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Content Overview general radon analysis
Passive sump analysis – update
New build initiative
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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!
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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)
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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?
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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 2007
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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
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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
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House questionnaire: information on house characteristics
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House type
Date built
Single storey or not
Floor level and number of floors
Double glazing
Ground floor type
Basement effects
Type of heating
Relative effectiveness of remedial methods
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Active Passive Natural Passive Positive
Sump system Ventilation Under floor Ventilation
Sealing
2
Active 1
6
Re
du
ctio
n fa
cto
r a
nd
co
nfid
en
ce
inte
rvals
P value<0.001
Effect of initial radon concentration
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Performance is measured in
two ways
Success:
the percentage reduced
to below the Action Level
Reduction factor:
Initial concentration
Final concentration
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’
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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’
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Data source Passive Sump update
All Passive sumps ~160
Pipe inside ~ 45
Pipe outside ~100
Still a question whether ‘standby sumps’?
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Information collated on UK national radon database
Around 7000 remediation projects 2000 to end 2013
Results: Passive sump ‘update’ (provisional)
Year Pipe Before After RF
Original Inside 360 189 1.9
Outside 348 193 1.8
Reanalysis Inside 379 207 1.8
Outside 342 223 1.5
All 349 224 1.6
All years Inside 362 223 1.6
to 2013 Outside 333 224 1.5
All 331 217 1.5
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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)
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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?
CON29 and TA6 forms
Results will inform:
Improved communications when buying and selling houses
(To builders, estate agents, etc improve questions on the current forms
used for the conveyance process)
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Aims
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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
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
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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
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Method
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• 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’
Questionnaire • Offer of a free radon measurement
• About the property
• Radon awareness
• Radon testing
• Comments
Source: HPA
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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.
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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
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Any questions? Thank you for listening
Sue.hodgson@phe.gov.uk
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