Flames shoot out of a gas line which has exploded
Posted in: Gas Detection

Combustible Gases: Detection and Care

Combustible gases are a major threat. They can make a normal work situation dangerous with very little warning.

Dealing with combustible gases is different than toxic gases. Although many combustible gases are also toxic, and so require a mask to work with, not all are.

As the name suggests the main safety issue with combustible gases is the threat of explosion. You can not pick up this threat by using standard toxic gas sensors which only look for the presence of certain gases in the environment.

Many factors can be the cause of combustibility. The amount of gas, the type of gas, the presence of oxygen, and the presence of an ignition source to set off the explosion.

How Combustible gas sensors Work

These gas sensors determine the combustibility of the air by detecting the concentration of Volatile Organic Compounds (VOC's) – the types of gas that are likely to be flammable.

For a gas to combust the amount of gas must fall within a specific range. This range is defined by the Lower and Upper Explosive limits (LEL and UEL).

Below the LEL the gas is too lean to combust. Over the UEL the gas is too rich.

For the most part combustible gas detection focuses on the Lower Explosive Limit.

Usually measured using a Photo-Ionization Detector, the gas detector will show the current combustibility of gases in the area as a percentage of the LEL.

Once the LEL reaches 100% there is an immediate risk for an explosion.

Regulating LEL's

In addition to the explosive risk there are many regulations which regulate the max LEL level. 

For example, in the province of Alberta the LEL must be less than 5 per cent prior to entering a confined space. Other laws may depend on your country and your state/province 

Also remember that these sensors do not account for the toxicity of the gas. Many combustible gases are also extremely toxic. 

When dealing with combustible gases it is a good idea to have sensors searching for other types of gases you expect to find. Additionally you should wear Personal Protective Equipment (PPE). 

Most Four-gas sensors can detect the presence of VOCs as well as toxic gases and oxygen. 

These multi sensors typically clip on to clothing. This allows the workers to have less bulk to bring with them, as well as allowing them a relative amount of comfort. 

For any questions about Gas Detectors contact Concept Controls at 1(800) 793-9548 to speak to one of our expert sales representatives. They will help you find the right tools.

18 mars 2021
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