DIN ISO 11665-8:2013-08

Radon is today considered to be the main source of human exposure to natural radiation. The UNSCEAR (2006) report suggests that, at the worldwide level, radon accounts for around 52 % of global average exposure to natural radiation. The radiological impact of isotope 222 (48 %) is far more significant than isotope 220 (4 %), while isotope 219 is considered negligible. The International Cancer Research Centre (ICRC) of the World Health Organization (WHO) has recognized radon as a lung carcinogen in humans since 1987. Radon activity concentration is usually higher in buildings than in the outside atmosphere due to the lower air renewal rates. The more the ventilation is reduced, the greater the accumulation of radon in buildings. The underlying soil is usually the dominant source of radon in buildings. In some cases, building materials, outside air, tap water and even city gas are additional sources that can also contribute to increasing radon activity concentration. This part of the DIN ISO 11665 series includes the relevant requirements in order to indicate the presence of radon in a building and to identify the source and transfer pathways of radon in the building (additional investigations). Different measuring stages can be necessary for a building: - initial investigation to estimate the annual average activity concentration of radon in the building. Suitable methods are integrated measurements during a period of at least two months (see Draft DIN ISO 11665-4:2010-06). The initial investigation can establish the required level of intervention in the building by comparing the annual average activity concentration of radon in the building with the values of interest. - Additional radon measurements are recommended if the results of the initial measurements are higher than the values of interest. This second stage is used to identify the sources and/or transfer pathways of radon. It shall assist in the building diagnostic which suggests a suitable technical solution. The technical solution could be applied immediately, provided that the level of radon activity concentration justifies this. The measurements of this stage can also be requested by building assessors in order to determine the critical points and the means for rehabilitation more precisely. - Control of effectiveness of the agreed mitigation techniques after their installation. This control is carried out by measuring the activity concentration of radon, which shall be carried out under the same conditions at the location of the initial measurement. The measurement methods applied permit the comparability with the values of interest (initial investigation). The requirements are applicable for the control of the effectiveness and sustainability of the rehabilitation measures. The draft also includes the relevant requirements for the radon measurements with regard to these stages and the necessary skills. It does not include the building diagnostic, however. The DIN ISO 11665 (VDE 0493-1) standard series consists of the following parts, under the general title Measurement of radioactivity in the environment - Air: radon-222: Part 1: Origins of radon and its short-lived decay products and associated measurement methods - Part 2: Integrated measurement method for determining average potential alpha energy concentration of its short-lived decay products - Part 3: Spot measurement method of the potential alpha energy concentration of its short-lived decay products - Part 4: Integrated measurement method for determining average activity concentration using passive sampling and delayed analysis - Part 5: Continuous measurement method of the activity concentration - Part 6: Spot measurement method of the activity concentration - Part 7: Accumulation method for estimating surface exhalation rate - Part 8: Methodologies for initial and additional investigations in buildings. The following parts are under preparation: - Part 9: Method for determining exhalation rate of dense building materials - Part 10: Determination of diffusion coefficient in waterproof materials using activity concentration measurement - Part 11: Test method for soil gas with sampling at depth. The DIN IEC 61577 (VDE 0493-1-10) series published the following standards on radon measuring devices, under the general title "Radiation protection instrumentation - Radon and radon decay product measuring instruments" (intended as future series DIN EN 61577 (VDE 0493-1-10)): Part 1: General principles - Part 2: Specific requirements for Rn-222 and Rn-220 measuring instruments - Part 3: Specific requirements for radon decay product measuring instruments - Part 4: Equipment for the production of reference atmospheres containing radon isotopes and their decay products (STAR). The responsible committee is DKE/GUK 967.2 "Aktivitätsmessgeräte für den Strahlenschutz" ("Activity measuring instruments for radiation protection") of the DKE (German Commission for Electrical, Electronic and Information Technologies) at DIN and VDE.