Review of WTC monitoring and cleaning scopes of work, Aug

NYC 9/11 Public Portal Document

c. Upon completion ofthe cleaning, air sampling will be conducted to verify attainment ofthe clean-up criteria. Based on consultation with the resident or owner, aggressive or modified aggressive air sampling will be conducted. Residents shall not be present during aggressive air sampling. i. Before beginning aggressive air sampling, a 1 horsepower electric leafblower will be used to direct exhaust air against walls, ceilings, floors and other surfaces. This shall continue for at least five minutes per 1,000 square feet of floor. When directing the exhaust, caution shall be taken to avoid disturbance and potential damage to furnishings and personal belongings. ii. HVAC systems shall be shut down or isolated locally during aggressive air sampling. iii. Room and window air conditioners shall not be operated during aggressive air sampling. iv. Leaf blowers shall not be employed for modified aggressive air sampling. V. All other procedures are identical for aggressive and modified aggressive air sampling, unless otherwise noted. d. At least one 20-inch fan shall be placed in the center ofeach room sampled. One fan per 10,000 cubic feet ofroom space shall be used. The fans shall be operated on slow speed and pointed toward the ceiling. The fans shall run for at least 15 minutes prior to the start ofsampling. The fans shall operate continuously throughout sampling and shall not be turned off until sampling is completed. e. For studio apartments 3 air samples shall be collected. For 1 -bedroom apartments and above, 5 air samples shall be collected. Sampling equipment shall be placed in living areas and away from obstructions. The samplingcassette must be placed on a tripod, not taped to existing surface and should be directed downward at a 45 degree angle. f. Common spaces will be sampled wiftiout the use offorced air devices (fans, leafblowers etc). For smalli^ces, less than 160 square feet, 3 samples will be collected. For large spaces greater than 160 square feet and less than 25,000 square feet 5 samples will be collected. For spaces greater than 25,000 square feet, 1 sample will be collected for each 5,000 square feet. Sampling equipment shall be placed away from obstructions. The sampling cassette must be placed on a tripod directed downward at a 45 degree angle and not taped to existing surfaces. g- Air samples shall be collected in accordance with the procedures specified in NIOSH 7400 Mefliod for PCM and 7402 for TEM. Air sampling cassettes need to be monitored to ensure that cassettes are not clogging by monitoring flow rates. The minimum sampling volume required is 3600 liters. All clearance air samples and copies of necessary documentation shall be hand delivered daily to EMSL Laboratories at: 307 W. 38‘^ St., New York, New York 212-290-0051. h. 24-hour tum-around time shall be specified for the analysis ofall post-cleaning air samples for Scope B cleanups and for all samples collected using the aggressive air sampling method. Standard tum-around time will be used for all other samples.

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NYC-WTC_000139243