20180307 Ver 2_More Info Received_20180614

Strickland, Bev
From:
Jason Marshall <[e-mail]>
Sent:
Thursday, June 14, 2018 12:49 PM
To:
Higgins, Karen
Cc:
Lindsay Matthy
Subject:
RE: [External] Stevens Creek Trunk Sewer response DMS Letter
Attachments:
Leakage Test Specification Response Letter - 02.14.2018 (001).docx;
PresTestwAirvsWaterR-25.pdf,
safety -co nsideratio ns_for_air_testing_of_pvc_sewer_pipes.pdf.pdf;
Air_Testing_of_Installed_PVC.pdf, 02735 Leakage Tests of Sewers.pdf
Karen,
See attachments, sorry if it's a lot, for what I sent over to previously. Our testing spec 02735 is also attached. When I
mentioned zero allowable leakage that refers to visible leakage and air testing must pass for acceptance. We never
accept a pipeline that has visible leakage or fails the test. Let me know if you would like to discuss and also see
responses below. I'll be out tomorrow but if you need anything Lindsay can assist copied on this email.
Thanks,
Jason
From: Higgins, Karen <[e-mail]>
Sent: Thursday, June 14, 2018 12:17 PM
To: Jason Marshall <Jason.Marshall @ghd.com>
Subject: RE: [External] Stevens Creek Trunk Sewer response DMS Letter
Jason -
Quick question — in some emails back and forth between you, Christyn and Sashi, there was some discussion
re the testing language and specifications but I'm not sure I have the final language. Please let me know if this
is correct:
In the specifications for leakage tests, the allowable leakage is 0 gallons for both pipe and manholes.
Yes, all visible. In addition to passing the air test, there shall be no visible leakage or moving water
observed in the pipe and invert. Correct. Infiltration testing or additional air testing and repairs will be
required if these situations occur. Correct, repairs and retesting will be required.
If you have updated specifications that reflect this already, please send those today if you can, or just let me
know if the language above accurately captures the discussion.
Thanks -
Karen

Karen Higgins
401 & Buffer Permitting Branch Supervisor
Division of Water Resources
Department of Environmental Quality
[phone] office
karen.higginsamcdenr.gov
https:Hdeg. nc.gov/about/divisions/water-resources/water-resources-permits/wastewater-branch/401-wetlands-buffer-
ep rmits
512 N. Salisbury Street (Archdale Building), Suite 942-E, Raleigh, NC 27604
1617 Mail Service Center, Raleigh, NC 27699-1617
Email correspondence to and from this address is subject to the North Carolina Public Records Law and may be disclosed
to third parties.
From: Jason Marshall [mailto:Jason.Marshal [e-mail]]
Sent: Wednesday, June 6, 2018 4:40 PM
To: Higgins, Karen <[e-mail]>; Wojoski, Paul A <[e-mail]>
Cc: Bartlett, Nicole <[e-mail]>; Lindsay Matthy <[e-mail]>; Woodie, David
<[e-mail]>; Fertenbaugh, Christyn L <[e-mail]>
Subject: RE: [External] Stevens Creek Trunk Sewer response DMS Letter
Karen,
Please see the attached submittal response to your comments dated May 24, 2018. Please let me know if there is
anything else you need or if you have any questions.
Thanks,
Jason
From: Higgins, Karen <[e-mail]>
Sent: Thursday, May 24, 2018 2:29 PM
To: Jason Marshall <Jason.Marshall @ghd.com>; Wojoski, Paul A <[e-mail]>
Cc: Bartlett, Nicole <[e-mail]>; Lindsay Matthy <[e-mail]>; Woodie, David
<[e-mail]>; Fertenbaugh, Christyn L<[e-mail]>
Subject: RE: [External] Stevens Creek Trunk Sewer response DMS Letter
Jason -
Please see attached request for additional information. Please note the letter gives 30 days for a response,
however for this project to make the July WQC meeting, I will need this add info ASAP.
Thanks -
Karen
Karen Higgins

401 & Buffer Permitting Branch Supervisor
Division of Water Resources
Department of Environmental Quality
[phone] office
karen.higginsa-ncdenr.gov
https:Hdeg. nc.gov/about/divisions/water-resources/water-resources-permits/wastewater-branch/401-wetlands-buffer-
ep rmits
512 N. Salisbury Street (Archdale Building), Suite 942-E, Raleigh, NC 27604
1617 Mail Service Center, Raleigh, NC 27699-1617
Email correspondence to and from this address is subject to the North Carolina Public Records Law and may be disclosed
to third parties.
From: Jason Marshall [mailto:Jason.Marshal [e-mail]]
Sent: Wednesday, May 23, 2018 1:24 PM
To: Higgins, Karen <[e-mail]>; Wojoski, Paul A <[e-mail]>
Cc: Bartlett, Nicole <[e-mail]>; Lindsay Matthy <[e-mail]>; Woodie, David
<[e-mail]>
Subject: [External] Stevens Creek Trunk Sewer response DMS Letter
Karen,
Please see the attached letter of acceptance for mitigation by NCDEQ Division of Mitigation Services. At this point we
would only plan to use this If required to do so pending EMC decisions on whether we can use the stream restoration
and mitigating effects of sewer as mitigation. The worst case area required for mitigation covers a 15' wide permanent
maintenance corridor totaling 121,546 sf within the 200' buffer. If required to make a payment do you think the EMC
would take into consideration a reduced amount due to mitigating effects of stream restoration? Please let me know if
there is anything else you need.
Regards,
Jason Marshall, PE
GHD
T: [phone] V: 864913 1 E: [e-mail]
222 South Church Street Suite 400 Charlotte North Carolina 28202 USA I www.ghd.com
WATER I ENERGY & RESOURCES I ENVIRONMENT I PROPERTY & BUILDINGS I TRANSPORTATION
Please consider our environment before printing this email
CONFIDENTIALITY NOTICE: This email, including any attachments, is confidential and may be privileged.
If you are not the intended recipient please notify the sender immediately, and please delete it; you should not
copy it or use it for any purpose or disclose its contents to any other person. GHD and its affiliates reserve the
right to monitor and modify all email communications through their networks.
This e-mail has been scanned for viruses

CONFIDENTIALITY NOTICE: This email, including any attachments, is confidential and may be privileged.
If you are not the intended recipient please notify the sender immediately, and please delete it; you should not
copy it or use it for any purpose or disclose its contents to any other person. GHD and its affiliates reserve the
right to monitor and modify all email communications through their networks.
This e-mail has been scanned for viruses
CONFIDENTIALITY NOTICE: This email, including any attachments, is confidential and may be privileged. If you are not
the intended recipient please notify the sender immediately, and please delete it; you should not copy it or use it for any
purpose or disclose its contents to any other person. GHD and its affiliates reserve the right to monitor and modify all
email communications through their networks.

SECTION 02735
LEAKAGE TESTS OF SEWERS
PART1 GENERAL
1.01. SECTION INCLUDES
A. Leakage testing by air pressure methods.
B. Manhole vacuum testing.
1.02. RELATED SECTIONS
A. Section 02601 — PRECAST CONCRETE MANHOLES AND STRUCTURES
B. Section 02732 - SANITARY SEWER PIPING
1.03. REFERENCES
A. Uni-Bell Plastic Pipe Association - UNI -B-6-98 Recommended Practice for Low Pressure Air
Testing of Installed Sewer Pipe. Refer to example calculation at end of this Section.
B. ASTM 1598 - Standard Test Method for Time -to -Failure of Plastic Pipe under Constant
Internal Pressure
C. ASTM D2122 - Standard Test Method of Determining Dimensions of Thermoplastic Pipe and
Fittings
1.04. SUBMITTALS
A. The CONTRACTOR shall submit proposed materials, methods, equipment, and operations
regarding cleaning and testing of gravity sanitary sewers to the ENGINEER for approval prior
to the start of cleaning and testing operations.
1.05. TEST REQUIREMENTS
A. Backfilling of the sewer trench to ground or road surface shall be in place and completed for
30 calendar days or as approved by Engineer, prior to start of testing of each Section of
sewer.
B. Testing shall be completed prior to final paving and final restoration.
C. Low pressure air test shall not exceed drop of 1.0 psig for time period listed in attached Table
02735-1. Test procedure shall conform to ASTM C828 except as modified by the UNI -Bell
Plastic Pipe Association Publication UNI -B-6-98, for Low Pressure Air Testing Of Installed
Sewer Pipe. Refer to Table 02735-1 for maximum allowable time for a 1.0 psig drop.
D. Deflection Test - Maximum deflection 5 percent. Refer to Section 02732, Sanitary Sewer
Piping, for detail of GO -NO-GO mandrel.
E. Maximum test length shall not exceed 1,000 feet.
Stevens Creek Trunk Sewer Phase 1
Charlotte Water Job No. 7030700047-17-503 02735-1 LEAKAGE TESTS OF SEWERS

In the case of sewers laid on steep grades, the length of line to be tested at any one
time may be limited by the maximum allowable internal pressure on the pipe and
joints at the lower end of the line. The recommendations of the pipe manufacturer
shall be followed in this regard.
F. The Engineer shall witness all tests.
G. Leakage Tests - Replacement of Existing Sewer Systems - Leakage tests shall be performed
on new sewer and manholes, replacing existing sewers and manholes, using one of the
two methods described as follows:
Where existing live sewers and live laterals have been replaced with new piping,
leakage tests shall be performed by the above-described methods if (a) the section
has no laterals between manholes; (b) can be plugged off without affecting existing
connected facilities; and (c) the flow at the upstream manhole can be pumped around
the section to be tested.
2. Where the section to be tested has live lateral connections, test methods shall be
performed by television inspection and joint testing methods. Where the new piping
fails to pass inspection or joint tests, the failed pipe or joint shall be re -excavated and
replaced with a permanent repair satisfactory to the Engineer (using chemical sealant
to stop leaks in new pipe is not an acceptable method).
1.06. PROJECT RECORD DOCUMENTS
A. Submit documents under provisions of Section 01700, Record Documents.
B. The following copies of forms for testing are attached to the end of this Section.
1. Low Pressure Air Testing of New Sewers.
2. Table 02735-1, Low Pressure Air Testing of Sewers, including attached Appendix I.
3. Manhole vacuum tests.
1.07. FIELD MEASUREMENTS
A. Low Pressure Air Testing
Measure length of section to be tested.
2. Measure time interval and pressure drop.
3. Record measurements on GHD Form 169.
1.08. COORDINATION
A. Coordinate maintenance of traffic with local authorities.
PART PRODUCTS
Not used.
Stevens Creek Trunk Sewer Phase 1
Charlotte Water Job No. 7030700047-17-503 02735-2 LEAKAGE TESTS OF SEWERS

PART 3 EXECUTION
3.01. EXAMINATION
A. Backfill has been in place the required time before start of test.
B. No connections to live sewers or live laterals have been made unless directly replacing
existing sewer.
3.02. PREPARATION
A. Pipelines and manholes have been flushed and cleaned of all debris, stones, silt, etc. such
that all surfaces of pipe and manholes are visible.
B. The Contractor shall have on the job all the proper tools, pipe plugs, air bags, gauges,
pumps, wires, water trucks, compressors, etc. necessary to properly test the pipe and
manholes.
3.03. TESTING
A. Low Pressure Air Testing
1. Prior to start of test permanently repair all visible leaks.
2. Isolate each section to be tested with air tight plugs.
3. Low pressure air testing procedures shall conform to ASTM C-828 as modified by
UNI -B-6-98.
4. On ductile iron pipe sewer sections, no pressure drop is permitted.
5. On PVC sewers, the maximum allowable drop in pressure from the test pressure
shall be 1.0 psig during the minimum holding time.
a. Test pressure shall be calculated using the following equation:
H
P = 3.5 + (psig)
2.31
where:
P = Test pressure, maximum of 10 psi
H = Height of groundwater above invert
6. All pressurizing equipment used for low-pressure air testing shall include a regulator
or relief valve set no higher than 10 psig to avoid over -pressurizing and displacing
temporary or permanent plugs. In no case should the starting pressure exceed 10.0
psig.
7. Either mechanical or pneumatic plugs may be used. All plugs shall be designed to
resist internal testing pressures without the aid of external bracing or blocking. If
pneumatic plugs are utilized, a separate hose shall also be required to inflate the
pneumatic plugs from the above ground control panel. Plug the upstream end of the
line first to prevent any upstream water from collecting in the test line. This is
Stevens Creek Trunk Sewer Phase 1
Charlotte Water Job No. 7030700047-17-503 02735-3 LEAKAGE TESTS OF SEWERS

particularly important in high groundwater situations. When plugs are being placed,
the pipe adjacent to the manhole shall be visually inspected to detect any evidence of
shear in the pipe due to differential settlement between the pipe and the manhole. A
probable point of leakage is at the junction of the manhole and the pipe, and this fault
may be covered by the pipe plug, and thus not revealed by the air test.
8. To facilitate test verification by the Engineer, all air used shall pass through a single,
above ground control panel. The above ground air control equipment shall include a
shutoff valve, pressure regulating valve, pressure relief valve, input pressure gauge,
and a continuous monitoring pressure gauge having a pressure range from 0 to at
least 10 psi. The continuous monitoring gauge shall have minimum divisions of
0.10 psi and an accuracy of ±0.04 psi. The equipment to include a separate certified
test gauge for periodic checking of the accuracy of the basic equipment gauges.
9. Two separate hoses shall be used to: (1) connect the control panel to the sealed line
for introducing low-pressure air, and (2) a separate hose connection for constant
monitoring of air pressure build-up in the line. Low pressure air shall be slowly
introduced into the sealed line until the internal air pressure reaches 4.0 psig greater
than the average back pressure of any groundwater above pipe, but not greater than
10.0 psig. After a constant pressure of 4.0 psig is reached, the air supply shall be
throttled to maintain that internal pressure for at least 2 minutes or until the
temperature of the entering air to equalize with the temperature of the pipe wall.
When temperatures have been equalized and the pressure stabilized at 4.0 psig, the
air hose from the control panel to the air supply shall be disconnected.
10. The continuous monitoring pressure gauge shall then be observed while the pressure
is decreased to no less than 3.5 psig (greater than the average back pressure of any
groundwater over the pipe). At a reading of 3.5 psig, timing shall commence with a
stop watch or other timing device that is at least 99.8 percent accurate.
11. If the time shown in Table 02735-1 (at the end of this Section) for the designated pipe
size and length elapses before the air pressure drops 1.0 psig, the section
undergoing test shall have passed the leakage test. The test may be discontinued
once the prescribed time has elapsed even though the 1.0 psig drop has not
occurred.
12. If the pressure drops 1.0 psig before the appropriate time shown in Table 02735-1
has elapsed, the air loss rate shall be considered excessive and the section of pipe
has failed the test.
13. If the section fails to meet the above requirements, the Contractor shall determine at
his own expense the source, or sources of leakage, and he shall repair or replace all
defective materials and/or workmanship to the satisfaction of the Engineer. The
extent and type of repair as well as results, shall be subject to the approval of the
Engineer. The completed pipe installation shall then be retested and required to
meet the requirements of this test.
14. The times shown in Table 02735-1 are for the length of main sewer tested. For
lengths other than those shown, the time to be interpolated. Further, the tables do
not have any reduction of time for length of laterals connected to the section of sewer
being tested since it normally is not significant. For all precise calculation of time
allowance including laterals, refer to UNI -Bell UNI -B-6 publication and the sample
calculations and formula shown at the rear of this section.
Stevens Creek Trunk Sewer Phase 1
Charlotte Water Job No. 7030700047-17-503 02735-4 LEAKAGE TESTS OF SEWERS

B. Manhole Vacuum Testing
General
a. After the manhole has been completely constructed, the frame installed
thereon, and the trench backfilled, a vacuum test shall be performed.
b. Any damage caused to properties due to sewage handling and/or sewage
backup while vacuum testing shall be the responsibility of the Contractor.
2. Vacuum Testing Equipment - Furnish testing equipment as specified in the
manufacturer's written instructions. For this procedure, pressure gauge MUST read in
inches of mercury, not in psi.
3. Vacuum Test Procedures
Perform vacuum testing in accordance with the testing equipment
manufacturer's written instructions.
b. Draw a vacuum of 10 inches of mercury and close the valves.
Manhole will be acceptable when vacuum does not drop below 9 inches of
mercury for the following manhole sizes and times:
1) 4 -Foot Diameter - 60 seconds.
2) 5 -Foot Diameter - 75 seconds.
3) 6 -Foot Diameter - 90 seconds.
Repair or replace defective manholes and retest.
4. If the manhole fails to meet the above testing requirements, the Contractor shall
determine, at his own expense, the source(s) of the leakage, and he shall repair or
replace all defective materials and/or workmanship to the satisfaction of the
Engineer. The extent and type of repair, as well as results, shall be subject to the
approval of the Engineer. The completed repairs shall then be retested and required
to meet the leakage requirements of this test.
Stevens Creek Trunk Sewer Phase 1
Charlotte Water Job No. 7030700047-17-503 02735-5 LEAKAGE TESTS OF SEWERS

TABLE 02735-1
LOW PRESSURE AIR TESTING OF SEWERS
PIPE
DIAMETER
(INCHES
*SHORTEST
TIME
(MIN:SEC)
LENGTH
FOR
SHORTEST
TIME (FT.)
I TIME FOR
LONGER
LENGTH
(SEC.)
TIME (MIN:SEC) FOR LENGTH (L) SHOWN
100 FT.
7150 FT.
200 FT.
250 FT.
300 FT.
350 FT.
4
3:46
597
0.380 L
3:46
3:46
3:46
3:46
3:46
3:46
6
5:40
398
0.855 L
5:40
5:40
5:40
5:40
5:40
5:40
8
7:34
298
1.520 L
7:34
7:34
7:34
7:34
7:36
8:52
10
9:26
239
2.374 L
9:26
9:26
9:26
9:53
11:52
13:51
12
11:20
199
3.418 L
11:20
11:20
11:24
14:15
17:05
19:56
15
14:10
159
5.342 L
14:10
14:10
17:48
22:15
26:42
31:09
18
17:00
133
7.692 L
17:00
19:13
25:38
32:03
38:27
44:52
21
19:50
114
10.470 L
19:50
26:10
34:54
43:37
52:21
61:00
24
22:40
99
13.674 L
22:47
34:11
45:34
56:58
68:22
79:46
27
25:30
88
17.306 L
28:51
43:16
57:41
72:07
86:32
100:57
30
28:20
80
21.366 L
35:37
53:25
71:13
89:02
106:50
124:38
33
31:10
72
25.852 L
43:05
64:38
86:10
107:43
129:16
150:43
36
34:00
66
30.768 L
51:17
76:55
102:34
128:12
153:50
179:29
*Time allowed for 1.0 psig drop in pressure.
Stevens Creek Trunk Sewer Phase 1
Charlotte Water Job No. 7030700047-17-503 02735-6 LEAKAGE TESTS OF SEWERS

{pl'1:11H>i 1
uts$ suit 17 scronds.
1►> Al LOWABLE A1R LDSS RATE
lateral sewers ha.6 bun Isnama-L rhe lest
10.11 EXAMPLE 0
A Q value Fair 91015 cubic fast pea asunuls
Ions shad be se:ampussd an lncludc all
!0 1 PUAPbfE
A mauludc t•. manhole modest at
per rquar6 foul clad be "lilt-64 it. auuat
lastral 84wtrs "sins ills following forestult:
It's Pappose of 11,11 Appendix is Ira Ilius.
14 Inch pipe It 12 feel lung. W-
file owner of qualisy pipe naerNals. 8,o.d
"-
line the pn.per applic4sluss of this. Ie:no1•
$tquheJ scat lune f..i s O S Pala
wolk.nanship, and missile joimk.
4-rojrd pascflce walk I.gaIJ fo appropriate
of ... P!
It 3 T f$Y TIPAE CAI. CIIs.A TION
•o al •_•,.n l g
4t.1 Ii... c selscll..n. ]ha 4.4noplt. dant Ad
S-4.446-o' laid. 11 moss be use
All lass Ibnrs abIll be c+.lcu1.ie4 6.dn$
�41a
7'sost A!f' i b, 1&I• . f•,l -_a 4
moa" include s wariclti of randillnns wldch
a 0.3 pill penult drop is 1pacifi.
Haniplu'a trluslWis:
Iuay be tna.util[seti In Iht held.
11 Ica is Ica litan Tl,e 99 fa.
[1!(
lit? EXAMPI E A
41tarl+.Ic.1 with lilt ndnhItulle test
T w OOIS
ai
A lanhnli lit pistillate Beads of nominal
■ 24 lucl. pirrhrle. tiler uslninauns
Wilted: T Slus61ssl thus, ht r6.onJa.
1 � inch plpt is 3S0 feel lung. too sass#.$
assail apply. Titus. site requutil
%Ylittst: T - Shusisto lime. In aeennds,
allowed fu& file all pus-
:•a.na<siana sahA in Aft leach. What It the
far a O S prig prsuwt dwp ntu6o
allowed Iu1 the ail era-
I'
rude 4a druji 1.0 ptlg
AraolItd dell lime for 4 01 pall PAnnut
(! I minue.s and 30 trcnudtf
cute to drop IApds,
ff s O 000119 (ill./ t 1711, •
Jf+.p•
10.6 EXAMPLE E
K - O tX10I19 111., bus nus less
s (pall.•), but not lets
.V.•h.Fksn- The requlrcd 1619 1114114c can mss
A 411 fool se:stun of nunAnel
Ilaan S 0.
linea I.U,
ae'al dltealy frlvaa table 1!" Fur 7S0 feel
rawer pope has been readied for 4'
Q - 0001S cubs: fe41/tnloulc/
ill 12 Inch pipe, lite requited feu links ilk
A hila! of 17S feel afasominal61
tgtsarc feet illmiensol
Q - anal$cat A, /In ill. /sq.fl.
9.12 (9 minuses and 31 seconds).
at piping and 141 feel of nnmin
6"oface,
of inlcanudl ouafars-
10.11XAMP/E 8
Ialsfas piping bf:.Itch aft of site
lb tdasabs.l pipe deamelss in
A 350 foul eccik.n of nomloal I? Inca pipe
sewer line. All saiesals has We-
Inches, anti
V ready for Icrllng. A notal of 131 feel of
anti/ua plugged anti will be tested
1. - I-syph of pipe being lest-
til, Da, + Nominal dlamelcfs of the
4 incoa fattest •ewes pipe U .nnns.sed to
anuli the IS Inch utslas line. ])as
ad In fees.
sac. dlffeeenl size plpsa being
she 350 fool seceloa and will be 1n.iYdad
pressure chop which will be: ibis
jelled.
in e1.6 rep. Wf.a will be the fequlacd je61
pd0_ wham is the appeoPmlase 1461
For anomic allkiesal Ieating of Ione tell
Ione foe a O.S psis rotsassre deep!
this pipe nctw'arkl
ascliuns andfor secralnns of Iris.. Ji.rocice
Lt. 1-l. Ite/ptcslve lenphl ed da
Sufa.rltts 1 social sawera sway be dis4epld-
Solusio.asr All Partial sewrt sites an
plrcm, a llmoacJ rscasuee Jror of U S pals
rlc. dilfrrrnl site pipes brills
NJ when saltilbtg test limes Isee Secaioss
assay be JaucgaaJeti 661ce Ihcif wl
assay be used ht lieu of Ills 1-0 pais lamed
jcnsJ-
9 41- 1 hele9inr, ills uquiaed sell 11.116 will
genitally nus dsealfkaa asu,asla s.
pse.lura dwp. If ■ O S pits pfessura drop It
1. the esrue so for kasaaple A. f r., 9 ntln-
conapulsllnn Isefes w Secla.t. 9.4
Itself, file appsskpelAc requiocd ren fb.1at
If lilt secontpuled Ica sinks Is shoes tnouoh
Wes and S0 sscunds.
11 assume be used foe a 0.5 pets
.hall he ax8cily hall as Inns a■ limed tit.-
to allose: rhe mclion Ieusd to pass. Ilaen she
Now If lateral "were lied Awl basis all-
sloop. The foams eohaasan In it"
P T
fainted using RamseieA% ea ssalloAs foe T
1
sectisvt dldl bit presunscJ to be fret of
resaadcJ, like requheJ Iasi lino would be
slides she appaapmisls fotmula for
ciesd abnwe.
dsftels a0J compiy trills Ill ls apsclficalion-
Ill minutes and 11 second&, it.. oody 34
Ins Ills Iegtshed Iasi Ilene because
9.4 TESi1Mfl MAIN SEWERS WITII
Y.6 SFFCI!'IEI) TI$4E TABLES
waskjs longer.
Is tangcr span rite 4hir4 column
I ATEHAL SEWERs
To fa.dllate lilt plapee use of Ibis rscom-
10.4 EXAP"I E C
1S feet.
It is often runwcnin.l lit Include couneresd
mellded puclke flu sit truing. Ths I.+dow-
Whai should she required Ira lime Its hu a
lateral ocwGIs when letting asw6t nsahtt
Ins lubles tie plovldsd- TaLle 1 contains
1 0 psis pressure deur In Ill fest of mount-
T - 11.74 L - ? 671 It 441 - 1.141a.
hawks lateral sewers. if ialtr.l stwur ars
lilt fps Hwis nalnhaum shave. «qubcJ (or b
bill IN lowh dianarics pipe between two
incluJeJ Ilk Ills lest, little knsllu mossy sen.
1 O pats rsriwos Jrup loans ■ pealing pies.
sn,nholcel
The required fest shut It 1.1130 sc
sully be isa ureal for campa4un8 4411.414d
osis of so seass 3.1 pals greaser than the
S••1.F4,w The exact less lime Is easily
IM naloaaoes aoJ 30 sa, at,.Ji-
test fines. 11.16 cook be tions because so,
arresst ba.L parnues of any 11uundwslci
cal-lactd by assists Table L Tabte 1 u
pescfke. IBnoalns of.. beaneh, lateral, or
above ohs plpe'a Iawle. Table 11 contain&
used because a 1.0 rale plead- drop Is
Louse ssweaa will nus..ally hacaaae mile
wccalseJ mitilmum sim6s sequ14ed foe a O. 1
rpt¢lflsd. Sines 327 =set ex,•o.ds Bl.r ?91
sswerdky of Ihs sir $ase wba tsve. It's tooled
psi$ pres■u.e chop film a $44411.8 pe6nuas
foot 34-011. smsoclsltd wish it.* miniaaaunb
suds., area 16 Its. than 625 squs.6 face ao
of ■s menu ].S Pals iesuea than sets average
1"I untr got on 4 t.-,h plpellns. ohs fe.wrh
still rise lord rub of 141sclian alar uniy be
back pseuuas of any 8joundwslse ab-s
tnl.a na Ors Table 1 (hall be used 1u quILILIV
Incfcws d about 2%. 1f Also total $esI'd But.
The Pire'e Invert
calculals 11.6 lequhed feel flea,. as (.flows,
Pica ails Is, gotates Than 61S mquire reel.
lsnnllns lite lascoal "-sit will only ■Iishlly
T - I.510 IL - 1.57 a 327 - 497 as:ands
dttttaes else bsrsaily of /he aero.
In Ila even$ a less section, having a
Th6raiarr. 1ht required Ie:I stns fom ■ 1.0
Iota) mstlessiat surfwe 8164 Iasi &has fits
PJI rialuA6 drop 4 497 secunda, no d min-
squaw (641, sells to p»e Ihs 814 leas "also
Stevens Creek Trunk Sewer Phase 1
Charlotte Water Job No. 7030700047-17-503 02735-7 LEAKAGE TESTS OF SEWERS

LOW PRESSURE AIR TESTING OF NEW SEWERS
Date:
Project:_
Contractor:
Weather:
Job No.
Contract No.
Section
Tested (List
Manholes)
Length
(Feet)
Diameter
(Inches)
Material
Time
Start/Time
Finish
Time
Interval
(Minutes)
Air Pressure
Initial/Final
(psig)
Total
Pressure
Loss (psig)
Pass/
Fail
to
to
to
to
to
to
to
to
COMMENTS:
WITNESS:
OWNER/ENGINEER
Name
WITNESS:
CONTRACTOR
Name
Title
Title
Signature
Signature
Stevens Creek Trunk Sewer Phase 1
Charlotte Water Job No. 7030700047-17-503 02735-8 LEAKAGE TESTS OF SEWERS

MANHOLE VACUUM TEST
Date:
Project:_
Contractor:
Weather:
Job No.
Contract No.
Manhole No.
Inside Diameter (Feet)
Required Test Time
(Seconds)
Initial Vacuum
(10 inches)
Final Vacuum
Pass/Fail
COMMENTS:
WITNESS:
OWNER/ENGINEER
Name
WITNESS:
CONTRACTOR
Name
Title
Title
Signature
Signature
END OF SECTION
Stevens Creek Trunk Sewer Phase 1
Charlotte Water Job No. 7030700047-17-503 02735-9 LEAKAGE TESTS OF SEWERS

1� PIP O
AIR TESTING OF INSTALLED PVC PIPELINES
GRAVITY SEWER PIPE
Air testing is often performed on sewer pipelines to ensure the integrity of installed materials and to verify that correct
construction methods have been used. Prior to testing, all connections and service laterals should be plugged and adequately
braced to resist test pressures.
The document most often specified for air testing is ASTM F1417 "Standard Test Method for Installation Acceptance of Plastic
Gravity Sewer Lines Using Low -Pressure Air." In sections 5.2 and 6.1.4, F1417 specifies an upper limit for test pressure by
requiring a pressure regulator set to a maximum of 9 psig.
. Safety Considerations
Although 9 psi is considered low-pressure testing, there are still significant forces involved. For example, end plugs on a 24 -
inch ASTM F679 sewer pipe pressurized to 9 psi must be braced to resist an end thrust of about 3,900 pounds. If a plug were
to let go, rapid expansion of compressed air could push it out of the pipe forcefully and create a rush of air — risking injury
for anyone in the manhole structure. Safety dictates that personnel should not be in a manhole during pressure testing.
PRESSURE PIPE
Water pipe is pressure tested for the same reasons as gravity pipe, but the pressures are much higher. Typically, project
specifications allow test pressure to be as high as the pressure class of the pipe. Using 24 -inch DR21 Pressure Class 200 AW WA
C905 pipe as an example, the end thrust would be about 86,000 pounds (more than 20 times as high as the sewer -pipe force
described above).
• Test PVC Pressure Pipe With Water Only
The compressible nature of air means that extremely high potential energy is stored in the pipe during high-pressure air
testing. According to the Handbook of PE Pipe, any failure in the piping system would have dangerous consequences, since the
energy released (compared to testing with water) would be much greater, more forceful, and of longer duration.
Even when water is used, it is important that all air be expelled from the pipeline during filling and again before pressure
testing. Automatic air -release valves are recommended. See Uni-Bell Technical Brief, "Air Valves: A Cost -Effective Way to
Enhance Pressure -Pipe Performance."
• Air -Pressure Testing of Installed PVC Pressure Pipe is Expressly Prohibited for Reasons of Safety
Because it sometimes difficult to obtain water due to site conditions, the question of air testing is sometimes raised. For
safety reasons, the PVC Pipe Association is adamant that PVC pressure pipe be tested with water only and that UNDER NO
CIRCUMSTANCES SHOULD AIR TESTING BE PERFORMED ON PRESSURE PIPE. See Uni-Bell's Handbook of PVC Pipe
and "Installation Guide for PVC Pressure Pipe."
References: ASTM standards F679 and F1417; AWWA standard C905; Handbook of PE Pipe; Handbook of PVC Pipe; and "Air Valves: A
Cost -Effective Way to Enhance Pressure -Pipe Performance;' Uni-Bell Technical Brief

February 14, 2018
North Carolina Division of Water Resources
Public Water Supply Section
Plan Review Group
Attn: Ms. Shashi Bhatta
512 N. Salisbury Street, Rm. 925S
Raleigh, NC 27604
Dear Ms. Bhatta:
Reference No. 11123681
Re: Stevens Creek Trunk Sewer Phase 1 — Variance Application: Leakage Test of Sewers
Specification Approval
Proiect Name: Stevens Creek Trunk Sewer
Coordinates: approximately (35.146,-80.650)
GHD Job Number: 11123681
Charlotte Water Proiect Number: 2017000405
We are working with Christyn Fertenbaugh with the PERCS Unit of NC-DWR on a variance request to
utilize PVC as an equal to ductile iron pipe for our gravity sewer project (Stevens Creek Trunk Sewer)
located within the Goose Creek Riparian Buffer. As part of this variance, we are requesting approval of
our quality testing method specifications for leakage tests of gravity sewers (attached). We are proposing
to low pressure air test the sewer main in place of the water pressure test method as specified in the
water main standards as found in 15 A NCAC 18C, per 15A NCAC 02T.0305(g)(5).
We have found air testing to be an adequate and effective method for leakage testing equal and/or greater
to that of water testing methods for low pressure gravity sewer main applications. We are proposing to
utilize PVC, AWWA C900 Pressure Class 165 psi, DR25 pipe for this project. As our project is a proposed
gravity sewer with generally lower pressures than pressurized water mains, and in utilizing a higher class
of PVC pipe than typically required for gravity flow applications, it is our understanding that high pressure
hydrostatic testing should not be required. Due to its lower viscosity and surface tension properties, air
has been shown to more effectively indicate leaks within pipes. These properties allow air to seep through
smaller openings than water which also allows for leakage testing at lower pressures.
Understanding the expansive properties of air and the potential for increased dangers versus the use of
water, low pressure testing is not to exceed 10 psi as indicated in our specifications. All necessary safety
precautions will be taken and have been outlined in our specifications procedure for air testing.
In addition to the above mentioned benefits for performing leakage testing with air for our application, due
to the location of the proposed sewer alignment through a largely wooded area and large horse pasture, it
may be difficult for the contractor to access water sources suitable to perform testing. It may also be
difficult for the contractor to de -chlorinate the test water prior to disposal to the environment should it be
required.
Included with this letter you will find plans, detail and specifications for the proposed project.
GHD appreciates your assistance with this project. Please contact me at [phone] or
Jason. [e-mail] if you have any questions or require additional information.
GHD
222 South Church Street Suite 400 Charlotte North Carolina 28202 USA XS0 9001
T704 342 4910 F 704 342 4911 W www.ghd.com ENGINEERING DESIGN

Sincerely,
GHD
Jason Marshall, PE
Project Coordinator
Encl. Plans
Specifications and Details
cc: Nicole Bartlett, Charlotte Water
Michael Bisignani, GHD
Lindsay Matthy, GHD
Leakage Test Specification Response Letter - 02.14.2018 (001).docx

Engineering
& Technical
Data
R-25
M
Pressure Testing
with Air
VS.
Pressure Testing
with Water
Pressure testing of water mains and sewage force mains to detect leakage prior to final payment, is common
construction practice. The EJP Service Department does pressure tests with either air or water, as required. We are
often asked why air testing must be done at lower pressures than with water. The following questions and answers
discuss the reasons for lower air test pressures.
Question: 150 (lbs./sq. inch) of water pressure equals how many (lbs./sq. inch) of air pressure?
Answer: 150 (lbs.Aq. inch) of water pressure equals 150 (lbs✓sq. inch) of air pressure. The force experienced
on the interior of the pipe is the same for either air or water. This would be significant if a pressure
test were performed to determine if the pipe had structural integrity, (i.e. will it burst during its ser-
vice life?). However, this is not the purpose of a pressure test for leakage.
Question: If the forces are the same for both air and water, why should people refuse to test to 150 (lbs./sq.
inch) with air?
Answer: It's veru dangerous!!! Unlike water, which is incompressible, air is veru compressible, making it
hydraulically equivalent to a large mechanical spring. If something were to break or come free during
a high pressure air test, the released air could propel an object a great distance with much force. This
is why the necessary elimination of trapped air when initially filling pipelines can be so hazardous;
air tries to move things to relieve built up pressure; water, because it is incompressible, does not.
Question: In finding leaks, why is a low pressure (30-50 lbs./sq. inch) air test as effective as a high pressure
(150 lbs./sq. inch) water test?
Answer: The viscosity and surface tension of water are eachrg eater than that of air. Both of these are
unique forces that prevent water from escaping through a very small hole, but do not prevent air
from escaping from the same small hole.
Reasonings: Dynamic Viscosity of Water @ 40 degrees F = 0.0000323 lb. ft. per sq. ft.
Dynamic Viscosity of Air @ 40 degrees F = 0.000000363 lb. ft. per sq. ft.
So, the viscosity of water is about 89 times greater than the viscosity of air, where... Viscosity is
the internal friction of water and makes it resist the tendency to flow, particularly through a small
opening.
Surface Tension of a Water to Air Surface = 0.005 IN ft./ft.
Air has no surface tension (no free surface).
O

I
P1
SAFETY CONSIDERATIONS FOR AIR -TESTING OF PVC SEWER PIPES
I
ON
i
1upw
Plastic sewer pipelines are typically leakage -tested after installation. The most common method is low-pressure air testing per ASTM
F1417 "Installation Acceptance of Plastic Non -Pressure Sewer Lines Using Low -Pressure Air." Since air is a compressible material that
expands rapidly if released, safety precautions should be followed.
AIR -TEST THRUST FORCES FOR LARGE -DIAMETER PVC SEWER PIPE
ASTM F1417 recommends air testing at 4 psi. However, the standard calls for increasing the internal test pressure to counteract ex-
ternal pressure caused by groundwater above the joint. The maximum internal pressure permitted is 9 psi. The table below provides
the thrust forces for large -diameter PVC sewer pipe for pressures in 1 psi increments from 4 to 9 psi.
Pipe Size (in)
4 psi
Thrust Force Against Air -Test End -Plug
Test Pressure
5 psi 6 psi 7 psi
8 psi
9 psi
24
1700
2100 2600 3000
3400
3900
27
2200
2700 3300 3800
4400
4900
30
2900
3600 4300 5000
5700
6400
36
4100
5200 6200 7200
8200
9300
42
5500
6900 8300 9700
11000
12400
48
7200
9000 10800 12600
14400
16200
54
9300
11600 13900 16200
18600
20900
60
10600
13300 15900 18600
21200
23900
Although pressures are less than 10 psi, thrust forces become very large (for 60 -inch pipe: over 10,000 lbs at 4 psi; about 24,000 lbs at
9 psi). With these high forces, it could be dangerous if an end -plug were to let go. Personnel should follow safety procedures.
SAFETY GUIDANCE
ASTM F1417: The ASTM air -testing standard cautions that measures should be taken to protect personnel. Section 6 provides safety
precautions, including the following:
• Clause 6.1.1: "No one shall be allowed in the manholes during testing."
• Clause 6.1.3: "When lines are tested, it is mandatory that all the caps and plugs be braced as an added safety factor."
• Clause 6.1.5: "A regulator or relief valve set no higher than 9 psi shall be included on all pressurizing equipment."
It is recommended that jobsite air testing procedures conform to ASTM F1417.
Plug Manufacturer's Installation Instructions: The installer of end -plugs should also review and conform to the recommenda-
tions of the producer of the plug being used.
SAFETY IS PARAMOUNT
Although the pressures specified for sewer -pipe air testing are considered low, the resulting thrust forces on a pipeline's end plugs
can be substantial.
Note: this document discusses low-pressure (maximum 9 psi) air testing for PVC gravity sewer pipes. Under no circumstances should
high-pressure air testing be performed on any PVC pipes. Uni-Bell's Handbook of PVC makes this point in section 11.8.3: "Air pressure
testing of installed PVC pressure pipe is expressly prohibited for reasons of safety."
References: ASTM F679 "Polyvinyl Chloride (PVC) Large -Diameter Plastic Gravity Sewer Pipe and Fittings" (2015); ASTM F1417 "Installation
Acceptance of Plastic Non -Pressure Sewer Lines Using Low -Pressure Air," (2011); Handbook of PVC Pipe, Uni-Bell (2013)
[or -291V