Gas warning device
A gas warning device is used to monitor the gas concentration in the air. It is used to warn of toxic or explosive gases and works with optical, infrared , electrochemical or catalytic gas sensors , depending on the application .
history
In the past, simpler, if very limited, means were used. Winemaker z. B. traditionally used a candle placed on the ground to detect dangerously high concentrations of the gas carbon dioxide, which is produced during fermentation and which collects on the ground, in the wine cellar , and miners took songbirds with them underground to avoid carbon monoxide poisoning. If the bird stopped singing and lay lifeless in the farmer, there was a risk of death.
Types
There are stationary warning devices that are permanently installed in endangered locations or mobile devices. A distinction is also made between single gas (single gas detector) and multi-gas devices (multi-gas detector). Single-gas devices are specially designed to detect a single gas (e.g. carbon monoxide ), multi-gas devices can detect several different gases (e.g. oxygen , carbon dioxide , hydrogen sulfide and methane ).
function
When a critical amount of the gas in the air is reached, a warning (optical, acoustic or vibration) is issued. In the case of stationary devices, the gas supply can also be switched off automatically.
commitment
Gas detectors are mainly used in mining and sewer work. The first measurement is made before entering the sewer; while working, the device is continuously guided by the man.
When measuring the oxygen content, the critical threshold is reached when it falls below 17%. The critical concentration of explosive gases is reached when it exceeds 10% LEL. LEL means " lower explosion limit ", 100% LEL is the concentration at which a mixture becomes explosive. Individual standards apply for the harmful concentration of toxic gases and vapors. In Germany, limit values are set by the Committee for Hazardous Substances (AGS).
Gas warning devices can also be found in the fire brigade and rescue service, for example, which can detect explosive, asphyxiating or toxic gas concentrations and thus warn the personnel deployed.
