Working Group 3

WG 3: Objective is to improve the measurement capacity to verify that existing and newly developed (WG 2) NORM containing building materials are in accordance to European legislative requirements.

Subtask 3.1: Optimization and initiatives towards standardization of the determination protocol for indicators related to the external exposure to gamma radiation.

The scientific focus of task 3.1 lays on the investigation and application of industrially useful methodology/protocols for measurement of the activity concentration index (Annex VII of the EU- BSS) to assess the applicability of newly developed building materials for the European building market. Specifically to further aid industry in the search for cost-efficient measurement solutions the applicability of in situ measurement methodology will be investigated. An important aspect is the validation of the developed methods which is even more important in case of in situ measurements [Stals et al, 2011, Schroeyers et al, 2010].

Deliverable: Publications regarding optimized (in situ if possible) measurement protocols and the validation of these protocols for the determination of the activity concentration index for NORM containing building materials.

Sub-task 3.2: Optimization and initiatives towards standardization of the determination protocol for indicators related to exposure to radon isotopes (Rn-222 and Rn-220) and radon progeny (PAEC – potential alpha energy concentration).

WG 3 works on the standardization of experimental methods to evaluate radon (possibly thoron) emanation and exhalation rate of building materials. In houses it is not straightforward to distinguish between radon emanation from soil and building materials and therefore specific parts of the new EC-BSS are dealing with radon issues separately from exposure related to gamma exposure of occupants. In Funke et. al [2007] and Schulz et. al [2008 and 2010] it is shown that the assessment of the radon situation in dwellings is a multidimensional question to solve. The contribution of radon to the radiation exposure is not (fully) incorporated in the activity concentration index used in the BSS. The EU-BSS uses a separated indicator for radon and theĀ current version of the draft fixes the maximum national reference level at 300 Bq m for dwellings although this is still under discussion. Another reason why Radon is treated separately in the EC- BSS is that Radon can be remediated (ventilation) unlike the gamma dose and that in many regions the main fraction of the radon exposure in buildings originates from soil. However, it is shown by international studies of the WHO and ICRP, that building materials might have a non-negligible share of radiation exposure of the public due to radon. Therefore radon emanation assessment and exhalation rates of newly developed building materials needs to be researched.

Deliverable: Publications regarding optimized (in situ if possible) measurement protocols to evaluate radon (possibly thoron) emanation and exhalation rate for NORM containing construction materials.

Subtask 3.3: An important research objective is to establish a calibration procedure for measurement methods of the activity concentration index and the radon emanation and exhalation rate towards traceable metrological reference materials and standard sources.

This Action aims at investigating potential radiological reference materials and standards for the determination of the activity concentration index of NORM containing building materials. This task will be performed in close collaboration with the above mentioned Metro-NORM project in a joint venture with several reference institutes. The focus of the Metro-NORM project is on NORM residues with high natural radioactivity concentration while sub-task 3.3 will focus on research towards standards when these NORM residues are incorporated in building materials.

Deliverables: Proposal for a calibration procedure and development of standard materials for the calibration of measurement procedures to determine the (i) activity concentration index and (ii) radon emanation and exhalation rate of NORM containing building materials.

Sub-task 3.4: Comparing the newly proposed measurement protocols for the activity concentration index and emanation assessment and exhalation rate with existing measurement protocols. The standard materials developed in sub-task 3.3 will be used for intercomparisons between institutes using several measurement protocols and instruments.

Deliverables: WG 3 will organize intercomparisons between institutes using several measurements protocols and instruments for (i) activity concentration measurements but also (ii) emanation assessment and exhalation rate measurements in close collaboration with reference institutes and the Metro-NORM project. A report of the result of the intercomparisons will be provided.

Sub-task 3.5: Preparation of a unified certification procedure of construction materials and subsequent legislation proposal.

Finally a unified measurement protocol and requirements for the certification of testing laboratories involved in building material certification process will be proposed.

WG 3 aims at establishing a uniform procedure for testing building materials (including measurement methods, quality assurance, quality management and sampling) for getting a certificate related to the radiological content of the building materials. Such approach must be grounded on relevant legislation, so a proposal of new regulation or changes in an existing

legislation will be developed by WG 4.

Deliverables: Factsheet for unified certification procedure of construction materials. The subsequent legislation proposal will be dealt with in WG 4.