CEN/TC 351/WG 3 - Radiation from construction products

This document describes a calculation method to determine the indoor gamma dose from construction products. The method includes calculation of the indoor gamma dose from the individual construction product under its intended use, as well as the dose from the building taking consideration of multiple building materials where this is deemed necessary and any shielding from the terrestrial background.
The calculation method builds on existing modelling principles for photon emission and absorption. Parameters of the modelling that are not product specific, such as room geometry, exposure coefficients, and conversion factors are predefined and form the underlying basis for the method in this EN. The choice for pre-defined model parameters is essential from a harmonization perspective, despite the fact that such parameters can vary considerably for every homeowner, building type, region or country. Typical examples are the exposure time, the location of exposure in the building, the terrestrial background radiation and the amounts and way the building materials are used in the building. The parameters are selected on the basis of international consensus, as laid down in ICRP, UNSCEAR, EU RP guidelines and other renowned publications. Product specific parameters such as density and thickness are specified in accordance with the product’s intended use. In addition, the products’ massic activities of 226Ra, 232Th and 40K are specified and obtained according to prEN 17216 (under development, [3]). The method provides a tiered approach with a basic approach intended for assessing individual construction products, followed by a more refined approach to assess a complete building design. The former approach assumes an identical structure of building materials on all six surfaces of the model room, and where needed complemented with other building materials that form an intrinsic part of the product’s intended use. The latter approach enables evaluation of a known building design. Here the user can specify the applied construction product to walls, floor or ceiling separately in accordance with the product’s intended use.
The indoor gamma dose from the individual construction product as well as the building is expressed in terms of an annual effective dose from gamma radiation in the indoor environment. The formulation of the indoor gamma dose in the building is consistent with the dose for indoor external exposure as stated under Article 75 of the Basic Safety Standards Directive. As a result, the described method enables assessment of the calculated annual dose of the building against the reference level as defined in the Basic Safety Standards Directive .
The method is designed for assessment of mineral based building materials applied in bulk or superficially and used as a construction product in buildings. This includes any building materials that have been identified by EU member states as being of concern from a radiation protection point of view. The method is envisaged for use by producers of building materials, architects and building constructors as well as authorities.
NOTE   It is important to state that following the calculation of dose, any subsequent regulatory classification falls explicitly outside the scope of this method and is the responsibility of the relevant authorities.

This document describes a test method for the determination of the activity concentrations of the radionuclides radium-226, thorium-232 and potassium-40 in construction products using semiconductor gamma-ray spectrometry.
This document describes sampling from a laboratory sample, sample preparation, and the sample measurement by semiconductor gamma-ray spectrometry. It includes background subtraction, energy and efficiency calibration, analysis of the spectrum, calculation of the activity concentrations with the associated uncertainties, the decision threshold and detection limit, and reporting of the results. The preparation of the laboratory sample from the initial product sample lies outside its scope and is described in product standards.
This document is intended to be non product-specific in scope, however, there are a limited number of product-specific elements such as the preparation of the laboratory sample and drying of the test portion. The method is applicable to samples from products consisting of single or multiple material components.

The aim of this Technical Report is to propose a methodology to determine indoor gamma dose from building materials and to help classify such a product as required in the Construction Products Regulation [7]. This first technical approach could be a precursor for the development of a harmonized European Standard based on this methodology.
NOTE 1   In this Technical Report, doses from radon and thoron exhalation are excluded. However, in 3.3, information is given on how radon exhalation is dealt with in (EU)2013/59/Euratom, the Basic Safety Standards Directive (2013/59/EURATOM) [1].
NOTE 2   Compliance with national exemption levels for NORM nuclides remains.

This document describes a test method for the determination of the activity of the radionuclides radium-226, thorium-232 and potassium-40 in construction products using semiconductor gamma-ray spectrometry.
This document describes sampling from a laboratory sample, sample preparation, and the sample measurement by semiconductor gamma-ray spectrometry. It includes background subtraction, energy and efficiency calibration, spectrum analysis, activity calculation with the associated uncertainties or the decision threshold and detection limit calculation, and the reporting of results.
The scope of this document is not product-specific. However, there are a limited number of product-specific components, such as the preparation of the laboratory sample and drying of the test portion. The method is applicable to samples from products consisting of single or multiple constituents.