25067_DynatechIII_MethaneDesignReport_Rev2_NoDesignDrawings

Prepared for
704 West Tremont Owner, LLC
(Prospective Developer)
4445 Willard Avenue, Suite 900
Chevy Chase, MD 20815
METHANE MITIGATION SYSTEM
DESIGN REPORT
DYNATECH III BROWNFIELDS PROPERTY
TOOMEY AVENUE AND
WEST TREMONT AVENUE
CHARLOTTE, NORTH CAROLINA
Brownfields Project No: 25067-21-060
Prepared by

1300 South Mint Street, Suite 300
Charlotte, NC 28203
Project Number GC8028
November 2022

CERTIFICATION PAGE
METHANE MITIGATION SYSTEM DESIGN REPORT
DYNATECH IIBROWNFIELDSPROPERTY
TOOMEY AVENUE
AND WEST TREMONT AVENUE
CHARLOTTE,NORTH CAROLINA
Brownfields Project No:25067-21-060
Prepared by:
Michael S.Burcham,PE(NC)
Senior Engineer
R.Matthey Jenny,PE(NC)
Senior Engineer
Reviewed by:
KetfreyM.Afrens,PENC)
Principal Engineer
Gregory T.Corcoran
Senior Principal Engineer
PROFESSIONAL ENGINEER SIGNATURE
I,Michael S.Burcham,a Licensed Professional Engineer for GeosyntecConsultants of NC,P.C.,do
certify that the information in this report is correct and accurate to the best of my knowledge.
The Methane Mitigation System (MMS)detailed herein is designed to mitigate intrusion of subsurface
vapors into the subject building from known Brownfields Property contaminants in a manner that is in
accordance with the most recent and applicable guidelines including,but not limited to,DWM Vapor
Intrusion Guidance,Interstate Technology &Regulatory Council (ITRC)guidance,andAmerican National
Standards Institute (ANSIVAmerican Association of Radon Scientists and Technologists (AARST)
standards.The sealing professional engineer below is satisfied that the design is fully protective of public
health from known Brownfields Property contaminants.
GeosyntecConsultants of NC,P.C,islicensedto practiceengineering in North Carolina.The
certification number (Firm's License Number)is C3500.LIWit,CAAIH
SEAL
WAELS.NEER
Michael S.Burcham,PE (NC)
Senior Engineer
North Carolina P.E.License No.0503 12
Expiration Date:31 December 2022
GeosyntecConsultants of NC,P.C.
2501 Blue Ridge Road Suite 430
Raleigh,NC 27607
Telephone:[phone]S76
NCHAM

GC8028/CAR21094 i November 2022
TABLE OF CONTENTS
1. INTRODUCTION .............................................................................................. 1
1.1 Terms Of Reference And Report Organization ........................................ 1
1.2 Regulatory Setting and Background ......................................................... 2
1.3 Environmental Site History ....................................................................... 2
1.4 Redevelopment Strategy ........................................................................... 5
2. DESIGN BASIS ................................................................................................. 6
2.1 Design Objective ....................................................................................... 6
2.2 Design Qualifications ................................................................................ 6
2.3 Design Criteria .......................................................................................... 6
2.4 Design Approach ....................................................................................... 6
2.5 Design Framework (Buildings 1 through 4) ............................................. 8
2.6 Geomembrane Vapor Barrier (Buildings 1 through 4) ............................. 9
2.7 Subslab Venting Layer and Venting Components (Buildings 1 through 4) ................................................................................................................. 10
2.7.1 Aerated Floor Cupolex Void Space ............................................ 10
2.7.2 Extraction Vent Piping ................................................................ 10
2.7.3 Air Inlet Piping ............................................................................ 11
2.7.4 Extraction Fans ............................................................................ 11
2.8 Monitoring System (Buildings 1 through 4) ........................................... 12
2.8.1 Indoor Air Methane Monitoring and Alarm Conditions ............. 13
2.8.2 Vent Riser Methane Monitoring ................................................. 14
2.8.3 Vent Riser Static Vacuum Monitoring ........................................ 15
2.8.4 Subslab Manual Monitoring ........................................................ 16
2.9 Electrical Installation and Connections (Buildings 1 through 4) ............ 16
2.10 Pool Equipment Room Mitigation .......................................................... 17
2.10.1 Geomembrane Vapor Barrier ...................................................... 17
2.10.2 Aggregate Venting Layer ............................................................ 17
2.10.3 Exhaust Piping and Wind-Driven Turbine .................................. 17
2.10.4 Subslab Monitoring ..................................................................... 18
2.11 Impervious Surfaces Mitigation .............................................................. 19
3. QUALITY ASSURANCE AND QUALITY CONTROL ............................... 20

GC8028/CAR21094 ii November 2022
3.1 Contingent Tenant Improvements (First-Floor Retail) ........................... 20
4. POST-CONSTRUCTION/PRE-OCCUPANCY SYSTEM EFFECTIVENESS TESTING ......................................................................................................... 22
4.1 MMS Diagnostic Testing ........................................................................ 22
4.1.1. Methane Monitoring .................................................................... 23
4.1.2. Pressure Field Extension Testing ................................................ 23
4.1.3. Flow and Vacuum Monitoring .................................................... 23
4.2 Pre-Occupancy Performance Monitoring ............................................... 23
4.2.1. MMS Operational Evaluation ..................................................... 24
4.2.2. Subslab Soil Gas Monitoring ...................................................... 24
5. POST-OCCUPANCY SYSTEM EFFECTIVENESS TESTING .................... 27
6. CONTINGENCY PLANNING ....................................................................... 28
7. FUTURE MMS MODIFICATIONS ............................................................... 32
8. REPORTING ................................................................................................... 33
9. OPERATIONS, MAINTENANCE, AND MONITORING PLAN ................. 34
10. PROFESSIONAL ENGINEER STATEMENT ............................................... 35
11. REFERENCES ................................................................................................. 36
LIST OF TABLES
Table 1 Design Air Exchange Rates
Table 2 Monitoring Network

LIST OF FIGURES
Figure 1 Site Location Map
Figure 2 Site Layout Map
Figure 3 Proposed Redevelopment Footprint

GC8028/CAR21094 iii November 2022
LIST OF APPENDICES
Appendix A Construction Drawings, Technical Specifications, and Construction
Quality Assurance
Appendix B Typical Material Product Sheets
Appendix C Historical Environmental Data
Appendix D Response to Reuse Plans Letter
Appendix E Example MMS OM&M Form

GC8028/CAR21094 1 November 2022
1. INTRODUCTION
Geosyntec Consultants of NC, P.C. (Geosyntec), has prepared this Methane Mitigation
System (MMS) Design Report (“MMS Design” or “Report”) on behalf of 704 West
Tremont Owner, LLC (“Prospective Developer” or “PD”) for the former Dynatech III
properties (NCBP Project No. 25067-21-060) located at West Tremont Avenue and
Toomey Avenue in Charlotte, North Carolina (Mecklenburg County parcel IDs:
11906424 and 11906420) (the “Site” as shown on Figure 1 and 2).
1.1 Terms Of Reference And Report Organization
The Site is proposed to be redeveloped as a multi-family mixed-use residential apartment
complex inclusive of first floor residential and retail amenity spaces. The overall Site
redevelopment proposes four new Site buildings, which will be referred to as the
“Buildings,” and ancillary structures, consistent with the overall design plan naming
conventions as prepared by others.
This Report presents the basis for the MMS design to be incorporated into and below the
proposed Site Buildings, including design plans to support passive ventilation of
subsurface gases below planned impervious surfaces (e.g., parking areas, sidewalks, etc.)
surrounding the Buildings. The Report also (i) summarizes the planned installation and
construction quality assurance (CQA) program for monitoring the system construction;
(ii) presents a conceptual overview of the approach for monitoring the performance of the
MMS; and (iii) discusses the framework for future MMS-related reporting. The
Construction Drawings, Technical Specifications, and CQA monitoring approach for the
MMS are collectively referred to herein as the Construction Documents (Appendix A).
Product specification sheets for typical products to be used in the construction of the
MMS are included as Appendix B. Actual products to be used will be approved by
Geosyntec’s Engineer of Record (EOR) following the review of proposed product
submittals issued by the Contractor and will be provided to the North Carolina
Department of Environmental Quality (NCDEQ) Brownfields Program (NCBP) as part
of post-construction documentation (Section 8). If the products identified in Appendix B
deviate, NCBP will be notified prior to installation. The EOR, Contractor, and other
pertinent project team members’ roles and responsibilities are defined in the Construction
Quality Assurance pages of the Construction Documents.
The outline of this Report has been prepared in general accordance with the Vapor
Intrusion Mitigation System (VIMS) Design Submittal New Construction Requirements

GC8028/CAR21094 2 November 2022
Checklist (NCDEQ, 2021) and the NCDEQ Brownfields Threshold Criteria for Methane
Site Development (NCBP Methane Guidance) (NCDEQ, 2020).
1.2 Regulatory Setting and Background
The Dynatech III Site (NCBP Project No. 25067-21-060) is located within an area of
several other NCDEQ Brownfields sites which include the adjacent Dynatech II (NCBP
Project No. 25001-21-060) and Dynatech IV (NCBP Project No. 25068-21-060)
Brownfields sites, as well as the adjacent Toomey Ave. (NCBP Project No. 17002-13-
060), Powers Site RN (NCBP Project No. 20045-16-060), and Adams Property (NCBP
Project No. 21022-17-060) Brownfields sites. Figure 2 depicts the property boundaries
of the Dynatech III Site and the locations of surrounding Brownfields properties.
With regard to the Dynatech II, III, and IV Brownfields sites, an initial Brownfields Letter
of Eligibility (LOE) was issued on 5 February 2021 for the “Dynatech II” Brownfields
site, which previously included properties located at 2207, 2213, 2301, and 2325 Toomey
Avenue, as well as 728 and 704 West Tremont Ave. Through a subsequent Brownfields
Property Application (BPA) Amendment, additional surrounding parcels have been
added and subdivided into what is now a grouping of properties with different PD’s,
known separately as “Dynatech II, III, and IV.” A BPA Amendment Request was
submitted on 13 August 2021, which proposed a realignment of Brownfields properties
with a change to the PD for each project, grouping the following properties into the
Dynatech III Brownfields property: 2207, 2301, 2325 Toomey Avenue, 704 West
Tremont Avenue, and a portion of the 2213 Toomey Avenue property. A revised Letter
of Eligibility reflecting this change was issued by NCDEQ on 17 November 2021.
Property parcels within this area have since been redrawn, and the current Mecklenburg
County parcel IDs 11906424 (3.08 acres) and 11906420 (3.38 acres) comprise the
Dynatech III Site (Figure 2).
This Report, along with the Environmental Management Plan (EMP) for Site prepared
by Hart & Hickman and dated 19 October 2021 (Hart & Hickman, 2021), are intended to
support NCDEQ in the development of the Brownfields Agreement (BFA) for the Site.
1.3 Environmental Site History
The following environmental Site history summarizes information provided in the 17
August 2021 Brownfields Assessment Report prepared by Partner Engineering North
Carolina, PLLC (Partner).

GC8028/CAR21094 3 November 2022
The Dynatech II parcel (located at 2213 Toomey Avenue) was developed for industrial
use in 1969 and was occupied by Eastern Transit Storage from 1968 to 1973, Frank G.W.
McKittrick Textile Machinery from 1973 to 1985, Dynatech Industries, Inc. from 1985
to 1990, and RG Automation/Carolina Custom Tank from 1996 to present. Dynatech
Industries performed chrome plating of compressor parts during its time at the site,
generating hazardous waste and reportedly discharging waste to a septic system located
on the 2315 Toomey Avenue parcel. Assessments carried out at the Dynatech II parcel in
the 1990s identified metals and methyl ethyl ketone (MEK) impacts to the subsurface.
Removal remedies were conducted for soil, groundwater, and wastewater in the early
1990s and the site was granted No Further Remedial Action Planned (NFRAP) status
under the federal Superfund Program in 1994. The Dynatech II parcel entered into the
North Carolina Brownfields Program with a Brownfields Agreement and Environmental
Land Use Restrictions (ELUR) dated October 23, 2003.
The parcels which currently make up the Dynatech III Site were occupied by 1931 and
development consisted primarily of residential properties and a single commercial
property. Several residences and the commercial property were demolished by 1993 and
a warehouse was constructed on the 704 West Tremont Avenue in 1994. Froehling &
Robertson, Inc. completed a 2019 Brownfields assessment of the southeastern-adjacent
Adams Property (located at 510 West Tremont Avenue) at the request of NCDEQ
(Froehling & Robertson, Inc., 2019). The Brownfields assessment identified metals,
petroleum hydrocarbons, semivolatile organic compounds (SVOCs), volatile organic
compounds (VOCs), and methane as being present in site soil, groundwater, and/or soil
gas. The soil and groundwater impacts appeared to be confined to the adjacent Adams
Property Brownfields Site, but methane was reportedly detected at 56.8 percent (%) by
volume (%v) at a sampling location within 50 feet (ft) of the 2207 Toomey Avenue parcel
boundary. Due to the proximity and elevated nature of the methane detection, the Adams
Property was identified as a potential source for methane migration onto the Site.
Additionally, a Brownfields assessment completed for the adjacent Powers Site (located
at 536 West Tremont Avenue) by others and included in the Environmental Management
Plan for the Powers Site (Civil & Environmental Consultants, Inc., 2018) identified
methane concentrations up to 84%v that has the potential to migrate onto the Site.
In 2021, Partner conducted multiple Site investigations to evaluate subsurface methane
concentrations within the Dynatech II and III properties. Methane was detected at one
sampling location, and at a concentration below 1.25%v in 2021 (Partner, 2021a).
Subsurface methane gas concentrations below the 1.25%v concentration threshold are
generally not recommended for further evaluation for methane mitigation considerations;

GC8028/CAR21094 4 November 2022
1.25%v volume is 25% of the methane Lower Explosive Limit (LEL) (NCDEQ, 2020).
However, during a subsequent methane assessment (Partner, 2021b) methane was
detected at concentrations up to 38.2%v at monitoring point MSG-16. Methane
concentrations above 1.25%v (25% of the LEL) were measured at three monitoring points
(MSG-8, 16, and 18) located on the Dynatech III parcels. The location of the methane
soil gas sampling locations in relation to the proposed redevelopment footprint are
presented on Figure 3 and tabulated methane data collected by Partner is included in
Appendix C. Additionally, select VOCs and SVOCs were detected by Partner (Partner,
2021c) above their respective NCDEQ Residential Vapor Intrusion Soil Gas Screening
Levels (SGLSs) on the current Dynatech III parcels (including benzene, ethylbenzene,
naphthalene, 1,3-butadiene, and vinyl chloride). Tables and figures from the Partner
August 2021 Brownfields Assessment Report are also included in Appendix C.
The conclusions from the referenced reports recommend the design and installation of a
MMS below the enclosed areas of the proposed redevelopment. In response to the
methane concentrations detected in soil gas above 30%v, an aerated floor system is
planned for each Building, as described in this Report. The aerated floor-based mitigation
system design concept has been approved by NCBP in response to a 11 June 2021
teleconference discussing potential methane mitigation strategies for the Site, and as
documented by NCBP in a 13 July 2021 Response to Reuse Plans letter (Appendix D).
An Additional Brownfields Assessment Report was prepared by Hart & Hickman and
dated 4 January 2022 (Hart & Hickman, 2022), which included soil gas and methane
sampling activities at six subslab probes installed within the existing building at 2213
Toomey Ave. (Dynatech II). Results of subslab soil gas sampling identified multiple
VOCs at concentrations that were each below their respective SGSLs. Results of
associated methane gas sampling did not identify the presence of methane in the
subsurface at concentrations above the LEL and pressure readings were not measured
above the margin of error reported for the field instrument. Tables and figures from the
Hart & Hickman January 2021 Additional Brownfields Assessment Report are also
included in Appendix C. Based on these results, the planned non-residential use of
Dynatech II, the current building construction, and as discussed between Geosyntec and
Carolyn Minnich (NCDEQ Brownfields), we understand that if there are no changes to
use nor modifications, no further assessment or mitigation is required for the existing
building located at 2213 Toomey Ave. Therefore, no additional mitigation measures for
this Building have been proposed herein. If future building use or construction changes,
additional assessment and/or mitigation may be warranted, pending findings and
discussion with NCBP.

GC8028/CAR21094 5 November 2022
1.4 Redevelopment Strategy
The Site is planned for mixed-use redevelopment as multi-family apartments (under a
single ownership/management entity), tenant space, and open parking lots. Appendix A
provides a summary overview of the proposed redevelopment for the Site as it relates to
the MMS design. Four buildings are proposed, referred to as Buildings 1, 2, 3, and 4.
• Building 1 is approximately 28,000 square ft (ft2) and is planned to consist of
residential apartments 4 stories high. Building 1 contains one elevator.
• Building 2 is approximately 33,700 ft2 and is planned to consist of retail tenet
space and residential apartments 4 stories high. Building 2 contains 2 elevators.
• Building 3 is approximately 26,800 ft2 and is planned to consist of residential
apartments 4 stories high. Building 3 contains one elevator.
• Building 4 is approximately 4,500 ft2 and consists of residential “townhome style”
rental units 3 levels high.
• Surrounding the Site buildings is largely impervious open parking and sidewalks,
though pervious vegetative parking islands and landscaping surround the parking
and sidewalk areas. There is also an enclosed pool equipment room, which is less
than 200 ft2. Portions of the parking areas and ancillary structures (such as waste
dumpsters) will extend onto the Dynatech II property.
The MMS design concept for Buildings 1 through 4 will consist of an aerated floor
Cupolex design. Additionally, a vapor intrusion barrier and ventilated gravel bed is
designed below the enclosed pool equipment room (Appendix A). The vegetative
parking islands and landscaping surrounding the sidewalks, as designed by the Site Civil
Engineer and Landscape Architect, will allow for passive ventilation of subsurface gases
in areas beyond the building footprints. Each of these components are discussed further
in subsequent sections.

GC8028/CAR21094 6 November 2022
2. DESIGN BASIS
2.1 Design Objective
The objective of the MMS is to mitigate the migration of subsurface methane into indoor
air from beneath the proposed building slabs. Certain VOCs and SVOCs have also been
detected in the subsurface at the Dynatech III Site, and while these are not the primary
focus of this mitigation effort, these constituents will also be mitigated by the MMS. The
Code of Federal Regulations (CFR) (40 CFR 258.23) requires the amount of methane
within a habitable space be less than 25 percent of the LEL (i.e., less than 1.25 %v or
12,500 parts per million volume [ppmv]) (USPEA, 1993). NCBP also references the
1.25% methane concentration by volume as the threshold in which a habitable space
should be immediately evacuated (NCDEQ, 2020). As such, these criteria form the basis
for the design of the MMS.
2.2 Design Qualifications
The Geosyntec design team that developed the MMS design for the Site has experience
in VIMS and/or MMS design that is relevant. The 13 July 2021 Response to Reuse Plans
letter (Appendix D) documents that NCBP has reviewed and approved of Geosyntec’s
methane mitigation design experience.
2.3 Design Criteria
Based upon the objectives of the MMS design and the regulatory requirements outlined
above, the design criteria for the MMS at the Site is that the measured concentration of
methane gas in the habitable units should be less than 25% LEL (1.25%v; 12,500 ppmv).
2.4 Design Approach
The MMS is designed to mitigate the potential for methane and other VOCs/SVOCs in
soil gas to build up immediately beneath the buildings’ slabs and result in potential
migration into the buildings. This will be accomplished by actively providing air flow
underneath the buildings’ concrete slabs, in the form of a subslab venting system (SSV).
Gases that migrate upward from the soil beneath the buildings (Buildings 1 through 4)
will be collected by the ventilation layer, which consists of an aerated floor Cupolex®
void space. In the case of the pool equipment room, subsurface gases will be vented
through a passive gas extraction system installed within a ventilated gravel bed below the
pool equipment room slab.

GC8028/CAR21094 7 November 2022
The NCBP Methane Guidance Residential Reuse criteria indicates that first-floor
residential occupancy is not allowable if methane concentrations in soil gas exceed 30%v
within 50 feet of the building footprint without the stated approval of NCBP. A 11 June
2021 teleconference discussion with NCBP conceptually approved the aerated floor
Cupolex design approach for this Site, and provided a Response to Reuse Plans letter on
13 July 2021 supporting the approach (Appendix D). It is noted that the volume of air in
the 10-inch Cupolex void space is greater than within a 4-inch aggregate bed, which offers
a dilutive effect conducive to passively manage the comparatively higher subsurface
methane concentrations. Therefore, based upon the elevated subsurface methane gas
concentrations measured on and near the Site, the MMS for Buildings 1 through 4 is
designed with an aerated floor Cupolex with active mitigation fans. A mechanically
induced vacuum will encourage gas migration through the Cupolex void space toward
the soil gas extraction piping. The exhausting of the gases collected from below the slab
will induce outdoor air to flow into the air inlet pipes through the Cupolex void space in
a sweeping manner. The inlet riser pipes also allow oxygen-rich outdoor air into the
system to facilitate biological degradation of methane in shallow soil gas below the slab.
The MMS monitoring system will consist of: (i) subslab manual monitoring soil gas
probes; (ii) automated methane sensors on the extraction vent risers; (iii) automated two-
tier methane monitoring in indoor air common areas; and (iv) automated one-tier methane
monitoring in indoor air of each first floor residential unit. Each of these components are
discussed in greater detail in Section 2.
The approximately 200 ft2 pool equipment room adjacent to Building 2, which is located
on the western portion of the Site where subsurface methane concentrations were detected
below 1%v during 2021 Site investigations, is designed with a membrane and gravel bed
ventilation system.
Surrounding Buildings 1 through 4 (including portions of the Dynatech II property) are
open air/uncovered areas consisting of asphalt parking, concrete sidewalks, and amenity
spaces, such as an outdoor pool. Passive ventilation of subsurface gases will be
accommodated by the pervious/open design features inherent to the Civil and
Landscaping Site redevelopment plans. The Civil and Landscaping Site design plans
consist of pervious surfaces throughout the Site, including vegetative parking islands,
landscaping adjacent to sidewalks, and vented pavers. The asphalt parking and sidewalks
throughout the proposed redevelopment are within 100-feet of a ventilated Site feature
(e.g., landscape area). Further, much of the pool area consists of pavers and flagstone,
which include spaces between the pavers/stone, offering a passive ventilation mechanism.

GC8028/CAR21094 8 November 2022
Lastly, manhole covers are designed to include a vent to allow for passive discharge of
gases from utility corridors. For each of these reasons, supplemental ventilation of
subsurface gas, beyond what is inherent to the Civil and Landscaping Site designs, is not
warranted.
Much of the following sections are focused on the MMS for Buildings 1 through 4. The
design of the MMS for the pool equipment room is discussed beginning in Section 2.10.
2.5 Design Framework (Buildings 1 through 4)
The MMS for Buildings 1 through 4 is comprised of a subslab venting layer and related
components and a monitoring system. The system consists of the following:
• Concrete slab
• Aerated floor Cupolex void space
• Offset perforated 3-inch polyvinyl chloride (PVC) air inlet piping
and 4-inch PVC extraction piping, connected to 6-inch PVC riser
piping
• EV40 Geomembrane vapor barrier (or approved equivalent as
determined by the EOR) at concrete slab joints

• Subslab vaccum and methane monitoring probes (manual
monitoring)
• Automated vent riser methane monitors
• Automated two-tier indoor air methane monitors in common areas
• Automated one-tier indoor air methane monitors in each first floor
residential unit
• Continuous vent riser vacuum monitors
The basis of design for each of these components is described below.
Subslab Venting Layer and Venting Components
Monitoring System

GC8028/CAR21094 9 November 2022
2.6 Geomembrane Vapor Barrier (Buildings 1 through 4)
A geomembrane will not be installed beneath the entirety of the first-floor slab for
Buildings 1 through 4; however, geomembrane will be installed as “swaths” and “strips”
of varying sizes/lengths under the portions of the concrete slab under which the Cupolex
do not extend (including to the edges of the buildings). Generally, the geomembrane will
be co-located with the Cupolex Benton Stops, which is a solid end form that prevents
concrete from filling the Cupolex void space and defines the edge of the concrete pour
for a given area. Typically, a concrete joint is produced at the Benton Stop, which is why
the geomembrane strips will be deployed in these areas to mitigate the potential gas
migration pathway at the concrete joint. The geomembrane will be sealed to the buildings’
structural features as described in the Construction Documents (Appendix A). The intent
of the geomembrane is to both improve the overall venting efficiency of the MMS by
limiting the downward migration of indoor air into the void space in areas directly
connected to the Cupolex void space and to reduce the potential for soil gas migration
into indoor air in areas not covered by the Cupolex void space.
The geomembrane vapor barrier will consist of an EPRO Geo-Seal® EV40 geomembrane
(described as “EV40” herein), or an approved equivalent as determined by the EOR. The
EV40 geomembrane is comprised of an ethylene vinyl alcohol geomembrane and
geotextile backing. The Construction Documents (Appendix A) refer to a non-woven
cushion geotextile to be installed between the geomembrane and the underlying prepared
subgrade. In the case of the EV40 geomembrane, the geotextile bonded to the base of the
composite EV40 product serves the function of the lower “non-woven cushion geotextile”
as referenced on the Construction Documents. The EV40 geomembrane will be rolled out
with the geotextile side facing down (i.e., in contact with the prepared subgrade). Seams,
as needed, will be overlapped a minimum of 6 inches. The EV40 seam will consist of a
total 60 mil spray of EPRO polymer modified asphalt (EPR Geo-Seal CORE; herein
referred to as “CORE”) at the overlap joint to create the seam. The full footprint of the
EV40 geomembrane will not be sprayed with CORE. Penetrations (e.g., plumbing,
electrical conduit) will be sealed by applying CORE, followed by EPRO reinforcement
fabric around the base of the penetration, then followed by a second layer of CORE.
CORE will also be applied at EV-40 terminations.
Smoke testing of the geomembrane system will not be performed as part of the
construction due to the limited footprint, relative to Cupolex, that the geomembrane
system covers. Thickness testing will not be performed because the spray application is
only applied at the membrane seams, penetrations, and foundation attachments.

GC8028/CAR21094 10 November 2022
2.7 Subslab Venting Layer and Venting Components (Buildings 1 through 4)
2.7.1 Aerated Floor Cupolex Void Space
A 10-inch aerated floor Cupolex void space will serve as the ventilation medium below
Buildings 1 through 4. The Cupolex void space will have a dilutive effect on gases that
enter the Cupolex void space from below and offers less resistance to air movement in
comparison to an aggregate bed.
2.7.2 Extraction Vent Piping
The extraction vent piping design is shown in the Construction Drawings (Appendix A).
Solid 4-inch Schedule 40 PVC pipe with varying lengths of perforated 4-inch Schedule
40 PVC will be used to collect gases in the Cupolex void space. The piping is designed
so that the perforated pipe’s open ends are placed in an approximately central location,
relative to air inlet piping, and that the perforated portions are oriented to encourage
outdoor air to sweep across the entirety of the Cupolex void space. Only one location (SP-
2B) will have a cap on the end of the perforated extraction vent piping. The solid 4-inch
pipe will transition to 6-inch Schedule 40 PVC that will penetrate the Cupolex and slab
at the locations presented on the Construction Drawings. The number of extraction vent
risers planned for each building was designed to accommodate at least 3 air exchanges of
the Cupolex void space per hour, while maintaining a riser pipe velocity below 1,600 ft
per minute to reduce the chances for nuisance noise (ANSI/ARST, 2018) as presented in
Table 1. Although the 3-air exchange rate was used as a design basis to develop the
spacing and frequency of the vent riser piping network, the MMS is not required to
achieve these flushing rates to demonstrate adequate system performance. Further,
diagnostic testing will be completed following construction to specify the active
mitigation fans and system flow rates.
Within 5 ft above the vent riser pipe slab penetration, a methane sensor and monitoring
port will be installed and plumbed into the vent riser for automated methane monitoring
and collection of exhaust gases. Methane sensors are discussed in more detail in Section
2.8. A differential pressure monitor will also be installed at each vent riser pipe to allow
for regular monitoring of static vacuum of the mitigation fan.
The vent riser pipes for Buildings 1 through 3 will be plumbed vertically inside each
building, and will generally not be enclosed within the interior walls. The risers will
penetrate the roof and the penetrations will be sealed in accordance with local code and
architectural requirements. The vent riser pipe for Building 4 will be plumbed vertically
along the exterior of the building. In each instance, vent risers will extend vertically at a

GC8028/CAR21094 11 November 2022
location such that the discharge point is a minimum of 10 ft from building intakes or
building openings. Where appropriate, minimal sections of horizontal vent riser will be
installed in the upper floor ceiling (prior to penetrating the roof) and sloped to drain
condensate to the subsurface (i.e., sloped to the vertical vent piping extending to the
subslab system). The top of the discharge pipe will be fitted with electric fans, which will
be specified pending the results of pre-occupancy field screening and diagnostic testing
(described in Section 2.7.3).
The extraction piping will be labeled every 10 ft, as shown in the Construction Drawings
(Appendix A).
2.7.3 Air Inlet Piping
The air inlet piping network is shown in the Construction Drawings (Appendix A). Air
will be distributed below the slab using a combination of 3-inch solid and perforated
Schedule 40 PVC pipes placed within the Cupolex void. The perforated pipe will connect
to solid pipe, near the edge of the building, where it will be routed to the exterior of the
building. The solid pipe will: (i) extend above the final exterior grade (the height varies
depending on final grade elevation relative to the slab elevation); (ii) include fittings to
minimize precipitation entering the open end of the pipe; and (iii) be covered with a
varmint guard screen to prevent animals/debris from entering.
2.7.4 Extraction Fans
The MMS will employ electric powered fans to generate air flow and vacuum gradients
to vent gases from beneath the slab and flush atmospheric air through the ventilation layer
below the slab.
One fan will be installed on each vent riser. The specific fan model selection will be made
after diagnostic testing has been completed. The selected fans shall be constructed of
non-sparking material. The fans for Buildings 1, 2, and 3 will be mounted on the top of
the vent riser piping and anchored to a Unistrut support system (or approved equivalent
as indicated by the EOR). The fan for Building 4 will be mounted on the exterior wall,
near grade level, because the roof design of Building 4 is pitched, which is not conducive
to long-term operation and maintenance (O&M) of the mitigation system fans. The
exhaust from the Building 4 fan will be routed to above the roof line.
A shut-off switch will be installed at each fan housing in a weather enclosure as per
applicable building code so that the fan can be turned on and off for maintenance. Power
will be supplied by individual circuit breakers to each vent riser. Alarming and

GC8028/CAR21094 12 November 2022
monitoring infrastructure for the contingent active fans is discussed in the following
section.
2.8 Monitoring System (Buildings 1 through 4)
Several monitoring mechanisms are included in the design of the MMS as summarized
below. The monitoring mechanisms are consistent with the Ongoing Monitoring
Requirements in the NCBP Methane Guidance (NCDEQ, 2020).
Details of each monitoring device are provided in the following subsections. A summary
of the methane monitoring system is provided in Table 2.
1. Indoor Air Methane Monitoring: two monitoring types will be
implemented for indoor air.
a. Automated two-tier methane monitoring sensors will be installed in
select common areas of first-floor indoor air spaces of Buildings 1
through 3 and within the first-floor living areas of two of the six
residential rental units in Building 4. The automated two-tier methane
monitoring sensors will provide internal and building-wide alarms at
two different methane concentration thresholds (10% LEL and 25%
LEL).
b. Automated one-tier methane monitoring sensors will be installed in
each first-floor floor residential rental units in Buildings 1 through 3,
and within the remaining four of the six residential rental units in
Building 4. The one-tier methane sensors will be installed near the
ceiling of the of the master bedroom, and away from bathrooms,
kitchens, or gas-fired appliances (e.g., hot water heaters, stoves, etc.).
The one-tier methane sensors will provide internal and building-wide
alarms at one methane concentration threshold (25% LEL)
2. Vent Riser Methane Monitoring: automated methane sensors will be
installed on vent riser piping for continuous monitoring to aid in MMS
operation decision making.
3. Vent Riser Static Vacuum Monitoring: continuous monitoring of MMS
fan operation will be performed to aid in MMS O&M.

GC8028/CAR21094 13 November 2022
4. Subslab Monitoring: soil gas probes will be installed below the slab and
routed to accessible utility spaces for monitoring of subslab conditions.
Each location is designed for manually monitoring subslab conditions.
2.8.1 Indoor Air Methane Monitoring and Alarm Conditions
Two types of automated indoor air methane monitoring sensors will be installed within
each Building: (i) two-tier sensors; and (ii) one-tier sensors.
Two-tier automated methane sensors will be installed on the first floor, within select
common areas in Buildings 1 through 3 (Honeywell Sensepoint XCL or approved
equivalent as determined by the EOR) and select first-floor living areas in Building 4
(two of the six residential rental units; RKI Model 35-3001 or approved equivalent as
determined by the EOR), at a rate of 1 methane sensor per every 2,250 ft2 to 7,000 ft2.
The two-tier automated methane sensors will be mounted to the ceilings when possible.
Where not practicable, they will be installed such that the intake for indoor air methane
sensor is at least 8 ft from the finished floor elevation (or within 1 ft of the ceiling if the
ceiling height is less than 8 ft from the finished floor elevation). The two-tier automated
methane sensors will be connected to a control panel and will be integrated with the
building alarming system.
The two-tier automated methane sensors will be set to trigger an alarm at two methane
concentration thresholds, as follows, based on the NCBP Methane Guidance (NCDEQ,
2020). Further details of contingency planning related to the alarm conditions’ responses
are provided in Section 6:
• A methane concentration of 10% LEL (0.5%v or 5,000 ppmv) will trigger an
internal notification (e.g., email, text) to the property owner and their designated
representative (Geosyntec, unless otherwise approved by NCDEQ) who will
initiate an investigation into the cause of the alarm.
• A methane concentration of 25% LEL (1.25%v or 12,500 ppmv) will trigger an
audible and visual alarm system within the building, a mandatory evacuation of
the building, and a notification to the local fire department. Occupancy of the
building will not resume until granted by the local fire department once the
methane concentrations are reduced to acceptable levels.
One-tier automated methane sensors (Macurco GD-2A or approved equivalent as
determined by the EOR) will be installed in the master bedroom of each of the first-floor

GC8028/CAR21094 14 November 2022
residential units in Buildings 1 through 3 and in the remaining four of six residential rental
units in Building 4 . This results in a monitoring rate of 1 one-tier methane sensor per
every 1,120 ft2 to 1,770 ft2. The one-tier automated methane sensors will be installed
within 1 ft of the ceiling. The one-tier indoor air methane sensors will be connected to a
control panel and will be integrated with the building alarm system.
The one-tier indoor air methane alarm will set to trigger at a single methane concentration
threshold of 25% LEL. This alarm will trigger an audible and visual alarm system within
the building, a mandatory evacuation of the building, and a notification to the local fire
department. Occupancy of the building will not resume until granted by the local fire
department once the methane concentrations are reduced to acceptable levels.
In total, two-tier and one-tier automated methane sensors will be installed at a rate of 1
methane sensor per every 750 ft2 to 1,350 ft2 of total building footprint.
Both methane sensors will be connected to a control panel telemetry system (Honeywell
Controller HA72 or approved equivalent as determined by the EOR) to notify the
appropriate entities in the instance methane levels exceed the above threshold(s). Backup
battery power will be provided for the indoor air methane sensors for a minimum of 24
hours.
The location of the control panel telemetry system and indoor air sensors will be in readily
accessible areas for ease of O&M. The two-tier automated methane sensor housing for
Building 4 will be in weather-proofed enclosures on the exterior of the building, and
methane monitoring tubing will be installed and routed indoors. Tenants and lessees of
the apartment Buildings will be made aware, during the signing of the lease agreement,
that an MMS is installed in each building, and summary information related to the MMS
will be provided to the tenant/lessee in the lease agreement. This will include information
regarding alarm conditions for indoor air sensors, including that, in the event of a high-
level methane alarms signal, building evacuation is necessary. Furthermore, placards
noting the presence of an MMS will be installed next to each methane alarm (not each
automated methane sensor) and control panel per the Construction Drawings (Appendix
A).
2.8.2 Vent Riser Methane Monitoring
The primary intent of the automated vent riser methane sensors and alarms is to guide
long-term MMS operational decision making and is not intended to alert Building
occupants. Methane in the vent risers does not necessarily indicate poor system

GC8028/CAR21094 15 November 2022
performance, as the vent risers are intended to collect gases below the building and
discharge the gases above the roof. However, the vent riser methane monitoring data can
be used to provide an understanding of the subslab soil gas conditions, which can then be
used to guide operational decision making as it relates to MMS operation. For example,
consistently low methane concentrations in vent risers may justify reducing fan speed or
operating the MMS passively, as that is likely suggestive of low methane concentrations
in subslab gas. The vent riser methane sensor alarming threshold is subject to change
pending the results of pre-occupancy field screening. NCBP approval will be required
prior to modifying the vent riser methane alarm thresholds.
Automated methane sensors (RKI Model 35-3001 or approved equivalent as determined
by the EOR) will be installed in the vent riser piping, within 5-feet of where the riser
penetrates the slab for Buildings 1, 2, and 3, and in the case of Building 4, outdoors on
the façade in a weather-proofed enclosure. The methane sensors will contain a pumping
mechanism, in-line sensor, or approved equivalent that allows for continuous methane
monitoring in the vent pipe. The automated methane sensor will be connected to a control
panel and preliminary notification alarm on the first floor.
The vent riser methane alarm will be set to trigger when a concentration of 25% methane
LEL is measured and will trigger an internal notification to the property owner and
designated representative for information purposes, and to indicate an inspection is
warranted. An inspection should be performed to confirm the sensor remains calibrated,
does not need replacement, etc. The 25% methane LEL threshold is subject to change
pending the results of pre-occupancy field screening.1
2.8.3 Vent Riser Static Vacuum Monitoring
Differential pressure transmitters (Dwyer Series 668 Compact Bi-Directional Differential
Pressure Transmitter or approved equivalent as determined by the EOR) will be installed
in the vent riser piping, within 5-feet of where the riser penetrates the slab for Buildings
1, 2, and 3, and in the case of Building 4, outdoors on the façade in a weather-proofed
enclosure. The differential pressure transmitter will be connected to the telemetry system
and will trigger if a given fan is operating below a minimum setpoint static pressure. The

1 The Los Angeles Department of Building Safety [LADBS] Methane Hazards Mitigation Measures Standard Plan (LADBS, 2010) establishes a 75% methane LEL [3.75%v or 37,500 ppmv] threshold to require an automated transition from passive to active system operation. The initial vent riser screening concentration of 25% methane LEL is a comparatively conservative initial setting considering the MMS is designed to initially operate actively. The NCBP Methane Guidance (NCDEQ, 2020) does not specifically reference the 75% methane LEL vent riser screening threshold but does reference the LADBS guidance in general.

GC8028/CAR21094 16 November 2022
telemetry system may be the same as the methane sensor control panel. The telemetry
system is intended to send an automatic notification to the property owner and designated
representative to investigate the cause of the alarm and inspect the fan, and not to alert
Building occupants.
2.8.4 Subslab Manual Monitoring
Subslab manual monitoring locations are spatially distributed throughout the buildings at
locations distant from suction points to monitor the subslab conditions at a rate of 1
subslab monitoring location per every 1,500 ft2 to 2,800 ft2, depending upon the Building.
These manual monitoring probes will allow for the manual collection of subslab data and
may be used to monitor cross-slab vacuum, subslab airflow, and/or to screen soil gas.
The subsurface portion of the monitoring probes will consist of ¼-inch Nylaflow tubing
connected via compression fittings to a 6-inch stainless-steel vapor implant. The
Nylaflow tubing will be routed through solid 1-inch Schedule 40 PVC conduits that run
beneath the slab though the Cupolex void space. The PVC conduit will connect to a
vertical PVC riser using a PVC fitting. The PVC riser will penetrate the slab and be
secured to an interior wall in a lockable access panel per the Construction Drawings
(Appendix A). The PVC conduit will be sealed per the Construction Drawings with
polyurethane caulking on both ends, and at each conduit joint.
Both ends of the Nylaflow tubing will be fitted with a ball valve. The ball valve at the
distal end of end of the subslab monitoring probe will allow for leak testing to be
completed (via a shut-in test) prior to pouring the concrete slab. This leak test will
evaluate the competency of the tubing and fittings between the vapor implant and the
¼-inch compression fitting. The manual monitoring probe termination point within the
access panel will consist of a ¼-inch compression fitting connected to a ball valve to
allow for monitoring.

2.9 Electrical Installation and Connections (Buildings 1 through 4)
Electrical connection for the MMS will be supplied by the building contractor. Electrical
conductor (240 volt/20 amp) will be provided at each vent riser on a designated circuit
breaker.
The methane sensor control panel will be supplied with backup battery for 24 hours. All
electrical work will be completed by a licensed electrician according to applicable codes.

GC8028/CAR21094 17 November 2022
2.10 Pool Equipment Room Mitigation
The approximately 200 ft2 pool equipment room adjacent to Building 2 is designed with
a membrane and gravel bed mitigation system as a conservative measure. Subsurface
methane concentrations in this area of the Site were detected below 1%v during 2021 Site
investigations. Given the low subsurface methane concentrations and small size of the
pool equipment room, no air inlet piping is designed for this isolated structure. Subslab
methane concentrations will be monitored during construction (described in Section
2.10.3) to evaluate whether soil gas conditions change following Site redevelopment. The
Construction Drawings provide detail of the pool equipment room design features
(Appendix A).
2.10.1 Geomembrane Vapor Barrier
A sprayed-seam geomembrane vapor barrier membrane will be installed under the pool
equipment room slab. An “upper” cushion geotextile will overlay the geomembrane for
protection during the concrete slab pour. An additional “lower” cushion geotextile will
be deployed below the geomembrane to protect the underside of the geomembrane from
the underlying clean venting aggregate. The Technical Specifications allow the use of
EPRO’s EV-40 geomembrane, or an EOR-approved equivalent, for the pool equipment
room. The EV40 product is a composite membrane containing a geotextile at the base of
the sheet. If the EV40 geomembrane is selected by the contractor, an additional lower
cushion geotextile will not be required between the venting aggregate and geomembrane.
The geomembrane will be sealed to the pool equipment room slab to improve the
ventilation efficiency in the subslab. A concrete slab will be poured directly over the
upper cushion geotextile in the pool equipment room.
2.10.2 Aggregate Venting Layer
A 6-inch aggregate venting layer will be installed below the pool equipment room to
allow soil gas to readily flow through the layer. The venting aggregate will be installed
between the geomembrane and an underlying non-woven filter geotextile. The non-
woven filter geotextile will be installed directly over the compacted subgrade to minimize
infiltration of fines into the venting aggregate.
2.10.3 Exhaust Piping and Wind-Driven Turbine
Under the pool equipment room, subsurface gas will be extracted using 4-inch perforated
Schedule 40 PVC that will connect to 4-inch solid Schedule 40 PVC. The solid PVC will
penetrate the geomembrane vapor barrier and concrete slab on grade and be routed above

GC8028/CAR21094 18 November 2022
to the roof. The exhaust piping will terminate at least 18-inches above the roof. The
exhaust piping will be labeled every 10 ft, as shown in the Construction Drawings
(Appendix A).
A non-sparking wind-driven turbine will be installed at the discharge point to passively
ventilate subsurface gases to above the pool equipment room roof. Subsurface gas
movement will rely on pressure gradients produced by the turbine, diurnal temperatures
and associated pressure changes, and the height of the pipe to vent gases from beneath
the slab.
The wind-driven turbines will be Empire model TV04G (or an approved equivalent as
indicated by the EOR) and made from galvanized steel construction. The turbine will be
mounted on top of the vent riser piping on the roof and secured with galvanized or
stainless-steel screws.
Because wind-driven turbines are not an active mitigation method, methane
concentrations in subslab soil gas will be monitored during construction to evaluate if a
wind-driven turbine is appropriate. The monitoring will be conducted approximately two
weeks following the Pool Equipment Room’s slab-on-grade pour and will include
screening of subslab soil gas at the vent riser and subslab monitoring probes. The
screening will be performed with a wind turbine temporarily installed on the vent riser to
represent passive operating conditions prior to occupancy. If methane concentrations
beneath the pool equipment room are measured to be greater than 25% of the LEL at any
monitoring location, two additional confirmation monitoring events will be conducted
within the following two weeks (each monitoring event separated by approximately 1
week). If 25% of the LEL is exceeded at any location during either monitoring event, an
active mitigation fan will be installed in place of the wind-driven turbine. The active
mitigation fan will be non-sparking and the fan model selection will be made after
diagnostic testing has been completed. The finishing details will be the same as those
described in Section 2.7.4. If 25% of the LEL is not exceeded at any monitoring location
during both monitoring events, or is exceeded during only one of the monitoring events,
the results will be provided to NCBP to discuss the need to install an active mitigation
fan.
2.10.4 Subslab Monitoring
Two manual subslab monitoring locations will be installed under the pool equipment
room to monitor cross-slab vacuum, subslab airflow, and/or to screen soil gases for
methane concentrations. The design of the subslab monitoring probes will be consistent

GC8028/CAR21094 19 November 2022
with the manual monitoring approach used for Buildings 1-4, as reflected in the
Construction Drawings (Appendix A).
2.11 Impervious Surfaces Mitigation
Surrounding Buildings 1 through 4 (and portions of the Dynatech II property) are open
air/uncovered areas consisting of asphalt parking, concrete sidewalks, and amenity
spaces, such as an outdoor pool. For the reasons mentioned previously, passive
ventilation of subsurface gases will be accommodated by the pervious/open design
features inherent to the Civil and Landscaping Site redevelopment plans. The Civil and
Landscaping Site design plans consist of pervious surfaces throughout the Site, including
vegetative parking islands, landscaping adjacent to sidewalks, and vented pavers. The
asphalt parking and sidewalks throughout the proposed redevelopment are within 100-
feet of a ventilated Site feature. Further, much of the pool area consists of pavers and
flagstone, which include spaces between the pavers/stone, also offering a passive
ventilation mechanism. For each of these reasons, supplemental ventilation of subsurface
gas, beyond what is inherent to the Civil and Landscaping Site designs, is not warranted.

GC8028/CAR21094 20 November 2022
3. QUALITY ASSURANCE AND QUALITY CONTROL
Quality Assurance (QA) and Quality Control (QC) measures are necessary to maintain
system integrity during construction activities. Construction Quality Assurance (CQA)
will be conducted by qualified personnel under the supervision of the PE who designed
the MMS (EOR). A CQA Monitoring Plan is provided in the Construction Documents
(Appendix A). NCBP will be provided a minimum of 48 business hour notification prior
to starting CQA.
Following construction, a final report will be prepared, as approved by the MMS EOR,
that will include a summary of MMS installation monitoring. Reporting is discussed in
more detail in Section 8.
3.1 Contingent Tenant Improvements (First-Floor Retail)
The western portion of Building 2 is planned for retail space, though the future tenants
are unknown. The first-floor slabs in these areas are planned to be completed during
initial construction using a ribbon slab construction. The ribbon slab consists of a
perimeter slab that is poured to the design thickness, that surrounds a thinner slab (poured
to the top of the Cupolex domes) in the center of the retail space to allow for easier
modifications by future tenants. After tenant improvements, the interior slab in the tenant
space will be brought to the finished floor elevation.
It is anticipated that sections of the thinner slab will require removal and repair post
construction to accommodate tenant-specific features, such as subslab utilities. The MMS
design includes slab repair details to support potential future improvements, or tenant
improvements. If slab repairs are required in the future, the repairs will be completed in
accordance with the MMS Construction Documents.
NCBP will be notified prior to potential tenant improvements for information purposes.
The automated methane sensors (indoor air and vent riser) will continue to operate during
the retrofit process to guide health and safety-related decision-making during
construction (e.g., supplemental above slab mechanical ventilation may be implemented
during construction to reduce elevated gas concentrations, if needed). Non-sparking tools
will be used if methane concentrations cannot be brought below 25% of the LEL.
If the future improvements require modifications to the MMS in excess of typical slab
repairs (e.g., rerouting subslab monitoring probes, repairing geomembrane around
columns) a brief addendum report will be submitted to NCBP documenting potential

GC8028/CAR21094 21 November 2022
tenant upfit activities and post-construction performance monitoring for NCBP review
and approval. The approach for monitoring MMS performance following construction
(including potential slab retrofits) is discussed in subsequent sections.

GC8028/CAR21094 22 November 2022
4. POST-CONSTRUCTION/PRE-OCCUPANCY SYSTEM
EFFECTIVENESS TESTING
Following the construction of the MMS and the first-floor concrete slab, but prior to
occupancy and MMS diagnostic testing, initial field screening data will be collected to
guide MMS operation. Following the slab-on-grade concrete pour, routine methane
screening is recommended to be performed daily at the vent riser pipes and subslab
manual monitoring probes to monitor subslab methane concentrations during
construction. This daily vent screening can be performed by the Contractor and is
recommended for health and safety considerations during construction and will aid in
decision making regarding potential passive/active mitigation system operation during
construction. During construction, if methane concentrations are measured above 25%
LEL in the vent risers, the EOR will be notified to investigate and implement corrective
actions (e.g., opening air inlets for passive venting). During construction, if methane
concentrations are measured above 75% LEL in the vent risers or 10% LEL in open air,
NCBP will be notified within 48 hours of the measurement.
4.1 MMS Diagnostic Testing
The objective of diagnostic testing is to evaluate the pneumatic connectivity below the
slab footprint and to specify mechanical fans. Diagnostic testing will include the
collection of airflow, vacuum, and methane screening data at the subslab monitoring
locations and vent risers. Additionally, the CQA field monitor will check for air leakage
at accessible construction joints and floor penetrations via smoke testing. Smoke will be
introduced to the areas of potential leakage and evaluated for downward migration while
the diagnostic test is occurring and a vacuum is being applied to the MMS. The diagnostic
testing will be performed at each Building after the entire subslab portion of the mitigation
system has been installed, the concrete slab has cured, and the penetrations and joints
have been sealed.
Mechanical fans will be specified based on the data collected during the diagnostic
testing; specifically, a combination of flow, vacuum, and methane screening data as
described in the following subsections. The data will be used to specify a fan that achieves
the overall design objective of mitigating methane intrusion into indoor air, and NCBP
will be notified of the design fan prior to installation.

GC8028/CAR21094 23 November 2022
4.1.1. Methane Monitoring
Prior to pressure and flow testing of the MMS, field monitoring equipment will be used
to screen subslab probes and vent risers for methane using a GEM 5000 (or equivalent
four gas meter capable of measuring methane in %v and % of LEL). During operation
of the temporary fan discussed below, methane concentrations will again be screened
with a handheld detector from each vent pipe and subslab manual monitoring probe to
evaluate the change in methane concentration under various flow regimes.
4.1.2. Pressure Field Extension Testing
A temporary fan will be connected to each vent riser to exhaust gases from below the
slab. Cross-slab differential pressure will be measured and recorded during the testing at
each of the subslab monitoring locations installed within the buildings. Given that the
MMS is designed as a subslab ventilation system, not a subslab depressurization system,
measurable vacuum may not be identified at the subslab manual monitoring locations.
However, that is not necessarily indicative of inadequate system performance. If no
vacuum is observed, other methods may be employed, such as temporarily closing air
inlet piping during testing to confirm pneumatic connectivity in the subslab.
4.1.3. Flow and Vacuum Monitoring
While operating the temporary fan, the fan vacuum and airflow rate will be measured via
monitoring ports installed on the exhaust pipe riser using a thermal anemometer and static
pressure gauge. This information, along with the pressure field extension data, will be
used to evaluate pneumatic performance of MMS components. The fan flow rate will be
varied and data will be collected at the subslab manual monitoring locations to evaluate
the effect of fan operational changes, if any. The information obtained by operating the
mechanical fans in various operating conditions will be used to specify a mitigation fan.
4.2 Pre-Occupancy Performance Monitoring
Upon completion of the post-construction routine methane field screening (conducted at
the vent riser stubs and subslab monitoring probes by the Contractor) and the MMS
diagnostic testing (as discussed in Section 4.1), the EOR will specify the mechanical fans
required. This will be followed by the installation of the mitigation fans by the Contractor.
Once the mitigation components are installed, and the mitigation fans are operating and
balanced based upon the diagnostic testing results, pre-occupancy field monitoring will
be performed to support Building occupancy approval from NCBP. The results of the

GC8028/CAR21094 24 November 2022
diagnostics and pre-occupancy testing will be submitted to NCBP for review and
occupancy approval, as discussed in the Reporting section. Details of the pre-occupancy
tasks are described in the subsections below.
4.2.1. MMS Operational Evaluation
The pre-occupancy field monitoring will consist of two rounds of operational monitoring,
at least one week apart. If the construction schedule allows, the pre-occupancy monitoring
will occur once each Building is substantially complete and only finishing work (e.g.,
painting, cabinet installation) remains; however, pre-occupancy performance testing may
occur prior to that to meet the occupancy schedule (in such a case, NCBP will be informed
of the change in pre-occupancy testing timing). During each monitoring event, the
following data will be collected.
• Methane concentrations will be collected from each of the vent risers and subslab
monitoring probes using handheld field monitoring equipment.
• Methane concentrations will be measured in indoor air at multiple locations within
each Building (at least 1 location per 4,000 ft2 in each Building) using a portable
methane detector (e.g., MultiRAE Four-Gas Meter).
• Differential pressures will be collected from the subslab monitoring probes
(assuming measurable differential pressures were also identified during
diagnostics).
• Flow and static vacuum will be collected from each vent riser.
• As needed (based on field observations and measurements), limited smoke testing
may be completed to evaluate potential slab leakage.
4.2.2. Subslab Soil Gas Monitoring
Analytical subslab soil gas samples will be collected and analyzed during (or following)
the second round of pre-occupancy operational monitoring due to historical detections of
VOCs in soil gas (Appendix C). VOCs have been detected in soil gas at concentrations
above the Residential Vapor Intrusion Screening Level (VISL) within the footprints of
each Building (most prominently 1,3-butadiene). Soil gas samples will be collected from
17 subslab monitoring probes, at a frequency of 1 sample per 4,500 ft2 to 5,620 ft2. The
subslab monitoring probes that will be sampled are indicated in Table 2.

GC8028/CAR21094 25 November 2022
One outdoor air sample will be collected each day of the sampling event and one duplicate
sample will be collected during the event.
A shut-in test will be performed prior to sampling to evaluate potential leaks in the sample
assembly. Sample assembly valves will be closed and a vacuum will be generated using
a lung box or equivalent. If the vacuum does not dissipate after at least 1 minute, the shut-
in test will be considered successful.
Following a successful shut-in leak test, subslab soil gas monitoring probes will be purged
of at least three times the volume of the subslab monitoring probes and sample assembly
prior to subslab soil gas sample collection. Each subslab soil gas probe will be constructed
with less than 100 ft of ¼-inch Nylaflow tubing; however, to be conservative, each probe
is assumed to be constructed with 100 ft of ¼-inch Nylaflow tubing, which equates to a
subslab probe volume of 0.6 liters (L). Subslab soil gas will be purged at a rate less than
or equal to 200 milliliters per minute (mL/min) and will be collected in a 1-L Tedlar®
bag. The purged soil gas will be screened for the presence of VOCs using a MiniRAE
3000 (or equivalent) PID and carbon dioxide, methane, and oxygen using a Landfill GEM
5000 (or equivalent multi-gas meter). The screening results will be recorded by field
personnel.
A helium leak test will not be completed during purging because methane within subslab
soil gas is likely to interfere with helium detectors, resulting in false positives.
Furthermore, each component of the subslab soil gas probe will be leak checked prior to
monitoring due to the subslab soil gas probe design and the shut-in test that will be
completed during construction. If leakage above the slab is suspected during monitoring,
modifications will be made to the sampling train to rectify the suspected leak prior to
sampling.
Subslab soil gas samples will be collected in pre-evacuated, batch certified-clean 1-L
SUMMA® canisters equipped with 200 mL/min flow controllers. An initial vacuum will
be recorded from each canister prior to sampling; if the initial canister vacuum decreases
by more than 10% from the vacuum as measured by the analytical laboratory, the canister
will not be used for sampling. The targeted final vacuum for sample collection will be 5
inches of mercury (inHg) and final canister vacuums as measured by the laboratory will
be provided in analytical reports. Filled SUMMA canisters will be labeled with a unique
ID, the date, and sample time. After sample collection, the canisters will be transported
to an accredited laboratory under standard chain of custody procedures and analyzed for
VOCs using EPA Method TO-15.

GC8028/CAR21094 26 November 2022
Based upon the results of the pre-occupancy subslab soil gas sampling, a recommendation
will be made regarding post-occupancy subslab soil gas sampling. Ongoing post-
occupancy soil gas sampling is not anticipated; however, a determination will be made in
response to the pre-occupancy data findings and with NCBP approval.

GC8028/CAR21094 27 November 2022
5. POST-OCCUPANCY SYSTEM EFFECTIVENESS TESTING
Following occupancy approval, on-going monitoring of the MMS will be performed in
general accordance with NCBP guidance documents.
As described in Section 2, automated methane monitoring (extraction vent risers and
indoor air) will be installed as part of the design and will be integrated with a control
panel and building alarming system. The indoor air methane sensors will trigger an alarm
at the conditions discussed in previous sections, which is consistent with NCBP Methane
Guidance (NCDEQ, 2020). In addition to the continuous indoor air methane monitoring,
routine field screening will be performed as follows.
• Methane concentrations will be collected from the subslab monitoring probes and
vent risers, and inspections of the alarming components will be performed once
per month for the first three months following occupancy approval and until three
consecutive sampling events demonstrate effective operation of the MMS. This
will be followed by quarterly monitoring of the subslab monitoring probes and
vent risers upon approval by NCBP. The determination for evaluating if the MMS
is operating effectively is based upon the design criteria (Section 2), which uses
the decision-making framework outlined in Section 6 (Contingency Planning).
• During methane screening, differential pressures will also be collected from
the subslab monitoring probes and flow and static vacuum will be collected
from each vent riser.
• Following one year of quarterly monitoring, modifications to the operation and
monitoring frequency may be requested, pending the data findings and approval
by NCBP.
Analytical sampling is not planned for the post-occupancy period; however, it may be
conducted pending the results from the pre-occupancy monitoring and discussion with
NCBP.

GC8028/CAR21094 28 November 2022
6. CONTINGENCY PLANNING
The contingency planning steps outlined in this section will be used to guide decision
making related to performance monitoring, and as appropriate, to address emergency
situations resulting from gas detections above certain thresholds. These contingency
planning steps are to be implemented by the new Site owner following redevelopment (or
their authorized representative) and will also be outlined in a future MMS Operations,
Maintenance, and Monitoring Plan (see Section 9 for details) to maintain the integrity of
the MMS long term. Low-level and high-level gas detection system responses will be
established for the gas detection system as follows.
1) Low-Level Gas Detection System Response
a) The low-level detection threshold will be set at 10% of the LEL (i.e., 0.5%v or
5,000 ppmv). If methane gas concentrations measured in indoor air by the
two-tier automated menthane sensors are greater than 10% of the LEL, the
following sequence of operation will be implemented.
i) The exceedance will trigger an internal notification alarm to the designated
property owner representative who will initiate an investigation into the cause
of the alarm. The two-tier automated methane sensors will be inspected and
maintained per the manufacturer requirements (e.g., calibrated, replaced, etc.).
If, following inspection and confirmation that false positive background
sources are not the cause of the alarm, the methane concentrations measured
inside the Building continues to be greater than 10% of the LEL, and a
methane source within the building has been ruled out, the following steps
will be implemented such that methane concentrations decrease to below 10%
of the LEL and are consistent with pre-alarm conditions:
(1) Heating, ventilation, and air conditioning (HVAC) system operations
should be reviewed to verify fresh air inlets, air circulation rates, and
operations in the vicinity of the exceedance are operating as designed.
(2) Fan operational conditions should be inspected and MMS operational
changes should be evaluated, such as increasing subslab ventilation rates,
confirming there are no blockages with the air inlet piping, etc. Air inlet
monitoring will be considered following construction, diagnostic testing,
and pre-occupancy testing, and will be documented in the forthcoming
Operation, Maintenance, and Monitoring (OM&M) Plan (Section 9). The

GC8028/CAR21094 29 November 2022
monitoring approach for air inlets will vary based on their design and
integration into the Building.
(3) As needed, leak checks should be performed at locations most likely to
leak (e.g., slab joints, plumbing penetrations) to identify potential
pathways for soil gas entry into the Building. If leaks are identified, they
shall be sealed using a polyurethane caulk.
(4) If the indoor air methane concentration cannot be reduced below 10% of
the LEL, NCBP will be notified within 48 business hours of the last field
mobilization to discuss further mitigative measures.
b) Subslab methane gas concentrations will be monitored manually during routine
O&M and performance monitoring events using a handheld detector (e.g., GEM
5000). If subslab methane gas concentrations exceed 10% of the LEL during
monitoring, the following sequence of operation will be implemented:
i) Indoor gas monitoring will be performed once with a portable methane
detector (e.g., MultiRAE Four-Gas Meter) in the vicinity of the corresponding
subslab monitoring probe (this will be done to supplement the automated
indoor air monitoring sensor located nearest the subslab monitoring probe).
The timing of the indoor air gas monitoring relative to the measurement of the
subslab soil gas exceedance will be documented in the forthcoming OM&M
Plan (Section 9).
ii) If the indoor air methane concentration measured inside the Building is less
than or equal to 2% of the LEL (i.e., 0.1%v or 1,000 ppmv), no additional
portable methane detector monitoring is required.
iii) If the indoor air methane concentration measured inside the Building is
between 2% and 10% of the LEL (i.e., 0.1%v or 1,000 ppmv to 0.5%v or 5,000
ppmv), the mitigation measure(s) outlined in item 1a above (e.g.,
supplemental HVAC and/or MMS ventilation, air inlet inspections, etc.)
should be implemented to reduce methane concentrations to pre-screening
conditions.
iv) If the indoor air methane concentration measured inside the Building is greater
than 10% of the LEL, but less than 25% of the LEL, the procedure as outlined

GC8028/CAR21094 30 November 2022
in item 1a above will be implemented. As described item 1a, NCBP will be
informed if indoor air methane concentrations remain above 10% of the LEL.
2) High-Level Gas Detection System Response
a) The high-level detection threshold will be set at 25% of the LEL (i.e., 1.25%v or
12,500 ppmv). If either the one-tier or two-tier automated methane sensors
measure methane gas concentrations in indoor air to be greater than 25% of the
LEL, the following sequence of operations will be implemented.
i) The exceedance will trigger an audible alarm system within the building.
ii) Mandatory evacuation of the building.
iii) Notification to the local fire department. Occupancy of the building will not
resume until occupancy approval is granted by the local fire department once
the methane concentrations are reduced.
iv) Assuming the fire department confirms the elevated methane levels using
portable monitoring equipment, the HVAC system will be operated within the
building to vent impacted indoor air to reduce methane concentrations.
b) Subslab methane gas concentrations will be monitored manually during routine
O&M and performance monitoring events using a handheld detector (e.g., GEM
5000). If subslab methane gas concentrations exceed 25% of the LEL during
either type of monitoring, the following sequence of operation will be
implemented:
i) Indoor gas monitoring will be performed once with a portable methane
detector in the vicinity of the corresponding subslab monitoring probe (this
will be done to supplement the automated indoor air monitoring sensor located
nearest the subslab manual monitoring probe). The timing of the indoor air
gas monitoring relative to the measurement of the subslab soil gas exceedance
will be documented in the forthcoming OM&M Plan (Section 9)
ii) If the methane concentration measured inside the Building is less than or equal
to 2% of the LEL, no additional portable methane detector monitoring is
required.

GC8028/CAR21094 31 November 2022
iii) If the indoor air methane concentration measured inside the Building is
between 2% and 10% of the LEL, the mitigation measure(s) outlined in item
1a above (e.g., supplemental HVAC and/or MMS ventilation, air inlet
inspections, etc.) should be implemented to reduce methane concentrations to
pre-screening conditions.
iv) If the indoor air methane concentration measured inside the Building is greater
than 10% of the LEL, but less than 25% of the LEL, the procedure as outlined
in item 1a (Low-Level Gas Detection Response) will be implemented. As
described item 1a, NCBP will be informed if indoor air methane
concentrations remain above 10% of the LEL.
v) If the indoor air methane concentration measured inside the Building is greater
than 25% of the LEL, the procedure as outlined in item 2a (High-Level Gas
Detection Response) will be implemented.

GC8028/CAR21094 32 November 2022
7. FUTURE MMS MODIFICATIONS
The Site owner, or an authorized representative, will be responsible for property
management and day-to-day operation of the MMS. This will include confirmation that
the methane mitigation alarms are operational and that work that could potentially
damage components of the MMS is not conducted without developing a plan for approval
by NCBP and in consultation with the EOR. In the event the MMS requires modification
or repair, the work will be conducted in general accordance with the Construction
Documents (Appendix A) and NCBP will be notified at least 48 business hours prior to
implementing the modifications.
Future tenants/lessees will be notified of a presence of an MMS through the leasing
agreement. The information provided will include a description of the MMS and pertinent
information regarding MMS management for future improvements or subslab
modifications (consistent with the information presented herein). This document will be
provided to NCBP for review prior to Building occupancy.

GC8028/CAR21094 33 November 2022
8. REPORTING
Within 60 days of completion of post-construction/pre-occupancy system testing or
completion of MMS construction (whichever comes last), Geosyntec will prepare a report
summarizing the installation monitoring, QA/QC measures, notable deviations from the
design, post-construction/pre-occupancy monitoring, and provide an opinion of whether
the MMS was delivered in a condition consistent with the Construction Documents,
which is designed to mitigate public exposure to methane within acceptable levels. The
report will include field monitoring documentation (field logs and photographs) and as-
built drawings as appendices. If appropriate, Safety Data Sheets for construction materials
used near ground surface that might contribute to background interference will be
included as an appendix. The report will include the professional engineer statement
(Section 10), be signed and sealed by the EOR (Licensed in North Carolina), and
submitted to the NCBP for review and approval.

GC8028/CAR21094 34 November 2022
9. OPERATIONS, MAINTENANCE, AND MONITORING PLAN
An OM&M Plan is anticipated to be developed for each Building and submitted prior to
occupancy of the specific Building, and separate from the Reporting as outlined in Section
8. The OM&M Plan(s) will be submitted at least 30 days prior to the specific Building
occupancy. If possible, the OM&M Plan for each Building will be combined into a single
report.
The OM&M Plan(s) will be provided for implementation by the Site owner (and/or their
authorized representative) and will include documentation of the as-built system(s) (as
provided by the Contractor), product information and manuals for the installed
equipment, and OM&M requirements for the MMS in the instance there are future
modifications to the building and/or first-floor slab. The objective of the OM&M Plan
will be to provide recommendations for effective ongoing system operation and
monitoring, which will include recommended frequencies for calibrating and replacing
methane sensors, inspecting the first-floor slab, mitigation fans, and will discuss
procedures for collecting field screening data from the various MMS monitoring
components and a recommended reporting frequency.
An example OM&M form is provided in Appendix E to demonstrate the type of
monitoring data that may be collected; this OM&M form is not Site-specific and is not
planned for use at the Site. Site-specific OM&M form(s) will be developed for this Site
and will be included in the OM&M Plan(s).

GC8028/CAR21094 35 November 2022
10. PROFESSIONAL ENGINEER STATEMENT
The MMS detailed herein is designed to mitigate intrusion of subsurface vapors into the
subject building from known Brownfields Property contaminants in a manner that is in
accordance with the most recent and applicable guidelines including, but not limited to,
DWM Vapor Intrusion Guidance, Interstate Technology & Regulatory Council (ITRC)
guidance, and American National Standards Institute (ANSI)/American Association of
Radon Scientists and Technologists (AARST) standards. The sealing professional
engineer below is satisfied that the design is fully protective of public health from known
Brownfields Property contaminants.

GC8028/CAR21094 36 November 2022
11. REFERENCES
ANSI/ARST, 2020. Radon Mitigation Standards for Multifamily Buildings, RMS-MF
2018 with 12/20 revisions prepared by AARST Consortium On National Radon
Standards. 2020.
Civil & Environmental Consultants, Inc. Environmental Management Plan, Revision III,
Powers Site, 536 W. Tremont Avenue, Charlotte, NC 28203, Brownfields Project
#20045-16-060. August 2018.
Froehling & Robertson, Inc., 2019. Brownfields Assessment Report, Adams Property
Brownfield Project Number: 21022-17-060, 510 West Tremont Avenue,
Charlotte, Mechklenburg County, North Carolina. August 2019.
Hart & Hickman, 2021. Environmental Management Plan Dynatech II, Dynatech III, &
Dynatech IV Toomey Avenue and W. Tremont Avenue, Charlotte, North Carolina,
Brownfields Project Nos. 25001-21-060, 25067-21-060, 25068-21-060. October
2021.
Hart & Hickman, 2022. Additional Brownfields Assessment Report, Dynatech II and III
Brownfields Property, Charlotte, North Carolina. January 2022.
Los Angeles Department of Building and Safety (LADBS). 2010. Methane Hazard
Mitigation Measures Standard Plan. Rev. March 2010.
North Carolina Department of Environmental Quality (NCDEQ) Brownfields Program.
Threshold Criteria for Methane Site Development. December 2020.
NCDEQ Brownfields Program. Vapor Intrusion Mitigation System (VIMS) Design
Submittal New Construction Requirements Checklist. July 2021.
Partner, 2021a. Phase II Subsurface Investigation Report, Toomey Avenue Multifamily
Project, 2207, 2301, and 2315 Toomey Avenue and 704 West Tremont Avenue,
Charlotte, North Carolina 28203. February 2021.
Partner, 2021b. Methane Assessment Report, Dynatech II Brownfields Property, 2207,
2213, 2301, 2315, 2320, and 2325 Toomey Avenue and 704 West Tremont Avenue,
Charlotte, North Carolina 28203. June 2021.

GC8028/CAR21094 37 November 2022
Partner, 2021c. Brownfields Assessment Report, Dynatech II Brownfields Property, 2207,
2213, 2301, 2315, 2320, and 2325 Toomey Avenue and 704 West Tremont Avenue,
Charlotte, North Carolina 28203. August 2021.
USEPA, 1993. EPA Report EPA530-R-93-017; Part 258 – Criteria for Municipal Solid
Waste Landfills, Subpart C, Explosive Gases Control prepared by United States
Environmental Protection Agency. November 2003.
TABLES
Variable Unit Building 1 Building 2 Building 3 Building 4
Cupolex Air Volume cubic feet 15,830 21,841 14,725 2,495
Riser Diameter inches 6 6 6 6
Air Exchanges per Hour --3 3 3 3
Maximum Riser Air Velocity feet per minute 1,600 1,600 1,600 1,600
Maximum Riser Air Flow Rate cubic feet per minute 314 314 314 314
cubic feet per hour 47,489 65,523 44,176 7,485
cubic feet per minute 791 1,092 736 125
Number of Risers Required for
Maximum Riser Air Velocity --3 4 3 1
Air Flow Rate per Riser cubic feet per minute 264 274 246 125
Notes:
Table 1 - Design Air Exchange Rates
Methane Mitigation System Design Report
Dynatech III Brownfields Property - Charlotte, North Carolina
NCBP Project No. 25067-21-060
Required Cupolex Air Flow Rate
(3 Air Exchanges per Hour)
1. The design air exchange rates presented in this table served as the basis for design of the methane mitigation system (MMS). The MMS is not
required to achieve these flushing rates to demonstrate adequate system performance.
1 of 1
Building Number Building 1 Building 2 Building 3 Building 4
Building Area (ft2)28,000 33,700 26,800 4,500
Building Number Building 1 Building 2 Building 3 Building 4
Number of Two-Tier Methane Sensor 4 6 4 2
Number of One-Tier Methane Sensor 25 19 23 4
Number of Total Indoor Air Monitors 29 25 27 6
Ft2 per Two-Tier Indoor Air Sensor 7,000 5,620 6,700 2,250
Ft2 per One-Tier Indoor Air Sensor 1,120 1,770 1,170 1,130
Ft2 per Total Indoor Air Sensor 970 1,350 990 750
Building Number Building 1 Building 2 Building 3 Building 4
Total Number of Vent Riser Monitors 3 4 3 1
Ft2 per Vent Riser Monitor 9,330 8,430 8,930 4,500
Building Number Building 1 Building 2 Building 3 Building 4
Number of Manual Monitoring Locations 10 15 10 3
Ft2 per Subslab Monitoring Probe 2,800 2,250 2,680 1,500
Building Number Building 1 Building 2 Building 3 Building 4
Performance Monitoring Locations SS-1B, SS-1D, SS-1E,
SS-1H, and SS 1J
SS-2B, SS-2E, SS-2G,
SS-2I, SS-2K, and SS-2N
SS-3B, SS-3D, SS-3E,
SS-3H, and SS-3I SS-4B
Total Number of Probes to be Sampled 5 6 5 1
Ft2 per Sampling Location 5,600 5,620 5,360 4,500
Notes:
Table 2 - Monitoring Network
Methane Mitigation System Design Report
Dynatech III Brownfields Property - Charlotte, North Carolina
NCBP Project No. 25067-21-060
Subslab Monitoring Probes
Pre-Occupancy Subslab Soil Gas Analytical Monitoring Locations
1. Subslab Soil Gas Analytical Monitoring Locations indicate the specific subslab monitoring probe locations where analytical soil gas samples will be collected as part of pre-occupancy system monitoring.
ft2: square feet
Building Footprint
Vent Riser Monitors
Indoor Air Sensors
2. Monitoring density is rounded to the nearest 10 ft2.
1 of 1

FIGURES
Path: (Titusville-01\DATA) T:\0GIS\GC8028_Dynatech\MXDs\202202\Site_Location.mxd 01 March 2022. Last Edited by: CSaville
Notes:
<INSERT NOTES HERE>
0 2,000 4,0001,000
Feet
³Dynatech III Brownfields Property
Brownfields Project No: 25067-21-060
Toomey Avenue and West Tremont Avenue
Charlotte, North Carolina
Site Location Map
Figure
1
GC8028 November 2022
Legend
Site Parcel Boundaries
Site Location
Note:
1. Topography Source: USGS The National Map.
2. Street Map Source: Esri, DeLorme, HERE, USGS, Intermap, iPC, NRCAN,
Esri Japan, METI, Esri China (Hong Kong), Esri (Thailand), MapmyIndia,
Tomtom
^_
^_
Site Location
Toomey AvenueWest Tremont AvenueWilmore DriveBill Lee FreewayVillage Court
Dynatech IVDynatech IIIDynatech IIIParcel ID: 119046262320 Toomey AvenuePowers SiteAdams PropertyDynatech IIToomey AvenueParcel ID: 119064282213 Toomey Avenue(Former Dynatech Parcel)Parcel ID: 11906424(No Address Associated with Property)Parcel ID: 11906420704 West Tremont AvenuePath: (Titusville-01\DATA) T:\0GIS\GC8028_Dynatech\MXDs\202202\Site_Layout.mxd 01 March 2022. Last Edited by: CSavilleLegendDynatech IIDynatech IIIDynatech IVOther Brownfields PropertiesSite Parcel BoundariesParcels0150Feet³Site Layout MapFigure2GC8028November 2022Note:1. Parcel Data from the City of Charlotte Open Data Portal.2. Parcel Identification Numbers (PIN) are presented for parcels within the boundary of the Brownfields.3. A portion of the 2213 Toomey Avenue parcel is not part of the proposed Brownfields redevelopment.4. 2019 Aerial Source: Esri, Maxar, GeoEye, Earthstar Geographics, CNES/Airbus DS, USDA, USGS, AeroGRID, IGN, and the GIS User Community.Dynatech III Brownfields PropertyBrownfields Project No: 25067-21-060Toomey Avenue and West Tremont AvenueCharlotte, North Carolina
#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*Toomey AvenueWilmore DriveVillage CourtWest Tremont AvenueDynatech IVDynatech IIIPowers SiteDynatech IIIAdams PropertyDynatech IIToomey AvenueMSVG-7/7AMSG-17MSG-16MSVG-6/6AMSVG-5/5AMSG-15MSG-14MSG-18MSG-3MSG-19MSG-21MSG-2MSG-22MSG-20MSG-13MSG-12MSG-6MSG-11MSG-1MSG-5MSVG-4/4AMSG-8MSVG-3/3AMSG-7MSG-9MSVG-2/2AMSG-10MSVG-1/1AMSG-4SG-1SG-2SG-3Path: (Titusville-01\DATA) T:\0GIS\GC8028_Dynatech\MXDs\202202\Proposed_Redevelopment.mxd 01 March 2022. Last Edited by: CSaville0100Feet³Dynatech III Brownfields PropertyBrownfields Project No: 25067-21-060Toomey Avenue and West Tremont AvenueCharlotte, North CarolinaProposed Redevelopment FootprintFigure3GC8028November 2022Note:1. Parcel Data from the City of Charlotte Open Data Portal.2. Only presenting sampling locations relevant to methane monitoring on site.3. Sampling results for methane assessments can be found in assessment reports completed in 2021 and 2022 by Partner Engineering and Hart & Hickman, PC.4. Parcel Identification Numbers (PIN) are presented for parcels within the boundary of the Brownfields.5. A portion of the 2213 Toomey Avenue parcel is not part of the proposed Brownfields redevelopment.6. 2019 Aerial Source: Esri, Maxar, GeoEye, Earthstar Geographics, CNES/Airbus DS, USDA, USGS, AeroGRID, IGN, and the GIS User Community.Legend#*Approximate Methane Soil Gas Monitoring LocationsDynatech IIDynatech IIIDynatech IVOther Brownfields Properties#*

APPENDIX A

Construction Drawings, Technical
Specifications, and Construction Quality
Assurance

APPENDIX B

Typical Material Product Sheets
Geo-Seal® EV40
Product Data Sheet
EPRO Services, Inc. [phone] eproinc.com
Product Description
Basic Use: Geo-Seal EV40 is a standalone geocomposite EVOH
passive barrier system used to mitigate vapor intrusion for
sites deemed to be low risk. Geo-Seal EV40 may also be used
in conjunction with an active sub-slab mitigation to increase
system efficiency and provide an additional layer of redundancy.
Geo-Seal CORE, , a specially formulated asphalt emulsion, is
applied within the Geo-Seal EV40 seam overlap, around pipe
penetrations, and at termination, points to eliminate the need
for costly tape. Combining a sheet membrane with spray-
applied detailing helps increase installation efficiency while also
ensuring a robust seal in critical areas.
Composition: Geo-Seal EV40 is a 41-mil composite EVOH
geomembrane with a 3 oz. geotextile bonded to one side to
increase tensile and puncture strength. Geo-Seal EV40 also
exceeds all Class A, B, and C vapor barrier requirements.
Benefits
• EVOH geocomposite sheet membrane provides increased
thickness and robustness over similarly priced sheet
membranes.
• Geotextile backing enhances tensile strength and puncture
resistance, while also increasing seam strength and
durability. Taped seams’ integrity can be compromised in
cold or wet conditions.
• Geo-Seal EV40 is smoke tested to ensure proper installation.
• Meets class A, B, and C vapor barrier standards.
Limitations
• A more robust composite system should be utilized for sites
with elevated risk or more complex applications as thinner
mil vapor intrusion barriers are less durable and and less
puncture resistant than thicker composite systems offered by
EPRO.
• Additional geotextile may be required to cushion the Geo-
Seal EV40s system from additional aggregate layers.
Technical Data
Properties: See physical properties table
Coverages: One roll covers 1200 square feet, not including
overlaps or waste
Specification Writer: Contact EPRO before writing specifications
on this product
Installation
Preparation: Please refer to manufacturer’s specifications for
substrate requirements. Rolls should be inspected for damage
prior to application.
Application: Please refer to manufacturer’s specifications.
Overlap the seams of Geo-Seal EV40 a minimum of 6” and with
a 60 mil application of Geo-Seal CORE in the seam overlap.
Availability and Packaging
Contact a local EPRO installer or authorized applicator
(www.eproinc.com).
Roll Size: 12’ x 100’ unfolded rolls, 165 lbs.
Warranty
Limited Warranty: EPRO Services, Inc. believes to the best of its
knowledge that performance tables are accurate and reliable.
EPRO warrants this product to be free from defects. EPRO
makes no other warranties with respect to this product, express
or implied, including without limitation the implied warranties
of MERCHANTABILITY OR FITNESS FOR PARTICULAR PURPOSE.
EPRO’s liability shall be limited in all events to supplying
sufficient product to repair the specific areas to which defective
product has been applied. EPRO shall have no other liability,
including liability for incidental or resultant damages, whether
due to breach of warranty or negligence. This warranty may
not be modified or extended by representatives of EPRO or its
distributors.
Equipment
Seaming: AD-55 Sprayer, available through EPRO for application
of Geo-Seal CORE in seam overlaps.
Smoke Testing: EPRO Smoke Test Machine for underslab
applications
Technical Services and Information
Complete technical services and information are available by
contacting EPRO at 800.882.1896 or www.eproinc.com.
Geo-Seal® EV40
Product Data Sheet
EPRO Services, Inc. [phone] eproinc.com
Physical Property Test Method Value
Film Material .....................................................................................................................................Polyethylene & EVOH
Film Color ..........................................................................................................................................White/Blue
Weight................................................................................................................................................618 g/m²
Film Thickness ...................................................................................................................................41 Mil
Classification .......................................................ASTM E1745 ........................................................Class A, B & C
Water Vapor Permeance ...................................ASTM E96 ............................................................0.0098 perms
Tensile Strength ..................................................ASTM D882 ..........................................................71 lbf
Elongation ...........................................................ASTM D882 ..........................................................735%
Puncture Resistance ...........................................ASTM D1709 ........................................................2600 grams
Life Expectancy ...................................................ASTM E154 ..........................................................Infinite
Low Temp. Impact ..............................................ASTM D1790 ........................................................Resistant to 105° C
Methane Gas Permeance .................................ASTM D1434 ........................................................3.68 x 10-12 m/s
Benzene Gas Permeance ..................................Queens University1 .............................................1.13 x 10-10 m2/sec
TCE Gas Permeance ..........................................Queens University1 .............................................7.66 x 10-11 m2/sec
PCE Gas Permeance ..........................................Queens University1 .............................................7.22 x 10-11 m2/sec
Ethylbenzene Permeance ..................................Queens University1 .............................................1.23 x 10-10 m2/sec
Toluene Permeance............................................Queens University1 .............................................1.57 x 10-10 m2/sec
Radon Diffusion Coeffiecent .............................K124/02/95 ..........................................................7.22 x 10-11 m2/sec
1 Queens University testing results are not directly comparable to other permeation/diffusion testing methods.
Dimensions: 12’ x 100’
Weight: 165 lbs.
Typical Physical Properties
GEO-SEAL FILM EV40
(GEOTEXTILE AWAY
FROM INSTALLER)
GEO-SEAL CORE 60 MIL6"AS A SUPPLIER OF FINISHED RPODUCTS ONLY, EPRO SERVICES, INC. DOES NOT ASSUME RESPONSIBILITY FOR ERRORS IN DESIGN, ENGINEERING OR DIMENSIONS.THE PROJECT TEAM MUST VERIFY ALL DIMENSIONS AND SUITABILITY OF DETAILS. THE PRODUCTS LISTED ARE TRADEMARKS OF EPRO SERVICES, INC.PAGE 1 OF 1
1328 E. KELLOGG DRIVE
WICHITA, KS 67211
1-800-882-1896
EPROINC.COM
08/31/2020
RJT NTS
DRAWN BY SCALE
DATE
UNDERSLAB
PERIMETER
FOOTING
TERMINATION
SYSTEM DESCRIPTION
GEO-SEAL EV40S
SYSTEM NAME
48.132.1-MOD
DRAWIMG NUMBER
G:\.shortcut-targets-by-id\0B1j3RtmQZ-btQUNqNGJPcEc0Z1k\Epro Master Folder\Drafting\_Job Specific\Detail Requests\T\The Quarter\48.132.1-MOD UNDERSLAB GEO-SEAL EV40S
PERIMETER FOOTING TERMINATION.dwg [Detail] October 20, 2022 - 8:05am
Product Name
(MARV) listed below:
1. The property values listed above are subject to change without notice.
2.
3. Maximum Average Roll Value (MaxARV)
4. At time of manufacturing. Handling may change these properties.
Minimum Average Roll Values (MARV) is calculated as the average minus two standard deviations.
Statistically, it yields approximately 97.5% degree of confidence that any samples taken from quality
assurance testing will meet or exceed the values described above.
This information is provided for reference purposes only and is not intended as a warranty or guarantee. SKAPS
assumes no liability in connection with the use of this information.
Property Method English (MARV2) Metric (MARV
2)
SKAPS GT-110 is a needle-punched nonwoven geotextile made of
100% virgin polypropylene staple fibers, which are formed into a
random network for dimensional stability. SKAPS GT-110 resists
ultraviolet deterioration, rotting, biological degradation, naturally
encountered alkalis and acids. Polypropylene is stable within the pH
range of 2 to 13. SKAPS GT-110 is NTPEP certified and meets
requirements as per AASHTO Standards and/or D.O.T. Standards.
SKAPS GT-110 conforms to the Minimum Average Roll Values
Grab Tensile Strength ASTM D 4632 250 lbs. 1.112 kN
Grab Elongation ASTM D 4632 50% 50%
Trapezoid Tear Strength ASTM D 4533 100 lbs. 0.444 kN
CBR Puncture Resistance ASTM D 6241 700 lbs 3.113 kN
Permittivity4 ASTM D 4491 1.2 sec-1 1.2 sec-1
Water Flow4 ASTM D 4491 80 gpm/ft2 3251 l/min/m2
Apparent Opening Size (AOS)3&4 ASTM D 4751 100 Std. U.S. Sieve 0.150 mm
UV Resistance ASTM D 4355 70%/500 hrs. 70%/500 hrs.
Note
Packaging
Roll Dimensions (W x L) 12.5 x 360 ft.
15 x 300 ft.
3.81 m x 109.8 m
4.6 m x 91.4 m
Area Per Roll 500 sq. yards 418.3 sq. meters
NON-WOVEN GEOTEXTILE
GT - 110
Features
• Available in LEL, O2, H2S, CO, CO2, H2 (ppm or LEL)• Multigas versions available with sensors in one enclosure• Internal sample pump with 100’ range• Flowmeter and LED’s for operational status• Low flow indication• NEMA 4X enclosure• Operates on 24VDC input• Optional 4-20mA outputIndustry Applications
• Petrochemical plants• Refineries• Water & wastewater treatment plants• Pulp & paper mills• Gas, telephone, & electric utilities• Parking garages• Manufacturing facilities• Steel• Automotive• HVAC
SAMPLE DRAW SENSOR / TRANSMITTER
35-3001 ModelGas Detection For Life
F017-0908
World Leader In Gas Detection & Sensor Technology www.rkiinstruments.com
RKI Instruments, Inc. • 33248 Central Ave. Union City, CA 94587 • Phone [phone] • [phone] • Fax [phone]
The 35-3001 series is a compact sample draw detector assembly with a built-in pump that is powered from 24VDC. This unit features a NEMA 4X enclosure, making it dust, water and corrosion resistant. It also features a low flow alarm which warns of any obstructions or restrictions in the flow system. Combustibles, oxygen, and carbon dioxide versions are available with or without a 4-20 mA transmitter. H2S and CO versions both have 4-20mA outputs. The 35-3001 is also available in many dual sensor configurations.
The 35-3001 is capable of single person calibrations and remote sampling at up to 5,000 ft. from a controller, and interfacing to any RKI or third party control system (utilizing a 4-20 mA feedback signal).
Authorized Distributor:
35-3001 Model
Specifications subject to change without notice.
Note: Transmitter provides 4-20mA output, built-in for all CO/H2S versions.
Specifications LEL LEL O2 H2S CO H2 CO2
Sensor Type Catalytic Infrared Galvanic cell Electrochemical MOS Infrared
Measuring Range 0-100% LEL
0-100% LEL
for CH4
and HC’s
0-25% Vol.0-100 ppm 0-300 ppm 0-2000 ppm
0 - 5000 ppm 0 - 5.0% Vol. 0 - 50% Vol. 0 - 100% Vol.
Signal Output RKI direct connect sensors (requires RKI controller) optional 4-20mA output (standard for CO/H2S)
Operating Voltage 24VDC nominal (18.5 – 30VDC)
Max Current Draw 250 mA 24VDC
Location Indoor or outdoor
Temperature -4 to 122° F (-20 to 50°C)
Humidity 0 – 95% RH non condensing
Housing Grey polycarbonate wall-mount hinged NEMA 4X
Dimensions Height 8.5” 216 mm
Width 7.0” 178 mm
Depth 4.3” 109 mm
Sampling Method Internal sample draw pump
Maximum Sample Length 100 Ft.
Sample Connections 1/4” OD rigid tubing (inlet and exhaust)
Display Flow meter, LED’s for pilot and fail
Warranty One year, materials and workmanship
0000363 ISO 9001
Toll Free: [phone] • Phone: [phone]
Fax: [phone] • www.rkiinstruments.com
Available Configurations
Single Channel Multi Channel
No Transmitter
LEL
IR LEL
IR Vol
H2 LELO2CO2
LEL / O2
IR LEL / O2
IR vol / O2
LEL / IR LEL
LEL / H2S
IR LEL / H2S
IR vol / H2S
O2 / H2S
LEL / CO
IR LEL / CO
IR vol / CO
O2 / CO
LEL / CO2
IR vol / CO2
With Transmitter
LELIR LELIR VolH2 LELH2SCOO2CO2
LEL / H2SIR LEL / H2SIR vol / H2SO2 / H2S
LEL / COIR LEL / COIR vol / COO2 / CO
Gas Detection
FEATURES & BENEFITS
Sensepoint XCL
Fixed Gas Detector
Sensepoint XCL is a fixed point gas leak detector that is designed to meet
the needs of commercial and light industrial applications. With over 50
years experience in gas leak detection, Honeywell offers a flexible range
of highly-reliable sensing devices to meet those needs.
• Quicker installation
• Rapid configuration
• Simple to operate
• Straightforward to maintain
Honeywell innovation enables customers to pair the gas detector with
their mobile phone, and then use an app to perform many tasks related
to installation, commissioning and maintenance.
Flexible Output Options
Sensepoint XCL is available with either mA loop analog output or
Modbus RTU with the option for relays on both. The result is a flexible
solution that can easily be incorporated into legacy systems as well as
new installations.
Faster Installation
Everything you need for installation is in the box, including simple drilling
templates.
Easy Control and Maintenance
Sensepoint XCL's smartphone interface makes for much faster
calibration, configuration and bump tests. Inspecting the status and
settings of individual Sensepoint XCL detectors is simple. Use the
mobile app to:
• Read gas concentrations in real-time
• Reconfigure settings
• Check unit histories
Automated Reporting
Increase the efficiency of your operations and reduce administration
time. The app and Sensepoint XCL provides easy access to diagnostic
information and generates calibration reports at the touch of a screen.
Compatible System Controller
Touchpoint Plus is the perfect complement to Sensepoint XCL, providing
an intuitive, easy to operate gas detection solution to meet the needs of
your business.
Visual Integration
Sensepoint XCL is designed with the needs of
building architects in mind. Clean aesthetics
and a choice of colors mean that the detector
is ideal for public spaces like lobbies and retail
environments.
Typical Applications
• Kitchens and food processing
• Manufacturing facilities and factories
• Hospitals
• Retail sites
• Transportation and parking
• Laboratories
• Hotel and leisure
• Apartments, accommodation blocks and
condominiums
Accessories
• Calibration cap / flow housing
• Duct mount kit for round or flat profile ducts
• Choose from a range
of mA or Modbus
output versions for
flexible system design
to meet the
customers
requirements.
• Selectable source or
sink current for
analog output
enables one detector
to be suitable for both
system
configurations.
• Optional relay output
for external control
systems or alarming
devices enables easy
integration and local
indication.
• The ingress
protection of IP65
allows units to be
mounted in wash
down areas.
• Multi-color visual
indicator to show
status makes it easier
to know the detector
status immediately
and identify detectors
that require attention
or are warning of
danger.
• Gassing port for
easier bump test of
units installed in
inaccessible
locations. No need to
purchase a separate
accessory and thus
saves money.
• Manage the detector
without making a
physical connection.
Remove the need for
physical access to
hard-to-reach
devices.
• Simplified
maintenance with
familiar smartphone
technology saves
money and time.
Sensepoint XCL Technical Specifications
For more information
www.honeywellanalytics.com
Europe, Middle East, Africa
Life Safety Distribution GmbH
Tel: [phone] (Freephone number)
Tel: [phone] (Alternative number)
Middle East Tel: [phone] (Fixed gas detection)
Middle East Tel: [phone] (Portable gas
detection)
Americas
Honeywell Analytics Distribution Inc.
Tel: [phone]
Toll free: [phone]
RAE Systems by Honeywell
Phone: [phone]
Toll Free: 1.888.723.4800
Asia Pacific, India
Honeywell Analytics Asia Pacific
North Asia Tel: [phone]
South East Asia Tel: [phone]
India Tel: [phone]
China Tel: [phone]-3000
www.honeywell.com
DS_01178 | Rev. 01 | 05/2018
© 2018 Honeywell International Inc.
PHYSICAL PROPERTIES
DIMENSIONS 113 x 113 x 59 mm
( 4.4 x 4.4 x 2.3 in )
WEIGHT 500 g (1.1 lb)
CASING MATERIAL Polycarbonate (charcoal or white)
INGRESS PROTECTION RATING IP65, Type 4 (in accordance with
NEMA 250)
LIFETIME 10 years (excludes sensor)
AVAILABLE SENSORS
FLAMMABLE, TOXIC GASES AND
OXYGEN RANGES
• Combustible: 0 to 100 % LEL (factory
calibrated to Methane)
• O₂: 0 to 25% vol
• CO: 300 ppm (adjustable between 50
and 1000 ppm)
• H₂: 1000 ppm
• H₂S Low Range: 50 ppm (adjustable
between 10 and 50 ppm)
• H₂S High Range: 100 ppm (adjustable
between 50 and 200 ppm)
• NO₂: 20 ppm (adjustable between
5 and 50 ppm)
• NH₃: 200 ppm (adjustable between
50 and 200 ppm)
• CO2 (ppm range): 5,000 ppm
(adjustable between 1,000 and 5,000
ppm)
• CO2 (% vol range): 5.0% vol
(adjustable between 1.0 and 5.0%
vol)
POWER SUPPLY
NOMINAL DC INPUT VOLTAGE 24 V DC†
NOMINAL AC INPUT VOLTAGE 24 V AC‡, 50/60 Hz
MAXIMUM INRUSH CURRENT 850 mA
OUTPUT
ANALOG OUTPUT 0 to 22 mA
DIGITAL OUTPUT Modbus RTU
RELAY OUTPUT 2 relays rated at 24 V DC / 240 V AC, 5 A
MAXIMUM POWER CONSUMPTION
mA VERSIONS < 1.2 W (toxic), < 1.7 W (flammable and CO2)
MODBUS VERSIONS < 0.7 W (toxic), < 1.2 W (flammable and CO2)
RELAY VERSIONS Additional 0.6 W total
† mA versions: 11 to 32 VDC, Modbus versions: 9 to 32 VDC
‡ All versions: 20 to 27 VAC
CONNECTION
TYPE Pluggable rising clamp style, 0.5 to
1.5 mm2, 20 to 16 AWG.
USER INTERFACE
VISUAL INDICATOR Multi-colour LED light ring
• Green: normal§
• Flashing red: Alarm
• Flashing green and yellow: Warning
• Flashing yellow: Fault
• Solid yellow: Inhibited
• Flashing blue: Bluetooth pairing in
progress
• Solid blue: Bluetooth connection
established
WIRELESS INTERFACE Bluetooth 4.0 (Bluetooth Low Energy).
Dedicated mobile app, enabling wireless
configuration and maintenance.
Connect up to 10 m away (mobile
device dependent). Use a compatible
smartphone or other mobile device
running Android 4.3 or above.
OPERATING ENVIRONMENT
OPERATING TEMPERATURE
STORAGE TEMPERATURE
HUMIDITY
ATMOSPHERIC PRESSURE
−20 to 50°C (−4 to 122 °F) 0 to 30°C
(32 to 86 °F)
15 to 90% RH (non-condensing)
90 to 110 kPa
APPROVALS
ELECTRICAL SAFETY EN/UL/IEC61010-1
CSA-C22.2 No. 61010-1-12
EMC EN 50270
RADIO RED, FCC
OTHER UL2075 (CO and CH4), AS 1668.2
§LED behavior in normal condition can be changed by the user: solid green, green confidence
flash or off.

GD-2B & GD-2A
The Macurco GD-2B and GD-2A combustible gas detectors are reliable, lightweight, and aesthetically pleasing gas detectors made to keep you and the people you care about safe
from harmful gases in residential and light commercial applications. They are low-voltage gas detectors designed for use with fire and security systems. The GD-2A is UL 2075 Listed for use in residential and commercial applications and is also approved by the California
State Fire Marshal.
Key Features
• Low replacement costs with long-life sensors
• Low maintenance with no calibration needed
• Local alarms (GD-2B only)
• Clip-in wire harness (GD-2B only) for in and out replacement
• Aesthetically pleasing. Flush mount or surface options
• Ties into any Fire/Burglary panel for
local and remote monitoring
• Made in America
Whether you are looking for gas
detection for a security system,
building automation, or HVAC system, for personal safety, or for monitoring specific gases in potentially hazardous
environments, Macurco has a gas
detector to meet your needs.
MacurcoTM
Building & Home Solutions Building & Home Solutions
Applications
• Homes
• Schools/university dorms
• Hotels/condos
• Offices
• Retail stores
• Common rooms/lobbies
• Apartments
• Airports
• Other light commercial
environments
www.macurco.com
Residential / light commercial combustible gas detectors
GD-2A (Combustible Gas)
GD-2B (Combustible Gas)
GD-2B / GD-2A MacurcoTM
Building & Home Solutions Building & Home Solutions
© Aerionics 2022. All rights reserved. Macurco is a trademark of Aerionics, Inc.
Macurco Gas Detection3601 N St. Paul Ave, Sioux Falls, SD 57104 Website: www.macurco.comPhone: 1-877-367-7891 Email: [e-mail]
11/2022
Since 1972 Macurco has been providing gas detection solutions for various
applications. Macurco provides the highest quality gas detection solutions to customers worldwide.ISO 9001:2015

ISO 9001:2015

CERTIFIED
Specifications
GD-2B: 3.25”(H) x 5.25”(L) x 1.75”(W)
GD-2A: 4.5”(H) x 5”(L) x 1.62”(W)
0.5 lb. (8 oz.)
GD-2B: 9-32 VDC or 12-24 VAC
GD-2A: 9-32 VDC or 12-24 VAC
GD-2B: 10 years w/EOL
GD-2A: 5 years w/EOL
Sensor Life
GD-2B: 40°F to 100°F (4.4°C to 37.8°C)
GD-2A: 32°F to 120°F (0°C to 48.9°C)
Operating Temperature
Voltage
Shipping Weight
Size
Model
GD-2B Single Detector Wiring
GD-2A Single Detector Wiring
Description
Ordering Information
Wiring Diagrams
GD-2B
GD-2A
Natural Gas (NG) or Propane (LP) Combustible Gas Detector
Natural Gas (NG) or Propane (LP) Combustible Gas Detector
Double Gang Adapter Plate used with the GD-2BCM-E1-IAK
GD-2B, GD-2A - refer to manual, based on
voltage and standby/alarmCurrent Draw
GD-2B, GD-2A - refer to user manual
Status Indicators
Relays
GD-2B: 85 dB at 10’
Alarm - 2 chirp sequence,
Trouble - single chirp
GD-2A: NA
Local Buzzer
GD-2B: LED (Red alarm, amber trouble,
green normal)
GD-2A: LED (Red alarm, green normal,
alternating red/green trouble)
Alarm Levels Per UL 1484, 25% LEL
Test Button GD-2B: Local Test, Alarm Test, Gas Test, Silence
GD-2A: NA
Approvals /
Listings
GD-2B: Sensitivity tested based on UL 1484
GD-2A: UL 2075 Listed. Tested to 1484
standard for residential gas detectors
Warranty Two year limited warranty
*Please read manual for more specifications
HA72 specificAtions
Gas Detection controller
SS01155_V1 12/12© 2012 Honeywell Analytics
General Specifications
Use Wall or rack/panel mountable digital gas controller for industrial or commercial use
Display QVGA 320 x 240 pixel graphic LCD with backlight; displays bar graphs, trends and engineering units in color
Five discrete LEDs indicate alarm status for five standard alarm relays
Ethernet Port Modbus TCP Master/Slave port
Alarm Relays 5 amp 30VDC or 250VAC resistive Form C
Analog Inputs (OPtIOnAl) 12 bit 4-20mA into 150 ohms input impedence; includes +power supply terminal for each channel for
routing power to two or three wire transmitters
Analog Output (OPtIOnAl) 10 bit 4-20mA output; max load 800 ohms with nominal 24VDC power supply
Serial Port (OPtIOnAl) Master and Slave RS-485 half or full duplex ports equipped with Tx / Rx LEDs
Protocol = Modbus RTU
Power Requirement 10 – 30VDC (24VDC nominal) 12 Watts max
Operating temperature Range -13°F to +140°F (-25°C to +60°C)
Housing Options NEMA 4X fiberglass wall mount
½ length 19" rack / panel mount
Full length 19" rack mount
Weight Panel mount ½ 19" rack: 8 lbs.
Full 19" rack: 12 lbs
Compact Fiberglass: 26 lbs
Large Fiberglass: 75 lbs
Large 316 Stainless Steel: 88 lbs
Warranty 12 months from date of commissioning or 18 months from date of delivery, whichever is less
Ratings and Certifications
Class I, Div. 2, Groups A, B, C and D
CAN/CSA-C22.2 No.152-M1984
ANSI/ISA-12.13.01-2000
CSA-C22.2 No. 213-M1987
UL Std No. 1604, Third Ed. – 1994
ANSI/ISA-12.12.01-2010
find out more
www.honeywellanalytics.com
Toll-free: 800.538.0363
Please note:
While every effort has been made to ensure accuracy in this publication, no responsibility can be accepted for errors or omissions.
Data may change, as well as legislation, and you are strongly advised to obtain copies of the most recently issued regulations,
standards, and guidelines. This publication is not intended to form the basis of a contract.

APPENDIX C

Historical Environmental Data
Phase II Subsurface Investigation Report
(February 2021)

Historical Environmental Data
Table 4: Summary of Soil Gas Results
Toomey Avenue Multifamily Project
2207, 2301, 2315 Toomey Ave / 704 West Tremont Ave
Charlotte, North Carolina 28203
Partner Project Number 20-296889.3
January 13-14, 2021 and February 2, 2021
Propylene NA NA NA 238 293 236 164 957 <1.60 446 NE 21,000 260,000
Dichlorodifluoromethane NA NA NA <0.678 <0.678 2.19 2.33 2.19 2.34 1.82 NE 700 8,800
Chloromethane NA NA NA 0.469 1.45 1.92 3.37 8.45 98.7 0.653 NE 630 7,900
Vinyl Chloride NA NA NA 0.394 J <0.243 0.458 J 0.849 1.83 10.8 <0.243 NE 5.6 280
1,3-Butadiene NA NA NA <0.230 19.0 19.2 13.7 77.9 75.5 22.6 NE 3.1 41.0
Chloroethane NA NA NA <0.263 <0.263 <0.263 <0.263 <0.263 29.5 <0.263 NE 70,000 880,000
Acetone NA NA NA 55.6 34.5 17.1 23.0 26.9 903 21.1 NE 220,000 2,700,000
Trichlorofluoromethane NA NA NA <0.460 <0.460 1.75 2.13 1.88 66.9 11.6 NE NE NE
Iso-propyl Alcohol NA NA NA <0.649 3.20 <0.649 2.11 J 2.17 J 38.3 1.04 J NE 1,400 18,000
Carbon Disulfide NA NA NA 21.4 6.47 5.14 4.36 7.87 73.1 14.0 NE 4,900 61,000
Carbon Tetrachloride NA NA NA <0.641 0.569 J 0.502 J 0.800 J 0.539 J <0.641 <0.641 NE 16.0 200
2-Butanone NA NA NA 20.1 13.4 5.10 9.85 13.4 1,030 6.22 NE 35,000 440,000
n-Hexane NA NA NA 101 12.7 22.9 31.7 31.6 159 15.5 NE 4,900 61,000BenzeneNANANA7.41 7.57 9.33 14.0 18.8 189 4.57 NE 120 160
Cyclohexane NA NA NA 47.2 2.53 2.71 4.44 <0.259 27.9 1.77 NE NE NE
cis-1,2-Dichloroethene NA NA NA 0.828 <0.311 <0.311 <0.311 <0.311 <0.311 <0.311 NE NE NE
Ethanol NA NA NA 15.3 <0.500 13.8 12.7 56.0 20.6 12.05 NE NE NE
Xylenes (Total)NA NA NA 15.31 15.88 16.32 41.8 20.12 93.9 10.85 NE 700 8,800
1,4-Dioxane NA NA NA <0.300 0.352 J <0.300 0.407 J <0.300 <0.300 <0.300 NE 19.0 250
1,1,2-Trichlorotrifluoroethane NA NA NA <0.608 0.701 J 0.651 J 0.843 J 0.812 J <0.608 <0.608 NE NE NE
2,2,4-Trimethylpentane NA NA NA 12.7 2.91 4.86 7.57 4.26 42.4 3.06 NE NE NE
Heptane NA NA NA 56.0 4.29 9.61 12.5 12.2 58.9 7.28 NE 2,800 35,000
4-Methyl-2-Pentanone NA NA NA 1.27 J 2.03 J 1.46 J 3.43 J 12.3 21.5 5.04 J NE 21,000 260,000
Methylene Chloride NA NA NA <0.340 <0.340 <0.340 1.08 <0.340 <0.340 <0.340 NE 3,400 53,000
Methyl Methacrylate NA NA NA <0.359 <0.359 1.69 <0.359 20.5 40.4 1.29 NE 4,900 61,000
Toluene NA NA NA 22.8 26.1 26.7 37.7 34.8 71.6 12.0 NE 35,000 440,000
2-Hexanone NA NA NA <0.544 <0.544 2.93 J 10.1 3.10 J <0.544 <0.544 NE 210 2,600
Tetrachloroethene NA NA NA <0.553 <0.553 0.571 J 0.643 J 0.678 J 1.35 J <0.553 NE 280 3,500
Ethylbenzene NA NA NA 7.80 3.60 <0.362 8.67 5.38 37.6 2.40 NE 37.0 490
Styrene NA NA NA 1.64 2.08 2.14 <0.335 3.96 <0.335 1.52 NE 7,000 88,000
4-Ethyltoluene NA NA NA 3.32 3.96 <0.384 <0.384 5.35 24.7 3.94 NE NE NE
1,2-Dichlorotetrafluoroethane NA NA NA 3.99 <0.622 <0.622 <0.622 <0.622 <0.622 <0.622 NE NE NE
1,3,5-Trimethylbenzene NA NA NA 1.56 1.31 1.44 2.86 1.72 9.62 1.60 NE 420 5,300
1,2,4-Trimethylbenzene NA NA NA 4.59 5.15 5.50 25.1 6.53 15.5 5.06 NE 420 5,300
Methane <0.0584 <0.0584 0.672 <0.0584 <0.0584 <0.0584 <0.0584 <0.0584 <0.0584 <0.0584 1.25 NE NE
Notes:
NCDEQ = North Carolina Department of Environmental Quality
NA = Not Analyzed
NC = Not Calculated
NE = Not Established
SGSLs = Soil Gas Screening Levels (dated July 2020)
TCR = Target Cancer Risk
THQ = Target Hazardous Quotient
VISLs = Vapor Intrusion Screening Levels
VOCs = Volatile Organic Compounds
µg/m3 = micrograms per cubic meter
%bv = Percent by volume
< = not detected above indicated laboratory reporting limit (RL)
Values highlighted and bolded where exceedances of initial screening NCDEQ Residential Sub-Slab and Exterior SGSLs. Subject to secondary screening
using the NCDEQ Risk Calculator (July 2020 version)
* = Additional soil gas samples collected on February 2, 2021 and analyzed for methane only
Methane via TO-15 (%bv)
NCDEQ Methane
Threshold Criteria for
Residential Re-Use
VOCs via TO-15 (µg/m3)
MSG-3 /
MSG-3A*
MSG-1 /
MSG-1A*Analyte MSG-2 /
MSG-2A*
MVSG-1 /
MSVG-1A*
MVSG-2 /
MVSG-2A*
MVSG-3 /
MVSG-3A*
MVSG-4 /
MVSG-4A*
MVSG-5 /
MSVG-5A*
MVSG-6 /
MVSG-6A*
MVSG-7 /
MVSG-7A*
NCDEQ Residential Sub-
Slab and Exterior SGSLs
(TCR=1E-06 or THQ=0.2)
NCDEQ Non-Residential
Sub-Slab and Exterior
SGSLs
(TCR=1E-06 or THQ=0.2)

Methane Assessment Report (June 2021)

Historical Environmental Data
INTERSTATE 77W TREMONT AVENUEAVENUEVILLAGE COURTParcel ID 119064242207 Toomey AvenueFormer Dynatech Parcel(Current Configuration)Parcel ID 119064282213 Toomey AvenueParcel ID 11906417728 W Tremont AvenueParcel ID 119064292301 Toomey AvenueParcel ID 119064262325 Toomey AvenueParcel ID 11906420704 W Tremont AvenueParcel ID 119046262320 Toomey Avenue(Not Part of Multifamily Parcels orMethane Assessment Work Plan)MSG-17Planned PropertyRecombination2213 Toomey AvenueMethane Assessment AreaSG1SG2SG3TOOMEY AVENUEWOODCRESTMSG-2/2AMSG-1/1AMM>M,PMSG-3/3ATP-3MSG-18MSG-14TP-4TP-1MSG-21B-3B-2MSG-6MSG-8TP-6MVSG-1/1AMVSG-3/3AMSG-7MSG-9MSG-4MVSG-2/2AMVSG-6/6AMVSG-4/4AMVSG-5/5AMSG-12MSG-5MSG-13MSG-11MSG-20MVSG-7/7AMSG-22MSG-10B-1MSG-15MSG-16TP-2B-4MSG-19TP-5APPROXIMATE SCALE IN FEET028014070IMAGE SOURCE: NC ONEMAPNSoil Boring Fill withDebris DepthsB-1: 0 Ft BgsB-2: 0 Ft BgsB-3: 6 Ft BgsB-4: 3 Ft BgsEXPLANATIONTest Pit Fill withDebris DepthsTP-1: ~8 Ft BgsTP-2: ~2 Ft BgsTP-3: ~2.5 Ft BgsTP-4: ~6.0 Ft BgsTP-5: ~4 Ft BgsTP-6: ~16 Ft BgsTest PitPrevious Phase IIAssessment LocationsSoil Boring LocationDynatech II Brownfields Project ParcelsMethane SoilVapor SampleMethane and VOC SoilVapor SampleMethane AssessmentLocationsSoil Gas SampleCharlotte, North Carolina 282178720 Red Oak Boulevard, Suite 528www.partneresi.comFax.: 704-353-7050Tel.: [phone]DateProject No.Reference Dwg.Project:PMDrafterSketch No.DesignerChecked ByTitle:Dynatech II Brownfields Project (25001-21-060)Toomey Avenue and West Tremont AvenueFigure 3Methane and Pressure Detections Map21-3706206.14.21DHADF3ADDH3Charlotte, North Carolina(Grading Plan)LEGENDNotes:1.Methane and pressure readings collected on May 26 through 28,2021. Refer to Table 4 for complete dataset.2.M = Methane above 1.25 percent by volume.3.>M = Methane detected greater than 30 percent by volume.4.P = Pressure DetectedM, >M, PSoil Gas Sample Location(Methane)Methane and Pressure ReadingDetections (See Notes)
Table 1A
Summary of Methane Soil Gas Results
Multifamily Parcels
Dynatech II Brownfields Project
Charlotte, North Carolina 28203
Partner Project Number 21-370620
Brownfields Project Number 25001-21-060
January 13 and 14, 2021
Methane NA NA NA NA NA NA NA NA NA NA 1.25
Methane 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 1.25
Static Pressure 0.1 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 N/A
Differential Pressure -0.021 -0.025 -0.020 -0.023 -0.023 -0.027 -0.027 -0.026 -0.035 -0.030 N/A
Notes:
NCDEQ = North Carolina Department of Environmental Quality
%bv = Percent by volume
< = not detected above indicated laboratory reporting limit (RL)
NA = Not analyzed
N/A = Not applicable
Methane via TO-15 (%bv)
Methane via LandTec Gem 2000 Field Instrument (%bv)
Pressure via LandTec Gem 2000 Field Instrument (Inches of Water)
MVSG-3 MVSG-4 MSVG-5 MVSG-6 MVSG-7
NCDEQ Methane
Threshold Criteria for
Residential Re-Use
Analyte MSG-1 MSG-2 MSG-3 MSVG-1 MVSG-2
Table 1B
Summary of Methane Soil Gas Results
Multifamily Parcels
Dynatech II Brownfields Project
Charlotte, North Carolina 28203
Partner Project Number 21-370620
Brownfields Project Number 25001-21-060
February 2, 2021
Methane <0.0584 <0.0584 <0.0584 0.672 <0.0584 <0.0584 <0.0584 <0.0584 <0.0584 <0.0584 1.25
Methane 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 1.25
Static Pressure 0.1 0.1 0.1 0.1 0.1 0.0 0.1 0.0 0.1 7.8 N/A
Differential Pressure -0.050 -0.050 -0.400 -0.098 -0.050 -0.098 -0.050 -0.044 -0.045 0.000 N/A
Notes:
NCDEQ = North Carolina Department of Environmental Quality
%bv = Percent by volume
< = not detected above indicated laboratory reporting limit (RL)
N/A = Not applicable
Methane via LandTec Gem 2000 Field Instrument (%bv)
Pressure via LandTec Gem 2000 Field Instrument (Inches of Water)
Methane via TO-15 (%bv)
MVSG-3A MVSG-4A MSVG-5A MVSG-6A MVSG-7A
NCDEQ Methane
Threshold Criteria for
Residential Re-Use
Analyte MSG-1A MSG-2A MSG-3A MSVG-1A MVSG-2A
Table 2
Summary of Methane Soil Gas Results
Foremer Dynatech Parcel
Dynatech II Brownfields Project
Charlotte, North Carolina 28203
Partner Project Number 21-370620
Brownfields Project Number 25001-21-060
August 18, 2020
Methane <0.11 <0.12 <0.12 1.25
Methane 0.00 0.00 0.02 1.25
Notes:
NCDEQ = North Carolina Department of Environmental Quality
%bv = Percent by volume
< = not detected above indicated laboratory reporting limit (RL)
Static and differnetial pressures not available for this event
Methane via TO-15 (%bv)
Methane via LandTec Gem 2000 Field Instrument (%bv)
NCDEQ Methane
Threshold Criteria for
Residential Re-Use
Analyte SG 1 SG 2 SG 3
Sample Locations Sample Type Sample Objectives Sample Depth Intervals Number of
Samples Analysis Work Plan Scope*
MSG-14, MSG-15, MSG-17 Soil Gas Vapor Intrusion Risk
Evaluation Centered on 5 ft bgs 12 Methane, carbon dioxide, oxygen,
hydrogen sulfide (Field Meter)
MSG-14 and MSG-15: Centered on 5 and 10 ft bgs
MSG-17: Centered on 5 and 10 ft bgs and from 15 to 20 ft bgs
MSG-4, MSG-5, MSG-6, MGS-12, MSG-
13, MSG-16, MSG-18, MSG-19, MSG-
20, MSG-21, MSG-22
Soil Gas Vapor Intrusion Risk
Evaluation Centered on 5 and 10 ft bgs 88 Methane, carbon dioxide, oxygen,
hydrogen sulfide (Field Meter)
MSG-13, MSG-16, MSG-18, MSG-19, MSG-20, MSG-21, and MSG-22:
Centered on 5 and 10 ft bgs and from 15 to 20 ft bgs
MSG-7, MSG-8, MSG-9, MSG-10, MSG-
11 Soil Gas Vapor Intrusion Risk
Evaluation
Centered on 5 and 10 ft bgs
and from 15 to 20 ft bgs 60 Methane, carbon dioxide, oxygen,
hydrogen sulfide (Field Meter)No Deviations
Notes:
ft bgs = feet below ground surface
Sample intervals at 5 and 10 ft bgs are 1 foot in thickness
* - Work Plan Scope column presents proposed sample point depths. The Sample Depth Interval column indcates depths of installed during the Methane Assessment, with deviations required due to shallow groundawter.
Table 3
Sample Summary
Methane Assessment Work Plan
Multifamily Parcels - Dynatech II Brownfields Project
Charlotte, North Carolina
Partner Project Number 21-370620 / Brownfields Project Number 25001-21-060
CH4 -
Methane
CO2 - Carbon
Dioxide O2 - Oxygen Balance CH4 % LEL Static Press.Diff. Press.Baro. Press.
H2S -
Hydrogen
Sulfide
Inches Hg
MSG-4 5 5/26/2021 11:05 0.2 0.9 15.9 83 4 -0.02 0.001 29.53 0
MSG-4 10 5/26/2021 11:16 0.2 6.2 9.1 84.5 4 -0.58 0.612 29.55 0
MSG-4 5 5/26/2021 11:44 0.1 1.1 16.2 82.6 2 0.02 -0.001 29.53 0
MSG-4 10 5/26/2021 11:47 0.2 6.5 8.5 84.8 4 -0.07 0.106 29.54 0
MSG-4 5 5/26/2021 11:53 0.1 1.2 16.4 82.3 2 -0.01 -0.010 29.54 0
MSG-4 5 5/27/2021 11:11 0 1.1 16.2 82.7 0 0.02 0.001 29.44 1
MSG-4 10 5/27/2021 11:14 0 5.8 7 87.2 0 -0.02 0.035 29.44 0
MSG-4 5 5/27/2021 11:57 0 1.2 16.2 82.6 0 -0.01 -0.006 29.44 0
MSG-4 10 5/27/2021 11:59 0.1 6.8 6.5 86.6 2 0.00 0.015 29.45 1
MSG-5 5 5/26/2021 10:46 0.1 0.4 15.7 83.8 2 -0.82 0.800 29.52 1
MSG-5 10 5/26/2021 10:52 0.1 4.8 11.7 83.4 2 -1.13 1.031 29.53 0
MSG-5 5 5/26/2021 11:33 0.1 0.4 16.3 83.2 2 -2.38 2.110 29.53 0
MSG-5 10 5/26/2021 11:38 0.1 4.8 11.9 83.2 2 -0.71 0.734 29.52 0
MSG-5 5 5/27/2021 11:04 0 0.5 15.2 84.3 0 -0.58 0.583 29.43 1
MSG-5 10 5/27/2021 11:07 0 5 11.4 83.6 0 -0.53 0.679 29.44 0
MSG-5 5 5/27/2021 11:48 0 0.4 16.1 83.5 0 -0.27 0.329 29.44 1
MSG-5 10 5/27/2021 11:51 0 4.9 11.4 83.7 0 -0.61 0.694 29.44 0
MSG-6 5 5/26/2021 12:47 0.1 1.8 10.3 87.8 2 0.02 -0.001 29.49 0
MSG-6 10 5/26/2021 12:49 0.2 1.1 14 84.7 4 -0.02 0.000 29.5 1
MSG-6 5 5/26/2021 15:08 0.3 4.2 0.4 95.1 6 0.02 0.004 29.4 1
MSG-6 10 5/26/2021 15:10 0.4 4.4 6.5 88.7 8 0.01 -0.006 29.4 1
MSG-6 5 5/27/2021 14:48 0.2 5.1 0.8 93.9 4 0.00 0.007 29.32 1
MSG-6 10 5/27/2021 14:50 0.3 7.5 0.3 91.9 6 0.00 0.001 29.32 1
MSG-6 5 5/27/2021 15:44 0.1 4.9 0.7 94.3 2 -0.04 0.003 29.35 1
MSG-6 10 5/27/2021 15:47 0.4 8 0.2 91.4 8 0.00 0.008 29.35 1
MSG-7 5 5/26/2021 13:09 0 0 7.3 92.7 0 -0.06 0.014 29.5 0
MSG-7 10 5/26/2021 13:11 0 2.7 4.9 92.4 0 0.02 0.000 29.49 0
MSG-7 15 5/26/2021 13:14 0 5.2 9.4 85.4 0 -0.02 0.020 29.5 1
MSG-7 5 5/26/2021 15:24 0.2 0.1 7.3 92.4 4 0.05 -0.006 29.42 0
MSG-7 10 5/26/2021 15:28 0.2 2.6 4.5 92.7 4 0.02 -0.002 29.42 0
MSG-7 15 5/26/2021 15:31 0.2 4.6 10.6 84.6 4 0.02 -0.001 29.42 0
MSG-7 5 5/27/2021 15:02 0.1 0.2 6.2 93.5 2 -0.02 0.022 29.33 1
MSG-7 10 5/27/2021 15:06 0.1 3.6 3.8 92.5 2 -0.05 0.094 29.34 1
MSG-7 15 5/27/2021 15:09 0.1 9.3 3.7 86.9 2 0.00 0.056 29.35 1
MSG-7 5 5/27/2021 16:01 0 0.4 6.7 92.9 0 -0.02 0.019 29.35 1
MSG-7 10 5/27/2021 16:03 0 3.5 4.1 92.4 0 0.00 0.075 29.35 1
MSG-7 15 5/27/2021 16:05 0 9.1 4 86.9 0 -0.03 0.013 29.35 1
MSG-8 5 5/26/2021 12:56 0.1 0.3 0.5 99.1 2 -0.04 -0.006 29.5 1
MSG-8 10 5/26/2021 12:59 1.3 1.3 2.1 95.3 26 -0.05 0.043 29.5 1
RemarksLocation ID Depth
(ft bgs)Date/Time
Inches H20 ppm% by volume
Table 4
Partner Project Number: 21-370620
Charlotte, Mecklenburg County, North Carolina 28203
2207, 2213, 2301, 2315, 2320, and 2325 Toomey Avenue & 704 West Tremont Avenue
Dynatech II Brownfields Property
Soil Gas Monitoring Data
CH4 -
Methane
CO2 - Carbon
Dioxide O2 - Oxygen Balance CH4 % LEL Static Press.Diff. Press.Baro. Press.
H2S -
Hydrogen
Sulfide
Inches Hg
RemarksLocation ID Depth
(ft bgs)Date/Time
Inches H20 ppm% by volume
Table 4
Partner Project Number: 21-370620
Charlotte, Mecklenburg County, North Carolina 28203
2207, 2213, 2301, 2315, 2320, and 2325 Toomey Avenue & 704 West Tremont Avenue
Dynatech II Brownfields Property
Soil Gas Monitoring Data
MSG-8 15 5/26/2021 13:01 1.4 4.9 0.3 93.4 28 0.00 0.041 29.5 1
MSG-8 5 5/26/2021 15:14 0.1 0.1 0.5 99.3 2 0.01 -0.002 29.41 0
MSG-8 10 5/26/2021 15:17 1.4 1.3 1.9 95.4 28 -0.07 0.069 29.42 1
MSG-8 15 5/26/2021 15:19 1.5 5.3 0.3 92.9 30 -0.03 0.057 29.42 1
MSG-8 5 5/27/2021 14:53 0.1 0.2 0.5 99.2 2 0.07 -0.010 29.32 1
MSG-8 10 5/27/2021 14:56 1.4 1.8 1 95.8 28 0.03 -0.006 29.33 1
MSG-8 15 5/27/2021 14:59 1.4 6.7 0.2 91.7 28 -0.05 0.092 29.33 1
MSG-8 5 5/27/2021 15:51 0 0.1 0.5 99.4 0 0.02 -0.002 29.36 1
MSG-8 10 5/27/2021 15:54 1.3 1.9 0.9 95.9 26 -0.01 0.061 29.36 1
MSG-8 15 5/27/2021 15:56 1.3 6.7 0.3 91.7 26 -0.04 0.052 29.35 2
MSG-9 5 5/26/2021 12:07 0.2 3.1 7.5 89.2 4 0.03 -0.005 29.5 0
MSG-9 10 5/26/2021 12:12 0.2 3 5.7 91.1 4 0.03 -0.006 29.5 0
MSG-9 15 5/26/2021 12:15 0.2 2.5 12.7 84.6 4 -0.10 0.124 29.49 1
MSG-9 5 5/26/2021 14:36 0.2 3 7.8 89 4 -0.01 -0.003 29.44 1
MSG-9 10 5/26/2021 14:39 0.2 3.1 5.8 90.9 4 0.01 -0.007 29.43 1
MSG-9 15 5/26/2021 14:42 0.2 3.3 17.3 79.2 4 -0.05 0.056 29.44 1
MSG-9 5 5/27/2021 13:05 0 3.2 6.8 90 0 -0.03 0.065 29.31 1
MSG-9 10 5/27/2021 13:08 0 3.6 4.9 91.5 0 -0.06 0.097 29.4 1
MSG-9 15 5/27/2021 13:11 0 5.2 6.6 88.2 0 -0.10 0.068 29.38 0
MSG-8 5 5/27/2021 15:14 0 3.6 5.3 91.1 0 0.05 0.000 29.34 1
MSG-9 10 5/27/2021 15:17 0 3.4 4.1 92.5 0 -0.12 0.131 29.36 1
MSG-9 15 5/27/2021 15:19 0 5 5.5 89.5 0 -0.08 0.043 29.35 1
MSG-10 5 5/26/2021 12:23 0.2 11.2 8 80.6 4 -0.30 0.184 29.48 0
MSG-10 10 5/26/2021 12:26 0.2 6.7 6.7 86.4 4 -0.11 0.125 29.48 0
MSG-10 15 5/26/2021 12:29 0.1 1.2 17.2 81.5 2 -0.04 -0.002 29.48 0
MSG-10 5 5/26/2021 14:47 0.2 10.8 7.9 81.1 4 -0.02 0.003 29.42 0
MSG-10 10 5/26/2021 14:49 0.2 7 6.6 86.2 4 -0.01 0.000 29.41 1
MSG-10 15 5/26/2021 14:52 0.2 6 5.6 88.2 4 -0.49 0.228 29.42 0
MSG-10 5 5/27/2021 14:28 0 11.9 8 80.1 0 -0.52 0.349 29.25 1
MSG-10 10 5/27/2021 14:30 0 8.3 5.7 86 0 -0.46 0.301 29.3 1
MSG-10 15 5/27/2021 14:34 0 7.1 4.7 88.2 0 -0.39 0.272 29.3 1
MSG-10 5 5/27/2021 15:24 0 11.3 7.2 81.5 0 -0.36 0.302 29.35 1
MSG-10 10 5/27/2021 15:26 0 7.4 11.2 81.4 0 -0.10 0.202 29.35 2
MSG-10 15 5/27/2021 15:28 0 6.6 6.9 86.5 0 -0.13 0.264 29.35 2
MSG-11 5 5/26/2021 12:34 0.3 0.2 14.3 85.2 6 0.00 0.000 29.48 0
MSG-11 10 5/26/2021 12:38 0.2 0 13.4 86.4 4 -0.01 -0.004 29.5 0
MSG-11 15 5/26/2021 12:41 0.2 0 16.1 83.7 4 0.03 0.001 29.5 1
MSG-11 5 5/26/2021 14:56 0.5 0 5.3 94.2 10 0.03 -0.018 29.41 1
MSG-11 10 5/26/2021 14:58 0.7 0.5 2.4 96.4 14 -0.03 0.001 29.41 1
CH4 -
Methane
CO2 - Carbon
Dioxide O2 - Oxygen Balance CH4 % LEL Static Press.Diff. Press.Baro. Press.
H2S -
Hydrogen
Sulfide
Inches Hg
RemarksLocation ID Depth
(ft bgs)Date/Time
Inches H20 ppm% by volume
Table 4
Partner Project Number: 21-370620
Charlotte, Mecklenburg County, North Carolina 28203
2207, 2213, 2301, 2315, 2320, and 2325 Toomey Avenue & 704 West Tremont Avenue
Dynatech II Brownfields Property
Soil Gas Monitoring Data
MSG-11 15 5/26/2021 15:01 0.7 0.2 0.3 98.8 14 -0.02 0.011 29.4 1
MSG-11 5 5/27/2021 14:37 0.4 0.1 2.6 96.9 8 0.01 -0.003 29.29 1
MSG-11 10 5/27/2021 14:40 0.6 0.5 1.7 97.2 12 0.00 -0.011 29.31 1
MSG-11 15 5/27/2021 14:43 0.6 0.5 0.3 98.6 12 0.01 -0.001 29.32 2
MSG-11 5 5/27/2021 15:33 0.3 0 2.2 97.5 6 0.06 -0.007 29.36 1
MSG-11 10 5/27/2021 15:36 0.6 0.5 1.9 97 12 0.01 -0.009 29.35 1
MSG-11 15 5/27/2021 15:38 0.6 0.5 0.2 98.7 12 0.01 -0.010 29.35 4
MSG-12 5 5/26/2021 10:33 0.1 0.3 16.7 82.9 2 -2.01 2.108 29.52 1
MSG-12 10 5/26/2021 10:38 0.1 0.2 17.4 82.3 2 -1.94 2.160 29.52 0
MSG-12 5 5/26/2021 11:23 0.2 0.3 17.4 82.1 4 -2.06 2.087 29.53 0
MSG-12 10 5/26/2021 11:27 0.2 0.2 18.1 81.5 4 -1.78 2.019 29.51 0
MSG-12 5 5/27/2021 10:57 0 0.3 16.4 83.3 0 -1.15 1.419 29.43 1
MSG-12 10 5/27/2021 10:59 0 0.1 17.4 82.5 0 -2.84 2.996 29.33 1
MSG-12 5 5/27/2021 11:36 0 0.2 17.1 82.7 0 -0.93 1.176 29.44 1
MSG-12 10 5/27/2021 11:42 0 0.1 19.3 80.6 0 -1.39 1.573 29.14 1
MSG-13 5 5/26/2021 9:48 0.2 4.6 14.1 81.1 4 -1.65 1.764 29.5 0 Water encountered at 10'
MSG-13 5 5/26/2021 10:24 0.2 4.9 13.9 81 4 -2.34 2.496 29.52 1 Water encountered at 10'
MSG-13 5 5/27/2021 10:47 0 5.6 13.6 80.8 0 -1.25 1.541 29.46 1 Water encountered at 10'
MSG-13 5 5/27/2021 11:31 0 5.2 14.1 80.7 0 -1.29 1.516 29.44 1 Water encountered at 10'
MSG-14 5 5/26/2021 9:13 0.2 0.3 18.8 80.7 4 0.00 0.007 29.5 0
MSG-14 5 5/26/2021 10:00 0.2 0.2 18 81.6 4 -0.19 0.142 29.51 0
MSG-14 5 5/27/2021 10:33 0 0.1 17.8 82.1 0 -0.74 0.655 29.42 1
MSG-14 5 5/27/2021 11:21 0 0.2 18.3 81.5 0 -0.44 0.314 29.45 0
MSG-15 5 5/26/2021 15:41 0.4 9 0.9 89.7 8 -0.10 0.101 29.37 1
MSG-15 5 5/26/2021 16:07 0.4 11.2 0.5 87.9 8 -0.10 0.122 29.42 1
MSG-15 5 5/27/2021 16:22 0.2 11.6 0.4 87.8 4 -0.10 0.163 29.35 1
MSG-15 5 5/27/2021 16:53 0.2 11.6 0.5 87.7 4 -0.08 0.086 29.35 1
MSG-16 5 5/26/2021 15:44 37.2 0.8 1 61 >100 0.10 -0.073 29.42 1
MSG-16 10 5/26/2021 15:51 2.6 0 19.9 77.5 52 0.31 -0.296 29.44 1 Water encountered
MSG-16 5 5/26/2021 16:11 38.2 0.9 0.4 60.5 >100 0.11 -0.156 29.42 0 Water encountered at 10'
MSG-16 5 5/27/2021 16:27 36.8 1.2 0.2 61.8 >100 0.12 -0.153 29.36 1
MSG-16 10 5/27/2021 16:29 15 0.4 8.9 75.7 >100 0.43 -0.272 29.36 2 Water encountered
MSG-16 5 5/27/2021 16:58 36.7 1.1 0.2 62 >100 0.07 -0.094 29.37 1
MSG-16 10 5/27/2021 17:01 5.8 0.2 11.4 82.6 >100 0.44 -0.327 29.35 2 Water encountered
MSG-17 5 5/26/2021 15:56 0.2 0.1 17.5 82.2 4 -0.03 -0.003 29.43 1
MSG-17 5 5/26/2021 16:16 0.5 0.2 17.5 81.8 10 0.02 -0.007 29.42 0
MSG-17 5 5/27/2021 16:35 0 0.5 16.7 82.8 0 0.02 -0.017 29.35 1
MSG-17 5 5/27/2021 17:10 0 0.4 16.8 82.8 0 -0.01 -0.004 29.37 1
MSG-18 5 5/26/2021 9:26 20.8 3.7 2.9 72.6 >100 -0.20 0.203 29.48 0
CH4 -
Methane
CO2 - Carbon
Dioxide O2 - Oxygen Balance CH4 % LEL Static Press.Diff. Press.Baro. Press.
H2S -
Hydrogen
Sulfide
Inches Hg
RemarksLocation ID Depth
(ft bgs)Date/Time
Inches H20 ppm% by volume
Table 4
Partner Project Number: 21-370620
Charlotte, Mecklenburg County, North Carolina 28203
2207, 2213, 2301, 2315, 2320, and 2325 Toomey Avenue & 704 West Tremont Avenue
Dynatech II Brownfields Property
Soil Gas Monitoring Data
MSG-18 10 5/26/2021 9:30 0.8 0.2 19.9 79.1 16 -0.02 0.049 29.48 0
MSG-18 5 5/26/2021 10:12 14.9 2.4 4.5 78.2 >100 -0.12 0.094 29.51 0
MSG-18 10 5/26/2021 10:17 1.6 0.1 18.6 79.7 32 -0.18 0.105 29.54 0
MSG-18 5 5/27/2021 10:40 10 3 6.2 80.8 >100 -1.31 1.230 29.44 1 Water encountered at 10'
MSG-18 5 5/27/2021 11:26 7.3 2.4 13.6 76.7 >100 -1.14 0.955 29.44 1 Water encountered at 10'
MSG-19 5 5/26/2021 16:01 0.2 0 17.3 82.5 4 0.00 0.000 29.42 0
MSG-19 10 5/26/2021 16:03 0.2 0 20.5 79.3 4 -0.01 0.001 29.41 1
MSG-19 5 5/26/2021 16:22 0.3 0 17.1 82.6 6 0.03 -0.004 29.43 0
MSG-19 10 5/26/2021 16:24 0.2 0 20.9 78.9 4 0.01 0.002 29.42 1
MSG-19 5 5/27/2021 16:42 0 0 16.3 83.7 0 0.01 -0.004 29.35 1
MSG-19 10 5/27/2021 16:45 0 0 19.8 80.2 0 0.01 -0.003 29.35 1
MSG-19 5 5/27/2021 17:16 0 0.1 17.1 82.8 0 -0.04 0.006 29.28 1
MSG-19 10 5/27/2021 17:18 0 0 19.8 80.2 0 0.01 -0.002 29.35 2
MSG-20 5 5/27/2021 9:53 0 0 16.7 83.3 0 -0.01 0.005 29.42 0
MSG-20 10 5/27/2021 9:57 0 0.7 12.3 87 0 0.00 0.001 29.42 0 Water encountered at 15-20'
MSG-20 5 5/27/2021 10:15 0 0 16.8 83.2 0 0.01 0.000 29.44 0
MSG-20 10 5/27/2021 10:20 0 0.9 12.1 87 0 -0.01 -0.002 29.44 0 Water encountered at 15-20'
MSG-20 5 5/28/2021 9:55 0 0.1 16.2 83.7 0 -0.01 -0.002 29.23 1
MSG-20 10 5/28/2021 9:58 0 0.9 11.6 87.5 0 0.04 0.003 29.23 1
MSG-20 15 5/28/2021 10:01 0 0.2 16.6 83.2 0 -1.73 1.999 29.24 1 Water Encountered
MSG-20 5 5/28/2021 10:24 0 0.1 16.2 83.7 0 0.01 -0.006 29.25 1
MSG-20 10 5/28/2021 10:26 0 1.1 11.5 87.4 0 -0.01 -0.001 29.25 0
MSG-20 15 5/28/2021 10:29 0 0.2 16.9 82.9 0 -1.28 1.737 29.25 1 Water Encountered
MSG-21 5 5/27/2021 9:47 0 0.2 14 85.8 0 -0.09 0.087 29.41 0
MSG-21 10 5/27/2021 9:50 0 1.2 2.3 96.5 0 -0.01 -0.003 29.41 0
MSG-21 5 5/27/2021 10:08 0 0.3 13.8 85.9 0 -0.08 0.156 29.42 0
MSG-21 10 5/27/2021 10:11 0 1.2 2.3 96.5 0 0.01 -0.005 29.43 0
MSG-21 5 5/28/2021 9:48 0 0.5 13.8 85.7 0 -0.13 0.227 29.13 1
MSG-21 10 5/28/2021 9:51 0 1.6 2.7 95.7 0 -0.01 -0.006 29.23 1
MSG-21 5 5/28/2021 10:17 0 0.5 13.8 85.7 0 -0.06 0.110 29.24 0
MSG-21 10 5/28/2021 10:19 0 1.7 2.7 95.6 0 0.01 0.004 29.25 0
MSG-22 5 5/27/2021 9:39 0 2.5 11.4 86.1 0 -0.15 0.212 29.41 0
MSG-22 10 5/27/2021 9:42 0 19.5 1.7 78.8 0 -0.45 0.348 29.41 0
MSG-22 5 5/27/2021 10:02 0 2.2 12.5 85.3 0 -0.16 0.198 29.42 0
MSG-22 10 5/27/2021 10:05 0 19.4 1.4 79.2 0 -0.42 0.323 29.43 0
MSG-22 5 5/28/2021 9:41 0 2.8 12.4 84.8 0 -0.20 0.243 29.22 1
MSG-22 10 5/28/2021 9:43 0 2.5 13.8 83.7 0 -0.16 0.268 29.21 1
MSG-22 5 5/28/2021 10:09 0 2.4 13.6 84 0 -0.08 0.116 29.24 1
MSG-22 10 5/28/2021 10:12 0 19.8 0.4 79.8 0 -0.18 0.326 29.24 0
CH4 -
Methane
CO2 - Carbon
Dioxide O2 - Oxygen Balance CH4 % LEL Static Press.Diff. Press.Baro. Press.
H2S -
Hydrogen
Sulfide
Inches Hg
RemarksLocation ID Depth
(ft bgs)Date/Time
Inches H20 ppm% by volume
Table 4
Partner Project Number: 21-370620
Charlotte, Mecklenburg County, North Carolina 28203
2207, 2213, 2301, 2315, 2320, and 2325 Toomey Avenue & 704 West Tremont Avenue
Dynatech II Brownfields Property
Soil Gas Monitoring Data
Notes:
Areas containing methane in soil gas above 1.25 %bv
Probe points where gas collection entrained groundwater

Brownfields Assessment Report – Dynatech II
Brownfields Property (August 2021)

Historical Environmental Data
INTERSTATE 77SG-2*SG-1*SG-3*Parcel ID 119064242207 Toomey AvenueFormer Dynatech Parcel(Current Configuration)Parcel ID 119064282213 Toomey AvenueParcel ID 119064292301 Toomey AvenueParcel ID 11906420704 W Tremont AvenuePlanned PropertyRecombination2213 Toomey AvenueParcel ID 119046262320 Toomey AvenueParcel ID 11906417728 W Tremont AvenueParcel ID 119064262325 Toomey AvenueMSG-19MSG-16MSG-17MSG-15DRIVEWILMOREW TREMONT AVENUEVILLAGE COURTTOOMEY AVENUESG1SG2SG3MSG-2/2AMSG-1/1AMSG-3/3AFCC-1FCC-3FCC-7FCC-6FCC-9FCC-8FCC-4FCC-5TP-3TP-4TP-1TP-6TP-2TP-5FCC-2MVSG-1/1AMVSG-3/3AMVSG-2/2AMVSG-6/6AMVSG-4/4AMVSG-5/5AMVSG-7/7AFC-9FC-1FC-10FC-2FC-3FC-5FC-6FC-12FC-11FC-7FC-8FC-13FC-15FC-16FC-14FC-20FC-21FC-22FC-24FC-23FC-19FC-25FC-4FC-18FC-26FC-17FC-27FC-28FC-29FC-30FC-31FC-32MSG-18MSG-14MSG-21MSG-6MSG-8MSG-7MSG-9MSG-4MSG-12MSG-5MSG-13MSG-11MSG-20MSG-22MSG-10B-5/MW-1B-6/MW-2MW-4/4RB-8/MW-3B-10B-9B-7B-3/B-3GW**B-2/B-2GW**B-1/B-1GW**B-4/B-4GW**B-3/B-3GW*B-1/B-1GW*B-2/B-2GW*APPROXIMATE SCALE IN FEET028014070IMAGE SOURCE: NC ONEMAPNCharlotte, North Carolina 282178720 Red Oak Boulevard, Suite 528www.partneresi.comFax.: 704-353-7050Tel.: [phone]DateProject No.Reference Dwg.Project:PMDrafterSketch No.DesignerChecked ByTitle:Dynatech II Brownfields Project (25001-21-060)Toomey Avenue and West Tremont AvenueFigure 4Site Map with Historical and Brownfields21-3706208.13.21DHADF4ADDH4Charlotte, North CarolinaAssessment Sample LocationsSoil Boring Fill withDebris DepthsB-1**: 0 Ft BgsB-2**: 0 Ft BgsB-3**: 6 Ft BgsB-4**: 3 Ft BgsTest PitPrevious Phase II SubsurfaceInvestigation LocationsEXPLANATIONTest Pit Fill withDebris DepthsTP-1: ~8 Ft BgsTP-2: ~2 Ft BgsTP-3: ~2.5 Ft BgsTP-4: ~6.0 Ft BgsTP-5: ~4 Ft BgsTP-6: ~16 Ft BgsSoil and GroundwaterSample LocationDynatech II Brownfields Project ParcelsMethane SoilVapor SampleMethane and VOC SoilVapor SampleBrownfields Assessment LocationsSoil Gas Sample Location (VOCs)Soil Sample Location(Metals, VOCs, SVOCs)Soil and Groundwater SampleLocation(Metals, VOCs, SVOCs)Methane AssessmentLocationsSoil Gas Sample Location(Methane)Soil Gas Sample Location(Methane all nestedzones; VOCs for BFAssessment shallow zone[5'] only)Fill Characterization SampleSoil Gas SampleNotes:1.Methane Soil Gas (MSG) points MSG-15, 16, 17, and 19 were alsosampled during the Brownfields Assessment for VOC analysis.Numbering continues from prior MSG assessment.2.* Indicates soil borings B-1, B-2, and B-3 and soil gas samples SG-1,SG-2, and SG-3 located on 2320 Toomey Avenue installed as part ofseparate assessment3.** Indicates soil borings B-1, B-2, and B-3 installed as part of Phase IIEnvironmental Subsurface Investigation on parcels southeast ofToomey Avenue.
INTERSTATE 77MSG-19MSG-16MSG-17MSG-15DRIVEWILMOREW TREMONT AVENUEVILLAGE COURTTOOMEY AVENUEAPPROXIMATE SCALE IN FEET028014070IMAGE SOURCE: NC ONEMAPNEXPLANATIONCharlotte, North Carolina 282178720 Red Oak Boulevard, Suite 528www.partneresi.comFax.: 704-353-7050Tel.: [phone]DateProject No.Reference Dwg.Project:PMDrafterSketch No.DesignerChecked ByTitle:Dynatech II Brownfields Project (25001-21-060)Toomey Avenue and West Tremont AvenueFigure 8ASummary of Soil Gas Analytical Data21-3706208.13.21DHADF8AADDH8ACharlotte, North CarolinaBrownfields AssessmentNotes:1.Concentrations reported in ug/m³.2.Values highlighted in yellow exceed the NCDEQResidential SGSL.Dynatech II Brownfields Project ParcelsBrownfields Assessment LocationsSoil Gas Sample Location (VOCs)
INTERSTATE 77SG-2*SG-1*SG-3*DRIVEWILMOREW TREMONT AVENUEVILLAGE COURTTOOMEY AVENUEMVSG-1/1AMVSG-3/3AMVSG-2/2AMVSG-6/6AMVSG-4/4AMVSG-5/5AMVSG-7/7AAPPROXIMATE SCALE IN FEET028014070IMAGE SOURCE: NC ONEMAPNEXPLANATIONCharlotte, North Carolina 282178720 Red Oak Boulevard, Suite 528www.partneresi.comFax.: 704-353-7050Tel.: [phone]DateProject No.Reference Dwg.Project:PMDrafterSketch No.DesignerChecked ByTitle:Dynatech II Brownfields Project (25001-21-060)Toomey Avenue and West Tremont AvenueFigure 8BSummary of Soil Gas Analytical Data21-3706208.13.21DHADF8BADDH8BCharlotte, North CarolinaPrior Phase II ESAPrevious Phase II Subsurface Investigation LocationsDynatech II Brownfields Project ParcelsMethane and VOC Soil Vapor SampleNotes:1.Concentrations reported in ug/m³.2.Values highlighted in yellow exceed the NCDEQResidential SGSL.3.Values highlighted in brown exceed the NCDEQNon-Residential SGSL.VOC Soil Vapor Sample
MSG-15 (5') MSG-16 (10') MSG-16 (5') MSG-16 (5') DUP MSG-17 (5') MSG-19 (5')
Acetone 220,000 2,700,000 19.1 501 55.6 86.3 30.4 38.7
Benzene 12 160 3.07 7.47 39.6 38.0 14.3 2.182-Butanone (MEK)35,000 440,000 5.84 572 <0.240 <0.240 7.05 10.4Carbon disulfide 4,900 61,000 23.1 25.8 23.6 <0.317 22.8 33.3Carbon tetrachloride 16 200 0.488 J 0.605 J <0.461 <0.461 <0.461 1.31Chloromethane6307,900 2.17 1.85 0.907 <0.213 <0.213 0.993
Cyclohexane 42,000 530,000 13.3 <0.259 <0.259 <0.259 21.1 1.96
Dichlorodifluoromethane 700 8,800 2.40 2.83 8.56 <0.678 2.17 2.321,1-Dichloroethane 58 770 0.850 <0.290 <0.290 <0.290 <0.290 <0.290DichlorotetrafluoroethaneNENE<0.622 <0.622 10.3 10.4 <0.622 <0.622EthanolNENE22.2 67.7 25.3 8.39 63.9 51.3Ethylbenzene374909.88 7.02 28.1 27.0 14.5 11.4
4-Ethyltoluene NE NE 15.7 6.97 41.8 44.2 24.3 22.6
n-Heptane 2,800 35,000 19.3 6.18 73.6 <0.425 31.5 3.15n-Hexane 4,900 61,000 26.2 20.3 258 325 93.4 4.94Methyl methacrylate 4,900 61,000 <0.359 87.2 <0.359 <0.359 <0.359 <0.3594-Methyl-2-pentanone (MIBK)21,000 260,000 2.54 J 1,620 <0.313 <0.313 5.85 5.20Naphthalene2.8 36 9.37 <1.83 7.64 12.1 10.9 12.52-Propanol 1,400 18,000 2.73 J 33.7 6.76 <0.649 <0.649 16.5
Propylene 21,000 260,000 114 <0.160 <0.160 <0.160 26.3 23.1
Tetrachloroethene 280 3,500 0.726 J 1.83 2.23 <0.553 2.08 3.73Toluene25,000 440,000 25.8 19.9 45.6 <0.328 24.5 16.4Trichloroethene14180<0.364 1.69 <0.364 <0.364 <0.364 0.654 J1,1,1-Trichloroethane 35,000 440,000 3.26 <0.400 <0.400 <0.400 <0.400 <0.400TrichlorofluoromethaneNENE1.25 1.87 0.770 J <0.460 80.4 162
1,1,2-Trichlorotrifluoroethane NE NE <0.608 <0.608 0.645 J <0.608 <0.608 <0.608
1,2,4-Trimethylbenzene 420 5,300 27.4 10.4 77.5 82.5 34.5 31.31,3,5-Trimethylbenzene 420 5,300 6.09 2.78 17.2 17.7 8.29 8.052,2,4-Trimethylpentane NE NE 6.96 7.43 260 406 167 4.91m&p-Xylene 700 8,800 35.3 18.9 116 112 67.6 50.3o-Xylene 700 8,800 15 8.89 46.4 45.5 26 25.1
Total Xylenes 700 8,800 50.3 27.79 162.4 157.5 93.6 75.4
Residential 4.0E-06 1.3E-06 6.9E-06 8.3E-06 5.6E-06 5.2E-06
Non-Residential 3.0E-07 9.6E-08 5.2E-07 6.3E-07 4.3E-07 3.9E-07
Residential 0.13 0.088 0.23 0.26 0.18 0.18
Non-Residential 0.011 0.007 0.018 0.021 0.014 0.014
Notes:
1. NCDEQ DWM SGSLs = North Carolina Department of Environmental Quality Division of Waste Management Residential/Non-Residential Sub-Slab and Exterior Soil Gas Screening Level; Dated June 2021
2. TCR = Target Cancer Risk
3. THQ = Target Hazardous Quotient
4. VOCs = volatile organic compounds
5 . µg/m3 = micrograms per liter6. NE = not established
7. J = Estimated concentration reported above method detection limits but below laboratory reporting limits.
8. Values in bold exceed laboratory method detection limits
9. < = not detected above indicated laboratory detection limits
10. Highlighted values exceed the NCDEQ DWM Residential Vapor Intrusion SGSL.11. Light blue shaded values indicate value above Hazard Index monitoring threshold of 0.2.
13. Orange shaded values indicate cumulative carcinogenic risk above TCR of 1.0E-06.
Table 5A
Summary of Soil Gas Analytical Data
Brownfields Assessment Report
Dynatech II Brownfields Property
Charlotte, North Carolina
Partner Project Number 21-370620 / Brownfields Project Number 25001-21-060
Hazard Index
Cumulative Carcinogenic Risk
VOCs via TO-15 (µg/m3)
Sample Date: 6/22/21
NCDEQ Non-Residential
Sub-Slab and Exterior
SGSLs
(TCR=1E-06 or THQ=0.2)
NCDEQ Residential Sub-
Slab and Exterior SGSLs
(TCR=1E-06 or THQ=0.2)
Analyte
MVSG-1 MVSG-2 MVSG-3 MVSG-4 MVSG-5 MVSG-6 MVSG-7
Acetone 220000 2700000 55.6 34.5 17.1 23 26.9 903 21.1Benzene1201607.41 7.57 9.33 14 18.8 189 4.571,3-Butadiene 3.1 41 <0.230 19.0 19.2 13.7 77.9 75.5 22.62-Butanone 35000 440000 20.1 13.4 5.1 9.85 13.4 1030 6.22Carbon Disulfide 4900 61000 21.4 6.47 5.14 4.36 7.87 73.1 14
Carbon Tetrachloride 16 200 <0.641 0.569 J 0.502 J 0.800 J 0.539 J <0.641 <0.641
Chloroethane 70000 880000 <0.263 <0.263 <0.263 <0.263 <0.263 29.5 <0.263
Chloromethane 630 7900 0.469 1.45 1.92 3.37 8.45 98.7 0.653
Cyclohexane NE NE 47.2 2.53 2.71 4.44 <0.259 27.9 1.77
Dichlorodifluoromethane 700 8800 <0.678 <0.678 2.19 2.33 2.19 2.34 1.82
cis-1,2-Dichloroethene NE NE 0.828 <0.311 <0.311 <0.311 <0.311 <0.311 <0.311
1,2-Dichlorotetrafluoroethane NE NE 3.99 <0.622 <0.622 <0.622 <0.622 <0.622 <0.6221,4-Dioxane 19 250 <0.300 0.352 J <0.300 0.407 J <0.300 <0.300 <0.300EthanolNENE15.3 <0.500 13.8 12.7 56 20.6 12.05Ethylbenzene374907.8 3.6 <0.362 8.67 5.38 37.6 2.44-Ethyltoluene NE NE 3.32 3.96 <0.384 <0.384 5.35 24.7 3.94Heptane280035000564.29 9.61 12.5 12.2 58.9 7.28n-Hexane 4900 61000 101 12.7 22.9 31.7 31.6 159 15.52-Hexanone 210 2600 <0.544 <0.544 2.93 J 10.1 3.10 J <0.544 <0.544Iso-propyl Alcohol 1400 18000 <0.649 3.2 <0.649 2.11 J 2.17 J 38.3 1.04 J4-Methyl-2-Pentanone 21000 260000 1.27 J 2.03 J 1.46 J 3.43 J 12.3 21.5 5.04 JMethyl Methacrylate 4900 61000 <0.359 <0.359 1.69 <0.359 20.5 40.4 1.29Methylene Chloride 3400 53000 <0.340 <0.340 <0.340 1.08 <0.340 <0.340 <0.340Propylene21000260000238293236164957<1.60 446Styrene7000880001.64 2.08 2.14 <0.335 3.96 <0.335 1.52Tetrachloroethene2803500<0.553 <0.553 0.571 J 0.643 J 0.678 J 1.35 J <0.553Toluene3500044000022.8 26.1 26.7 37.7 34.8 71.6 12TrichlorofluoromethaneNENE<0.460 <0.460 1.75 2.13 1.88 66.9 11.61,1,2-Trichlorotrifluoroethane NE NE <0.608 0.701 J 0.651 J 0.843 J 0.812 J <0.608 <0.6081,2,4-Trimethylbenzene 420 5300 4.59 5.15 5.5 25.1 6.53 15.5 5.06
1,3,5-Trimethylbenzene 420 5300 1.56 1.31 1.44 2.86 1.72 9.62 1.6
2,2,4-Trimethylpentane NE NE 12.7 2.91 4.86 7.57 4.26 42.4 3.06Vinyl Chloride 5.6 280 0.394 J <0.243 0.458 J 0.849 1.83 10.8 <0.243Xylenes (Total)700 8800 15.31 15.88 16.32 41.8 20.12 93.9 10.85
Residential 9.6E-07 6.9E-06 7.1E-06 6.0E-06 2.7E-05 4.3E-05 7.7E-06
Non-Residential 6.9E-08 5.2E-07 5.3E-07 4.5E-07 2.0E-06 3.2E-06 5.9E-07
Residential 0.029 0.29 0.3 0.25 1.2 1.4 0.34
Non-Residential 0.0023 0.023 0.024 0.020 0.093 0.11 0.027
Notes:
1. NCDEQ DWM SGSLs = North Carolina Department of Environmental Quality Division of Waste Management Residential/Non-Residential Sub-Slab and Exterior Soil Gas Screening Level; Dated June 20212. TCR = Target Cancer Risk
3. THQ = Target Hazardous Quotient
4. VOCs = volatile organic compounds
5 . µg/m3 = micrograms per liter
6. NE = not established
7. J = Estimated concentration reported above method detection limits but below laboratory reporting limits.
8. Values in bold exceed laboratory method detection limits9. < = not detected above indicated laboratory reporting limit (RL)
10. Highlighted values exceed the NCDEQ DWM Residential Vapor Intrusion SGSL.11. Highlighted values exceed the NCDEQ DWM Non-Residential Vapor Intrusion SGSL.12. Light blue shaded values indicate value above Hazard Index monitoring threshold of 0.2.13. Orange shaded values indicate cumulative carcinogenic risk above TCR of 1.0E-06.
Cumulative Carcinogenic Risk
Hazard Index
Table 5B
Summary of Soil Gas Analytical Data - Prior Phase II Subsurface Investigation
Brownfields Assessment Report
Dynatech II Brownfields Property
Charlotte, North Carolina
Partner Project Number 21-370620 / Brownfields Project Number 25001-21-060
Sample Date: 1/13/2021NCDEQ Non-
Residential
Sub-Slab and
Exterior
SGSLs
(TCR=1E-06 or
THQ=0.2)
NCDEQ Residential
Sub-
Slab and Exterior
SGSLs
(TCR=1E-06 or
THQ=0.2)
Analyte
SG-1* SG-2* SG-3*
Acetone 220,000 2,700,000 16.5 5.99 29.7
Benzene 120 160 39.0 10.3 6.39
1,3-Butadiene 3.1 41.0 83.6 19.4 7.08
2-Butanone 35,000 440,000 13.0 12.5 10.6
Carbon Disulfide 4,900 61,000 37.1 6.91 4.86
Chloroethane 70,000 880,000 0.625 <0.528 <0.528
Chloromethane 630 7,900 4.61 1.68 1.32
Cyclohexane NE NE 6.4 4.03 2.35
Dichlorodifluoromethane 700 8,800 2.05 1.96 1.88
1,4-Dioxane 19.0 250 0.840 <0.721 <0.721
Ethyl Acetate 490 6,100 8.79 21.9 <1.80
Ethanol NE NE 56.9 19.2 <9.42
Ethylbenzene 37.0 490 14.3 13.3 10.3
4-Ethyltoluene NE NE 3.87 6.49 5.56
Heptane 2,800 35,000 23.5 11.5 5.49
n-Hexane 4,900 61,000 160 36.7 10.2
2-Hexanone 210 2,600 21.6 23.8 25.9
Iso-propyl Alcohol 1,400 18,000 10.3 2.56 <1.23
4-Methyl-2-Pentanone 21,000 260,000 15.4 19.2 17.3
Naphthalene 2.8 36.0 <1.05 <1.05 1.67
Propylene 21,000 260,000 482 360 83.8
Styrene 7,000 88,000 4.16 1.41 <0.852
Tetrachloroethene 280 3,500 <1.36 1.45 1.55
Tetrahydrofuran 14,000 180,000 5.66 5.04 <1.47
Toluene 35,000 440,000 130 65.2 46.7
Trichlorofluoromethane NE NE <1.12 1.21 <1.12
1,2,4-Trimethylbenzene 420 5,300 14.5 26.3 24.4
1,3,5-Trimethylbenzene 420 5,300 3.45 6.15 5.70
2,2,4-Trimethylpentane NE NE 5.23 8.36 4.76
Vinyl Chloride 5.6 280 0.544 <0.511 <0.511
Xylenes (Total)700 8,800 60.8 67.8 53.0
Residential 3.1E-05 7.5E-06 3.1E-06
Non-Residential 2.3E-06 5.7E-07 2.4E-07
Residential 1.3 0.37 0.17
Non-Residential 0.1 0.029 0.013
Notes:
2. TCR = Target Cancer Risk
3. THQ = Target Hazardous Quotient
4. VOCs = volatile organic compounds
5 . µg/m3 = micrograms per liter
6. NE = not established
7. J = Estimated concentration reported above method detection limits but below laboratory reporting limits.
8. Values in bold exceed laboratory method detection limits
9. < = not detected above indicated laboratory reporting limit (RL)
10. Highlighted values exceed the NCDEQ DWM Residential Vapor Intrusion SGSL.
11. Highlighted values exceed the NCDEQ DWM Non-Residential Vapor Intrusion SGSL.
12. Light blue shaded values indicate value above Hazard Index monitoring threshold of 0.2.
13. Orange shaded values indicate cumulative carcinogenic risk above TCR of 1.0E-06.
Cumulative Carcinogenic Risk
Hazard Index
1. NCDEQ DWM SGSLs = North Carolina Department of Environmental Quality Division of Waste Management Residential/Non-Residential Sub-Slab
and Exterior Soil Gas Screening Level; Dated June 2021
Table 5C
Summary of Soil Gas Analytical Data - Prior Limited Phase II Site Assessment
Brownfields Assessment Report
Dynatech II Brownfields Property
Charlotte, North Carolina
Partner Project Number 21-370620 / Brownfields Project Number 25001-21-060
Sample Date: 12/2/20NCDEQ Non-
Residential
Sub-Slab and Exterior
SGSLs
(TCR=1E-06 or
THQ=0.2)
NCDEQ Residential Sub-
Slab and Exterior SGSLs
(TCR=1E-06 or
THQ=0.2)
Analyte
VOCs via TO-15 (µg/m3)

APPENDIX D

Response to Reuse Plans Letter

July 13, 2021

Sent Via USPS and email
Wes McAdams
Abacus Acquisitions, LLC
1200 E. Morehead Street, Suite 280
Charlotte, NC 28024
[e-mail]
Subject: Response to Reuse Plans
Dynatech II
2207, 2213, 2301, 2325 Toomey Ave; 728 & 704 W. Tremont Ave.
Southern Pines, Moore County
Brownfields Project Number 25001-21-060

Dear Mr. McAdams,

The North Carolina Department of Environmental Quality (DEQ) Brownfields Program
has received your request for residential use suitability on the Dynatech II Brownfields Property.
As well as your proposal for DEQ to consider Geosyntec Consultants, Inc., as the engineers and
consultants with demonstrated methane experience meeting the criteria outlined in the NCDEQ
Brownfields Program Minimum Threshold Criteria for Methane Site Development (December
2020).

From the information submitted and ensuing discussions, it has become clear to us that
Geosyntec has demonstrated specific relevant expertise in the redevelopment of multiple dozens
of methane sites, and, for this site, qualifies as an environmental consultant with the
demonstrated expertise needed to assess, mitigate, monitor, and safely redevelop such a site.
This includes the use of Cupolex as part of an overall methane mitigation and monitoring design
for this site. We understand that Geosyntec will not only be the designer, but also be involved in
the installation and effectiveness demonstration of the systems proposed, all appropriate phases
of which will be signed and sealed by Geosyntec engineers. We view this continuity as vital for
public health protection and this too, fits with our guidelines.

Please note that this letter is a threshold determination under the aforementioned
guidance that a residential reuse can be contemplated, and that we will work with you and
Geosyntec towards a brownfields agreement for that reuse and the approval of such a mitigation
and monitoring system. It does not guarantee terms of a brownfields agreement will be reached.

Dynatech II Response to Reuse Plans
July 13, 2021
Page 2

Note also that this does letter does not waive any applicable requirement to obtain any
necessary permits, licenses or certifications which may be required from other state or local
entities. If you have questions about this correspondence or require additional information,
please feel free to contact your Project Manager, Carolyn Minnich by phone at 704-661-0330 or
by email at [e-mail]. The Brownfields Program looks forward to working
with you toward the successful, safe redevelopment of this property.

Sincerely,
Bruce Nicholson
Brownfields Program Manager

ec: Central Files, DEQ
Carolyn Minnich, DEQ
Tracy Wahl, DEQ
Chris Walker, Alexander Ricks, PLLC

GC8028/CAR21094 2 November 2022

APPENDIX E

EXAMPLE MMS O&M FORM
Site:Project No.:
Field Personnel:Date:
Recorded By:
Extraction Vent ID VMP-1 VMP-2 VMP-3 VMP-4
Equipment
Date
Time
Differential Pressure (Pa)
Methane (%)
Carbon Dioxide (%)
Carbon Monoxide (ppm)
Oxygen (%)
VOCs (ppm)
Extraction Vent ID VMP-5 VMP-6 VMP-7 VMP-8
Equipment
Date
Time
Differential Pressure (Pa)
Methane (%)
Carbon Dioxide (%)
Carbon Monoxide (ppm)
Oxygen (%)
VOCs (ppm)
Extraction Vent ID VMP-9 VMP-10 VMP-11 VMP-12
Equipment
Date
Time
Differential Pressure (Pa)
Methane (%)
Carbon Dioxide (%)
Carbon Monoxide (ppm)
Oxygen (%)
VOCs (ppm)
EXAMPLE: MMS - Monitoring Probe Measurements
Site:Project No.:
Field Personnel:Recorded By:Date:
Vent Riser
ID
Velocity
(ft/min)
Methane
(%)
VOCs
(ppm)Comment
VR-1
VR-2
VR-3
VR-4
VR-5
VR-6
VR-7
VR-8
VR-9
VR-10
Overall Comments: (non-routine maintenance, observations, problems, etc.)
EXAMPLE: MMS - Vent Riser Measurements
Vent Risers
Calculated
Flow Rate
Static Vacuum
(Pa/in H2O)