114 LIBERTY 2 OF 2

NYC 9/11 Public Portal Document

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3. A turnaround time of 24 hours is required for all samples.

Asbestos Air Monitoring

1. Five (5) ambient air samples shall be collected outside but in the general vicimty of the work site. Samplers shall be placed in reasonable proximity to the building and away from obstructions, vents, and drafts that may unduly affect airflow.

2. Five (5) air samples shall be collected per day during cleanup activities. The flow rate shall be set at the minimum collection flow rate specified by the manufacturer for the sampling pump. The flow rate shall not exceed 3 liters per minute. A minimum sampling volume of 3600 liters shall be collected.

Samples shall be collected at isolation barriers outside the work area, the clean room of the worker/waste decontamination facility, and outside of the building.

3. Sample collection methodologies shall be in accordance with Title 15, Chapter 1 of the Rules of the City of New York (RCNY) and AHERA regarding documentation and sample locations and the requirements set forth herein regarding the rates of flow, and required volumes to achieve the necessary analytical sensitivity.

4. Sampling equipment shall be placed at representative locations and away from obstruction. Sampling cassette must be placed on a tripod and not taped to existing surfaces. All air sampling equipment shall be pre- and post- calibrated to insure accurate air sampling volumes. 5. The Air Sampling Technician shall perform clearance air sampling after the areas are fi-ee of dust accumulations as determined by the Project Monitor. All surfaces must be completely dry prior to the start of sampling. Clearance air sampling shall be performed at each apartment. Five samples shall be collected in each apartment and two samples shall be collected at the first floor lobby. The elevator shaft shall be cleared separately. Clearance air monitoring shall be performed after the completion of all clean up activities at the work site. Clearance air sampling shall be aggressive and performed in accordance with Title 15, Chapter 1 of the RCNY Section 1-43 (a)-(d).

6. Clearance air samples shall be collected in accordance with the procedures specified in the NIOSH 7400 Method. The flow rate for collection of air samples shall be at least 10 liters per minute and no more than 15 liters per minute. Air sampling cassettes must be monitored to ensure the filters do not develop dark spots that would indicate clogging. The minimum sampling volume is 3600 liters. If clogging develops, the cassette must be changed.

7. All clearance air samples and completed chain of custody forms must be transported to the laboratory immediately after sampling is completed^___

Clearance Criteria

1. The following clearance levels have been established by the USEPA for clean up activities resulting from the collapse of the WTC.

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