Updated WTC cleaning and monitoring scopes of work, July 2002

NYC 9/11 Public Portal Document

b. All surfaces must be completely dry prior to the start of sampling. c. Window air conditioning units where applicable shall be run/operated at least 15 minutes prior to the start ofsampling. The air conditioning units shall operate continuously throughout the sampling. 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. Aggressive or modified aggressive air sampling will be used for Scope A clean-ups, based on consultation with resident. In aggressive air monitoring sampling situations, before the start of sampling, a 1 horsepower electric leaf blower will be used to direct exhaust air against walls, ceilings, 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 below for modified aggressive sampling techniques will also be employed e. In modified aggressive sampling, one 20-inch fen 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. f. For studio apartments 3 samples shall be collected. For 1-bedroom apartments and above 5 samples shall be collected. Sampling equipment shall be placed in living areas and away from obstructions. The sampling Osettd m a tripod and not taped to existing surfaces. g- 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 than25,000 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. 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. 1. 24-hour turn-around-time shall be specified for the analysis ofall post-cleaning air samples for Scope B cleanups. j- The contractor shall document all the necessary information regarding sampling activities, fill out all field logs, data sheets, and chain-of-custody forms. The contractor shall use F2L for all sample and chain-of-custody documentation. Samples must be labeled and accompanied with completed chain-of-custody forms before shipping to the designated laboratory. The label must include the EPA Project Tracking Number. Samples will be packed, sealed and for analysis to EMSL laboratories at: 307 W. 38* St., New York, New York 212-290- 0051. k. All information must be maintained using the secure EPA website (url, user name and password to be provided by EPA). Dates for monitoring and/or cleaning shall be provided to EPA and DEP electronically in an EPA approved format within 24 hours. Information on

NYC-WTC_000138602