Passive sump analysis New build initiatives Sue Hodgson 17 February Irish National Radon Forum

Transcription

1 Passive sump analysis New build initiatives Sue Hodgson 17 February 2014 Irish National Radon Forum

2 Content Overview general radon analysis Passive sump analysis update New build initiative 2 Irish National Radon Forum

3 Exposure to Radon Increases your risk of developing lung cancer Latest analysis Radon and Public Health RCE-11 Over 1,000 deaths per year from radon in UK homes Lower the radon level lower the risk! 3 Irish National Radon Forum

4 Reducing the risk - UK advice The main aims of remedial work: To reduce radon levels as low as reasonably possible Reduce levels to: Below Action Level 200 Bq m -3 Below Target Level 100 Bq m -3 (especially those at higher risk such as smokers, ex smokers) 4 Irish National Radon Forum

5 Previous work An analysis of remediation methods (2011) S A Hodgson et al, HPA-CRCE-019 Report How effective are remediation measures? What factors govern the success of remedial measures? What are typical costs? Are there differences with work done by specialist contractors or DIY? 5 Irish National Radon Forum

6 Data source original analysis Information collated on UK national radon database Remediation programmes to find and fix houses with high radon levels, encouraging householders to reduce levels Study based: on ~ 3100 remediation projects in ~ 2700 dwellings Remediation projects installed between 2000 and Irish National Radon Forum

7 Data Collected Questionnaires completed by householder: The type of remedy used Details about the house Who did the work 3 month measurements provided: Radon concentrations before and after remediation 7 Irish National Radon Forum

8 Type of remedies used Sumps Active (with fan) Passive with interior stack pipe Passive with exterior stack pipe Positive ventilation (fan unit in ceiling) Passive ventilation (trickle vents on windows) Active under-floor ventilation (with fan) Natural under-floor ventilation (air-bricks) Sealing floors and/or loft hatches 8 Irish National Radon Forum

9 House questionnaire: information on house characteristics House type Date built Single storey or not Floor level and number of floors Double glazing Ground floor type Basement effects Type of heating 9 Irish National Radon Forum

10 Results original analysis 10 Irish National Radon Forum

11 Reduction factor and confidence intervals Relative effectiveness of remedial methods P value<0.001 Active Passive Positive Passive Active Natural Sealing Sump system Ventilation Under floor Ventilation 11 Irish National Radon Forum

12 Effect of initial radon concentration Performance is measured in two ways Success: the percentage reduced to below the Action Level Reduction factor: Initial concentration Final concentration 12 Irish National Radon Forum

13 Passive sump re-analysis and update Reasons for the analysis Analysis of radon remediation methods showed an unexpected result for passive sumps: HPA-CRCE-019, 2011 Passive sumps performed as well as active sumps for some homes? If passive sumps prove to be effective: Cheaper and more environmentally friendly solutions can be recommended Standby sump only provides a health benefit when activated Could be working in new houses rather than standby 13 Irish National Radon Forum

14 Passive Sump Analysis Dataset cleaned and included data collected more recently end 2013 Statistical analysis of data to obtain reduction factors in different situations > e.g. pipe outside, pipe inside > Age of property (not yet analysed) Compare with other passive mitigation methods Combine these results with work commissioned from BRE on: The effectiveness of cowls for use with passive stack radon sump systems 14 Irish National Radon Forum

15 Data source Passive Sump update Information collated on UK national radon database Around 7000 remediation projects 2000 to end 2013 All Passive sumps ~160 Pipe inside ~ 45 Pipe outside ~100 Still a question whether standby sumps? 15 Irish National Radon Forum

16 Results: Passive sump update (provisional) Year Pipe Before After RF Original Inside Outside Reanalysis Inside Outside All All years Inside to 2013 Outside All Irish National Radon Forum

17 Summary Passive sumps typical reduction factor ~ 1.5 (~33%) No real difference if stack is positioned inside or outside of building Passive sumps (WORKING) could be considered as preventive measures in new build homes cost effectiveness study needed Further work: build date ie membranes, and cowls (BRE) 17 Irish National Radon Forum

18 New build survey 18 Irish National Radon Forum

19 Introduction Survey to find out What do new home buyers know about radon? Do house buyers know: > That their home has a radon risk and is built with protection? >That they should measure on occupation? >They can activate radon protective secondary measures if high? Conveyance process does this raise radon awareness? Results will inform: CON29 and TA6 forms Improved communications when buying and selling houses (To builders, estate agents, etc improve questions on the current forms used for the conveyance process) 19 Irish National Radon Forum

20 Aims Health Protection > To raise awareness about radon > Measure radon level by offering a free test > Provide advice on reduction of levels Provide evidence and recommendations > To find out what house holders of newly built homes know about radon > To improve communications via stakeholders and via the conveyance processes 20 Irish National Radon Forum

21 House buying and selling Radon awareness increased in late 1990s when: Royal Institution of Chartered Surveyors Advised members that radon should be mentioned in valuation or pre-purchase reports for all houses in radon affected areas Conveyance process in developed in England and Wales: Con 29 Local authority search TA6 Property information form 21 Irish National Radon Forum

22 Con29 and TA6 CON29 (R) Local authority search form (implemented July 2002) Question 3.13 Do records indicate that the property is in a Radon Affected Area as identified by the HPA? TA6 Property information form - completed by seller Has a radon test been carried out at the property? If yes, a) please supply a copy of the report b) was the test result below the recommended action level? Were any remedial measures undertaken on construction to reduce radon gas levels in the property? TA8 Used for new properties currently no questions on radon 22 Irish National Radon Forum

23 Method Targeting properties that should have full radon protective measures in place according to the building regulations requirement C1. Reasonable precautions shall be taken to avoid danger to health and safety caused by contaminants on or in the ground covered by the building, and any land associated with the building Guidance stated in BR 211 Radon, Guidance on protective measures for new buildings 23 Irish National Radon Forum

24 Questionnaire Offer of a free radon measurement About the property Radon awareness Radon testing Comments 24 Irish National Radon Forum Source: HPA

25 New Build Project What s happened so far Questionnaires and a free test offers sent to more than 4000 houses Responses from 503 people Questionnaires could be submitted online or by post (9% completed online) Uptake of free test ~ 11% Results from questionnaires have been collected on the database What next? Analysis of questionnaire and radon tests to answer specific questions Consider where improvements in communication are required to better inform buyers of new build houses eg. via builders, local authorities, conveyance documentation, estate agents etc. 25 Irish National Radon Forum

26 Newbuild - summary Analysis underway Publication in due course Recommendations to improve awareness in new home owners: Conveyance documents Con29 and TA6 currently raise awareness consider improvements in questions/guidance such as: need to test, that new build preventive measures are in place (new build) Develop informed communications with builders, estate agents, LAs etc: - improve information for house buyers - Through information packs, leaflets, websites 26 Irish National Radon Forum

27 Any questions? Thank you for listening 27 Irish National Radon Forum