Estimating Worker Exposure to Gases and Vapors Leaking from Pumps and Valves

Abstract

The industrial hygienist is frequently asked by a process design group about the required level of engineering control for toxic materials in process streams. The potential hazard to the worker is not only a function of the toxic material concentration in the process stream, but also the equipment (point source) characteristics and the process stream properties. Not all of these parameters can be evaluated for streams and complex processes still on the drawing board. However, the hygienist can estimate worker exposure due to potential leaks or spills from equipment. This paper presents a method that can be used to estimate the concentration of a toxic material in a worker's breathing zone, based upon the concentration of the material in the process stream, the process stream properties, and the equipment leak potential. The paper concentrates on leaks from pumps and valves, but the methods is applicable to leaks from other types of process equipment. The method is a three step process consisting of estima...