Types of toxic gas monitors and gas detectors

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There are various technologies that are used to make toxic gas detectors. Also these instruments are available in various forms, like fixed, portable or pocket types. There are different sensors used to detect different types of toxic gases. Some types of sensors can detect a variety of different gases, others can detect only one type of gas.

Fixed toxic gas detectors

These are very commonly found in large manufacturing plants and similar facilities. Each fixed gas detector is mounted at a place where it is very likely to sense the toxic gas, in case of a leak. The detector may or may not have a local display that shows the concentration of the gas. Each detector is connected via cables to a central system, that is monitored by plant personnel. In case of a leak this panel will generate alarms to warn the operators about the dangers and may also carry out any interlock actions (like triggering closure of valves or initiating a shutdown).

Portable toxic gas detectors

Portable gas monitors are used by workers to sweep a work area, to know if there is any toxic gas lurking around the area. These detectors are also called as handheld gas detectors. These detectors are normally battery powered and have a display with a buzzer and lights, to warn the operator, in case a dangerous level of toxic gas is detected. They may have their own inbuilt sampling pumps, to draw air into the sensor. Some variants also store data, to calculate time weighted average values, peak values and other important data for regulatory compliance.

Pocket toxic gas detectors

A typical personal toxic gas monitor is shown in the picture above. These are similar to the portable types, except that they are very small and meant to be carried by individual workers, by use of a belt clip, or inside a pocket. These instruments are normally throw away types and have a lifetime of about two years (lesser if they are constantly exposed to the toxic gas being detected). They also have a display, buzzer and light, but due to the small size there are no sampling pumps or data logging chips inside.

Typically, a worker carries it with him, when he enters an area that could contain such a gas (for example, he will carry a pocket H2S detector when he enters a process vessel for cleaning, if it had processed H2S previously). The vessel might still have some amount of Hydrogen Sulfide inside (or the gas may enter later through some piping that still remains connected). The worker's pocket gas detector now acts like his guardian angel, or personal bodyguard and warns him immediately, should the gas be detected. This allows him to escape or be rescued by his co-workers.

Where to get more information?

You can download a very useful e-learning course on toxic gas detectors here. This training course on gas monitors covers all types of gas detectors and gas monitors, including toxic gas monitors. It will take about three to four hours to complete and if you take an online test (optional, free of cost), you can also get a certificate of achievement, that would be a useful testimonial.