09048_Universal Stainless_ Req Add Assessment 20101014

1646 Mail Service Center, Raleigh, North Carolina 27699-1646
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An Equal Opportunity \ Affirmative Action Employer

October 14, 2010

Sent Via E-mail

Amanda K. Short
C/O ADH Properties
McGuireWoods LLP
201 N. Tryon St.
Charlotte, NC 28202
[e-mail]

Subject: Request for Additional Assessment
Former Universal Stainless Facility
10801 Nations Ford Road
Charlotte, Mecklenburg County
Brownfields Project Number 09048-05-60

Dear Ms. Short:

The North Carolina Department of Environmental and Natural Resources (DENR) has reviewed
the Report of Indoor Air Assessment prepared by MACTEC dated September 16, 2010. Based on the
results of the indoor air sampling, we required additional sampling to assist in making risk management
decisions for inclusion in the brownfields agreement (BFA).

For the next sampling events, conduct the work in accordance with the work plan dated July 12,
2010 and approved on July 29, 2010 with the following edits:

• Conduct two additional indoor air sampling events.
o One sampling event should be conducted in January. The high temperature on the day the
samples are collected should not exceed the mean high for that day by more than 1 degree
Fahrenheit.
o One sampling event should be collected be conducted in April or October. The high
temperature on the day the samples are collected should be within 4 degrees Fahrenheit of
the mean high for that date.
• Collect field parameters: barometric pressure, wind, temperature, precipitation.
• Collect indoor samples from the same locations as were collected and reported in the report dated
September 16, 2010.
• Samples collected in the warehouse space and the office space should be collected under worse
case conditions. Warehouse doors and windows should be closed, and mechanical blowers should
not be operated during sampling operations. This may again require that sampling be conducted
North Carolina Department of Environment and Natural Resources
Dexter Matthews, Director Division of Waste Management Beverly Eaves Perdue, Governor
Dee Freeman, Secretary

Ms. Short
October 14, 2010
Page 2 of 2

during the weekend or other times when the warehouse operations are not taking place. If it is not
possible to sample under these conditions, door openings and fan operation should be documented
in the sampling report.

Once these activities are complete, we will determine if any additional information is needed to
complete our evaluation of site risks and preparation of the draft Brownfields Agreement.

Sincerely,
Carolyn Minnich
Carolyn F. Minnich
Brownfields Project Manager
Division of Waste Management

cc: Project File

ec: Bruce Nicholson, DENR
Will Service, DENR
Vapor Intrusion Sampling
Draft Guidance
NCDENR
Brownfields Program
February 17, 2010

Objectives:
1. To provide guidelines for information gathering during indoor air (IA) and sub-
slab soil vapor (SSV) sampling for Brownfields Project (BFP) vapor intrusion
assessment.
2. To provide guidelines for creating worse case vapor intrusion conditions during
BFP vapor intrusion sampling.
3. To develop information about environmental conditions, building characteristics
and building ventilation during a BFP indoor air sampling event, in order to judge
how those variables might affect IA and SSV results.

Application
This information should be used as a guideline for data and information gathering
during indoor air and sub-slab soil vapor sampling for vapor intrusion assessment.
This information should be used to judge the degree of variability in indoor
ventilation and other conditions that might be anticipated in the building in question
and whether worst-case conditions for vapor intrusion were in place during the
sampling event.

Sampling and Analysis Methods
For indoor vapor, outdoor vapor (background), and sub-slab soil vapor sampling,
methods should be used that are consistent with the following guidelines and information:
• EPA Compendium Method TO-15 (EPA/625/R-96-010b). (8- 24 hour sample
duration).
• Section 3.0 of the “Assessment of Vapor Intrusion in Homes Near the Raymark
Superfund Site Using Basement and Sub-Slab Air Samples”
(http://www.epa.gov/ada/download/reports/600R05147/600R05147-fm.pdf ).
• Appendix E of “OSWER Draft Guidance for Evaluating the Vapor Intrusion to
Indoor Air Pathway from Groundwater and Soils (Subsurface Vapor Intrusion
Guidance)”
• Methods described by the contractor in a work plan and approved by NC DENR
BFP.

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Vapor Intrusion Sampling Checklist

Weather
Barometric pressure/building pressure
• Measure the building/outdoor air pressure differential for at least two building
locations near the start of the sampling period, near the middle of the sampling
period, and near the end of the sampling period. Manometers should be sensitive
to 0.01 inches water gage or equivalent.

Wind
• Measure wind speed, and direction, near the start of the sampling period, near the
middle of the sampling period, and near the end of sampling period.

*Temperature
• Measure ambient temperature near the start of the sampling period, near the
middle of the sampling period, and near the end of sampling period.

*Precipitation
• Report recent precipitation trends and conditions during sampling.

Building
*Floor plan with sample locations
• Report indoor air sample locations relative to sub slab sample locations, HVAC
system zones, local exhaust ventilation systems and wind direction. (In addition
to spatial relationship to soil vapor data.)
• Report building floor area and volume.

Natural ventilation
Operable windows and doors, and other openings in the building envelope.
• Report size and locations of operable doors and windows.

Windows and doors, and other openings in the building envelope should be
closed during the sampling period.

Heating, ventilating and air conditioning (HVAC) system
HVAC systems
• Provide mechanical drawings for HVAC system that include air handling unit
(AHU) location and AHU service area.
• Describe blower operation (cycled or continuous).
• Describe mechanical outdoor air ventilation that is provided through the HVAC
system including the outdoor air ventilation (OAV) rate in cubic feet per
minute(describe whether the designed or measured rate is provided).
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If the OAV rate is variable, the OAV control should be set to minimum
during sampling. The cooling or heating system should be operational
during sampling.

Exhaust ventilation
Whole building exhaust ventilation (including appliances and fireplaces).
• Volumetric flow rate (designed/measured)
• Is there a makeup air source?
• Consult with BFP manager about whether to operate the system during sampling.

Large whole building exhaust ventilation systems may depressurize the building if
there is not adequate makeup air, which could increase vapor intrusion rates.
The same circumstances could create very high air change rates, particularly if
there is adequate makeup air, which would prevent building depressurization, and
could reduce indoor vapor concentrations significantly. Consider whether to
operate the system during sampling on a case by case basis.

Local exhaust ventilation
• Volumetric flow rate (designed/measured)
• Is there a makeup air source?

Operation of exhaust systems may depressurize the building, particularly where
there is no provision for makeup air, and may create a worse case condition.
Alternatively, exhaust ventilation may increase air change rates which could
reduce VOC concentration.

Indoor VOC sources
• Identify and catalog indoor sources of volatile organic compounds that could
influence indoor vapor sample results.

Outdoor air background sampling
• Outdoor or background sampling should be done concurrently with IA sampling.
• Outdoor samples should be collected upwind of the buildings where sampling is
being conducted.

*Information required for sub-slab vapor sampling.

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