An alternative approach to radon exhalation from building materials

Pieter Lanser

The STRAVEN Foundation

30 October 2009 Pieter Lanser 2

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

30 October 2009 Pieter Lanser 3

Goal

Maintain the relatively low indoor air radon concentrations (< 23 Bq/m3) in the Dutch housing sector by building materials management and (the proper use of) ventilation devices between 2000 and 2014.

30 October 2009 Pieter Lanser 4

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

30 October 2009 Pieter Lanser 5

What do we do?

BORA‘fundamental’ radon exhalation research of building materials

BOMOannual monitoring of radon exhalation properties op building materials

VERA‘fundamental’ ventilation research in conjunction with indoor air concentrations

VERVENdevelopment and testing of new ventilation techniques

30 October 2009 Pieter Lanser 6

Is there a European parallel?

No

30 October 2009 Pieter Lanser 7

Are there solutions?

indoor air radon concentrations

low high

improve radon outflux reduce radon influx

safeguard, a. building measures

and/or

improve air ventilation rates b. limitation of Bq/kg Ra-226

30 October 2009 Pieter Lanser 8

Air ventilation ratesIndoor Air Radon Concentration as a Function of Time and

Ventilation Rate

0

5

10

15

20

25

30

35

1 87 173 259 345 431 517 603 689 775 861 947 1033 1119 1205 1291 1377

Time in Minutes

Rad

on

Co

nce

ntr

atio

n i

n B

q/m

3

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Building measures

ERRICCA-II (2005)

Work package 5

Radon mitigation in existing buildings

Deliverables D11, D12 and D13

European Radon Solutions Database

30 October 2009 Pieter Lanser 10

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

30 October 2009 Pieter Lanser 11

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)

30 October 2009 Pieter Lanser 12

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

30 October 2009 Pieter Lanser 13

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.