Chain of custody form for air monitoring, 385 South End

NYC 9/11 Public Portal Document

4.2 Air Sampling Procedures technician ALC's licensed technicians collected air samples using TEM Methodology. The collected five (5) air samples on each floor. The samples were taken in three (3) apartments and at identified the locations that g4` two separate areas in the hallways on each floor. The technician appeared to contain the most visible dust and debris to perform sampling.

Once the pumps were in The air samples were collected using high volume air sampling pumps. technician recorded the location, time, date, sample numbers, pump number, place the air sampling flow rate, start and stop times and his initials.

prevent the vibrations of the motor he air cassette was independent of the pump motor. This is to or tripod was used to hold the cassette in from affecting the fibers in the cassette. A separate stand downward from the horizontal stand. This is to insure place. The cassette was angled 45 degrees that no asbestos will drop into the cassette while sampling.

rate, noting this rate on the Using a rotameter, we calibrated each pump to the required flow sample record. After calibrating the pumps, the end cap from the cassette was removed; the pump was turned on and run for the required amount of time. still operating, the cassettes The sampling pumps were checked periodically to ensure they were equipment. If at any time the area being sampled were still in place, and no one has disturbed the counts, the filter inside the cassettes were examined for was suspected of having high fiber `overloading", at an excessive amount of fibers and/or debris on the filter.

technician then calibrated the When the pre-determined volume of air has been collected, the often be different from the sampling pump again to determine the current flow rate. This rate will period. That difference is usually due to the flow rate measured at the beginning of the sampling clogging of the filter, thereby adding increased resistance to the flow of air.

was recorded as well as on the Once the pre determined volume of air has been reached, the time was turned off, the cassette was angled upward and the cap replaced cassette. Before the pump labeled with an identifying code and the end plug. The cassettes were placed in sealed containers, laboratory to be analyzed for and a sample log was kept. The samples were then submitted to the and accompanied the samples to the asbestos content. A chain of custody record was prepared laboratory.

43. Asbestos Analysis and Methodology internal code to ensure proper, Each air sample is cross-referenced by field designation and lab consistent handling through a chain of custody. Sample preparation takes place within a HEPA Filter clean bench to avoid any possible contamination. Air sampling was conducted at a level approximating the breathing zone of persons anticipated to be present in the area during normal represent the typical airborne fiber concentration of the area. s operations. Samples collected

5. Findings and Conclusions contrast microscopy (PCM) Eight (8) initial background air samples were collected and analyzed via phase at building 500. Four (4) samples were analyzed via Transmission Electron Microscopy (TEM). After analysis via TEM all were below the permissible limits.

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