor and control
package.
4) Engine shall have a dry type air cleaner, coolant, fuel filters, and oil filters
with replaceable elements.
5) Engine shall be liquid cooled and shall have a radiator, coolant pump,
thermostat, and fan. Air cooled engines may be approved by the Town for
installation of less than 10 kW.
6) Governor shall be mechanical flyweight type with a speed regulation of 5
percent maximum.
7) Lubrication shall be by a positive displacement lube oil pump with positive
pressure lubrication to all bearings. Full flow lube oil filter shall be provided.
8) Starting system shall be 12 volts, 35 amps with solid state voltage regulator.
A battery float charger shall be provided.
9) An engine block heater shall be provided with control thermostat. The unit
shall be 120 volt.
b) Generator.
1) The synchronous generator shall be a single bearing, self-ventilated, drip-
proof design in accordance with NEMA MG 1 and directly connected to the
engine flywheel.
2) Voltage regulation shall be within +/-0.5% at steady state from no load to
full load. The momentary voltage drop shall not exceed the specified
percent without starter coils dropping out or stalling the engine at any time
Section 800—Wastewater Pumping Systems & Force Mains - Page 38 of 70
Effective Date: April 12, 2022
when applying or starting the specified loads. Recovery to stable operation
shall occur within 2 seconds. Unit shall be capable of adjusting voltage
under varying load conditions within 16 milliseconds.
3) The voltage regulator shall be a totally solid state design, and include
electronic voltage buildup, volts per hertz regulation, overexcitation
protection, shall limit voltage overshoot on startup, and shall be
environmentally sealed.
4) The insulation material shall meet NEMA standards for Class H insulation
and be fungus resistant.
5) The generator shall be a self-excited generator type. The excitation system
shall be of brushless construction.
6) The generator shall be supplied with a 240V single phase anti-condensation
heater protected by a circuit breaker inside the main control panel. When
the generator set is not running the heater is automatically connected to the
AC supply through a power relay mounted in the control panel. Upon
receiving a start signal the AC supply is automatically disconnected by the
power relay and automatically reconnected when the start signal is removed
and the engine has stopped. A temperature set point shall determine the
start and stop signal.
7) A sound retention enclosure shall be installed rated to a maximum decibel
level of 65.
c) Fuel System.
1) Each engine-generator unit shall be furnished with a complete fuel system,
including an integral fuel tank, fuel filter, fuel shut off valve, air filter,
pressure regulator(if applicable), and piping along with all other accessories
as required for proper operation. All items shall be suitable for the specified
fuel and located inside the enclosure above the base plate and serviceable
from inside the enclosure. The fuel system shall conform to NFPA 58.
2) The fuel tank shall have a capacity of at least 250 gallons to provide fuel for
a minimum run time of 72 continuous hours at 100% prime load.
3) The fuel tank shall be double walled with a rupture basin of 110% capacity.
It shall be pressure tested for leaks prior to shipment and have all necessary
venting per US142 standards. A locking fill cap, a mechanical reading fuel
level gage, low fuel level alarm contact, and fuel tank rupture alarm contact
shall be provided. The fuel system shall require a polishing/filtration system
for larger units to be determined by the Town. Any drain lines shall
associated with the generator need to include brass plugs. Plastic plugs
will not be accepted.
Section 800—Wastewater Pumping Systems & Force Mains- Page 39 of 70
Effective Date: April 12, 2022
4) Fuel piping shall be designed for a working pressure of 250 psi. Sizing shall
be in accordance with the manufacturer's recommendations, but not less
than % inch in diameter.
5) A vapor withdrawal system shall be installed, to include a manual shut-off
valve at the tank(s), a vaporizer, dry fuel filter, line service regulator,
solenoid fuel shut-off valve to pen when engine runs, flexible pipe
connection at the engine, and a gas flow regulator.
6) An 80% charge of propane in the propane storage tank shall be provided at
the time of final acceptance.
7) Complete charges of antifreeze and oil shall be provided.
d) Lubrication.
1) Equipment shall be adequately lubricated by systems which require
attention no more frequently than weekly during continuous operation.
Lubrication systems shall not require attention during startup or shutdown
and shall not waste lubricants.
2) Lubricants shall be provided in sufficient quantities to fill all lubricant
reservoirs and to replace all consumption during testing, startup, and
operation prior to acceptance of equipment. Unless otherwise specified or
permitted, the use of synthetic lubricants will not be acceptable.
3) Lubrication facilities shall be convenient and accessible. Oil drains and fill
openings shall be easily accessible from the normal operating area or
platform. Drains shall allow for convenient collection of waste oil in
containers from the normal operating area or platform without removing the
unit from its normal installed position.
e) Alternator.
1) Alternator shall be revolving field, broad range, brushless type designed
for minimum resistance, low voltage, waveform distortion, and maximum
efficiency. Rotor shall be dynamically balanced permanently aligned to
engine by flexible disc coupling. Maximum allowable voltage dip shall be
30%.
2) Exciter shall be 3 phase, full-wave rectified with silicon diodes mounted on
a common motor shaft, sized for maximum motor starting.
3) Voltage regulator shall be solid state with silicon-controlled rectifiers with
phase controlled sensing circuits.
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Effective Date: April 12, 2022
4) Temperature rise at rated load shall be within limits for class F insulation
in accordance with NEMA MG 1-22.40.
5) Insulation system shall be Class F in accordance with NEMA MG1-1.65.
Rotor shall be vacuum impregnated with 100% solid epoxy resin for
complete environmental protection. Stator shall be impregnated twice with
varnish conforming to MIL-I-24092, Type M, Class 155.
6) Output circuit breaker shall be 3-pole, rated at 145% of alternator full load
current.
f) Exhaust System.
1) Each engine-generator unit shall be furnished with a complete exhaust
system including an exhaust silencer, exhaust piping, expansion joints, and
accessories as required for a complete operating system.
2) A rain cap shall be provided to prevent rain from entering the exhaust pipe.
The rain cap shall open from exhaust pressure from the engine and shall
close when exhaust flow tops. The cap shall be stainless steel counter-
balancing with vertical discharge.
g) Starting System.
1) Each engine-generator unit shall be furnished with a complete electric motor
start system including starting motors, maintenance free starting batteries,
battery pack with rack, cables, and battery charger.
2) The engine starter shall be a 12-volt DC or 24-volt DC, solenoid shaft,
electric starting system with positive engagement.
3) The batteries shall be of the high rate, diesel starting, lead acid type. The
batteries shall be sized for five 10 second cranks with battery and engine
oil temperature of 30 degrees F and a battery end voltage of 70 percent of
system voltage.
4) The battery charger shall be current limiting and shall be furnished to
automatically recharge the batteries. The charger shall be dual charge rate
with automatic switching to the boost rate when required. Output voltage
regulation shall not exceed VA. The charger shall include temperature
compensation, NEMA 2 corrosion resistant enclosure, overload protection,
silicon diode full wave rectifiers, voltage surge suppressor, DC ammeter,
DC voltmeter, and fused AC input, on/off switch, remote annunciation of
loss of AC power, low battery voltage, and high battery voltage, AC input
and DC output circuit breakers or fuses, floating voltage equalization,
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Effective Date: April 12, 2022
equalizing timer. AC input voltage shall be 120 volts or 240 volts, single
phase.
5) The battery charger shall have a DC output suitable to supply power for all
continuous loads and to recharge the batteries from a full discharge state
to normal operating voltage within 8 hours.
6) The batteries, battery rack, and battery charger shall be located within the
engine-generator enclosure. The battery rack frame shall be constructed
of corrosion resistant material.
7) The engine-generator shall automatically supply power to the battery
charger when it is operating and utility power is not available.
h) Cooling System.
1) Each engine-generator unit shall be cooled with unit-mounted radiator
cooling system complete with radiator, expansion tank, water pump, belt-
driven fan, fan guard, thermostatic temperature control, high-water
temperature cutout, and all accessories as required for proper operation.
The radiator shall be sized to provide sufficient capacity for cooling of the
engine and all other accessories required for proper operation at an ambient
temperature of 125 degrees F and taking into account the enclosure static
pressure restriction. The fan shall draw air over the engine and discharge
through the radiator.
2) The cooling system shall be filled with a permanent antifreeze mixture of
the ethylene glycol type with rust inhibitor.
3) The engine generator unit shall have a 240V coolant heater protected by a
safeguard breaker inside the main control panel. A controller shall be
included to regulate the output temperature to within safe limits. When the
generator set is not running the heater is automatically connected to the AC
supply trough a power relay mounted in the control panel. Upon receiving
a start signal the AC supply is automatically disconnected by the power
relay and automatically reconnected when the start signal is removed and
the engine has stopped.
i) Enclosure.
1) The engine-generator unit, fuel system, control panel, battery rack, battery
charger, power panel, exhaust silencer, and other ancillary equipment, shall
be housed in a weatherproof enclosure.
2) The enclosure shall consist of a roof, side walls, and end walls, and shall
be weatherproof and sufficiently sealed to prevent the entry of rodents.
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Effective Date: April 12, 2022
3) The enclosure shall be constructed of 12 gage or heavier metal panels that
can be easily removed, or doors.
4) Doors shall be lockable with stainless steel hardware for access to the
engine-generator, controls, and accessories. Doors shall also provide easy
accessibility for maintenance. Doors shall have lock arm to prevent
swinging when open.
5) The enclosure shall be provided pre-wired, requiring only external
connection to the power panel and ATS.
6) Lube oil and coolant drains shall be extended to the exterior of the enclosure
and terminated with drain valves.
7) All moving parts inside of enclosure, including cooling fan and charging
alternator, shall be fully guarded to prevent injury.
8) Lifting points shall be provided on base frame suitable for lifting combined
weight of base tank, engine generator unit, and enclosure.
9) An LED floodlight shall be provided inside and outside the enclosure to
illuminate the generator equipment located within the interior of the
enclosure. The floodlight shall be provided with a switch mounted on the
generator control panel.
j) Control System.
1) Provide a generator set mounted control panel for complete control and
monitoring of the engine and generator set functions. Critical components
shall be environmentally sealed to protect against failure from moisture and
dirt. Components shall be housed in a NEMA 1/IP22 enclosure with hinged
door secured with a twist lock latch. The panel door will have a voltage
shunt switch. The panel itself shall be mounted on a separate support stand
shall be mounted inside the enclosure such that the face of the panel faces
outward and is isolated from vibrations of the engine/generator
arrangement. Panel/breaker arrangements shall be mounted in such a
manner as to not restrict access to the generator, engine, or other parts of
the system that need periodic maintenance or repair.
2) The control panel shall be automatic and safety type and shall include at
least all items required by NFPS 110 Level 1.
3) Panel shall include the following instrumentation and controls (at a
minimum): AC voltmeter, AC ammeter, frequency/tachometer, engine
running hours, coolant temperature gauge, lube oil pressure gauge, battery
condition voltmeter, run/off/auto switch, emergency stop push-button, lamp
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Effective Date: April 12, 2022
test pushbutton, 7 position voltmeter phase selector switch, 4 position
ammeter phase selector switch, 3 attempt start timer, cool down timer,
remote start/stop terminals for 2-wire starting from ATS, charge rate
ammeter, and exciter circuit breaker with manual reset.
4) Panel shall include the following emergency shutdowns with individual
warning lamps (at a minimum): fail to start, high coolant temperature, low
lube oil pressure, overspeed, overcrank protection, and alarm contact for
auto-dialer (generator fail signal)
5) Panel shall include the following alarms with individual warning lamps (at a
minimum): approaching low oil pressure, approaching high engine
temperature, low/high battery voltage, battery charger failure, control switch
not in auto mode.
6) Panel shall have at least 2 spare shutdown channels and 1 spare alarm
channel and 4 additional fault channels for shutdown or alarm programming.
7) Panel shall have the ability to send up to 8 channels back to the existing
SCADA system at the pump station.
8) Engine generator unit shall be provided with a fuel level gauge indicating
relative fuel tank level in % values.
9) The panel shall be provided with a switched light that illuminates the panel
face.
10)The panel shall include a stainless steel canopy with LED hood lights.
k) Circuit Breaker. Provide a generator mounted, molded case or insulated case
construction, UL rated, 3 pole, and circuit breaker, sized as required. Breaker
shall utilize a thermal magnetic trip. Breaker shall be housed in a steel NEMA
1 enclosure mounted on a separate support stand vibration isolated from the
engine/generator arrangement. Bus bars, sized for the cable type shown on
drawing, shall be supplied on the load side of breaker.
I) Receptacles. The engine generator will be supplied with two 120V, 20 amp
duplex receptacles and two 120V, 20 amp twist lock receptacles. Receptacles
will have individual circuit breakers, and will be placed inside the enclosure or
will have weatherproof covers.
m) Shop Painting.
1) All steel and iron surfaces shall be protected by suitable coatings applied in
the shop. Surfaces which will be inaccessible after assembly shall be
protected for the life of the equipment. Coatings shall be suitable for the
Section 800-Wastewater Pumping Systems &Force Mains -Page 44 of 70
Effective Date: April 12, 2022
environment where the equipment is installed. Exposed surfaces shall be
finished, thoroughly cleaned, and filled as necessary to provide a smooth,
uniform base for painting. Electric motors, engine, alternator, enclosure,
piping, and valves shall be shop primed and finish painted prior to shipment
to the site.
2) Stainless steel, nonferrous, and nonmetallic surfaces shall not be painted.
n) Power Transformer. An externally mounted power transformer shall be
supplied to provide required 240V single phase power to the coolant heater
and anti-condensation heater for each engine generator unit. The amp load
shall be calculated by a licensed engineer or the generator manufacturer.
F. Automatic Transfer Switch
1. An automatic transfer switch (ATS) shall be provided on all pump stations for
switching power to the onsite backup generator when normal grid power fails. The
ATS shall be provided by the same manufacturer as the generator, and included
under the same warranty as the generator.
2. General
a) The ATS shall be rated for the voltage and ampacity as shown on the plans
and shall have 600 volt insulation on all parts in accordance with NEMA
standards.
b) The current rating shall be a continuous rating when the switch is installed in
an unventilated enclosure, and shall conform to NEMA temperature rise
standards. Designs which require cabinet ventilation are unacceptable and do
not meet this Specification.
c) The unit shall be rated based on all classes of loads, i.e., resistive, tungsten,
ballast and inductive loads. Switches rated 400 amperes or less shall be UL
listed for 100% tungsten lamp load.
d) As a precondition for approval, all transfer switches complete with accessories
shall be listed by Underwriters Laboratories, under Standard UL 1008
(automatic transfer switches) and approved for use on emergency systems.
e) The withstand current capacity of the main contacts shall not be less than 20
times the continuous duty rating when coordinated with any molded case circuit
breaker established by certified test data. Refer to required withstand and
close ratings as detailed in this Specification.
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Effective Date: April 12, 2022
f) Temperature rise tests in accordance with UL 1008 shall have been conducted
after the overload and endurance tests to confirm the ability of the units to carry
their rated currents within the allowable temperature limits.
g) Transfer switches shall comply with the applicable standards of UL, CSA, ANSI,
NFPA, IEEE, NEMA, and IEC.
h) The transfer switches shall be supplied with a microprocessor based control
panel as detailed further in these Specifications.
i) The transfer switch shall be capable of detecting if the source switch was
successful and if the pump station is receiving power. It shall also be capable
of transmitting a failure signal if it was not successful in switching sources and
the pump station is not receiving power.
3. Sequence of Operation
a) The ATS shall incorporate adjustable three phase under-voltage sensing of the
normal source and emergency source.
b) When the voltage of any phase of the normal source is reduced to 80% of
nominal voltage, for a period of 0-10 seconds (programmable) a pilot contact
shall close to initiate starting of the engine generator.
c) When the emergency source has reached a voltage value within 10% of
nominal voltage and achieved frequency within 5% of the rated value, the load
shall be transferred to the emergency source after a programmable time delay.
d) When the normal source has been restored to not less than 90% of rated
voltage on all phases, the load shall be re-transferred to the normal source after
a time delay of 0-30 minutes (programmable). The generator shall run
unloaded for 5 minutes (programmable) and then automatically shut down. The
generator shall be ready for automatic operation upon the next failure of the
normal source.
e) If the engine generator should fail while carrying the load, retransfer to the
normal source shall be made instantaneously upon restoration of proper
voltage (90%) on the normal source.
f) The transfer switch shall be equipped with a microprocessor based control
panel. The control panel shall perform the operational and display functions of
the transfer switch. The display functions of the control panel shall include ATS
position and source availability.
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Effective Date: April 12, 2022
g) The front panel display shall include indicators for timing functions, capability
to bypass the TD on transfer or retransfer, and an ATS test switch and afford
on-board diagnostic capability.
h) The control panel shall be provided with calibrated pots (accessible only by first
opening the lockable cabinet door) to set time delays, voltage and frequency
sensors. Designs which make use of DIP switches to render such adjustments
are not acceptable. The ATS shall be capable of being adjusted while the
controls are energized and the unit in automatic mode. Designs which force a
"programming mode" or require the controls be de-energized during adjustment
are unacceptable.
i) The control panel shall be opto-isolated from its inputs to reduce susceptibility
to electrical noise and provided with the following inherent control functions and
capabilities:
1) An LED display for continuous monitoring of the ATS functions.
2) Built-in diagnostic display.
3) Capability to support external communication and network interface through
an optional RS 485 port.
4) Mechanical test switch to simulate a normal source failure.
5) Time delay to override momentary normal source failure prior to engine
start. Field programmable 0-10 minutes (continuously adjustable via a
calibrated potentiometer factory set at 3 minutes).
6) Time delay on retransfer to normal source, continuously adjustable 0-30
minutes, factory set at 15 minutes. If the emergency source fails during the
retransfer time delay, the transfer switch controls shall automatically bypass
the time delay and immediately retransfer to the normal position.
7) Time delay on transfer to emergency, continuously adjustable 0-15 minute,
factory set at 1 minute.
8) An in-phase monitor shall be provided. The monitor shall compare the
phase angle difference between the normal and emergency sources and be
programmed to anticipate the zero crossing point to minimize switching
transients.
9) An interval-type automatic clock exerciser shall be incorporated within the
microprocessor.
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Effective Date: April 12, 2022
10)Provide a momentary pushbutton to bypass the time delays on transfer and
retransfer.
4. Construction and Performance
a) The automatic transfer switch shall be of double throw construction operated
by a reliable electrical mechanism momentarily energized. There shall be a
direct mechanical coupling to facilitate transfer in 6 cycles or less.
b) The normal and emergency contacts shall be mechanically interlocked such
that failure of any coil or disarrangement of any part shall not permit a neutral
position.
c) For switches installed in systems having ground fault protective devices, and/or
wired so as to be designated a separately derived system by the NEC, a 4th
pole shall be provided. This additional pole shall isolate the normal and
emergency neutrals. The neutral pole shall have the same withstand and
operational ratings as the other poles and shall be arranged to break last and
make first to minimize neutral switching transients. Add-on or accessory poles
that are not of identical construction and withstand capability are not
acceptable.
d) The contact structure shall consist of a main current carrying contact, which is
a silver alloy with a minimum of 50% silver content. The current carrying
contacts shall be protected by silver tungsten arcing contacts on all sizes above
400 Amps.
e) The transfer switch manufacturer shall submit test data for each size switch,
showing it can withstand fault currents of the magnitude and the duration
necessary to maintain the system integrity. Minimum UL listed withstand and
close into fault ratings shall be as follows:
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Effective Date: April 12, 2022
Any molded case breaker:
Size (Amps) (RMS Symmetrical)
Up to 200 10,000
201-260 35,000
261-400 35,000
401-1200 50,000
1201-4000 100,000
Specific coordinated breakers:
Size (Amps) (RMS Symmetrical)
Up to 150 30,000
151-260 42,000
261-400 50,000
401-800 65,000
801-1200 85,000
1201-4000 100,000
Current limiting fuse:
Size (Amps) (RMS Symmetrical)
Up to 4000 200,000
*All values 480 volt, RMS symmetrical, less than 20% power factor.
f) A dielectric test at the conclusion of the closing tests shall be performed.
g) The automatic transfer switch manufacturer shall certify sufficient arc
interrupting capabilities for 50 cycles of operation between a normal and
p g p Y p emergency source that are 120 degrees out of phase at 480 volts, 600% of
rated current at 0.50 power factor. This certification is to ensure that there will
be no current flow between the two isolated sources during switching.
h) All relays shall be continuous duty industrial type with wiping contacts.
Customer interface contacts shall be rated 10 amperes minimum. Coils, fuses,
relays, timers and accessories shall be readily front accessible. The control
panel and power section shall be interconnected with a harness and keyed
disconnect plugs for maintenance.
i) Main and arcing contacts shall be visible without major disassembly to facilitate
inspection and maintenance.
j) A manual handle shall be provided for maintenance purposes with the switch
de-energized. An operator disconnect switch shall be provided to defeat
automatic operation during maintenance, inspection, or manual operation.
k) The switch shall be mounted in a NEMA 3R enclosure unless otherwise
indicated on the plans.
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Effective Date: April 12, 2022
I) Switches composed of molded case breakers, contactors or components
thereof not specifically designed as an automatic transfer switch will not be
acceptable.
804 Odor/Chemical Facilities
1. Odor control measures shall be evaluated for all possible sources of odor related
to wastewater pumping systems. Source locations to be analyzed shall include,
but not be limited to, the wetwell at the pump station, the force main discharge
location, and force main air release valves. Odor control measures to be analyzed
shall include, but not be limited to, oxidizing agent added to the wastewater, odor
masking agents added to the air, activated carbon treatment, biofilter treatment,
and wet scrubber treatment. Final determination of appropriate odor control
measures shall be made by the Director of Water Resources.
2. Solutions that include chemical feed must consider the feasibility of chemical
delivery to the site, provide appropriate chemical storage facilities including
secondary containment, and must incorporate chemical feed systems as listed in
the Town of Apex Approved Manufacturers List.
3. Odor control facilities not located on the pump station site (air release valves and
discharge points, for instance) shall be constructed in underground vaults or if
necessary to be above ground, shall be house inside a structure. Appropriate
consideration shall be given to changing media or supplying chemical at the
remote locations, as well as the safety of the maintenance staff while servicing the
systems.
805 Inspections, Testing, and Training
A. Inspections
1. All materials and equipment used in the construction of the wastewater pumping
system must be verified for compliance with the Specifications (or other approval
granted by the Town) by the Infrastructure Field Technician prior to installation.
Non-conforming materials or equipment shall be immediately removed from the
job site.
2. Compliance with plans and Specifications shall be verified on a regular basis by
the Infrastructure Field Technician.
B. Testing
1. General
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Effective Date: April 12, 2022
a) The Contractor shall furnish all materials, labor, and equipment to perform all
testing and start up services. Water for testing purposes may be obtained from
the Town of Apex. The Contractor shall reimburse the Town for all water used
at Inside Utility Rates.
b) All water or wastewater used during testing of the pump station, force main, or
any of the systems described in this section, must be returned to the Town of
Apex sanitary sewer system after proper coordination with the Town of Apex
Department of Public Works and Utilities.
c) Before the operational tests are conducted, the required copies of the
Operation and Maintenance Manuals shall be delivered to the Town.
d) The Town reserves the right to require further testing, as necessary, to assure
that all components and infrastructure are performing in accordance with the
manufacturer recommendations and Town Specifications. All testing, repairs
and/or readjustments, and necessary re-testing, shall be at no additional cost
to the Town.
e) All on-site testing and/or installation verification shall be performed in the
presence of the Infrastructure Field Technician or other representative
authorized by the Town.
f) All testing, installation verification, and training, shall be performed in the
presence of, or by, an experienced, competent, and authorized manufacturer's
representative.
g) Factory testing shall consist of testing all operating functions of the equipment
under varying operating conditions to assure that it will perform as specified.
Any specific testing that may be required is discussed under the individual
equipment items below. Results of factory testing shall be presented to the
Town prior to delivery of the equipment.
h) Installation Verification shall consist of a visit to the site by a manufacturer's
representative to inspect, check, adjust if necessary, and approve the
equipment installation. The manufacturer's representative shall certify that the
equipment has been properly installed and lubricated, is in accurate alignment,
and is free from any undue stress imposed by connecting piping or anchor
bolts. Any specific verification requirements are discussed under the individual
equipment items below. Results of the installation verification shall be
presented to the Town prior to start-up of the equipment.
i) On-Site Testing shall consist of all manual and automatic operating functions
under various operating conditions, including full load conditions. The
equipment shall also be tested under adverse or emergency conditions. All
alarms and remote signals shall also be tested. Any specific testing that may
Section 800—Wastewater Pumping Systems & Force Mains - Page 51 of 70
Effective Date: April 12, 2022
be required is discussed under the individual equipment items below. Results
of the on-site testing shall be presented to the Town prior to final acceptance
of the project.
j) All functions and systems of the pump station, even those not specifically listed
below, shall be tested to ensure proper operation under normal and emergency
situations.
k) All defective equipment or malfunctioning systems shall be replaced or
corrected, and the full system placed in a fully operational condition to the
satisfaction of the Infrastructure Field Technician.
I) Results of all factory testing, installation certifications, and on-site operational
testing shall be provided to the Town of Apex in the final construction
documents as described in the Submittals portion of this Specification section.
2. Pump Testing
a) Each pump shall be tested at the factory for capacity, power requirements, and
efficiency at specified rated head, shutoff head, operating head extremes, and
at as many other points as necessary for accurate performance curve plotting.
All tests and test reports shall conform to the requirements and
recommendations of the Hydraulic Institute Standards. Acceptance testing
shall be Level A, with no minus tolerance or margin allowed. The test result
report shall include data and test information as stipulated in the Hydraulic
Institute Standards, copies of the test log originals, test reading to curve
conversion equations, and certified performance curves. The curves shall
include head, bhp (brake kW), pump efficiency, and shop test NPSH available,
plotted against capacity. The curves shall be easily read and plotted to scales
consistent with performance requirements. All test points shall be clearly
shown.
b) All pumps shall receive installation verification.
c) On-site testing shall be performed to the maximum extent possible (flow
availability could limit the range of testing conditions).
3. Grinder Testing
a) Each grinder unit shall be factory tested.
b) Each grinder unit shall receive installation verification.
c) Each grinder unit shall receive on-site testing.
4. Generator Testing
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Effective Date: April 12, 2022
a) Each engine generator set shall be fully assembled with its control panel and
factory tested to demonstrate that the equipment conforms to specified
requirements for load capacity. The tests shall consist of repeated starts and
stops operation under a load bank at specified capacity for a minimum of 4
continuous hours, and tests to demonstrate that each safety shutdown device
is working properly.
b) Each engine generator set shall receive installation verification.
c) Each engine-generator set shall receive on-site testing to demonstrate that the
equipment conforms to specified requirements for load capacity, and starting
duty. The complete system (engine, generator, control panel, and automatic
transfer switch) shall be field tested together by the manufacturer or
manufacturer's representative as a complete system to assure compatibility. A
resistive load bank with temporary connections shall be provided to complete
the field testing. Each unit shall be mechanically checked for proper operation.
Each alarm and safety shutdown shall be checked by artificially simulating an
alarm condition. The testing shall consist of repeated starts and stops, a "cold
start", normal operation under full load conditions at the specified power rating
for a minimum of four continuous hours, and a one step rated load pickup test
in accordance with NFPA 110. The following items shall be measured,
recorded, and submitted in a field test report: outdoor ambient temperature,
barometric pressure, kW output, engine speed (RPM), engine jacket water
temperature, engine oil pressure, start time, completion time. Test reports shall
verify that the specified tests have been performed and shall state results.
5. Automatic Transfer Switch Testing
a) Each automatic transfer switch shall receive field verification.
b) Each automatic transfer switch shall receive on-site testing in conjunction with
the engine generator. At a minimum, the main power supply from the
commercial power grid shall be cut and the switch shall automatically properly
transfer the power feed to the standby generator.
6. Control System Testing
a) All electrical, instrumentation, control, and telemetry systems shall receive on-
site testing to ensure complete operation of all systems. At a minimum the
testing shall include the following:
1) Pump automatic control and operation
2) Level-sensing equipment operation
3) Alarm and telemetry system automatic operation
4) Backup power generation automatic control and operation
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Effective Date: April 12, 2022
5) Vibration testing of all rotating equipment
7. Structure Testing
a) Wetwells and other wastewater containing structures at the pump station shall
be inspected and tested for watertightness. Structures shall be thoroughly
cleared of dirt, mud, gravel and other foreign debris prior to testing.
b) The watertightness test shall be performed in accordance with ACI 350.1R
"Testing Reinforced Concrete Structures for Watertightness". If the structure
is a small diameter precast manhole, a vacuum test in accordance with ASTM
C1244 "Standard Test Method for Concrete Sewer Manholes by Negative Test
Pressure (Vacuum) Test" may be used in lieu of the hydrostatic test.
c) Watertightness testing shall not commence until the structure is fully assembled
and backfilled.
d) Any structure that fails to meet the requirements of the watertightness test shall
be inspected, made watertight, and retested until the structure passes.
C. Operator Training
1 . Suppliers of major equipment packages shall provide training to Town of Apex staff
as to the proper operation and maintenance of their equipment.
2. Training shall be performed by an experienced, competent, and authorized
manufacturer's representative.
3. Training shall be at no additional cost to the Town.
4. Training shall be provided for, but not limited to, the equipment listed in the table
below. The training times presented below for Operation Training and
Maintenance Training are the minimum required. Complicated systems can
require more than the minimum requirements.
Equipment System Operation Training Maintenance
(hours) Training (hours)
Pumps and Pump Control 2 4
Systems
Grinder System 1 2
Engine Generator and 2 4
Automatic Transfer Switch
Chemical on/or Odor Control 1 2
Systems
Alarm Dialer/ 1 0
SCADA/Telemetry
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Effective Date: April 12, 2022
5. Operational training shall include, but not be limited to, the following procedures or
information: normal startup of the unit, normal shutdown of the unit, emergency
shutdown of the unit, normal operation of the unit (typical temperature, pressures,
signals, rpm, etc., for gages and instruments which are displayed on the panel), a
presentation of all operational features (alternative run modes, bypasses, other
features not typically used in day-to-day operation, etc.), presentation of all alarm
signals, etc.
6. Maintenance training shall include, but not be limited to, the following procedures
or information: standard lubrication procedures and schedules, removal and
replacement of equipment, disassembly and re-assembly, replacement of wear
parts or common replacement parts, standard troubleshooting procedures, etc.
7. Simplified operation instructions shall be submitted for review in accordance with
the submittals section of this Specification. When the review is complete, the
instruction sheets shall be printed on heavy paper or cardboard stock and
laminated with clear plastic. Two copies of the laminated instructions shall be
furnished with the unit. One copy shall be located or displayed at the control
panel for the unit. The reserve copy shall be delivered to the Town. The
instructions specified here are in addition to the required operation and
maintenance manuals.
806 Force Main General
1. These Specifications apply to all force mains that are to be owned, operated, and
maintained by the Town of Apex. Design of private pump stations and force mains
and associated facilities is not covered by these Specifications or otherwise herein,
and the applicant should look for guidance from other appropriate agencies
(NCDEQ, NC Plumbing Code, etc.).
2. All aspects of the design of wastewater force mains, and associated facilities shall,
at a minimum, meet the requirements of the latest version of the NCDEQ "Minimum
Design Criteria for the Fast-Track Permitting of Pump Stations and Force Mains".
Requirements presented in the Town of Apex Standard Specifications hereunder
that are more restrictive or go above and beyond the requirements of the Minimum
Design Criteria are required by the Town of Apex.
3. All aspects of the design of pump stations, force mains, and associated facilities
shall be submitted for review and approval to the Town of Apex Water Resources
Department.
4. Wastewater force main interconnections shall be prohibited. All wastewater force
mains shall extend to the nearest gravity sewer or pump station wet well that has
sufficient long term capacity.
807 Wastewater Force Mains
Section 800—Wastewater Pumping Systems & Force Mains - Page 55 of 70
Effective Date: April 12, 2022
A. Design
1. Force mains shall be installed with a minimum cover of 3 feet measured from the
top of the pipe to the finished grade (or subgrade if installed under roadways). The
engineering drawings shall include profile drawings for the entire length of the
main.
2. All force mains shall be located within dedicated right of way of Town roads,
outside of the right of way on NCDOT roads, or dedicated easements with a
minimum width of 20 feet. When wastewater force mains are constructed adjacent
to gravity sewer mains or for construction of parallel wastewater force mains, the
minimum horizontal clearance shall be at minimum 7-ft from pipe edge to pipe
edge when the depth of installation is 8-ft or less. Otherwise, the minimum
horizontal separation between pipelines shall be 10-ft up to installation depth of
10-ft. Clearances for pipelines greater than 10-ft depth shall be designed by
Engineer of Record and approved by the Town of Apex Water Resources
Department. Easement widths outlined below shall be widened by at least the
clearance between the pipelines when constructing a shared gravity sewer and
wastewater force main corridor. If sewer main is located within road right-of-way
or on Town owned property there shall be no permanent structures, equipment,
retaining walls, embankments, impoundments, or other elements that would inhibit
maintenance operations unless approved by the Water Resources Director.
3. All force mains shall be installed outside of all Zone 1 and Zone 2 buffers whenever
practical. Sewer main shall be installed outside of all floodplain unless No Practical
Alternative is available and prior approval is obtained from the Water Resources
Director.
Standard Easement Width for Sewer Force Mains
Pipe Depth* Permanent Town Road R/W
Easement Width
8-ft or less 20-ft Allowed
8-ft— 15-ft 30ft As Specified by the WR
Department
15-ft— 20-ft 40-ft Not Allowed
As Specified by
Deeper than 20 ft the WR Not Allowed
Department
*Depth of the sewer main shall be measured from the top of the pipe to the final grade or road subgrade
at the deepest point between manholes.
4. Dedicated easements for force mains and appurtenances shall be recorded as
"Town of Apex Public Forcemain Easement". Town of Apex force main easements
shall contain only Town of Apex utilities unless otherwise approved by an
encroachment agreement.
Section 800—Wastewater Pumping Systems & Force Mains -Page 56 of 70
Effective Date: April 12, 2022
5. Wastewater force main discharge manholes and intermediate air release locations
that require odor control shall be provided with sufficient easement area to
accommodate the odor control systems as designed by the Engineer of Record,
whether utilizing passive, forced-air or chemical treatment for odor control. The
maintenance easement for odor control systems shall be sized based on site
specific conditions and shall provide sufficient area for routine maintenance
operations, such as refilling media, chemicals, replacing equipment, etc.
6. Force mains shall discharge at the invert of the receiving manhole and shall be as
close as possible to 180 degrees from the outlet pipe.
7. Force main design shall facilitate cleaning and inspection. The use of 90 degree
bends is prohibited.
8. Force mains shall be constructed with a pigging/bypass connection located within
50-ft of the pump station valve vault.
9. Force main minimum design velocity shall not be less than 2-ft per second
throughout the length of the force main. As a design preference, force main
systems when operating at higher flows shall reach velocities of 3 to 5 ft/s to re-
suspend any settled solids.
Force main systems shall be of adequate sizing and design to effectively convey
the ultimate peak flows as applied by the connected pump station to the
discharge point.
10.The force main route shall be such that the number of high points requiring
combination air valves is minimized to the extent possible. Combination Air Valves
rated for use with raw wastewater shall be installed at all the high points or runs
exceeding 3000-ft on all force mains in accordance with the Standard Details. A
high point shall be determined as any location where the vertical separation
between the adjacent low point and high point in the force main is greater than or
equal to 10 vertical feet.
11.Restraint:
a) General: All pipe, valves, and fittings shall be restrained. Pipe joints shall also
be restrained an adequate length away from valves and fittings in accordance
with AWWA manual M41 (or the latest edition of Thrust Restraint Design for
Ductile Iron Pipe as published by the Ductile Iron Pipe Research Association).
In all cases, there must be a pipe restraint plan with the method of restraint to
be used and the length of pipe to be restrained clearly identified on the plans
at all necessary locations. The pipe restraint plan shall be included under the
design responsibility of the NC Professional Engineer sealing the plan
drawings. All restraint systems shall be factory produced by the manufacturer.
Section 800—Wastewater Pumping Systems & Force Mains - Page 57 of 70
Effective Date: April 12, 2022
b) Pipe Joints: The standard joint restraint method shall be to use manufacturer
provided restrained joint pipe. Pipe up to and including 12-inches in diameter
may utilize mechanical joint pipe with approved wedge action retainer glands
(for the specified distance). All joint restraint products that include the means
of restraint within the joint gasket shall be prohibited. Fusible C-900 DR 18
PVC may be utilized as an acceptable means of restraint.
c) Valves: Valves shall be restrained in a manner consistent with operation as a
dead end. This includes restraining the valve to the pipe and restraining a
sufficient number of pipe joints on both sides of the valve to accommodate dead
end restraint.
12. A plug valve shall be installed at least every 3000 feet of force main length.
13. All air release valves, plug valves greater than 12-inches, or other
appurtenances that have moving or operating parts and require maintenance
and routine access shall have a manhole placed over them or over the operating
portion of the device.
14. Separation Requirements:
a) Separation between Sewer Force Main and Storm Water Pipes:
Sewer force mains shall have a minimum vertical separation of 24 inches
between storm pipes when the horizontal separation is 3 feet or less.
Where sanitary and storm sewers cross with a vertical separation of less
than 24 inches, the entire leg of sanitary sewer shall be made of standard
ductile iron pipe with joints rated for water main service and the void space
between the pipe crossing shall be backfilled with 3000-psi concrete or
minimum 500-psi, quick setting, non-excavatable flowable fill that meets or
exceeds NCDOT Specifications.
b) Separation between Sanitary Sewer and Sewer Force Main:
There shall be a minimum 7 foot horizontal separation between parallel
gravity and/or force mains in outfall locations when the depth of installation
is 8-ft or less. Otherwise, the minimum horizontal separation between
pipelines shall be 10-ft in outfalls.
c) Separation between Sewer Force Main and Water Main:
Parallel Installations: 10-ft lateral separation (pipe edge to pipe edge) or
minimum 5-ft lateral separation, and water line at least 18-inches above
sewer force main measured vertically from top of sewer pipeline to bottom
edge of water main.
d) Crossings (Water Main over Sewer Force Main): All water main crossings of
sewer force mains shall be constructed in conformance with Town of Apex
Specifications. At a minimum, 18-inches of clearance shall be maintained
Section 800—Wastewater Pumping Systems & Force Mains - Page 58 of 70
Effective Date: April 12, 2022
between the bottom edge of the water main and the top edge of the sewer
force main. If 18-inches of clearance is not maintained, the water main and
sewer force main shall both be constructed of ductile iron pipe with joints in
conformance with water main construction standards. The ductile iron
sewer force main shall extend 10-ft on both sides of the crossing. When the
separation between pipelines is 18-inches or less, the void space between
the pipes shall be filled with minimum 5000-psi, quick setting, and non-
excavatable flowable fill extending 3-ft on both sides of the crossing.
Regardless of pipe material, at least 12-inches of vertical separation is
required for sewer force main crossings of potable water mains.
e) Crossings (Water Main under Sewer Force Main: Allowed only as approved
by Town of Apex, when it is not possible to cross the water main above the
sewer force main. At a minimum, 18-inches of separation shall be
maintained, (measured from pipe edge to pipe edge) and both the water
main and sewer force main shall be constructed of ductile iron in
conformance with water main construction standards to a minimum of 10-ft
on both sides of the crossing. If local conditions prevent providing 18-inches
of clearance, then at least 12-inches of clearance shall be provided and the
void space between the pipes shall be filled with minimum 5000-psi, quick
setting, and non-excavatable flowable fill extending at least 3-ft on both
sides of the crossing. In all cases the water main pipe shall be centered at
the point of crossing with joints equally spaced from the point of crossing.
f) Sanitary Sewer Force Main and Stream Crossings:
The top of the sewer force main shall be at least three feet below the stream
bed. If three feet of cover cannot be achieved, prior approval from the Water
Resources Director must be obtained and concrete encasement and ductile
iron pipe shall be required
Sewer force mains shall not be installed under any part of water
impoundments or area to be impounded. Sewer mains shall not be installed
through, above, or below any retained earth structure. Sewer main location
and depth shall not be within the theoretical 1:1 slope of any impoundment
dam or structure, or shall maintain a minimum of 10' horizontal separation
from the toe of slope, whichever is greater. The entire easement shall be
outside of the toe of slope, unless prior approval is obtained from the Water
Resources Director.
The following minimum horizontal separations shall be maintained:
1) 100 feet from any private or public water supply source, including
wells, WS-1 waters or Class I or Class II impounded reservoirs used
as a source of drinking water (except as noted below).
2) 50 feet from any waters (from normal high water) classified WS-ll,
WS-Ill, B, SA, ORW, HOW or SB (except as noted below).
Section 800—Wastewater Pumping Systems& Force Mains- Page 59 of 70
Effective Date: April 12, 2022
3) 10 feet from any other stream, lake, or impoundment (except as
noted below).
4) 50 feet from private wells (with no exceptions).
5) 50 feet from sources of public water supply (with no exceptions)
Where the required minimum separations cannot be obtained, ductile iron
sewer force main pipe with joints equivalent to water main standards shall
be used. Steel casing and/or concrete may also be required for protection,
at the direction of the Water Resources Director.
15.AII retaining walls shall have a separation from the easement boundary of at least
1:1, vertical to horizontal. For example, if the retaining wall is 10 feet tall, it shall
be placed no closer than 10 feet from the easement.
B. Materials
1. Pipe Materials
a) The minimum wastewater force main size shall be 4-inches in diameter.
b) Ductile Iron Pipe or PVC C900 DR18 shall be required for all wastewater force
mains.
c) Ductile iron pipe shall be designed and manufactured in accordance with
AWWA C150 and C151 and provided in nominal 20-ft lengths. The minimum
requirements for ductile iron pipe and required laying conditions are tabulated
below. For all other installations other than specified, the laying condition,
bedding requirements or the minimum pressure class rating and/or thickness
class shall be increased in accordance with AWWA C151. A pipe thickness
design shall be submitted for external loading in all cases where the pipe depth
exceeds the specified range of depths outlined in the following table.
Pressure Class, Max. Depth and Laying Condition for DI Wastewater Force Mains
Pipe AWWA C- Pressure Maximum
Diameter 150, Laying Class Depth of
Condition Cover
4-8 -inch type 1 350 psi 3-16 feet
4-8 -inch type 4 350 psi 16-20 feet
10-12 -inch type 1 350 psi 3-10 feet
10-12 -inch type 4 350 psi 10-20 feet
14-20 -inch type 4 350 psi 3-25 feet
24 -inch type 4 350 psi 3-25 feet
Section 800—Wastewater Pumping Systems & Force Mains - Page 60 of 70
Effective Date: April 12, 2022
Note: For cases not specified, a ductile iron pipe and bedding design certified by a
Professional Engineer licensed in the State of North Carolina shall be required in
compliance with AWWA C150 and the Ductile Iron Pipe Research Association.
All ductile iron pipe shall be marked in conformance with ASTM A-746.
The following table lists approved manufacturers of DIP, DIP fittings, and RJDIP that are
allowable for installation within the Town's system.
Product Approved Model/Series Pressure/Load Reference Requirements
Category Manufacturer Rating Standard
40-mils of
US Pipe Tyton Joint Protecto 401
Ductile
Iron Pipe AWWA Lining (lining
4-inch & American C150 and must be less
Larger ACIPCO Fastite Joint 250-350 psi C151 and than 1 year
( ) old); McWane
Diameter DIPRA
Protecto Standards pipe stamped
"McWane by
401 Lined
McWane Tyton Joint Atlantic States
or Clow" only
Ductile
Sigma Mech. Joint
Iron AWWA
Fittings 4- Tyler Union Mech. Joint C110/C111 Shall always
inch & 250-350psi and meet or exceed
Larger SIP Industries Mech. Joint AWWA pipe pressure
Diameter Star Mech. Joint C153 rating
Protecto
401 Lined American Mech. Joint
Ductile US Pipe TR Flex
Iron
Restrained
American Boltless
Joint Pipe Flex Ring AWWA restraint unless
4-inch & (ACIPCO) 250-350 psi C150 and otherwise
Larger TR Flex C151 specified
Diameter
Protecto McWane (pipes 24"
401 Lined and smaller)
d) All ductile iron wastewater force mains and fittings for sewer construction shall
receive an interior ceramic epoxy coating, consisting of an amine cured novalac
epoxy containing at least 20% by volume of ceramic quartz pigment, as
manufactured by Protecto 401. The interior coating shall be applied at a
nominal dry film interior thickness of 40-mils. All DIP bells and spigots shall be
lined with 8-mils of Protecto 401 joint compound applied by brush to ensure full
coverage. All pipe supplied with Protecto 401 interior lining shall be provided
free of holidays. Pipe installed with defects in the lining will be rejected.
Patching of Protecto 401 coating defects after installation shall not be
Section 800—Wastewater Pumping Systems & Force Mains- Page 61 of 70
Effective Date: April 12, 2022
approved. Protecto 401 lined pipe must be installed within one year of the
application date on the pipe.
The liner manufacturer shall have a minimum of ten (10) years of successful
experience and be able to demonstrate successful performance on comparable
projects.
Permeability rating of 0.00 when tested according to Method A of ASTM E-96-
66, Procedure A with a test duration of 30 days.
e) PVC pipe shall conform to AWWA C900 standards along with the following
requirements:
1) Outside diameter shall conform to that of ductile iron pipe.
2) Pipe shall have plain end and elastomeric gasket bell ends.
3) Green in color.
f) Pipe fittings shall be made of ductile iron designed and manufactured per
AWWA C110 or C153. All fittings up to and including 24 inches in diameter
shall be designed for a minimum internal pressure of 350 psi, unless otherwise
approved by the Town of Apex. Fittings shall be mechanical joint or proprietary
manufacturer provided restrained joint. Gaskets shall be in accordance with
AWWA C111. All fittings shall be interior coated with Protecto 401 as specified
herein for ductile iron pipe. Two 45 degree fittings shall be used in lieu of 90
degree fittings in all horizontal and vertical installations.
g) Restrained Joint Pipe shall be the boltless type unless otherwise approved. For
installations requiring welded locking rings, the rings shall be factory welded.
The restrained joints shall provide a minimum of 4-degrees of deflection for
pipe sizes, 4-inches through 12-inches in diameter.
All proprietary pipe restraint systems shall be approved by the Town of Apex
and provided in compliance with all standards for coatings, linings, pressure
classes, etc. as required for PVC C900 or ductile iron pipe. All restrained joint
pipe shall be installed based on laying conditions, pressure class, etc. as
required for typical ductile iron pipe.
Pipe and fitting manufacturer(s) must have a supplier within 200 miles of the
Town of Apex.
2. Manhole Materials:
a) All sewer force main manholes shall be installed according to Section 0700 of
the Town of Apex Standard Specifications when design and installation criteria
are not otherwise covered herein.
b) All force main discharge locations (including all downstream manholes within
1,200 feet) and other manholes for wastewater force mains (excluding those
Section 800—Wastewater Pumping Systems & Force Mains - Page 62 of 70
Effective Date: April 12, 2022
housinglarge diameter plugvalves) shall be epoxy coated at minimum 80-mils
9 p Y
thickness.
c) Force Main Manhole Epoxy Coating: Sewer force main receiver manholes,
sewer force main combination air valve manholes and other concrete structures
subject to high levels of hydrogen sulfide gas shall be provided with an
approved monolithic epoxy coating system consisting of a 100% solids,
solvent-free, two-component epoxy resin that meets the following
Specifications for up to 100 mils of coating with a manufacturer approved set
time of 6-hours or less.
1) Surface Preparation: Concrete manholes must be well cured prior to
application of the protective epoxy coating. Generally, 28 days is
adequate cure time for standard Portland cement. If earlier application
is desired, compressive or tensile strength of the concrete can be tested
to determine if acceptable cure has occurred. (Note: Bond strength of
the coating to the concrete surface is generally limited to the tensile
strength of the concrete itself. An Elcometer pull test to determine
9
suitability of concrete for coating may be required).
Surface preparation shall be based on the requirements of the
manufacturer of the epoxy coating and applicable NACE International
standards.
2) Installation: A minimum 80-mils thickness shall be applied to new
manholes (120-mils for existing manholes). During application a wet film
thickness gage, meeting ASTM D4414 - Standard Practice for
Measurement of Wet Film Thickness of Organic Coatings byNotched
9 9
Gages, shall be used to ensure a monolithic coating and uniform
thickness during application.
Temperature of the surface to be coated should be maintained between
40° F and 120° F during application. Prior to and during application,
care should be taken to avoid exposure of direct sunlight or other intense
heat source to the structure being coated. Where varying surface
temperatures do exist, care should be taken to apply the coating when
the temperature is falling versus rising or in the early morning. The
humidity should also be observed to ensure compliance with the epoxy
manufacturers' recommendations.
Manufacturer approved heated plural component spray equipment shall
be used in the application of the specified protective epoxy coating. The
spray equipment shall be specifically designed to accurately ratio and
apply the specified protective coating materials and shall be regularly
maintained and in proper working order.
Section 800—Wastewater Pumping Systems & Force Mains- Page 63 of 70
Effective Date: April 12, 2022
If necessary, subsequenttop coating to coatin or additional coats of the protective
coating should occur as soon as the basecoat becomes tack free, ideally
within 12 hours but no later than the recoat window for the specified
products. Additional surface preparation procedures will be required if
this recoat window is exceeded.
d) Force Main Receiver Manholes: Sewer force mains shall not discharge directly
into existing gravity sewer lines. Sewer force mains shall typically discharge
into a receiver manhole that has been epoxy coated as specified herein. The
receiver manhole shall be provided in the typical eccentric tapered design at
minimum 5-ft diameter. The bench shall be sloped up to 8-inches from the
invert channel to the manhole wall. The invert shall be provided with a gradual
upsloping alignment from the force main entry to the gravity transition point.
Sufficient grade shall be placed on the invert such that wastewater falls back
into the force main when the pumps are not in operation creating a vapor lock
between the force main and the manhole. Drop connections into force main
receiver manholes shall be prohibited.
The interior surface of the receiving manhole at the discharge end of the force
main and all manholes within 1,200 feet downstream of a force main connection
shall receive 2 coats of Sherwin Williams Sher-Flex or equivalent. Coatings
shall conform to US Army Corps of Engineers Specification C-200. The coating
shall have a total dry film thickness of 80-125 mils, and all blemishes shall be
touched up prior to acceptance.
Force mains shall discharge at the invert of the receiving manhole and at an
angle which is as close as possible to 180-degrees of the outlet pipe.
e) Combination Air Valve Manholes: Manholes for combination air valve
installation shall be provided in flat top configuration to accommodate the
excess length of wastewater combination air valves. In cases where the
combination air valve assembly shall be located in a paved area, provide
typical eccentric, tapered manhole design with typical manhole frame and
cover for paved areas. The minimum manhole diameter for combination air
valve assemblies shall be 5-ft. Minimum 6-ft diameter manholes shall be used
with force mains 20-inches and larger and when an odor control system is
required. Any manholes located in NCDOT or street right-of-way shall be
provided flush with finished grade. ARVs shall be 2-inch and manufactured
by ARI, model D-02P sewage dual ARV with plastic body.
C. Installation
1. General
Ductile iron pipe shall be installed in accordance with the requirements of AWWA
C600 and the Ductile Iron Pipe Handbook published by the Ductile Iron Pipe
Section 800—Wastewater Pumping Systems& Force Mains - Page 64 of 70
P 9 Y 9
Effective Date: April 12, 2022
Research Association. Materials at all times shall be handled with mechanical
equipment or in such a manner to protect them from damage. At no time shall pipe
and fittings be dropped or pushed into ditches.
Pipe trench excavation and backfilling shall be performed in accordance with
Section 0450 of these Specifications.
Pipe and fitting interiors shall be protected from foreign matter and shall be
inspected for damage and defects prior to installation. In the event foreign matter
is present in pipe and fittings, it shall be removed before installation. Open ends of
pipe shall be plugged or capped when pipe laying is not in progress.
All pipe shall be constructed with at least 48 inches of cover below the finished
surface grade. Pipe shall be laid on true lines as directed by the Engineer. The
wastewater force main shall be installed at a grade which will allow air to migrate
to a high point where the air can be released through an air valve. A minimum
pipe slope of 1 foot in 500 feet should be maintained and there shall be no
intermediate high points in the line.
Trenches shall be sufficiently wide to adjust the alignment. Bell holes shall be dug
at each joint to permit proper joint assembly. The pipe shall be laid and adjusted
so that the alignment with the next succeeding joint will be centered in the joint and
the entire pipeline will be in continuous alignment both horizontally and vertically.
Pipe joints shall be fitted so that a thoroughly watertight joint will result. All joints
will be made in conformance with the manufacturer's recommendations for the
type of joint selected. All transition joints between different types of pipe shall be
made with transition couplings approved on shop drawings showing the complete
assembly to scale.
Forcemains shall not be installed within roundabouts or alleys.
2. Utility Coordination
Prior to beginning construction, the Contractor shall contact local utility companies
and verify the location of existing utilities. The Contractor shall be completely and
solely responsible for locating all existing buried utilities inside the construction
zone before beginning excavation. The Contractor shall be solely responsible for
scheduling and coordinating the utility location work. When an existing utility is in
conflict with construction, it shall be exposed prior to beginning construction to
prevent damage to the existing utility.
D. Valves and Appurtenances
1. General: The rated working pressure of all valves and appurtenances shall meet
the maximum design pressure of the pump station and pipeline.
Section 800—Wastewater Pumping Systems& Force Mains -Page 65 of 70
Effective Date: April 12, 2022
2. Check Valve: Check valves shall be iron bodied, fully bronze mounted with bronze
clapper disc and bronze seat ring, and shall have a spring loaded lever arm
capable of being mounted on either side of the valve.
3. Pluq Valve: Plug valves shall be non-lubricating, eccentric action and resilient plug
facing with heavy duty Type 316 stainless steel bearings. Plug valves shall be
designed for a minimum working pressure of 175 psi for valves 12" and smaller,
150 psi for valves 14" and larger. Valves shall be bi-directional and meet the
pressure rating in both directions of flow. The plug valve body shall be cast iron
ASTM A126 Class B with welded-in overlay of 90% nickel alloy content on all
surfaces contacting the face of the plug. Sprayed, plated, nickel welded rings or
seats screwed into the body are not acceptable.
All plug valves 12" and smaller shall have round port design that provides a
minimum 80% port area. The valve plug shall be ductile iron ASTM A536 Grade
65-45-12 up to 20-inches in diameter, with EPDM, Buna N, or Neoprene resilient
seating surface to mate with the body seat. Valves 24-inches and larger may have
plugs made of cast iron in accordance with ASTM A126 class B. Large plug valves
with rectangular plugs shall provide clean passage for a solid sphere of at least
67% of the adjoining pipe diameter to facilitate pigging of the force main. Force
main plug valves with rectangular port shall be "full-port" cross-sectional area
perpendicular to the flow of at least 100% of the adjoining pipe.
All buried plug valves shall be provided with worm gear actuators. All plug valves
shall be buried and provided with a 2-inch operator nut and valve box as shown in
the details. Plug valves greater than 12-inches shall be installed such that the
actuator and gearing is accessible in a manhole as shown in the details. All plug
valves shall be provided with typical mechanical joint end connections and
restrained with wedge action retainer glands on both ends of the valve assembly
as described herein.
Valves shall be installed according to the manufacturer's recommendations.
Typically for wastewater this means installing the seat side toward the pump
station so that the flow is against the face of the plug in the closed position. In the
open position, the plug should rotate up to the top of the pipeline which may require
installing the valve on its side.
4. Rubber Seated Ball Valve: For larger diameter force mains where plug valves are
not available, rubber seated ball valves shall be of the tight-closing, shaft-mounted
type that fully comply with AWWA Standard C507 to provide a full port
unobstructed waterway with no additional pressure drop. Design pressure ratings
shall be 150 psi or greater and provide tight shutoff against flow. With the valve in
the closed position, the rubber seated valve shall be bubble tight at rated pressure.
All ball valves shall be provided in an epoxy coated manhole with worm gear
actuators and a handwheel.
Section 800—Wastewater Pumping Systems & Force Mains - Page 66 of 70
Effective Date: April 12, 2022
5. Valve Box Covers: Force main plug valves or ball valves shall have valve box
covers and/or manhole lids with the word "Sewer" cast into them.
6. Combination Air Valves shall be provided to purge air from the system at startup,
vent small pockets of air while the system is being pressurized and running, and
prevent critical vacuum conditions during draining. Combination air valves
approved for use in wastewater force main installations shall be installed at all high
points of wastewater force mains 6 inches in diameter or larger and at other
locations, such as major changes in slope, as directed by the Town. A high point
shall be determined as any high location where the difference between the high
elevation and adjacent low elevation exceeds 10-ft unless otherwise determined
by the Director of Water Resources based on special circumstances. The
combination air valve shall automatically exhaust large volumes of air from the
system when it is being filled and allow air to re-enter the pipe when the system is
being drained. The wastewater force main shall be installed at a continuous grade
between low and high points without intermediate high points unless an air release
valve is being installed. A minimum pipe slope of 1 foot in 500 feet should be
maintained. Combination air valves shall be sized by the Engineer and approved
by the Town.
a) Combination air valves shall be of the single housing style with Type 304 or
316 stainless steel body that combines the operation of both an air/vacuum and
air release valve. The valve must meet the requirements of AWWA C512 and
be installed in accordance with the Details. The valve shall have a minimum
145-psi working pressure unless the pipeline design requires a higher pressure
rating.
b) The valve shall have a minimum 2-inch male NPT inlet for a 2-inch valve
assembly. Combination air valves sized from 3-inches to 8-inches shall be
provided with studded inlet connectors or flanged connections. The
combination air valve shall be provided with cylindrical shaped floats and anti-
shock orifice made of high density polyethylene. Combination air valves with
spherical floats shall not be accepted. All combination air valves shall be
installed in accordance with the Details.
c) Installation of Combination Air Valve Assembly:
1) The Engineer of Record shall provide ample depth of installation to
accommodate the extended height of combination air valves for
wastewater force mains. All combination air valves shall be
connected to the main by an MJ x FLG tee with the branch diameter
equal to at least half of the main diameter.
2) The 2-inch combination air valve shall be provided with male NPT
threads and isolated with a 2-inch gate valve. The isolation valve
Section 800—Wastewater Pumping Systems & Force Mains - Page 67 of 70
Effective Date: April 12, 2022
shall be provided with NPT threads and connected with brass or
bronze piping.
3) Combination air valves 3-inches and greater shall be connected by
flange or studs. If needed due to a larger diameter tee, a flanged
reducer shall be provided between the tee and the isolation valve.
Gate valves shall be used for 3-inch assemblies. Combination air
valves 4-inches and larger shall be isolated with a plug valve. In all
valve shallsizedequal to the combination air
cases the isolation ale be I o
q
valve.
4) The ARV shall be installed in a 5 foot diameter manhole per the
standard detail. The manhole interior surface shall receive two coats
of Sherwin Williams Sher-flex or equivalent with a total dry film
-12 mils, and all blemishes shall be touched thickness of 80 5 up prior
to acceptance.
7. Pigging Station: Force mains shall be constructed with a pigging/bypass
connection located within 50-ft of the pump station valve vault. This pigging leg
shall consist entirely of Protecto 401 coated ductile iron pipe of the same diameter
as the main. A restrained MJ wye shall be provided in the main line and valved on
each branch. The pigging leg shall extend out of the ground and be closed with a
blind flange. The protruding pipe shall be protected by concrete bollards spaced
6-ft apart.
8. Bypass Connection Assembly: On some wastewater force mains, an additional
bypass connection assembly may be required. The size, criticality and proximity
to a downstream manhole will be important factors in the need for this connection.
The bypass assembly shall include either a ball valve or plug valve assembly for
isolation from the primary wastewater force main. Additionally, the primary force
main shall be provided with a main line plug valve or ball valve on the upstream
side of the bypass assembly to prevent bypass flow from draining back to the pump
station. The bypass assembly shall be brought to the final graded surface with a
visible blind flange assembly for connection by an outside pumping contractor.
9. Force Main Odor Control Systems: Force main odor control shall be included in
the design plans for any proposed force main at discharge locations, intermediate
air release locations and otherwise as directed by the Town of Apex Water
Resources Department. In limited cases, air release valves located in isolated
areas may be approved without odor control systems. The suggested odor control
technology shall be designed by the Engineer of Record to achieve 95% or greater
hydrogen sulfide removal. All systems, including those utilizing activated carbon,
shall be manufactured specifically for addressing hydrogen sulfide gas. Forced air
systems should be avoided due to the need to include provisions for electrical
power to the odor control system. For all odor control systems, the Engineer of
Section 800—Wastewater Pumping Systems & Force Mains - Page 68 of 70
Effective Date: April 12, 2022
Record shall provide sufficient easement area for long term maintenance of the
system.
10.Marker Posts: Force mains shall be marked with a plastic marker at every valve,
every horizontal fitting, and spaced every 1,000 feet along the force main. The
post shall having a minimum diameter of four inches and a minimum bury of thirty
inches with a minimum of four feet exposed. The exposed portion shall be painted
green and label "Apex Sewer". Marker posts shall be installed through outfalls,
easements, all non-residential areas, and as directed by the Water Resources
Director. Valves shall have marker posts only when they are installed outside of
paved areas.
808 Force Main Inspections and Testing
A. Inspections
1. All materials and equipment used in the construction of the wastewater pumping
system must be verified for compliance with the Specifications (or other approval
granted by the Town) by the Inspector prior to installation. Non-conforming
materials or equipment shall be immediately removed from the job site.
2. Compliance with plans and Specifications shall be verified on a regular basis by
the Inspector.
B. Testing
1. General
a) The Contractor shall furnish all materials, labor, and equipment to perform all
testing. Water for testing purposes may be obtained from the Town of Apex.
The Contractor shall reimburse the Town for all water used at Inside Utility
Rates.
b) All water or wastewater used during testing of the pump station, force main, or
any of the systems described in this section, must be returned to the Town of
Apex sanitary sewer system after proper coordination with the Town of Apex
Water Resources Department.
c) All on-site testing and/or installation verification shall be performed in the
presence of the Inspector or other representative authorized by the Town.
2. Force main Testing
a) The force main shall be tested in accordance with the water main standards
set forth in Section 600.
Section 800—Wastewater Pumping Systems & Force Mains - Page 69 of 70
Effective Date: April 12, 2022
The following tests must be run on coupons from factory lined ductile iron pipe:
a) ASTM B-117 Salt Spray (scribed panel)— Results to equal 0.0 undercutting
after two years.
b) ASTM G-95 Cathodic Disbondment 1.5 volts @ 77°F. Results to equal no
more than 0.5mm undercutting after 30 days.
c) Immersion testing rated on using ASTM D-714-87.
1) 20% Sulfuric Acid — No effect after two years.
0
2) 140°F 25% Sodium Hydroxide — No affect after two years.
3) 160°F Distilled Water— No effect after two years.
4) 120°F Tap Water (scribed panel) — 0.0 undercutting after two
years with no effect.
d) An abrasion resistance of no more than 3 mils (0.075mm) loss after one
million cycles using European Standard EN 598: 1994, Section 7.8
Abrasion Resistance.
Section 800—Wastewater Pumping Systems & Force Mains- Page 70 of 70
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Effective Date: April 12, 2022