Here’s how to choose a toxic gas detector for different requirements and scenarios

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For various production environments and testing requirements, selecting the appropriate gas detector is something that every professional working in safety and hygiene must pay attention to. Here, Oguma will provide an introduction to some specific situations for your reference only. 1) Determine the type of gas to be tested and its concentration range. The types of gases encountered in each production department are different. When choosing a gas detector, all possible scenarios must be taken into account. If methane and other alkanes with lower toxicity are predominant, choosing a LEL detector is undoubtedly the most suitable option. This is not only because LEL detectors have a simple principle and are widely used, but they also feature ease of maintenance and calibration. If there are many organic toxic and harmful gases, and considering that the concentrations at which they can cause poisoning in humans are relatively low – such as aromatic hydrocarbons, halogenated hydrocarbons, ammonia (amines), ethers, alcohols, fats, etc. – a photoionization detector should be used; LEL detectors must not be employed in such cases, as this could lead to casualties. If detecting toxic gases such as hydrogen sulfide and carbon monoxide, it is preferable to choose a multi-gas detector, such as the lightweight and portable Biogas Elf, to simultaneously measure the concentrations of methane, hydrogen sulfide, and carbon monoxide in biogas, thereby ensuring the safety of workers. Therefore, if the types of gases to be detected cover the categories mentioned above, choosing a composite gas detector or a gas detector capable of detecting multiple components can achieve twice the result with half the effort. 2) Determine the application scenario: Depending on the industrial environment, different types of gas detectors are required. A) Fixed gas detectors: These are the types of detectors that are commonly used in industrial installations and during production processes. It can be installed at specific detection points to detect particular gas leaks. Fixed detectors are generally of a two-part design: the detection head, which consists of a sensor and a transmitter, is installed at the site where detection takes place, while the secondary instrument, which includes electrical circuits, power supply, and display/alarm functions, is installed in a safe location for easy monitoring. They are more suitable from a process and technical standpoint for continuous, long-term, stable monitoring, but the choice still depends on the type and concentration of gases present in the area. It is also important to install them in locations where leaks of specific gases are most likely to occur; for example, the optimal height for installing sensors should be determined based on the density of the gases. B) Portable gas detectors – Due to their ease of use and compact size, portable instruments can be taken to various locations in the production process. Electrochemical detectors are powered by alkaline batteries and can operate continuously for 1000 hours ； New types of LEL detectors, PID detectors, multi-component gas detectors, and composite instruments use rechargeable batteries (some of which are memory-free nickel-metal hydride or lithium-ion batteries), allowing them to operate continuously for nearly 12 hours on average. As a result, these instruments are being used more and more widely in various factories and health departments. In open areas such as open workshops where such instruments are used for safety monitoring, portable diffusion-type gas detectors or monitoring and alarm devices can be employed. Devices like the Biogas Elf can be used to continuously monitor the concentrations of gases such as methane, hydrogen sulfide, and carbon monoxide in the area, as they are capable of displaying the concentrations of toxic and harmful gases in real time and with high accuracy, while also issuing alarms when these concentrations exceed safe limits. Some of these portable detectors or alarm devices are equipped with vibration alarms to ensure that sound alerts can still be heard in noisy environments. They also contain computer chips for recording peak values, STEL (Short-Term Exposure Limit), and TWA (8-hour Time-Weighted Average). Some of them even come with smartphone app-based smart devices that allow users to set alarm thresholds, providing specific guidance for maintaining their health and safety. If entering confined spaces such as reaction tanks, storage tanks or containers, sewers or other underground pipelines, underground facilities, agricultural silos, railway tank cars, ship holds, tunnels, and other work areas, testing must be carried out before workers enter, and this testing should take place outside of the confined space. At this point, it is necessary to choose a multi-component gas detector with a built-in sampling pump. This is because the gas distribution and types of gases in different areas (upper, middle, lower) within a confined space vary greatly. In a detection site filled with marsh gas, the flammable methane gas has a low density and is mostly found in the upper part of the enclosed space ； Carbon monoxide has a density similar to that of air, and it generally settles in the middle of enclosed spaces ； Heavier gases such as hydrogen sulfide, on the other hand, are found in the lower part of enclosed spaces ； Additionally, oxygen concentration is also one of the types that must be measured. Therefore, a complete gas detector for enclosed spaces should have a built-in pumping function to enable contactless, localized detection ； It has a multi-component gas detection function to detect hazardous gases with different spatial distributions ； Equipped with an oxygen detection function to prevent hypoxia or hyperoxia ； Portable instruments with a compact size that do not interfere with workers’ tasks, such as the Gasboard-3200Plus (smart portable model) equipped with a built-in sampling gas pump. These instruments can be used to measure the concentrations of various gases in biogas, including methane, hydrogen sulfide, carbon dioxide, carbon monoxide, and oxygen. They are lightweight and easy to carry. Only in this way can the absolute safety of workers entering confined spaces be ensured. Furthermore, once inside a confined space, it is necessary to continuously monitor the gas composition there, in order to prevent changes in the concentration of toxic and harmful gases caused by the entry of workers, sudden leaks, or changes in temperature.