Young woman holding a 4-gas detector in her hand

The best 4 gas detectors | multigas 2023 | Complete buying guide

Toxic gas asphyxiation is an infrequent cause of accidental death, but the likelihood of it is not non-existent. This type of accident can occur at any time, both in the workplace and at home. The risk is linked to the diffusion of toxic gases in a closed environment. The risk is further increased by the physical properties of the gases. Colourless and odourless, they are difficult, if not impossible, to detect by smell alone.

Unfortunately, leaks are not inevitable. To prevent accidents, sometimes fatal, the installation of detection devices in your premises or in your home is highly recommended. Gas detectors are part of these prevention devices and are very practical to use.

Our selection for the year 2023

Comparison updated on 22/03/2023

Thinking of buying a 4-gas detector online and don't know which one to choose? Don't worry, we've got you covered.
In this article, we help you make an informed decision with a clear and concise buying guide. It will help you identify the product that best suits your needs, based on the opinions of many consumers.

To be noted 4-gas detectors: few 4-gas detectors are available to the general public. In order to facilitate your choice, we have limited our selection to one product. Although it is not CE and ISO approved, it has nevertheless passed the control tests of an EPI company according to the opinion of a consumer.

Widely used in industry, agriculture or underground workers, the 4-gas detector is also a practical tool for domestic use. The Hitbox 4-gas detector is a useful device if you wish to detect an abnormal concentration of oxygen (O2), carbon monoxide (CO), hydrogen sulphide (H2S) or explosive gases (EX) in the air around you.

Featuring an LCD display and manufactured from high strength ABS with a non-slip rubber grip, this monitor provides acoustic, visual and vibratory alerts when critical gas thresholds are reached. Compact and lightweight, this product also benefits from a quality customer service department that listens to your problems. In case of dissatisfaction or problem, you just have to contact the brand by email. They will then offer you a solution adapted to your needs (return or replacement of the detector).

What is a 4-gas detector?

The 4-gas detector, also known as a multi-gas detector, is a safety device that plays a more or less similar role to the smoke detector

As a reminder, a smoke detector is used to signal the start of a fire in order to prevent the risk of fire and to be able to evacuate as quickly as possible. The principle of the 4 gas detector is quite similar, as it uses specific sensors to identify the unusual presence of toxic gases or explosive gases in its immediate environment. In practical terms, used as a preventive measure, the device identifies and evaluates the quantity of dangerous gases present in its immediate environment. In the event of a leak, it triggers an acoustic signal to indicate to users the presence of an increased risk of inhalation or explosion.

The 4-gas detector is therefore used to detect gas leaks that escape the human sense of smell.

ACS Prevention | Use of 4-gas detector

What are the main gases detected?

The 4-gas detector allows, as its name indicates, to detect 4 types of gas in its default configuration. To achieve this, this prevention device is equipped with a variable number of identification cells, each dedicated to a specific type of gas.

Unlike a single gas detector, the 4-gas detector can measure the following gases on its own:

  • Oxygen (O2); 
  • Carbon monoxide (CO); 
  • hydrogen sulphide (H2S);
  • explosive gases (hydrocarbons, natural gases, liquefied petroleum gas [LPG], solvents). 

Explosive gases (calibrated to the LEL of methane)

Explosive gas leaks are one of the main accident risks that the use of a 4-gas detector reduces by its prevention work. These gases, which include LPG (butane, methane, propane) and natural gases, are extremely combustible. Once released into the air, they can ignite at the slightest spark, or even at the slightest rise in temperature, as a result of a chemical reaction.

The 4-gas detector reduces the risk of explosion and fire from leaking explosive gases. The device is programmed to recognise and measure the concentration of identified gases in the space. If the concentration exceeds a certain flammability threshold, the detector automatically triggers an alarm.

The measurement taken by the multi-gas safety detector is calibrated to the lower explosive limit (LEL) of a natural gas (the reference gas may differ from one detector to another). Above this threshold, the dangers inherent in the combustion of the gas are proven, which triggers the alarm.

Set of different industrial liquefied gas containers

Oxygen (O2)

The 4-gas detector has a sensor dedicated to assessing the concentration of oxygen present in the atmosphere. While this device focuses on the abnormal excess of a toxic or explosive gas, its oxygen sensor allows it to point out the deficiency or insufficiency of O2 in the ambient air. 

In this context, the use of the multi-gas detector makes it possible to reduce the risks of asphyxia, hypoxia or anoxia caused by the absence of oxygen in the atmosphere. In addition, the oxygen cell of the device also allows the detection of any increase in the ambient oxygen concentration. 

Carbon monoxide (CO)

Vintage carbon monoxide hazard sign

Carbon monoxide, chemical symbol CO, is a toxic gas resulting from the incomplete combustion of organic material. It is commonly found in the chemical and metallurgical industries. In everyday life, this gas is mainly found in the exhaust pipes of our internal combustion cars. This gas, extremely dangerous and harmful to humans, is completely colourless and odourless.

Highly toxic, the inhalation of carbon monoxide above a certain threshold can cause intoxication and even loss of consciousness in the victim. In short, monoxide is a dangerous gas that can easily diffuse and go undetected in the atmosphere of a closed space. In order to protect the health of users, one of the default cells of the 4-gas detector is dedicated to CO measurement and thus makes it possible to avoid inhalation accidents and poisoning by this deadly gas. 

Hydrogen sulphide (H2S)

The fourth and final default cell of the 4-gas detector detects and measures the concentration of hydrogen sulphide (H2S) in a room. For your information, hydrogen sulphide is a natural gas that also results from the decomposition of organic matter. 

Unlike the other risky gases identified by the multi-gas detector, this one has a particular, nauseating smell. Similar to the smell of a rotten egg, the use of the device should not be ruled out, as it limits the risks of intoxication that accompany the accidental inhalation of this gas. 

When to use a 4-gas detector?

In general, the portable multi-gas detector is used in confined areas where there is a high risk of gas leakage. If it is strongly recommended to use it in a hazardous environment, its use is sometimes a legal obligation under the Labour Code. This is particularly the case for :

  • work in confined spaces; 
  • deep interventions (drilling works); 
  • poorly ventilated environments or enclosed spaces; 
  • all work relating to gas piping, hydrocarbon transport and the like. 

The use of a 4-gas detector is a safety measure that guarantees the health and integrity of those working in hazardous areas. This small portable device alone can prevent all kinds of accidents caused by a dangerous gas leak, to name but a few:

  • intoxication and asphyxiation caused by inhalation of toxic gases or oxygen deficiency; 
  • Fire caused by explosive gases.

How to use a 4-gas detector?

The 4-gas detector is a delicate device. Its correct operation is a matter of safety and health of the workers. It is customary to follow the manufacturers' technical recommendations for set up and handle the device correctly.

Generally, the use of this gas detector involves : 

  • a calibration ;
  • bump tests; 
  • regular maintenance.
Close-up of a multi-gas detector held in the hand by a woman

Why do you need a bump test? 

The gas leak detection device must be recalibrated before each use: this is the bump test. This step is used to check the functionality of the device and to ensure its ability to detect gases effectively before venturing into the area to be monitored. 

The bump test requires the use of a calibration kit and is used to correct any anomalies in the operation of the instrument, such as a deviation in the measurement of the gas concentration threshold by the detector cells. 

How do I maintain the appliance after use? 

The 4-gas detector must be cleaned regularly to keep it functional in the long term. Neglect or lack of maintenance can affect its measurements. In practice, regular maintenance of the gas detector is limited to cleaning the device with a damp cloth. However, do not use a corrosive household cleaner as this may damage the detector's detection cells. 

Is the gas detector periodically checked? 

A regular check is necessary to ensure that the device is still operational. At the time of purchase, you will receive instructions from the manufacturer on how often these checks should be carried out. As a rule, they should be carried out every six months. Carrying out periodic checks will ensure that the equipment and the measurements taken are correct.