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Passive sump analysis

New build initiatives Sue Hodgson

17 February 2014

Irish National Radon Forum

Content Overview general radon analysis

Passive sump analysis – update

New build initiative

2 Irish National Radon Forum

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!


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)


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?


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


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


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


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

Results – original analysis


Relative effectiveness of remedial methods


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


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’


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’


Data source Passive Sump update

All Passive sumps ~160

Pipe inside ~ 45

Pipe outside ~100

Still a question whether ‘standby sumps’?


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


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)


New build survey


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)


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

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


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


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’

Questionnaire • Offer of a free radon measurement

• About the property

• Radon awareness

• Radon testing

• Comments

Source: HPA


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.


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


Any questions? Thank you for listening

[email protected]


mailto:[email protected]





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