Abstract
Michigan's Division of Occupational Health has a unique instrument for continuously monitoring and recording carbon monoxide concentrations. Maximum concentration recorded is 200 ppm, with a sensitivity of ±2 ppm, Built in are automatic circuits allowing the instrument to purge, check zero reading, and check upscale (185 ppm) calibration once every 12 hours. All components are housed in an aluminum case 13¾ by 31¾ by 17¾ inches, weighing 105 pounds. It is possible for one engineer to transport it and set it up. One year's field experience has shown that the instrument is reliable and will operate in the field up to 36 hours, with minimum supervision.