Determine the type of gas to be detected and its concentration range:
The types of gases encountered by each production department are different. When choosing a gas detector, all possible scenarios should be considered. If methane and other less toxic hydrocarbons are predominant, choosing an LEL detector is undoubtedly appropriate. This is not only because the principle of LEL detector is simple and widely used, but also because it has the characteristics of easy maintenance and calibration. If there are toxic gases such as carbon monoxide and hydrogen sulfide, it is necessary to prioritize the use of a specific gas detector to ensure the safety of workers. If there are more organic toxic and harmful gases, considering their low concentration that may cause poisoning to personnel, such as aromatic hydrocarbons, halogenated hydrocarbons, ammonia (amines), ethers, alcohols, lipids, etc., the photoionization detector introduced in the previous chapter should be chosen instead of using LEL detectors, as this may result in casualties.
Portable gas detector: Due to its convenient operation and compact size, it can be carried to different production sites. The electrochemical detector is powered by an alkaline battery and can be used continuously for 1000 hours; The new LEL detectors, PID and composite instruments use rechargeable batteries (some have already adopted memory free nickel hydrogen or lithium-ion batteries), which allow them to work continuously for nearly 12 hours. Therefore, as such instruments are increasingly being used in various factories and health departments.
If this type of instrument is used as an alarm in an open environment, such as an open workshop, a portable diffusion gas detector can be used because it can continuously, real-time, and accurately display the concentration of toxic and harmful gases on site. Some of these new instruments are also equipped with vibration alarm attachments - to avoid audible alarms in noisy environments, and computer chips are installed to record peak values, STEL (15 minute short-term exposure level), and TWA (8-hour statistical weighted average) - providing specific guidance for worker health and.
If entering a confined space, such as reaction tanks, storage tanks or containers, sewers or other underground pipelines, underground facilities, agricultural enclosed grain warehouses, railway tankers, shipping cargo holds, tunnels, etc., personnel must undergo testing before entering, and testing must be conducted outside the confined space. At this point, it is necessary to choose a multi gas detector with a built-in sampling pump. Choosing a composite gas detector may achieve twice the result with half the effort for gases.
