Selecting Types of Gas Detectors According to Different Industrial Environments
Portable instruments feature easy operation and compact size, and can be carried to various production locations. Electrochemical detectors powered by alkaline batteries can operate continuously for 1000 hours. New‑generation LEL detectors, PID and composite instruments adopt rechargeable batteries (some use memory‑free nickel‑hydrogen or lithium‑ion batteries), enabling nearly 12 hours of continuous operation. Therefore, such instruments are increasingly widely used in various factories and health‑related departments.
For open‑air locations such as open workshops, wearable diffusion‑type gas detectors can be used for safety alarming. They can continuously, real‑time and accurately display on‑site toxic‑hazardous gas concentrations. Some new‑model instruments are equipped with vibration alarm accessories to prevent missed audible alarms in noisy environments, and built‑in computer chips to record peak values, STEL (Short‑Term
Exposure Limit, 15‑minute) and TWA (Time‑Weighted Average, 8‑hour), providing concrete guidance for workers' health and safety.
Before personnel enter confined spaces such as reaction tanks, storage vessels, sewers and other underground pipelines, underground facilities, sealed agricultural granaries, railway tank cars, ship cargo holds and tunnels, gas detection must be performed outside the confined space. Multi‑gas detectors with built‑in sampling pumps shall be selected for this scenario. Gas composition and distribution vary greatly among upper, middle and lower zones inside confined spaces. For example, most combustible gases are relatively light and accumulate in the upper part; carbon monoxide has similar density to air and tends to distribute in the middle layer; heavier gases such as hydrogen sulfide gather at the lower section. Oxygen concentration is also a mandatory measurement item. In addition, considering possible volatilization and leakage of organic substances inside tanks, an organic‑gas capable detector is also required. Accordingly, a qualified confined‑space gas detector shall be a compact portable unit with built‑in pump‑sampling function for non‑contact multi‑point measurement, multi‑gas detection capability for inorganic and organic hazardous gases, and oxygen monitoring function to guard against oxygen deficiency or oxygen enrichment, without hindering staff operations. Only in this way can absolute safety of personnel entering confined spaces be guaranteed.
Furthermore, continuous gas monitoring shall be maintained after entering confined spaces, so as to cope with concentration fluctuations of volatile organic compounds and other toxic‑hazardous gases caused by personnel access, sudden leakage or temperature variation.
For emergency response, leak hunting and patrol inspection, pump‑sampling instruments with short response time, high sensitivity and high resolution are preferred, which facilitate locating leakage sources.
For industrial‑hygiene testing and health investigation, instruments with data logging, statistical calculation and computer‑connecting functions bring great convenience.
