In-Depth Survey Report: Evaluation of the Ventilation and Filtration System and Biohazard Detection System for the Automated Facer Canceller System at United States Postal Service Dulles Processing and Distribution Center Dulles, Virginia, October 2003

摘要

Researchers from the National Institute for Occupational Safety and Health (NIOSH) conducted an evaluation of the Ventilation/Filtration System (VFS) developed for the United States Postal Service (USPS) mail processing equipment-the Automated Facer Canceller System (AFCS). The ventilation control system was developed and installed by a private contractor hired by the USPA to reduce the potential for employee exposure to harmful substances that could be contained in mail processed by the equipment. The ventilation system for the AFCS was designed to be used with a Biohazard Detection System (BDS) that samples and analyzes air from the AFCS to determine if a biohazard is present. This effort is in response to terrorist attacks in the fall of 2001 that used the mail as a delivery system for anthrax. NIOSH was asked to assist in USPS in evaluating controls for this and other mail processing equipment. Evaluations were based on a variety of tests including tracer gas experiments, air velocity measurements, and smoke release observations. The experiments showed that generally there is good capture by the VFS. Without the BDS installed, the measured VFS capture efficiencies exceeded 98% except in two positions. Lower efficiency was measured under the flats extractor, but following a modification by the vendor, the efficiency in this area was also greater than 98%. Another position that had lower capture efficiency was above the first pinch point in the singulator. This is the area in which the BDS would be installed, so it was not a concern. Testing conducted with the BDS installed showed good capture efficiencies under most conditions. When tracer gas was released around the BDS and under the BDS hood, capture efficiencies exceeded 98% for most positions and exceeded 90% for all positions. Smoke release experiments and velocity measurements were consistent with the results of tracer gas testing.