FIRE AND GAS DETECTION
“Without auxiliary tools humans are not able to recognize these dangers early enough to initiate appropriate counter measures. With only some exceptions our nose has turned out to be an extremely unreliable warning instrument. For example, hydrogen sulfide in low concentrations is sensible by its typical odor of rotten eggs, but lethal high concentrations of hydrogen sulfide are not detectable by our nose. Escaping into areas assumed to be non-dangerous because of the missing smell has already caused a lot of fatal accidents.”
Even harmless gases such as argon, helium or nitrogen may become dangerous when the vitally important oxygen is displaced by a sudden release. Danger of suffocation! Oxygen concentrations of less than 6 Vol% are known to be lethal. Oxygen in excess (more than 21 Vol%) increases the danger of flammability and might even cause auto-ignition of flammable material. Not only can flammable gases and vapors cause considerable plant damages by ignition, also human life is compromised.