An Evaluation of Charcoal Cloth as a Potential Field Monitor for the Efficacy of Chemical Protective Clothing

Abstract

Generally the results of manufacturers' permeation tests are used to select chemical protective clothing. However, these test results are subject to several sources of error. In addition, certain conditions, such as temperature, exposure time and duration, immobility of the garment, and sample thickness, which is dependent on the location from which the garment is sampled for testing, are controlled in the experiment in ways which may not reflect actual use conditions. The only way to accurately determine the efficacy of a garment is to monitor its permeation resistance in the field. For volatile permeants this is difficult, since the most obvious way to trap these compounds after permeation is with a sorbent, and the efficiency of this process is not certain given the natural ventilation that occurs during use of protective clothing, especially gloves. In this study charcoal cloth was made into gloves and used beneath polyvinylchloride gloves to monitor permeation. The glove system was flexed at rates of 0, 30, or 50 times per minute. The weight loss of the system was monitored as an indicator of the permeation through the glove, and the charcoal gloves were assayed via gas chromatography for the heptane permeant. Under no-flex conditions the charcoal cloth was near 100 percent effective at trapping the heptane. Under conditions of flex, 61 to 86 percent of the heptane was captured. Given the inexact nature of the clothing selection process, these appear to be acceptable results. However, a few other factors, such as the polarity of the permeant, need to be considered.