Prediction of workplace contaminant levels.
NIOSH 1981 Jan; :190-206
Vapor emission rate data for estimating losses from equipment, piping, and open pools of chemicals were presented for vinyl- chloride (75014) (VC) and acrylonitrile (107131) (AN) to demonstrate a procedure for the process design engineer to predict workplace concentrations of specific chemicals. The design procedure was based on a gaussian dispersion model and allowed definition of a chemical's physical properties related to its probability as a workplace contaminant. The air dispersion equation predicted maximum downwind concentrations as a function of distance from source, without solid surface reflectance of the dispersed plume. The dispersion correlation used assumed that the source and receiver were relatively close. Graphical analyses determined maximum workplace concentrations for VC and AN for normal ambient conditions. A table of diffusion functions was included for determination of workplace concentrations at ambient conditions other than those in the graphs. Emission rate data were shown for quiescent pools of pure VC or pure AN, water VC or water AN mixtures, and vapor emission leaks of VC and AN. For open pool or tank data, a more detailed correlation was necessary when emissions from the open surface were critical to the design. It was emphasized that based on the equation or graphical analyses, valid emission rate data was central to determining contamination levels. It was recommended that this data be determined experimentally during research and development of a project. Emission points were not unit operations but dynamic or static seal points. A method for determining impact of proposed design alternatives was demonstrated using correlations and data described. The procedure included summarizing key emission points for each design case; defining ambient conditions and identifying key operations areas impacted by emissions; calculating workplace concentrations for each hot spot by summing concentrations from individual sources; and reviewing risk associated with each engineering control or operations change and identifying actions providing maximum cost benefits.
Regulations; Industrial-safety-programs; Safety-monitoring; Occupational-exposure; Workplace-studies; Industrial-hazards; Environmental-contamination; Mathematical-models
DHHS (NIOSH) Publication No. 81-107
Symposium Proceedings. Control Technology in the Plastics and Resins Industry, Division of Physical Sciences and Engineering, NIOSH, U.S. Department of Health and Human Services, Cincinnati, Ohio, DHHS (NIOSH) Publication No. 81-107