Determination of Toxic Gas Concentrations from Exhaust Stacks Using
Erle B. Jones, C.I.H. - Motorola, Inc. (SSA Journal Volume 5 Number 2 - June 1991 pp. 34 - 37 )
Knowledge of the stack discharge concentration for both catastrophic and non-catastrophic toxic gas leas is important to assess potential health effects of the worker and public citizen residing in the immediate community. This article reviews the basic gas flow formulas utilized to determine toxic gas concentrations at the stack. The microcomputer program, Safe-Gas, which uses Lotus 1-2-3 (version 2.2), is also introduced. This program calculates a variety of toxic gas parameters, which are displayed in the Solutions Block, once other toxic gas inputs have been entered. Those inputs include the toxic gas, its location, quantity and cylinder pressure. A critical orifice size and location of the gas leak, relative to the critical orifice, are also required inputs. Two examples of Safe-Gas are given to illustrate stack concentrations resulting from toxic gas leaks before and after a critical orifice. This program evaluates gas parameters from a full gas cylinder leaking inside an exhausted gas cabinet. Any attempted use of Safe-Gas outside and exhausted gas cabinet negates the program's intended purpose.