An Evaluation of H2S Continuous Monitors Using Metal Oxide Semiconductor Sensors.
A determination was made of the usefulness of five different commercial monitors to detect hydrogen-sulfide (7783064). These devices used metal oxide remote semiconductor sensors wired to a controller. On some models the sensors can be located at distances up to a mile from the controller. A two point calibration and linearization was employed by three of the devices. Two brands employed only a one point calibration. The performance of each monitor is reported along with long term zero and span stability, response time, reproducibility of exposure and response with various temperatures, humidities, and interferences. Usually the long term span stability of the monitors which employed a two point calibration technique and linearization of the sensor signal were better than those employing a one point calibration technique. Temperature and humidity changes affected each of the monitors. None of them was significantly affected by interferences from carbon- monoxide and methane. The authors conclude that semiconductor sensor based monitoring systems seem satisfactory and are offered in a number of configurations. While no direct measurements of sensitivity were taken in this study, several of the monitors examined would be effective at the 5 parts per million concentration level.
NIOSH-Author; Air-quality-monitoring; Toxic-gases; Inhalants; Air-sampling-equipment; Workplace-studies; Environmental-hazards;
NTIS Accession No.
NIOSH, U.S. Department of Health and Human Services, Cincinnati, Ohio, 47 pages, 9 references