How to choose a toxic and harmful gas detector in tunnel construction?
1. Analysis of toxic and harmful gases in tunnel construction
Toxic and harmful gases in tunnels have always been the main source of danger in construction, and major safety accidents can easily occur if construction is improper. The harmful gases in the tunnel mainly include methane, carbon monoxide, carbon dioxide, hydrogen sulfide, nitrogen, heavy hydrocarbons and trace amounts of rare gases.
The toxic gases in the tunnel are divided into three categories: irritating gases, asphyxiating gases and acute poisoning organic gases (VOCs) according to their different mechanisms of action on the human body. Irritant gases include chlorine, phosgene, diphosgene, sulfur dioxide, nitrogen oxides, formaldehyde, ammonia, ozone and other gases. The characteristics of irritant gases on the body are that they have a strong stimulating effect on the skin and mucous membranes, and some of them have a strong corrosive effect at the same time. Asphyxiating gases include carbon monoxide, hydrogen sulfide, hydrogen cyanide, carbon dioxide and other gases. Hypoxia of tissue cells caused by these compounds entering the body. That is to say, it is necessary and necessary to test the toxicity of organic compounds.
Second, the choice of toxic and harmful gas detector
At present, when we choose various gas detectors, there are still many problems, which are embodied in:
A) The detection of combustible gas is more important than the detection of gas with du.
B) The detection of gas that may cause acute intermediate duo is more important than the detection of gas that may cause chronic poisoning.
For various production occasions and testing requirements, choosing a suitable gas detector is a must for every person engaged in safety and production work.
1. Determine the type and concentration range of the gas to be detected
If methane and other less toxic alkanes are in the majority, choosing a combustible gas detector (LEL) is undoubtedly the best choice. This is not only because the principle of the combustible gas detector (LEL) is simple and widely used, it also has the characteristics of convenient maintenance and calibration. If there are toxic gases such as carbon monoxide (CO), hydrogen sulfide (H2S), etc., a specific gas detector must be selected first to ensure the safety of workers. If there are more organic toxic and harmful gases, taking into account the low concentrations that may cause human poisoning, such as aromatic hydrocarbons, halogenated hydrocarbons, ammonia (amines), ethers, alcohols, esters, etc., the photoionization detector should be selected. (PID), and never use a combustible gas detector (LEL), as this may result in injury or death. If the gas types cover the above types of gases, choosing a composite gas detector may achieve twice the result with half the effort.
2. Determine the occasion of use
Different types of gas detectors are selected for different use environments.
A. Fixed gas detector
This is a detector that is used more in industrial installations and production processes. It can be installed at specific detection points to detect specific gas leaks.
B. Portable gas detector
The portable gas detector adopts the pumping method to detect the gas, and the sensitive element adopts the excellent gas sensor, which has excellent sensitivity and excellent repeatability; the instrument adopts the embedded microcomputer control, which is easy to operate, has complete functions, high reliability, and has a variety of adaptive capabilities. ; Use the dot matrix LCD display, intuitive and clear; the small and beautiful portable design not only makes you love it, but also facilitates mobile use. The shell of the portable gas detector is made of high-strength engineering plastic and composite anti-skid rubber, which has high strength, good hand feeling, and is waterproof, dustproof and explosion-proof.
