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-279-17a.
Beamer-B; Crouch-KG; Topmiller-JL
NIOSH 2003 Nov; :1-18
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) on December 13, 2002. Evaluations were based on a variety of tests including air velocity measurements, smoke release observations and tracer gas experiments. Testing indicated the following regarding DBCS locations targeted by the VFS. Smoke observations indicate that the VFS is highly effective at capturing potential contaminants at all Stacker Modules except at the far-right end. Some smoke escapes at the far-right side of the Stacker Modules when large amounts of smoke are introduced. This situation could be easily improved by attaching a panel to the right hand side of the Stacker Modules. The capture of the VFS at the Feeder Table and Jogger Module is good along the intake slot. Smoke generated at about 11 inches away from the slots (location of envelope corner) takes much longer to become entrained into the VFS. The VFS was effective at capturing smoke at exposed locations of the Feeder Module. At the Jogger Module and Feeder Table, TG capture efficiencies as low as 77% were recorded at locations representing envelope corners away from the intake slot. At the Jogger Module and Feeder Table, TG capture was highly variable, ranging from about 40% to 100% capture efficiency. At the Jogger Module and Feeder Table, air velocities were consistently low at locations away from the intake slot. These measurements reinforce results from TG experimentation and smoke release observations. Based on these results and others discussed in this report, the following recommendations are suggested regarding the VFS. It is recommended that a panel be attached to the right hand side of the Stacker Modules. It is also recommended that the VFS be modified so that there is higher contaminant capture capability at points corresponding to the corners of letters that are not adjacent to the VFS intake slots at the Feeder Table and Jogger Module.
Control-technology; Engineering-controls; Environmental-control-equipment; Postal-employees; Machine-operation; Materials-handling; Materials-handling-equipment; Ventilation-equipment; Ventilation-systems; Air-contamination; Filtration; Biological-warfare-agents; Chemical-warfare-agents; Equipment-design; Exposure-assessment; Region-3
National Institute for Occupational Safety and Health, Division of Applied Research and Technology, Engineering and Physical Hazards Branch, Mail Stop R-5, 4676 Columbia Parkway, Cincinnati, OH 45226-1998
Field Studies; Control Technology
National Institute for Occupational Safety and Health