Concrete Flues (Hansard, 24 February 1999)

§ Mr. Raynsford

I have been made aware of concerns about the safety of certain flue liners, which are intended for use in chimneys serving appliances burning solid fuel. They are made of concrete, although those solely comprising kiln-burnt aggregate, pumice and cement (other than products used to facilitate manufacture) are not known to give rise to any problems.

Despite these concerns, the two principal housing warranty providers have reported no change in the frequency of claims relating to defective chimneys and my Department is unaware of any marked change in the frequency of soot fires requiring chimney reconstruction.

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However, a number of chemical analyses and performance tests of thermal insulation, thermal shock resistance and gas tightness of concrete flue components have been carried out independently by flue component manufacturers and by building control enforcement bodies over the last few months attempting to prove or disprove the adequacy of certain manufacturers' components. These tests have so far proved inconclusive. Nevertheless they have shown that building control enforcement bodies and warranty providers may have grounds for concern, and that further investigation would be prudent.

My Department has already asked the expert technical committee within the British Standards Institution (BSI) to consider how the issues being raised impact on existing British Standards and prospective harmonised European Standards (ENs). These ENs will eventually become the performance criteria for compliance with the Construction Products Regulations which ensure that products are sufficiently safe to be placed on the market. The BSI Committee have also been asked for their opinion on the standards of performance presently referred to in the relevant Approved Document to the Building Regulations and whether these can be improved. I have asked the Committee to consider these matters swiftly and impartially and I look forward to their response with interest.

My Department has also listened to the collective views of manufacturers, importers, building control bodies and housing warranty providers. There appears to be insufficient evidence at present to warrant advising householders to take any additional care in the ways that they use their fireplaces and that for the time being there is only the possibility that some chimneys lined with concrete may need attention to ensure satisfactory service life. However these uncertainties cannot be allowed to continue.

I have therefore decided that the issues being raised should be explored by way of an expert risk assessment, and my Department is now proceeding to engage a suitable contractor. The aims of this study will be to establish how many dwellings already built or under construction have chimneys with potentially risky concrete components, to establish the nature of the risks to householders, to collect together and appraise the results of the tests on flue components carried out by the various parties, to seek national expert technical opinion on the ways that the risks to householders can be resolved into quantifiable flue component performance standards, to evaluate to what extent, if any, the possible problems raised are real, and to provide advice on possible remedial measures.

At the same time I have asked my Department in conjunction with the Building Regulations Advisory Committee to consider with builders, building control professionals, warranty providers, the Building Research Establishment and others what amendments it might be necessary to make to Part J of the Building Regulations and the supporting Approved Document to address these issues more directly for the future.

I shall make a further announcement as soon as I can.