1. An alternative approach to radon exhalation from building materials Pieter Lanser The STRAVEN Foundation

2. 2 30 October 2009 Pieter Lanser The STRAVEN Foundation STRAVEN STRAling + VENtilatie (Radiation + Ventilation) Participants C&BC, VOBN and BFBN Covenant partner of the Dutch Minister of Housing and Environmental Affairs

3. 3 30 October 2009 Pieter Lanser Goal Maintain the relatively low indoor air radon concentrations (< 23 Bq/m 3 ) in the Dutch housing sector by building materials management and (the proper use of) ventilation devices between 2000 and 2014.

4. 4 30 October 2009 Pieter Lanser Is there a problem? Yes, according to Dutch authorities, radon: is a lethal gas in indoor air is not to be considered as ‘natural’ mainly comes from stony building materials risks exceed the maximum individual risk concentrations tend to go up Njazz, according to STRAVEN, radon concentrations in Dutch dwellings are relatively low and without peak values is not caught by the conception of maximum individual risks concentrations might have gone up, but that’s not due a change in building materials properties

5. 5 30 October 2009 Pieter Lanser What do we do? BORA ‘fundamental’ radon exhalation research of building materials BOMO annual monitoring of radon exhalation properties op building materials VERA ‘fundamental’ ventilation research in conjunction with indoor air concentrations VERVEN development and testing of new ventilation techniques

6. 6 30 October 2009 Pieter Lanser Is there a European parallel? No

7. 7 30 October 2009 Pieter Lanser Are there solutions? indoor air radon concentrations low high improve radon outfluxreduce radon influx safeguard, a. building measures and/or improve air ventilation ratesb. limitation of Bq/kg Ra-226

8. 8 30 October 2009 Pieter Lanser Air ventilation rates

9. 9 30 October 2009 Pieter Lanser Building measures ERRICCA-II (2005) Work package 5 Radon mitigation in existing buildings Deliverables D11, D12 and D13 European Radon Solutions Database

10. 10 30 October 2009 Pieter Lanser Limitation of Bq/kg Ra-226 Justification Resolution Legal framework Measurements Effects Limited, there must be a legal ground which prevents known radio-active wastes to be used as or in building materials. Good, limit values can be placed on a sensible level where both false rejection and false approval are close to zero. Revised BSS, Polish and Austrian regulation? Relatively easy to perform, relatively cheap, guidance parameter for radon exhalation Prevention of bad practices

11. 11 30 October 2009 Pieter Lanser Limitation of radon exhalation rates Justification Resolution Legal framework Measurements Effects Disputable Poor Not in EU-27 Difficult to perform, relatively expensive. Much ado about nothing (W. Shakespeare, 1598)

12. 12 30 October 2009 Pieter Lanser Problems of radon measurements In indoor air radon exhalation of building materials At low levels, different measurement cups give different results due to thoron ‘pollution’. 1. Preparation and storage of test specimen 2. Data spread 3. Systematic differences between laboratories

13. 13 30 October 2009 Pieter Lanser Recommendations Concentrate on gamma’s Connect with art. 31 of BSS Develop a European standard for gamma dose for building materials under the CPD (CPR). Stay away from limit values Stay away from radon.