WTC cleaning program scope of work draft August 2002

NYC 9/11 Public Portal Document

a. Sampling shall not begin until a visual inspection confirms the absence ofvisible dust and debris. Post cleaning air sampling shall be performed upon successfid visual inspection and completed within 24 hours. A successful visual inspection shall be an inspection that verifies the absence of dust and debris. b. All surfaces must be completely dry prior to the start of sampling. c. Upon completion ofthe cleaning, air sampling will be conducted to verify attainment ofthe clean-up criteria. Based on considtation 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 shall 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 minimize disturbance and potential damage to furnishings and personal belongings ii. Residents shall not be present in their residence during aggressive air sampling activities. iii. Personal protective equipment including disposable clothing, gloves, and respirators shall be worn during aggressive air sampling activities. iv. HVAC systems shall be shut down or isolated locally during aggressive air sampling. V. Room and window air conditioners shaUnot be operated during aggressive air sampling. vi. Leaf blowers shaUnot be employed for modified aggressive air sampling. vii. 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 of each 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 of sampling. 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 sampling cassette 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 without the use offorced air devices (fans, leafblowers etc). For small spaces, 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.

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NYC-WTC_000140637