Gas Detection: Frequently Asked Questions

Take a look through our Gas Detection Frequently Asked Questions below, where you can find out all of the information needed for your workers to operate safely in hazardous environments.

What are gas detectors?

Gas detectors are used to measure the concentration of selected gases within an atmosphere, providing readings that can save lives. It is often necessary to monitor the levels of a specific gas in an area to ensure the safety of people within that space, whether that be a domestic or industrial environment.

Gas detectors are available in three main variants – portable, fixed and semi-fixed. Portable gas detectors are usually worn on or carried by a worker in an industrial area. These are often battery-operated and used for toxic or combustible gas detection within a confined space. Fixed gas detectors are generally used within large-scale facilities that require continuous monitoring of certain gases. They are permanently installed at a potentially hazardous location, using sensor heads in various areas to provide readings that feed back to a control panel which is usually located in a safe area.

  1. What is the use of gas detectors?

The main use of a gas detector is to monitor the atmosphere for levels of certain gases in order to prevent injuries or fatalities. One of the most critical uses for a gas monitor is when working within a confined space. This is where portable gas detectors are typically used to ensure the safety of a worker, as ventilation is often limited and exits can often be difficult to access quickly in case of an emergency. By using a compact and portable gas detector, a worker can be sure that their immediate vicinity is safe from selected gases and will have enough time to escape the area should any harmful gases be present.

Gas detectors are also commonly used in domestic and commercial buildings to protect from commonly-found gases such as CO2. Even minimal exposure to Carbon Monoxide can be fatal to both humans and animals, which leads to a requirement for homes and commercial properties to be fitted with CO2 detectors.

  1. What are the dangers of toxic gases?

Exposure to a toxic gas can cause serious injuries and even fatalities, which is why the use of gas monitors in potentially hazardous environments is vital. However, there are different symptoms for overexposure to each gas.

Many gases such as Ammonia (NH3), Chlorine (Cl2) and Sulfur Dioxide (SO2) will cause severe burning in the eyes, nose, throat and windpipe within moments of exposure, while less soluble gases can have a delayed effect that can sometimes take hours to become apparent. Some gases such as Methane and Carbon Dioxide (CO2) will displace the Oxygen content within the body, which will cause issues such as breathing difficulties and can lead to death.

The use of a suitable gas monitor will ensure that any workers within a hazardous are can vacate the space before any symptoms from gas exposure appear.

  1. How do gas sensors work?

Gas detectors are generally categorised by the type of gas they monitor – combustible gas or toxic gas. Combustible gases are mainly detected using catalytic and infrared sensors, while toxic gases use electrochemical and metal oxide semiconductor technology.

Catalytic sensors are the most commonly used for gas detection due to their efficiency and low cost of manufacture. They use a wire coil treated with platinum that will release heat when it comes into contact with a combustible gas. When a certain temperature is reached, the sensors will set off an alarm. Infrared sensors use a series of transmitters and receivers to emit and detect IR light. If a gas is present in the optical path, it will interfere with the light and an alarm will sound.

Electrochemical sensors are extremely sensitive and use electrodes to constantly monitor the parts per million of a gas in the air. When a dangerous level is reached, electric signals send a warning message to a digital display.  Metal Oxide Semiconductors use a gas-sensitive film made from tin or tungsten oxides which will react when a toxic gas is present, triggering an alarm.

  1. How do I bump-test my gas detector?

Regular bump testing should be carried out on your device to ensure that it is working properly, ensuring that it can perform safely in a hazardous environment. A bump test checks that your sensors are responding to the applicable gas, however, it does not check the accuracy of the instrument in the way that a calibration does. See our Calibration vs Bump Test article for more information.

The most efficient way to bump test is with a docking station, however manual bump tests are equally as easy to carry out. To manually bump test your device, you simply need to put your device into bump test mode and then apply the relevant gas using a gas cylinder, regulator and tubing. The instrument will display the results, allowing you to easily see whether it passed or failed the bump test.

Take a look through our range of gas detectors and gas analysers to find the right device for your requirements, as well as our range of gas detector sensors.

If you need more information on Gas Detection or you have any enquiries, please contact us on 02920 759 683 or email our team at

Posted by Laura Dronfield

Back to news