In-depth survey report: evaluation of ventilation and filtration system for delivery bar code sorter at United States Postal Service Dulles Processing and Distribution Center, Dulles, Virginia, report no. CT-279-11a.
Beamer-B; Topmiller-JL; Crouch-KG; Shulman-S
NIOSH 2002 Apr; :1-23
Researchers from the National Institute for Occupational Safety and Health (NIOSH) conducted evaluations of a Ventilation and Filtration System (VFS) for the United States Postal Service's Delivery Bar Code Sorter (DBCS). The VFS was designed by the manufacturer of the DBCS to reduce operator exposure to any potentially hazardous contaminants emitted from letter mail during normal mail processing. Evaluations were conducted at the Dulles, Virginia Processing and Distribution Center (P&DC) during two separate field surveys. Survey 1 took place on January 23,2002 and Survey 2 took place on March 20,2002. Evaluations were based on a variety of tests including particle count measurements, air velocity measurements, smoke release observations and tracer gas experiments. Testing indicated the following regarding DBCS locations targeted by the VFS: At the Vibrator Module, capture efficiency ranges from about 89% to 99% under normal working conditions; At the Feeder Table, efficiency is about 76% under normal conditions. .The Feeder Module has capture effectiveness of about 99%; At the Stacker Modules, efficiency ranges from about 97% to 99%; With overhead ceiling fans on, there is some evidence that the VFS efficiency marginally decreases at the Stacker Modules, Vibrator Module and Feeder Table. Based on these results and others discussed in this report, the following recommendations are suggested regarding the VFS: The contaminant capture velocity at the Vibrator Module should be increased to a level that makes its efficacy comparable to that of the Feeder Module and Stacker Module; The contaminant capture velocity at the Feeder Table should be increased to at least 100 feet per minute; The VFS exhaust slots at the Vibrator Module and Feeder Table should be moved to a height above the tallest envelope to ensure unobstructed contaminant capture; Revision of the inlet area for the top row of Stacker Modules should be made to ameliorate the effects of ceiling fans on ambient air currents; More testing should be done regarding the decay rate of smoke from areas under cabinet hoods since access to these hoods to clear jams is a frequent occurrence.
Ventilation-systems; Ventilation-equipment; Ventilation-hoods; Postal-employees; Biological-warfare; Biological-weapons; Microorganisms; Indoor-air-pollution; Particulates; Particulate-dust; Dust-control-equipment; Dust-control; Dust-particles; Dusts; Region-3; Indoor-environmental-quality
Control Technology; Field Studies
NTIS Accession No.
National Institute for Occupational Safety and Health