E-mails M. Gilsenan 2002

NYC 9/11 Public Portal Document 14. fax or alternative format agreed upon and within two days ofrequest. Final air sampling shallbe performed with 24 hours of final visual inspection. Post Clean-up Air Sampling Procedures a. Sampling shall not begin until a visual inspection confirms the absence of visible dust and debris. Post cleaning air sampling shall be performed upon successful visual inspection and completed within 24 hours Within 24 hours of what?. A successful visual inspection shall be an inspection that verifies the absence of dust and debris. b. C. All surfaces must be completely dry prior to the start of sampling. Window air conditioning units where applicable shall be run/operated at least 15 minutes prior to the start of sampling. The air conditioning units shall operate continuously throughout the sampling. Why is the air conditioning unit operated after clean up when it wasn't operated during sampling prior to clean up? It should be operated during sampling priorto clean up as well: d. Upon completion of the cleaning, either aggressive or modified aggressive air sampling procedures will be conducted to verify attainment of the clean-up criteria. Aggressiveor modified aggressive air sampling will be used for Seope A clean-ups, based on consultation with resident. In aggressive air monitoring sampling situations, before the start of sampling, a l horsepower electrie leaf błower will be used to direct exhaust air against walls, eeilings. floors and other surfaces. When directing the exhaust, caution shall be taken to minimize disturbance and potential damage to furnishings and personal belongings. The procedure described bełow for modified aggressive sampling techniques will also be emptoyed e. In modified aggressive sampling, one 20-inch fan shall be installed per 10,000 cubic feet of room space and run at low speed. The fan shall operate continuously throughout sampling and shall not be turned off until sampling is completed. When should this fan be turned on? f. 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 and not taped to existing surfaces. g Common spaces will be sampled without the tise of forced air devices (fans, leaf błowers ete). For small spaces, less than 160 square feet, 3 air samples will be collected. Forlarge spaces greater than 160 square feet and less than 25,000 square feet 5 air samples will be collected. For spaces greater than 25,000 square feet, 1 air 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. h Air samples shall be collected in accordance with the procedures specified in NIOSH 7400 Method for PCM and 7402 for TEM. Air sampling cassettes need to be monitored to ensure pumps are not clogging by monitoring flow rates. The minimum sampling volume required is 3600 liters. i. 24-hour turn-around-time shall be specified for the analysis of all post-cleaning air samples for Scope B cleanups. The contractor shall document all the necessary information regarding sampling activities, fill NYC-WTC_000164041