gra

b Italian National Institute of Health (Istituto Superiore di Sanit ISS), Technology and Health Department, Viale Regina Elena 299, 00161 Rome, Italy

nt in EUeffectivdataba

x is herexes ar

heir natural radioactivity. Some of them also account for the contribution of

40K) in building material has been set up in the last years [2],through a large review of scientic literature and personal commu-nications from some experts. Since in some publications only theaverage values for activity concentration were available, in orderto make data comparable the authors decided to use only the arith-metic means (source data set) for each material reported in each

f both bulk mate-nd phospho-gyp-and supin most M

of non-stonmaterials (bricks, concrete, cements and gypsum: about 690ples) for each MS is quite different in some cases very smaactivity concentrations vary widely [2]. The database contents havebeen used for the calculation of the activity concentration index I(IRP112) as dened in the EC guideline Radiation Protection 112[3], for some of these non-stony bulk materials [4]. This is animportant starting point for a discussion at the European level onthe consequences of future legislative requirements, since this in-dex was adopted in the Proposal for a COUNCIL DIRECTIVE layingdown basic safety standards for protection against the dangers arising

Corresponding author. Tel.: +39 0694181264.

Construction and Building Materials 49 (2013) 448454

Contents lists availab

B

evE-mail address: r.trevisi@inail.it (R. Trevisi).Building materials can cause signicant gamma dose indoors,due to their natural radionuclide content. Moreover, they can alsobe a source of indoor radon: building materials contribution is esti-mated to be up to 30% [1]. A large database of activity concentra-tion measurements of natural radionuclides (226Ra, 232Th and

underestimated.The database refers to about 10,000 samples o

rial (bricks, concrete, cement, natural-gypsum asum, sedimentary and igneous bulk stones)material (igneous and metamorphic stones) usedStates of the European Union (MS). The number0950-0618/$ - see front matter 2013 Elsevier Ltd. All rights reserved.http://dx.doi.org/10.1016/j.conbuildmat.2013.08.059ercialembery bulk0 sam-ll andReceived in revised form 1 August 2013Accepted 29 August 2013

Keywords:Natural radioactivityBuilding materials indexEffective dose

radon to the annual effective dose. In this paper the authors review these methods and apply some ofthem to the contents of a database of natural radioactivity of building materials in the European Union,that was established by the authors. Based on the activity concentration index introduced by the EC Radi-ation Protection 112 guidance, IRP112, a new index is also proposed, that accounts for the radon contribu-tion to the effective dose indoors. The results obtained with different indexes are compared in order toevaluate the impact of the new Basic Safety Standards Directive implementation in the EU MemberStates, particularly in Countries where radioactivity in building materials is already regulated. Moreover,some non EU screening tools were considered to provide suggestions for possible future improvements ofthe EC IRP112.

2013 Elsevier Ltd. All rights reserved.

1. Introduction paper. For this reason, the variability of activity concentration isArticle history:Received 25 March 2013

Until now various methodmaterials on the basis of th i g h l i g h t s

Database of natural radionuclide conte Various methods available to evaluate We applied different approaches to the Based on the RP112 Index, a new inde The results obtained with different ind

a r t i c l e i n f obuilding materials.e dose due to building materials.se.eby proposed.e compared.

a b s t r a c t

s have been developed in several countries to evaluate and classify buildingRosabianca Trevisi , Cristina Nuccetelli , Serena Risicaa Italian National Workers Compensation Authority (INAIL), Department of Occupational Hygiene, Via Fontana Candida 1, 00040 Monteporzio Catone (Rome), ItalyScreening tools to limit the use of buildinwith enhanced/elevated levels of naturalAnalysis and application of index criteria

a, b

Construction and

journal homepage: www.elsmaterialsdioactivity:

b

le at ScienceDirect

uilding Materials

ier .com/locate /conbui ldmat

Buildfrom exposure to ionising radiation (ECBSS), as a screening tool toharmonise the control, and allow the free transportation and tradeof building products within the EU [5].

Aim of this paper was to analyse the various indexes reported inthe literature, apply them to the contents of the database, andcompare the results in terms of the materials that could possiblybe excluded from the market.

2. Review of the main methods for screening building materialsfrom the radiological protection point of view

Numerous methods have been published in the literature toscreen building materials from the radiological protection pointof view. Several of them estimate effective dose indoors from gam-ma radiation, and some of them also account for the contributionfrom radon exhaled by such materials. This is the case with Aus-trian, Czech, Dutch and Israeli indexes, which have long been inforce as national regulations. These methods were reviewed andare summarized in the following, in order to evaluate the impactof the new Basic Safety Standards Directive implementation inthe EU Member States. The non EU country screening tools, likethe Israeli index and the former Yugoslavia method, were consid-ered to provide suggestions for possible future improvements ofthe EC IRP112.

2.1. The general approach to an index I

In general, an index is introduced and used as a screening toolto limit gamma exposure from building materials; it consists ofthe sum of the contributions of the natural radionuclides to thegamma dose. In order that the material complies with the screen-ing, the index should not generally exceed the value of 1 (see Eq.(1)).

I CRa-226=ARa-226 CTh-232=ATh-232 CK-40=AK-40 6 1 1where Cx is the measured activity concentration (Bq kg1) and Ax isthe xed parametric values (Bq kg1).

The Ax parametric values are calculated after assuming a dosecriterion to be complied with and a background to be subtracted.These values also depend on the geometric and structural charac-teristics of the indoor environment and the dose coefcients perunit activity concentration used, i.e. the chosen room model. Forthis reason, Ax values may signicantly vary from country to coun-try. Frequently, the assumptions account for the radionuclide con-centrations of typical materials of each country, due to the socio-economic consequences of banning the use and trade of thesematerials.

2.2. Index IRP112

The guideline Radiation Protection 112 [3] chose the values300 Bq kg1, 200 Bq kg1 and 3000 Bq kg1 for ARa-226, ATh-232 andAK-40, respectively, for bulk building material, therefore the IRP112index is dened in the following way

IRP112 CRa-226=300 Bq kg1 CTh-232=200 Bq kg1

CK-40=3000 Bq kg1 2The index derives from the consideration that Within the

European Union, doses exceeding 1 mSv year1 should be takeninto account from the radiation protection point of view. Thismeans that the Ax values were obtained assuming: (i) a dose crite-rion of 1 mSv year1 as the excess to the average background

R. Trevisi et al. / Construction andoriginating from the Earths crust (ii) an occupancy factor of7000 h year1, and (iii) a conversion coefcient 0.7 Sv Gy1. Thebackground dose rate, corresponding to an average value outdoorsin Europe, was assumed to be 50 nGy h1. With the cited hypoth-eses, 50 nGy h1 correspond to about 0.25 mSv year1. The otherdata used to calculate the Ax values of Eq. (2) were: a room of4 5 2.8 m3, with walls, ceiling and oor made of concrete with0.2 m thickness and 2350 kg m3 density.

RP112 also considers a second dose criterion of 0.3 as anexemption level i.e. the level below which building materialsshould be exempted from all restrictions concerning their radioac-tivity and provides the relevant Ax values: 121 Bq kg1, 101 Bqkg1and 1390 Bq kg1 for radium, thorium and potassium, respec-tively. However, instead of changing the Ax values, it prefers tochange the limit value of the index concluding that . . .the sameactivity concentration index can be used if its limit value is set at0.5 instead of 1.

It is worth highlighting that RP112 states very clearly that theactivity concentration index should be used only as a screeningtool for identifying materials which might be of concern, butany actual decision on restricting the use of the material shouldbe based on a separate dose assessment.

The RP112 guide [3] was the basis for the IRP112 screening tooladopted in the new ECBSS [5]. However, at present this draft is stillunder discussion and signicant modications could be introducedbefore the new ECBSS is issued.

Lastly, the guideline also considers how to screen materials tobe used supercially, but this is not discussed in this paper.

In 2002, Denmark [6] adopted this index for the exemption ofbuilding materials (dose criterion 0.3 mSv year1 and I 6 0.5).

2.3. Index I in Austria

In 1995 Austrian legislation established an index I that accountsfor exposure from both gamma radiation and radon exhalationfrom building materials [7].

I 1 0:15kCRa-226=1000 Bq kg1 CTh-232=600 Bq kg1

CK-40=10;000 Bq kg1 6 1 3where k is a constant which depends on some characteristics of thematerials, i.e. density, thickness and radon emanation power. Thedose criterion used to calculate the Ax is 2.5 mSv year1.

In 2009 a new regulation was issued, which improved the radoncontribution estimate to the excess indoor effective dose [8],changing the index denition in this way:

I 1 0:07eqdCRa-226=880 Bq kg1

CTh-232=530 Bq kg1 CK-40=8800 Bq kg1 6 1 4where e is the radon emanation power, q the wall density, d thewall thickness and 0.07 is a constant, expressed in (m2 kg1), result-ing from the exposure model applied [8]. Where specic informa-tion is not available, e can be set at 10%, d at 0.3 m and q at2000 kg m3.

These parameters affect only the contribution of the radonterm, and the estimation of the excess gamma dose remains inde-pendent of the density of the material and geometry of the room.The dose criterion used to calculate the Ax is 1 mSv year1, andthe assumed outdoor background dose is 1.2 mSv year1 [9].

2.4. Index I in Israel

In 2009, Israel also adopted a similar approach and issued thestandard SI 5098 for building materials radioactivity [10]. It shouldbe pointed out, however, that this is not a screening tool, but a

ing Materials 49 (2013) 448454 449standard, actually the third version of it: the rst SI 5098 Standardwas issued in 2002 and a revised Standard in 2007. The 2009 stan-dard accounts for both gamma radiation and radon exhalation

from building material, and introduces a total activity concentra-tion index I:

I CRa-226=A11 e CRa-226=A2e CTh-232=A3 CK-40=A4 5and the gamma activity concentration index Ic.

ues has been set for three classes of building products according

450 R. Trevisi et al. / Construction and Buildto their density.

2.5. The Ra equivalent (Raeq) method

In 1985 Beretka and Mathew [12] proposed a criterion to limitradioactivity in building material based on the denition of the ra-dium equivalent activity (Raeq), which is still used by many authors,see e.g. [13,14].

Raeq is dened (see Eq. (7)) as the weighed sum of 226Ra, 232Thand 40K activity concentrations (CRa, CTh and CK in Bq kg1) reportedbelow, and accounts for the external gamma radiation hazardsassociated with them.

Raeq CRa 1:43CTh 0:077CK 7This denition was based on the authors assessment that

370 Bq kg1 of 226Ra, 260 of 232Th and 4800 of 40K (at that time10, 7 and 130 pCi g1, respectively) yield the same gamma doserate, estimated in 1.5 mGy year1, corresponding for this energyspectrum to about 1 mSv year1. In order to limit the gamma dosefrom materials to this value, Raeq should be lower than or equal to370 Bq kg1. This condition can also be expressed by the weighedsum

CRa=10 CTh=7 CK=130 8which should be less than or equal to 37 Bq kg1.

Table 1Ax values for different typical specic areas in Israel.

Buildingmaterials

Typical specicarea (qd)(kg m2)

A1(Bq kg1)

A2(Bq kg1)

A3(Bq kg1)

A4(Bq kg1)Ic CRa-226=A1 CTh-232=A3 CK-40=A4 6As for the total index I in Eq. (5) the rst, third and fourth terms

account for the excess indoor gamma dose; the second term, forthe radon inhalation dose. The rst term takes into account thegamma dose reduction from the 226Ra chain due to emanationand exhalation of 222Rn.

Indeed, radioactive equilibrium disturbance in the material, dueto radon emanation, results to activity contents of 214Pb and 214Biin the material lower than that of 226Ra.

As reported by Haquin et al. [11], Ax values depend on the typ-ical specic area (qd) of building material. In this work, interpolat-ing the published values, A1, A2, A3 and A4 have been calculated forconcrete and bricks (see Table 1).

The Ax parameters are calculated assuming an excess dose of0.3 mSv year1 (dose criterion) above background, i.e., the typicallevels of indoor exposure which would be received in a room builtfrom materials with typical activities. This dose criterion refers tothe sum of gamma and radon exposure. Indeed, the building prod-uct must comply with both the total activity concentration index Iand the gamma activity concentration index Ic, which have twodifferent series of reference values, e.g., in the case of concrete,I 6 1 and Ic 6 0.4 [11]. In a similar way, the background dose ac-counts for both gamma radiation and radon and like I and Ic val-Concrete 470 414 11 293 4070Brick 225 605 23.5 433 62102.6. The Dutch radiation performance index

Some years ago, Netherlands [15] launched a new so-calledRadiation Performance Index, a model which estimates the annualeffective dose from the indoor gamma radiation and radon concen-tration in the following way:

E Chcdc Ec 6 1 9where E is the annual effective dose rate (mSv year1); Ch the an-nual average indoor concentration of radon exceeding the valueoutdoors (Bq m3), released from building materials and, for groundoor rooms only, from the crawl space; cdc the dose conversion fac-tor (mSv year1 per Bq m3) and Ec is the effective dose rate due togamma radiation (mSv year1).

This effective dose from gamma radiation is calculated with thefollowing equation

Ec kUCRa kThCTh kKCK 10where kx are conversion factors for U, Th and K (mSv year1 perBq kg1) depending on the shape and dimensions of the room, posi-tion in the room, chemical composition, density and thickness ofthe building material. The Radiation Performance Index, based onthe Koblinger room model [16,17], seems to be rather a sophisti-cated assessment method than an easy-to-use screening tool.

2.7. Index I in the former Yugoslavia

In 1987, the former Yugoslavia introduced an index Iwhich alsoaccounted for articial radionuclide concentrations [18]. This indexis expressed by the following equation:

I CRa-226=400 CTh-232=300 CK-40=5000 Ca=4000 6 1 11where Ca is the sum of activity concentrations (in Bq kg1) of allarticial radionuclides in the sample.

The regulation was designed and drafted several months afterthe Chernobyl accident in 1986 and adopted early in 1987. The rea-son for introducing limits for articial radionuclides in buildingmaterials resided on the fact that the former Yugoslavia importedat this period several products from the former Soviet Union,including building materials, timber, etc., potentially contaminatedwith long-lived articial radionuclides from the Chernobyl acci-dent. It should be noted however that no contamination was everreported in Yugoslavia.

It is interesting to note that the same equation for radioactivitycontent of building materials as in the former Yugoslavia still existsin the newer legislation of the two Western Balkan states, Serbiaand Montenegro. However, it seems that no articial nuclide wasever detected in building material either in Serbia or inMontenegro.

2.8. The Slovenian method

At present Slovenian legislation does not account for articialradionuclides. General requirements to control the dose due tobuilding materials are now given in the Decree on dose limits, radio-active contamination and intervention levels [19], which prescribesthat building materials must not cause excessive external or inter-nal exposure to groups of members of the public or the populationas a whole. The derived limits for radionuclide concentrations mustbe calculated by qualied radiation protection experts on the basisof the dose limits for members of the public and dose constraints.However, an index I is also used, as dened in Radiation Protection112, and in any case the measured activity concentrations shall be

ing Materials 49 (2013) 448454such that IRP112 6 1.Less stringent criteria are applied when the material is only

used in limited quantities in a building.

already mentioned in their previous papers, some literature datawere incomplete, namely, the activity concentrations of 226Ra,232Th and 40K were not available for all the samples. In these casesno index or screening tool (from now on index) could be calcu-lated, and for this reason the number of datasets to which the in-dexes were applied is lower than the total number of data foreach category of material.

The results of the application of index IRP112 to the database aresummarised below. For each country, Figs. 1 and 2 show IRP112 val-ues calculated on the minimum, maximum and mean values ofactivity concentrations of bricks and concrete, respectively. Thenumber of samples with a complete data set is specied in paren-thesis for every country (24 MS).

The percentages of materials exceeding the two dose criteria of1 1

Build2.9. The indexes in the Czech Republic

Starting from 1970, the Czech Republic had to face a serious sit-uation with several thousand houses built with material rich in ra-dium or contaminated with residues from uranium paint andradium factories (with 226Ra activity concentration up1 MBq kg1). The Czech Republic is also one of the countries withthe highest indoor radon concentration in the world (mean radonconcentration = 140 Bq m3) [20].

2.9.1. The previous regulationFor the above reasons, in 1987 the Czech Republic had to intro-

duce an ad hoc legislation stating interventional levels for alreadyexisting houses, which is the only example found in literature ofthe use of an index to identify existing dwellings of concern.

For this purpose, the following index S was introduced, in orderto limit both gamma and indoor radon exposures in dwellings:

S D=2lGy h1 CRn=400 Bq m3 12where D is the gamma dose rate (lGy h1) and CRn the annual aver-age radon concentration (Bq m3).

This index results from the choice of a recommended value of400 Bq m3 for radon activity concentration, and 2 lGy h1 for in-door gamma dose rate, to remediate existing buildings. This sumrule (used only if D > 0.5 lGy/h) and value S = 1 were used for deci-sion making on remedial measures with governmental support[20].

For new houses, the limit value for 226Ra was calculated in orderto keep 6 30% the building material contribution to the indoor ra-don limit value (200 Bq m3). With a room model under conserva-tive conditions, the resulting value was 120 Bq kg1. Possiblelimitations for radon exhalation rate or emanation coefcient werediscussed but rejected at the end because of the sophisticated mea-surements of exhalation, long-term changes, and the complicatedsystem of limitation proposed [20].

2.9.2. The present regulationCzech legislation concerning radioactivity in building materials

is now based on a two-step procedure to account for both gammaand radon exposure: rstly, the index I, as dened by the RP 112document, is used as a screening tool. Producers and importersshould ensure systematic measurements of natural radionuclidesin building materials and submit the results to the State Ofce forNuclear Safety. If the index I is higher than 0.5 a value correspond-ing to the exemption level of 0.3 mSv year1 a cost-benet anal-ysis should be done by the producer with a criterion aimed atreducing the public doses to a level as low as reasonably achievable(see details in [20]). In the second step, in order to control radonexhalation from building materials, the producer must also applythe limit levels for 226Ra activity concentrations of Table 2.

3. Index IRP112 with the radon contribution

A modied IRP112 index is here proposed to also account for ra-don contribution to the effective dose indoors. This index followsthe same approach of the Austrian index, however differenthypotheses and dose criterion were applied. The modied IRP112 in-dex (IRP112 Rn) is

IRP112Rn 1 aCRa-226=300 Bq kg1 CTh-232=200 Bq kg1

CK-40=3000 Bq kg1 13

R. Trevisi et al. / Construction andwhere a is a factor calculated accounting for the Rn exhalation rate(E) from building materials, the subtracted outdoor 222Rnbackground and the dose criterion chosen for the indoor 222Rn.The outdoor radon background is assumed to be equal to the typicaloutdoor radon concentration of 10 Bq m3 [21]. With the same ap-proach as in par. 2.2, it corresponds to an effective dose indoors athome of about 0.3 mSv year1 [22]. In order to estimate the a value,the following expression was used

a 300keqd=2 SV1CRn; 14where C

Rn is the sum of Rn activity concentration corresponding to

the dose criterion chosen and the outdoor background of10 Bq m3; m the ventilation rate (h1); SV1 the surface to volumeratio of the room (m1); k the 222Rn decay constant (h1); e theemanation power; q the density of building materials (kg m3)and d is the building material thickness (m).

This equation comes from the classical expression of the radonactivity concentration produced by building materials [23]:

CRn E SV1 m1 15where

E Exhalation rateBq m2 h1 CRakeqd=2 16with CRa = 226Ra activity concentration in building materials(Bq kg1).

The dose criterion chosen for indoor 222Rn is 3 mSv year1, thelowest dose reference level in the range recommended by ICRPfor exposure to radon in dwellings [24]. It now corresponds toabout 100 Bq m3 indoors at home [22].

Assuming the same geometry and size as for the RP 112 room,e = 0.1 and m = 0.7 h1, a is equal to 1.09.

4. Application of the indexes and other screening tools to thebuilding material database

The database [2] was recently updated with new data [2528]and now contains data for 26 out of the 27 MS. As the authors have

Table 2Limit values for 226Ra in the Czech Republic legislation.

Type of building material 226Ra limit value (Bq kg1)

Buildingswhere peoplelive or stay

Other constructionswhere people do notlive or stay

Material used in bulk amount (e.g.brick, concrete, gypsum)

150 500

Other material used in smallamounts (e.g. tile. . .) and rawmaterial (sand, building stone,gravel aggregate, bottomash. . .)

300 1000

ing Materials 49 (2013) 448454 451IRP112 0.3 mSv year (I > 0.5) and 1 mSv year (I > 1) were alsoevaluated and showed to be substantially the same as in theprevious assessment [2], that is 91% of bricks and 62% of concrete

599

uild0.00

0.20

0.40

0.60

0.80

1.00

1.20

1.40

Fig. 1. Index IRP112 in bricks (on 1

Out of range: 2.90

452 R. Trevisi et al. / Construction and Bsamples exceed the dose criterion of 0.3 mSv year1, whereas only5% of samples exceed 1 mSv year1.

Several discussed indexes were applied to some building mate-rial of the database (bricks, concrete and cement), even if these in-dexes often start from different dose criteria and backgroundhypotheses, which are summarised in Table 3 for the sake ofcomparison.

Different indexes reect different national situations. For exam-ple, in Israel screening tools to limit natural radioactivity in build-ing materials were created to recycle industrial residues (y ash) asmuch as possible, balancing the need of landlls within the na-tional territory with the increase of the effective dose of the public.As regards the Austrian index, the outdoor background dose fromradon and gamma radiation (1.2 mSv year1) is much higher thanthe average background dose reported for many EU Countries [1].

Table 4 reports the percentages of materials which do not com-ply with the indexes. The different screening tools were also ap-plied to cement data, because more than 2000 samples of thismaterial are present in the database. Cement was considered asconcrete component using the standard percentage (20%) forthe calculations.

As regards the Israeli standard, the following hypotheses wereassumed for concrete and bricks, respectively:

0.00

0.50

1.00

1.50

2.00

2.50

Fig. 2. Index IRP112 in concrete (2714Imin

Imean

Imax

samples out of a total of 1682).

ing Materials 49 (2013) 4484541. For radon emanation power, 0.12 and 0.07.2. For density, 2350 kg m3 and 1500 kg m3.3. For thickness, 0.2 and 0.15 m.

For cement the same parameters of concrete were applied.It is interesting to compare the results relevant to different in-

dexes with the same dose criterion. On the one hand, for the dosecriterion of 0.3 mSv year1, the application of IRP112 and the Israelistandard (which also considers the Rn contribution to dose) to theconcrete data set gives similar results: upon analysing the equationstructures, a substantial equivalence of the two Ax sets was found,although the hypotheses on the background to be subtracted differsignicantly. This is not the case with bricks, probably becauseIRP112 uses xed parameters (elaborated for concrete), which donot t other materials well [29]; the Israeli standard, instead, de-nes Ax coefcients and I values on the basis of the supercial den-sity (dened as mass per unit area, expressed in kg m2) of thebuilding material [11]. On the other hand, for the dose criterionof 1 mSv year1, IRP112, Raeq and the Austrian Index provide similarresults for concrete and bricks, i.e., a low percentage of samples ex-ceed the reference values.

It can also be observed that the addition of the radon contribu-tion to IRP112 does not change the results dramatically, i.e., the

Imin

Imean

Imax

Out of range: 4.93

samples out of a total of 2737).

ard

g m3 < q

ncy

d)

Buildpercentage of concrete and brick samples increases just from 5% to8% and from 5% to 16%, respectively. Therefore, the practical appli-cation of an index of this type is feasible, and could be consideredin the EU legislation, representing the exposure situation moreaccurately from a radiation protection perspective.

A general comment can be made about cement considered asthe radioactive fraction of hypothetical concrete: the percentageof analysed samples exceeding the screening levels of the appliedmethods is not signicant and completely different from that ofconcrete, particularly for the 0.3 mSv year1 criterion. This is quite

IRP112 0.3 mSv year1

1 mSv year1

Austrian index 1 mSv year1 from c + RnIsraeli standard 0.3 mSv year1 from c + Rn (both Ic and I complieIRP112+Rn 1 mSv year1 (c) + 3 mSv year1 (Rn)Raeq 1 mSv year1

a Assessed as concrete component (about 20%).Table 3Dose criteria and background hypotheses of the indexes applied to the database.

Hypotheses Indexes

IRP112 Austrianindex

Israeli stand

Dose criterion (mSv year1) 60.3 61 61 60.3

Outdoor backgrounda

(mSv year1)0.25 0.25 1.2

Indoor backgroundb (mSv year1) If q > 1500 kIf 600 kg m

a Outdoor gamma or radon background dose calculated with the indoor occupab Indoor background dose from typical material subtracted from the indoor dose.

Table 4Percentages of samples exceeding the reference values of various indexes.

Indexes Dose criterion

R. Trevisi et al. / Construction anda strange result. Indeed, it cannot follow from the hypothesis onthe percentage of cement used, because even if the percentagewere doubled, the results would not improve much. The simplestexplanation is that cements contained in the concrete samplesare not included in the cement samples of the database. But shouldit also be assumed that other components of concrete have a non-negligible radioactivity content and should also be investigated?

5. Conclusions and future perspectives

Although the database has recently been updated, yielding apartial picture of the situation in 26 out of 27 MS, it is still notdescriptive of the EU population exposure: the collection of sam-ples is not representative and the data from some countries arescarce.

As regards screening tools for radioactivity in building materi-als, the paper analyses different approaches used inside and out-side the EU, and reports the results of the application of severalof them to database information. Furthermore, a modied IRP112accounting for Rn contribution to dose from building materials isalso presented and applied to the database.

Notwithstanding the different basic hypotheses of the describedmethods, the application of various indexes to the building mate-rial database for the dose criterion of 1 mSv year1 yielded similarresults as for the percentage of materials which should be excludedfrom the market. This is quite a useful result and should nd apractical application in the BSS Euratom Directive. This Directivewill provide requirements for screening building materials asgamma source in order to limit the population exposure, inagreement with the Regulation (EU) No. 305/2011 [30], layingdown harmonised conditions for the marketing of constructionproducts. This Regulation includes as generically already donein the Council Directive 89/106/EEC [31] the emission of radia-tion from building works (i.e. building materials) as a threat tothe hygiene or health and safety of workers, occupants or neigh-bours, throughout their life cycle [30].

As for 0.3 mSv year1, the quite different results for bricks (91%with IRP112 and 18% with Israeli Index) conrm the IRP112 inade-quacy for building materials different from concrete. This is the

IRP112+Rn Raeq

61 for c 6163 for 222Rn0.25 from c 0.3 from 222Rn

3 0.25 from c; 0.85 from 222Rn6 1500 kg m3 0.20 from i; 0.35 from 222Rn

factor subtracted from the indoor dose.

Building material

Bricks (%) Concrete (%) Cementa (%)

91 62 0.35 5 00 3 0

18 61 0.316 8 00 4 0

ing Materials 49 (2013) 448454 453reason why new research efforts will be devoted [32] to obtainmore reliable indexes that will better represent the different char-acteristics of materials and account for radon exhalation as well.

Acknowledgements

The authors are very grateful to Jiri Hulka, Helena Janzekovic,Konstantin Kovler and Milko J. Krizman for kindly providing themwith information about their national legislations, and to MonicaBrocco (ISS) for the linguistic revision of the manuscript.

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454 R. Trevisi et al. / Construction and Building Materials 49 (2013) 448454

Screening tools to limit the use of building materials with enhanced/elevated levels of natural radioactivity: Analysis and application of index criteria1 Introduction2 Review of the main methods for screening building materials from the radiological protection point of view2.1 The general approach to an index I2.2 Index IRP1122.3 Index I in Austria2.4 Index I in Israel2.5 The Ra equivalent (Raeq) method2.6 The Dutch radiation performance index2.7 Index I in the former Yugoslavia2.8 The Slovenian method2.9 The indexes in the Czech Republic2.9.1 The previous regulation2.9.2 The present regulation

3 Index IRP112 with the radon contribution4 Application of the indexes and other screening tools to the building material database5 Conclusions and future perspectivesAcknowledgementsReferences