Notice regarding preservation of WTC documents for legal evidence, undated

NYC 9/11 Public Portal Document

conducted. Residents shall not be present in their residence during aggressive air sampling activities. 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. 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 employe^ for modified aggressive g^pling. V. All other procedures are identical for aggressive and modified aggressive air sampling, unless otherwise noted, i b. At least one 20-inch fan shall be placed in the cepfe of^ch 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. c. 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 shouldbd directed downward at a 45 degree angle. d. Common spaces will be sampled without the use offorced air devices (fans, leafblowers etc). For small spaces, less than160 square feet, 3 samples will be collected. For large spaces greater160 square feet and less than 25,000 square feet 5 samples will be collected. For spaces^eater than 25,000 square feet, 1 sample will be collected for each 5,000 square feet, Stoipling equipment shall be placed away from obstructions. The sampling cassette must be placed on a tripod, not taped to existing surfaces and directed downward at a 45 degree angle and e. Air samples will be collected in accordance with the procedures specified inNIOSH 7400 Method 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 sample 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. f. Wipe samples will be collected at 10 percent ofthe residences where sampling only has been requested, up to a maximum of5 0 residences, as instructed by EPA. This sampling will consist ofthe collection of3 wipe samples each for dioxin, total metals and mercury (Note: a separate wipe sample is required for each parameter at each location). Metals and mercury wipe samples will be collected in accordance with procedures specified in

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NYC-WTC_000139216