Calibration is the process of configuring a measuring instrument to provide an accurate result. The process involves testing the instrument against one or more substances referred to as “calibrators.” These substances have known values and are used to “tune” the measuring instrument for greater accuracy by ensuring that the result of the measurement matches the known value of the substance.
Most measuring instruments must be re-calibrated repeatedly throughout their lifetime to ensure that they continue producing accurate results.
Safeopedia Explains Calibration
Calibration is an extremely important aspect of workplace safety. Workplace safety regulations across jurisdictions impose a duty upon employers to monitor potentially hazardous workplaces and to conduct regular calibration of all testing instruments to ensure accuracy. For instance, OSHA standards for various industries and work environments (e.g. 29 CFR 1910.146, 1910.120, and 1910.272) require the use of direct-reading portable gas monitors (DRPGMs) to prevent exposure to harmful gases in the workplace. These standards include requirements for regular calibration and recording of calibration tests.
According to OSHA guidance, the use of improperly calibrated gas monitors in select safety-sensitive workplaces can lead to hazardous levels of toxic gases (which could result in worker poisoning), combustible gases (which could result in an explosion), or an oxygen-deficient atmosphere (which could result in worker asphyxiation). Recommendations for safety equipment by the International Safety Equipment Association (ISEA) include regular calibration of equipment, such as the re-calibration of DRPGMs at the start of each workday.
Calibration of measuring instruments is expected to occur on both a planned schedule and on an as-needed basis, such as when an instrument begins to provide unexpected measurements. An instrument must also be re-calibrated for each substance that it is used to measure. Furthermore, calibration must take place in an environment that is similar to the one it will be used within. Instruments such as combustible gas meters will provide different results depending on the amount of oxygen in their immediate environment.