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

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4 Data4.1 All the available data relies to some extent on surveys, analysis of data which isincomplete or assumptions. However, the accuracy of the detail may not affect theoverall conclusions significantly. A draft version of the data and assumptions belowwere circulated to the technical experts involved to ensure that it did not contradicttheir practical experience.4.2 The main sources of data and other information were: press release of the CO and Gas Safety Society dated 10 February 1999 analysis of deaths and ’near misses’ provided by the Solid Fuel Association("SFA") conversations with Clay Pipe Development Association and variousmanufacturers various documents supplied by CRE Group including letters from manufacturersindicating sales figures and material compositions.The following paragraphs set out how we have derived estimates for the variousnumbers required from the above. Particular note should be taken of the sometimesvery broad assumptions made.Deaths (and injuries)4.3 Between 1995 and 1997 the CO Gas Safety Society recorded 73 deaths and 135 nearmisses resulting from CO from solid fuel. 60% of near misses (gas and SF) resultedin hospitalisation: owing to the method of recording numbers are more likely to be understated there is insufficient data to detect any trend over time the recorded number of deaths from closed appliances was 65.4.4 The only breakdown given is by type of housing and type of appliance: 20% of deaths are recorded as council housing The SFA suggested 25% of solid fuel users are council 16% of housing stock (or 21% including housing associations) is council the death rate is probably not statistically significant by type of housing.4.5 The SFA has provided a more detailed analysis of roughly the same number of deathsover a slightly different period. However, the breakdown by appliance differs betweenA4
the two analyses. The Society figures attribute 40% to room heaters whereas theSFA figures attributed 60% of deaths and 50% of near misses to room heaters. Thisis only relevant if the proportion of different types of appliances being sold is changing(see trends).4.6 The analysis of individual cases gives the following breakdown by chimney type.Flue typeNumber ofdeathsNumber ofnear missesLined flue 5 16Prefabricated flues 6 13Unlined brick stack 29 37Brick stack with no type of inner recorded 23 374.7 The difficulty here is the treatment of the last category. The following table assumesthat some (but less than a proportionate number) of the unknown were lined.Flue type Deaths % Near %missesLined flue 7 11 21 20Prefabricated flues 8 13 17 17Unlined brick stack 48 76 65 6363 1034.8 A possible explanation of the different split for deaths and near misses? A highproportion of deaths are elderly people. A lined chimney implies newer housing whichimplies younger occupants who are more likely to notice problems and are able to getout. Therefore, the analysis of deaths may understate the relative proportion of linedchimneys giving rise to potential fatalities?Number of closed appliances4.9 Based on the SFA figures there were an average of 730,000 closed appliances in usein the period 1995-97.A5
Page 1 and 2: Appendix A
Page 4 and 5: 2 Summary2.1 The available data was
Page 9 and 10: 5 Results5.1 We have 730,000 closed
Page 11: Trends5.12 Based on SFA figures, th

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

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