Gas Purging & Gas Tightness Testing

Flair Facilities offer a range of gas purging services and gas tightness testing procedures

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Purging & Tightness Testing For All Properties

Gas purging is an essential service that must be carried out for safety reasons under a number of different scenarios. Purging commercial pipework must be carried out by qualified, professional gas engineers qualified up to TPCP1A (Testing & Purging not exceeding 1m³) and TPCP1 (Testing & Purging exceeding 1m³), and will also involve a full risk assessment prior to purging.

Our highly trained, London based, Gas Safe registered engineers are fully qualified to undertake all gas purging and gas tightness testing procedures. We offer a full range of gas purging services and gas tightness testing procedures with no job too big or small; from purging into service, pre-demolition purging, all the way through to pipework installation and is available at highly competitive prices to commercial property owners and businesses.

Purge into service (commissioning)

Purging into service is carried out when a new gas system has been installed or if there has been any major pipework or system components replaced. Inert gas (typically carbon dioxide) is introduced into the system to flush out any concentrations of oxygen that might have been introduced into the pipework so that when the gas is introduced it eliminates the possibility of accidental ignition. Purging into service is also done to remove any dirt or debris that may have a negative effect on the system once started.

Purge out of service (de-commissioning)

Purging out of service is carried out when the system/plant room as whole or in part is no longer required and is to be removed. This is to eliminate all remaining gas in the pipework and other components, so that during the removal works or demolition, there will be no unexpected additional explosive events or release of dangerous gases occurring.

Gas Tightness Test

A gas tightness test is carried out before purging to test the integrity of the pipework, but is also often carried out during an annual gas safety inspection

A gas tightness test may not be an annual legal requirement for commercial boilers, but is conducted as part of an annual gas safety inspection to ensure that your gas installation is safe to use. It can also be undertaken if you believe you may have a gas leak somewhere in the system.

The Gas Safety (Installation and Use) Regulations 1998, it is made clear that business owners are responsible for ensuring that any gas installation located on their premises is safe to use. This is why a tightness test will normally be included as part of an annual gas safety inspection, to ensure there is no gas leaks and the pipework is maintained and installed correctly. To find out more about what certification boilers need check out this article!

equipment used for purging gas from a central heating system

Our Gas Purging Services:

  • Gas purging & gas tightness test
  • Direct & Indirect Purging
  • Gas purge into service (Commissioning)
  • Gas purge out of service (De-Commissioning)
  • Pre-demolition gas purging
  • Install new or update your existing gas pipework
  • Upgrade the existing pipe work so you can have a larger heating system or a completely different system altogether

Gas Purging FAQs

Your questions about gas purging answered

Gas purging is the introduction of an inert (non-combustible) gas into a closed system to prevent the chance of an explosion from air and a combustible gas mixing. Purging into service is conducted to push out any oxygen remaining in a system and replace it with an inert gas so that when a combustible gas enters the system it doesn’t mix with the oxygen and form an explosive concoction. Purging out of service is the opposite, an inert gas is put into the system to push out combustible gas to prevent it from mixing with oxygen when the system is shut down.

Gas purging occurs for a variety of reasons, mainly to remove combustible gas or oxygen from the system to prevent an explosive reaction. It is also done to remove any impurities which may damage the system or affect its function, especially when a sensitive gas mixture is needed for operation.

Gas should be purged once a system has been installed but before the combustible gas is introduced to the system. It should also be purged if any work is being done on the system’s gas pipes e.g. cutting into a pipe, removing a pipe or disengaging the system once use has ceased.


How long a gas purge takes depends on the size of the system, the larger the system the longer it will take. To find out about a specific system contact an engineer who should come to service the property and advise on an appropriate time span for the purge.

Purging is normally for commercial properties only unless the domestic property is especially large. To purge up to 1 cubic metre of gas you need a TPCP1a qualification and to purge over 1 cubic metre you need a TPCP1 qualification.

Yes, there are different levels for purging and they refer to the amount of gas in your system. The typical gas purging qualification is TPCP1A which allows you to purge gas pipework not exceeding 1m³ in volume. Our team are qualified up to TPCP1 so we are qualified to purge pipework exceeding 1m³ also. It is always good practice to check what your engineer is qualified for so your works can be carried out safely and correctly. To find out more details on the different types of qualifications for gas engineers click here and also check out why it’s important to check your engineer is apart of the Gas Safe Register.

Service Areas

We service Central London and all surrounding boroughs within the M25 including:

Battersea Park
Central London

Richmond upon Thames
Sloane Square
St John’s Wood
Waltham Forest
and more …

*Optional image or document upload. Details of current boiler such as photos of boiler/plant room and boiler plate with make and model no.