Appendix A: Report on risk assessment of chimney ... - Planning Portal

2 Summary2.1 The available data was not adequate to undertake a full risk assessment. We havetried to pull together all the various comments made by industry experts and estimatesgiven to make up for lack of hard data. As a result only very broad conclusions shouldbe regarded as credible.2.2 Taking account of: the relative incident rates for lined and unlined flues the comments regarding age (section 4.6) the increasing number of closed appliancesthe conclusion must be that the number of deaths from CO is likely to increase overtime rather than reduce unless changes are made.2.3 In order to justify specific action on liners with high sand content already in use thetechnical experts would need to assess the risk relative to other concrete liners to besignificant. Assuming that the majority of these particular liners being used withclosed appliances do in fact crack the expected number of deaths is one per annum.This is roughly equivalent to assuming a risk for these liners ten times that of otherlined (non-prefabricated) flues.A2