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Gas Detector Help Guide

Gas detectors are installed to provide audible and visual warning of dangerous levels of combustible and poisonous gases. The type of gas detected and the cause for its presence is dependent on the application. Industrial environments may use a range of gases for commercial production purposes, meaning that multi-gas detectors would be an essential part of their health and safety requirements. A residential property would typically require the detection of just one or two different types of gas according to the domestic appliances and central heating system used.

The diverse range of hazardous gases has led to the development of fixed and portable gas detection units from leading manufacturers including Dräger, Honeywell, Crowcon, Kidde and Ei Electronics.

Carbon Monoxide (CO) Detection

Carbon monoxide (CO) is a colourless and odourless poisonous gas that, when a person is exposed to high levels or over a long period of time, can cause severe illness or even death. Caused by the incomplete combustion of fossil fuels such as gas, oil, coal and wood, CO is a danger for both domestic and commercial premises.

Domestic CO detectors are available as battery or mains powered devices, generally positioned at a fixed point on the wall or left free-standing. These detectors feature variable concentration trigger points (typically beginning at 30 to 50ppm) and constantly monitor the surrounding air. If CO is detected and a trigger level has been maintained for the appropriate period of time the detector is activated and a warning alarm sounds – check the manual for your specific CO alarm for its exact concentration thresholds and response times. The current British Standard for domestic CO detectors is BS EN 50291: 2018. When choosing a detector for your home, ensure it is Kitemarked to the latest standards.

For commercial applications, there are a range of fixed and portable single or multi-gas detectors. The detection requirements are dependent on the individual user and the parameters of their working role. Supplied as portable devices, industrial CO detectors act as a personal monitor and can be easily fastened to clothing for continuous detection whilst on the move. Portable CO detectors such as those from Dräger or Honeywell have been designed with an impact-resistant housing and many have been tested to an IP rating to cope with outside elements.

LPG (Butane) and Natural (Methane) Gas Detection

LPG and natural gas are used in thousands of households and work premises for central heating and cooking appliances. Natural gas is obtained from the mains supply whereas LPG is purchased in cylinders. Although safe for everyday use, LPG and natural gas are flammable, making them extremely dangerous if high levels or a leak are undetected.

LPG and natural gas detectors provide a vital warning when the percentage of gas in the air lays between the lower explosive limit (LEL) and upper explosive limit (UEL). These limits are dependent on the environment.

Domestic LPG and natural gas detectors are fixed point devices generally installed to monitor the level of gas produced from a cooker, boiler or gas fire. This type of detector is ideal for all households that use mains or bottled gas; however, they are more often installed to help promote independent living for the elderly or those with special needs. High levels of LPG and natural gas in the home can be caused from appliance faults that produce leaks, and also from a cooker hob that may have been left on without a flame.

Portable LPG and natural gas detectors are mainly used by professionals when a gas leak is suspected and the source of the leak needs to be found quickly. These handheld devices provide both visual and audible warning should dangerous levels of gas be detected. Portable devices only monitor for LPG and natural gas when in use by a professional and should not be installed for domestic applications that require continuous detection.

Industrial Combustible and Toxic Gas Detection

Available as a single or multi-gas monitor, industrial gas detectors are designed to provide warning and reliable measurements of atmospheric hazards. Suitable for a range of industrial applications, combustible and toxic gas detectors can prove vital for personal safety, in particular for those working in volatile environments.

To cope with the vast range of hazardous gases, leading manufacturers such as Dräger and Honeywell have developed a range of detectors with single or multi-gas sensors including oxygen, hydrogen sulphide, hydrogen chloride and hydrazine. Portable detectors are ideal for professionals working on a potentially hazardous site, in confined spaces, or those checking for gas leaks. Their advanced technology ensures early detection, and enables a site to be evacuated and/or the cause to be rectified before explosion or a severe toxic danger level is reached.

Portable gas detectors are available as rechargeable units with a replaceable sensor, or as single use devices with a limited lifespan. The detectors with a replaceable sensor require periodic calibration and testing to ensure readings remain accurate. To cope with hostile environments, industrial gas detectors have a robust construction and generally carry a high IP rating.

Carbon Dioxide (CO2) Detection

Carbon dioxide (CO2) is a natural gas that is produced through respiration, combustion and decay of materials, and during the fermentation process for beer and wine making. Part of the air we breathe, CO2 is a non-toxic gas; however, when produced in high concentrations, CO2 becomes hazardous to health with the risk of intoxication or poisoning.

CO2 detectors are used by a number of employees where there is a risk of high concentration levels, including breweries, laboratories and cellars. Available as fixed or portable devices, CO2 detectors, provide accurate readings and effective warning of danger, and are robustly designed to cope with industrial applications.


(doc:689 V1.0). Our articles are reviewed regularly. However, any changes made to standards or legislation following the review date will not have been considered. Please note that we provide abridged, easy-to-understand guidance. To make detailed decisions about your fire safety provisions, you might require further advice or need to consult the full standards and legislation.


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