Advice for Flues in Voids


The current position

For some time there have been concerns around the installation of gas-fired boilers in private dwellings, in particular flats or apartments constructed over the past 10 years that are located away from external walls. In such cases the boiler flue, which exhausts poisonous gases from the combustion process, is more likely to be conduited through ceiling or wall voids. An essential aspect of gas boiler safety is the ability of the installer and an inspecting service engineer to check the integrity of this exhaust flue. This can only be done if a flue located in a void or partition can be examined via a correctly positioned aperture or inspection porthole providing access. The previously recognised practice has been for a service engineer who is unable to inspect a flue located in a void, to assess the installation as 'not to current standards' in accordance with the Gas Industry Unsafe Situations Procedure (GIUSP). This assessment would not necessarily mean that the installation would be closed down by the service engineer because the flue could not be inspected, unless other risks were present which made the boiler unsafe.

In October 2008 the HSE issued a Safety Alert regarding flues in voids as a result of a fatality earlier that year, with the purpose of raising awareness to the potential dangers from this type of flue. This Safety Alert referred to the relevant gas industry technical guidance which gas engineers were expected to follow at that time. A revised version of this guidance has now been published by the industry regulatory organisation, Gas Safe Register (previously known as CORGI). This changes the approach that Gas Safe registered engineers will take when they encounter a flue located through an internal wall of a dwelling.

As a result of this change to the gas industry technical guidance, action is now required to be taken by householders or the owners of properties that have a boiler flue in a void.

The HSE have published a Safety Notice (December 2010) to update the information in the 2008 Safety Alert and the Executive is participating in the Flues in Voids cross industry team. Membership of this body also includes representatives of Gas Safe Register, house builders, home warranty providers, registered gas engineers and appliance manufacturers. Its purpose is to provide clear communication to the industry and consumers around the issue of flues being located in voids which do not allow inspection.

The health and safety risks

Boiler flue gas is a chemical hazard which becomes a significant risk to people when inhaled in a confined space or as a concentrated substance. Component gases of the combustion process, in particular carbon monoxide are toxic to humans preventing blood from bringing oxygen to cells, organs and tissue and acts quickly on the body, without warning. It is therefore a critical risk in sleeping accommodation being capable of killing people whilst they sleep.

Management of the hazard is to vent the exhaust gas to the open atmosphere where it will dissipate without adversely affecting human health. The vent is through a flue and usually directly out of an exterior wall of the premises. This flue is capable of being readily examined as part of a regular gas boiler safety regime. Successful management of this hazard is made more difficult when the boiler is located on an internal wall, where the flue is conduited through wall or ceiling voids to vent to the atmosphere. Under such circumstances the flue joints must be correctly assembled and appropriately sealed; the flue must be continuous throughout its entire length and adequate support exists to sustain the weight of the apparatus. These elements of the construction must be capable of inspection by a competent engineer to ensure the integrity of the installation and ensure that any deterioration or failure of the installation does not compromise safety.

Legal standards

The Health and Safety at Work Act is the general legislation which ensures compliance with gas safety under these circumstances and the Gas Safety (Installation & Use) Regulations 1998 specify flue and associated apparatus requirements.

The requirements for property management companies

The effect of this HSE Health & Safety Notice (OPSTD 10-2010) is to inform duty holders of their responsibilities and actions that should be considered. As a result, those responsible for the communal areas of multi-occupancy properties should assess the presence and extent of any concealed flues carrying boiler emissions within the communal areas. This is particularly important for any areas where spaces are confined or not adequately ventilated such as utility service cupboards. There is also the issue of the integrity and safety of any communal exhaust flue to consider.

If the assessment indicates the presence of a concealed flue in a communal area, the management company must arrange for inspection hatches to be installed by the end of December 2012. Their purpose is to ensure that any flue carried in a void is capable of physical inspection, as the industry assessment of 'not to current standard' is no longer acceptable.

Any gas engineer working on affected systems after 1st January 2013 will advise the occupier that the system is 'at risk' in accordance with the GIUSP. This could result in the system being closed down and remediation work required to be undertaken before the boiler is reinstated.

A period of grace has been established in the interim period up to January 2013 in premises where no flue inspection hatches are fitted. This will entail the registered engineer assessing the safety condition of the boiler and of the flue route as far as practicable. A carbon monoxide warning alarm must also be installed and checked as operating correctly in the affected premises. It is accepted that occupiers and responsible persons will ensure that inspection hatches are installed before January 2013 for this period of grace to operate successfully.

Recommended actions to be taken by Merlin Estates

  • Conduct a health and safety risk assessment of all premises where flues are carried in voids to establish their effect on the communal areas
  • Install carbon monoxide warning alarms in communal areas where flues are hidden
  • Arrange for a programme of works for all the premises to install inspection hatches according to the Gas Safe specifications
  • Apply contract management rules to the contractors appointed to undertake these works
  • The flues should then be inspected by a Gas Safe registered engineer and the appropriate documentation retained
  • An annual inspection regime for the flue should be followed as specified in the Gas Safety (Installation & Use) Regulations 1998
  • Inform all owners of dwellings where the properties have communal areas of their new responsibilities regarding flues in voids (document actions taken)
  • Assess the risks from dwellings where properties remain vacant or unoccupied for extended periods (document actions taken)
  • In properties with communal areas that are less than 2 years old contact the original builder for assistance with the retro fitting of inspection hatches and repair of any flue defects
  • Extend this advice to property owners in these premises
  • For properties between 2 & 10 years old contact the home warranty provider if a flue defect is suspected or discovered
  • Extend this advice to property owners in these premises
  • For properties 10 years or older contact the original builder for guidance on the fitting of inspection hatches
  • Extend this advice to property owners in these premises
  • Recommend that where properties are sold or transferred on developments that have flues in voids the required inspection hatches are fitted prior to sale or transfer

This report was generated for us by Pulse London Roads

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