American Industrial Hygiene Conference and Exposition, May 21-26, 2005, Anaheim, California. Fairfax, VA: American Industrial Hygiene Association, 2005 May; :42
Accurate determination of permeation parameters (including breakthrough time and permeation rate) is essential for selecting suitable chemical protective clothing. Since the data analysis involves a number of equations and experimental factors, experimenter bias and possible calculation errors are critical issues when determining permeation parameters. For instance, significant experimenter bias could result in selecting an inappropriate "steady-state permeation" region for calculating the steady-state permeation rate (SSPR). Accurate calculation of normalized breakthrough time, using a closed loop testing system, requires the use of polynomial curve fitting, polynomial derivatives, and quadratic equations. This calculation is labor intensive and somewhat difficult to do without the necessary computer program. Therefore, a Microsoft Windows compatible program, referred to as "Permeation Calculator", has been developed in an attempt to automate the data analysis. The program imports data files collected by a data acquisition system during a permeation test, which contain time versus concentration or voltage. More information is then entered under the "Additional Data Input" screen, such as the challenge chemical(s), type and thickness of the barrier material, diameter of the permeation cell, instrument settings, sampling flow rate and dead volume if a MIRAN IR analyzer is used. The program then determines each of the permeation parameters, including breakthrough detection time, normalized breakthrough time, and SSPR for either an open loop or a closed loop test. At the end, the program displays all the permeation parameters together with relevant information as a report file which can be saved and printed. This presentation will provide an overview of the program and describe the strategies, approaches and algorithms involved in the program development.
American Industrial Hygiene Conference and Exposition, May 21-26, 2005, Anaheim, California