Working in a coal mine subjects personnel to a harsh environment where the average mine height is approximately 42 inches, there is no light, the surfaces are wet and slippery, and the average temperature is approximately 55 degrees. The environment may contain methane and other harmful gasses. Mine Safety and Health Administration (MSHA) must be prepared to monitor the working environment of the mines in order to determine if the concentration of harmful or noxious gasses is being effectively controlled by the measures utilized by the mine operator. The unit used to measure these gasses underground must be MSHA approved as intrinsically safe. Daily “bump testing” using a calibration station is required to ensure the unit is properly calibrated.
Moreover, space and weight concerns are of paramount importance to MSHA inspectors. MSHA inspectors frequently need to work
in very tight spaces, many of which are less than 30 inches in height. MSHA inspectors need to carry a significant amount of
equipment, often weighing as much as 45 pounds. As a result, smaller, lighter equipment lessens the load that inspectors need to
carry. This is not just a question of comfort but of safety.