Glossary of terms used on this site

A component of a gas detector that is capable of generating electrical energy from chemical reactions or causing chemical reactions by adding electrical energy, generating a potential difference from which a concentration value can be calculated.

An explosion is a rapid increase in volume and release of energy in an extreme manner, usually with the generation of high temperatures and the release of gases. Usually, an area designated as susceptible to explosion danger is one where two of the three requirements for a combustive explosion are or can be present: a combustible material, an oxydizer and a source of ignition. Areas classified into zones (0, 1 and 2 for gases, vapours and mist or zone 20, 21 and 22 for flammable dust) must be protected from effective sources of ignition. Zone 0 and 20 represent the highest risk. The intrinsic safety certificate of a piece of equipment classifies it for use in certain zones, depending on how likely it is to act as a source of ignition. Areas classified as zone 0 or 20 require category 1 equipment; zones 1 and 21 category 2; while zone 2 and 22 require category 3 equipment.

The highest and lowest concentrations at which a given gas can ignite while mixed with air at 25

Or occupational exposure limit, an upper limit on the acceptable concentration of a hazardous substance in workplace air for a particular material or class of materials. Exposure limits are usually set and enforced by national authorities, although sometimes they are merely recommended. Many means are available to companies to restrict the risks associated with the substances present at its premises, of which gas detection is certainly a very important component, both in the risk assessment stage and in the enforcement stage.