Es. Moyer et al., PRELIMINARY EVALUATION OF AN ACTIVE END-OF-SERVICE-LIFE INDICATOR FORORGANIC VAPOR CARTRIDGE RESPIRATORS, American Industrial Hygiene Association journal, 54(8), 1993, pp. 417-425
Data are presented on a microwatt chemiresistor microsensor for use wi
th negative-pressure organic vapor respirators. This sensor would oper
ate at or within a sorbent bed and detect parts per million levels of
chemical vapors and/or gases as a function of sensor resistance. Senso
rs were evaluated against four challenge concentrations of ethyl aceta
te (750 ppm, 1000 ppm, 1500 ppm, and 2000 ppm). Direct comparison of b
reakthrough times and curves for the chemiresistor microsensor and a s
tandard infrared (IR) detector system were made. The chemiresistor sen
sor responses were found to correlate well with the IR system. The eva
luation showed that although the chemiresistor sensors were not as sen
sitive as the IR detectors, they could be used if located inside the c
harcoal bed. Thus, these sensors could function as organic-vapor detec
tors and could be used in cartridge applications. However, further imp
rovements in stability and sensitivity of these chemiresistor sensors
is necessary.