Gas detectors are designed to protect workers from unknown hazards that may be present in the workplace, including confined spaces. It is very important that these instruments are fully maintained and calibrated according to the manufacturer's instructions and recommendations. Serious industrial injuries due to detector inaccuracy due to erratic or incorrect calibration are a very real threat.
Exposure to excessive amounts of toxic substances or an oxygen-deficient environment can cause serious illness and even death in workers. Combustible gas explosions can be catastrophic, seriously injuring or killing workers and destroying property. Many manufacturers of gas detectors and protective equipment recommend checking sensor accuracy prior to daily use.
The only way to ensure that a detector is accurately detecting substances is to test it with a known concentration of test (or calibration) gas. By exposing the detector to a known or verified concentration of the test substance, it is determined whether the sensors are responding to that gas and whether the instrument's alarms are functioning properly.