Information‑Related Problems in Selecting Hazardous Gas Detectors
Oxygen requires close attention in industrial applications, especially in confined‑space environments. Oxygen content exceeding 23.5 % is defined as oxygen enrichment, which carries a high risk of explosion. An oxygen level below 19.5 % indicates oxygen deficiency (hypoxia), which may cause suffocation, coma and even death among workers. The normal oxygen concentration is approximately 20.9 %. An oxygen detector adopts an electrochemical sensor.
Current problems in the selection of hazardous gas detectors:
Due to historical factors and cognitive limitations, many problems still exist in the selection of gas detectors in China, which are reflected in the following aspects:
More emphasis is placed on the detection of flammable gases than toxic gases.
Greater attention is paid to gases that may cause acute poisoning than those that lead to chronic poisoning.
Bloody lessons from explosion accidents caused by flammable‑gas leaks have drawn widespread attention to flammable‑gas detection. In petrochemical and chemical plants, the majority of hazardous‑gas detectors are LEL (Lower Explosive Limit) detectors. Nevertheless, LEL detectors alone are far from sufficient to safeguard workers' safety and health.
Admittedly, most volatile hazardous gases are flammable. However, catalytic‑combustion LEL detectors are not the optimal solution for all flammable gases. They are calibrated primarily for methane and deliver poor performance for other substances. Therefore, the lower detectable limit for flammable gases other than methane is far higher than their permissible exposure limits. For hazardous toxic gases such as benzene and ammonia, relying solely on LEL detectors poses substantial risks.
