Single Vs Multi Gas Detectors in Confined Space

For many industries, reliable gas detection is a critical safety element. The three main risks that gas detectors can help to identify are asphyxiation (oxygen depletion), combustion (flammable gases) and poisoning (toxic gases). Solutions include single or multi gas detectors as wearable or portable. Selecting which of these to use will depend on the application and the potential gas hazards present.

Differences between Single and Multi-Gas Detectors

Single gas detectors are compact and lightweight. They are used to monitor one specific gas where the risk is known, for example if the risk is asphyxiation due to a lack of O2, then a single gas O2 unit would be best suitable. Common examples of these also include carbon monoxide, hydrogen sulphide and sulphur dioxide. Monitors for personal risk should always be worn as close to the breathing area as possible to measure exposure. The advantage of single gases monitors is that they can easily be worn on the lower collar or overall pocket with minimal disturbance to the user, due to their light weight. The monitors being disposable, maintenance free and having a 2-3 battery life is also what makes single gases valuable.

Multi-gas detectors are commonly used for both investigation and personal protection. Investigation includes pre-entry checks and gas testing, while personal protection is for the workers during the process carrying out the task. The monitors simultaneously detect several different gases within one unit. Typically, multi-gas instruments will have larger screens that can show readings for up to six gases but are still personal detectors. Additionally, instruments can be supplied with a fixed or removeable pump to allow measurements from outside of the area of risk. Each model will have a different battery life, detection range, set of alarms and log for readings with different levels of customisation. These are all crucial factors to consider when selecting the device.


How to choose the appropriate instrument

The choice between single and multi-gas detectors must be carefully considered. In many situations there may be several gas hazards present, so expert analysis of the workspace is essential. Many industries that primarily need to monitor a single gas, such as in the oil and gas industry, will also monitor combustible gases, such as oxygen, carbon monoxide and hydrogen sulphide. Testing for combustible gases, oxygen deficiency or enrichment and toxic gases will typically be required in confined spaces, both before entry and during the work.

Shawcity offers a wide range of single and multi-gas instruments are available from world-leading partners including Blackline Safety, Crowcon, Gas Clip Technologies, Honeywell and Ion Science. Providing various different functionality, they can be deployed across a broad scope of industries and applications.

Different sensor technologies, such as MPS, IR or pellistor for flammable gases and traditional electrochemical sensors for oxygen and toxic fumes, can be used in suitable configurations depending on the specific application. Additional information is also key; for example, working in inert environments where there is likely to be zero oxygen, or the presence of certain adhesives or solvents, could potentially impact sensor choice.


The Benefits of Shawcity

An industry leader with more than 45-years’ experience and a ‘go-to’ reputation in the industry for solutions, Shawcity provides a complete gas detection service. With single or multi-gas options in portable and fixed gas detection technology, most portable solutions are available to hire or buy.

All customers receive free consultations, free ongoing technical support and free product training, as well as fleet management support. Our in-house service centre completes delivers manufacturer-authorised servicing, calibration, spares and repairs.

Contact us for more information or to arrange a free consultation, demonstration or site visit to help you understand the best solutions available for your specific application

Telephone: 01367 899553

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