Symposium proceedings: control technology in the plastics and resins industry. Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 81-107, 1981 Jan; :115-151
Use of a high resolution, high sensitivity Fourier Transform Infrared Gas Monitoring and Analysis system for compliance with OSHA requirements for monitoring workplace levels of vinyl-chloride (75014) monomer (VCM) and other toxic gases was described. The basic gas analyzer consisted of a rapid scanning Michelson interferometer modulator with beamsplitter, infrared source, infrared detector, Wilks 40 meter sample cell and necessary optics in a free standing optical bench and electronics console housing the system controller, data acquisition unit, minicomputer, recorder, audio alarm, and input/output terminal for programming, systems diagnostics, and printing 8 hour averages, and alarm excursions. Basic requirements met by this system were speed, sensitivity, specificity, multicompound adaptability, multisample station adaptability, and output adaptability for comprehensive display and recording. Fourier derivations of the interferogram were discussed with regard to frequency, interference, resolution, concentration, absorption, reference, and internal spectral intensity. A study of area monitors was performed for 18 months by EOCOM Corporation of Irvine, California, and the Pantasote Company of New York. Objectives of fast excursion detection, accurate employee time weighted averages, elimination of requirements for personal sampling, and a management information system aiding in achieving OSHA performance standards were evaluated by quantifying the nature of workplace gases, determining the appropriate sampling sequence for an area monitoring system, and relating employees to results of the area monitor and determining exposure. The sampling algorithm, parameters of plant data measured by the probes, were mathematically described. The authors note that excursions due to work practice were significantly decreased due to speed of the monitor.