Most gas detection systems are designed to detect hazardous gases: though you’ll often see some systems talking about detection of toxic gases, or other kinds of gases. Hazardous gases refer to all kinds of gas that can be potential harmful to humans in certain concentrations. Hazardous gases can be classified into several different categories:
- Toxic gases: these are gases that are harmful to humans when inhaled or ingested in various quantities. This includes gases such as ammonia, chlorine, sulfur, and many others. The official definition of a toxic gas is: “A compressed gas or vapor that has a median lethal concentration (LC50) in air of 200 parts per million (ppm) by volume, or 2 milligrams per liter of mist, fume, or dust, when administered by continuous inhalation for one hour (or less if death occurs within one hour) to albino rats weighing between 200 and 300 grams each.”
- Flammable gases: these gases are capable burning in certain concentrations. Flamable gases will only burn the presence of oxygen; however, without oxygen there is probably a bigger problem for workers.
- Combustible gases: this category of hazardous gas includes all gases that can explode in certain concentrations. Like flammable gases, combustible gas requires the presence of oxygen.
Thus a toxic gas detector is designed with gas sensors to detect certain toxic gases, but not flammable or combustible gases. In addition to the various hazardous gases, many gas detection systems also include sensors to detect dangerously low levels of oxygen. These oxygen deficiency detectors are not technically a hazardous gas detector, but are an important part of industrial gas detection.
It’s worth stressing that a toxic gas detector will not detect every kind of toxic gas just as a flammable gas detector will not detect every kind of flammable gas. Regardless of the type of gas detector, it will only detect the specific gases it was designed for.
Gas Detection Systems 