ISO 11665 discusses the measurement of radioactivity in the environment. Since radon present in soil can leech into the environment, it can pose a health risk to occupants of buildings where it has entered indoor air. It is important to measure the quantity of radon in this air to determine whether the occupants are safe.
ISO 11665‑3 is the third part of the multi-series on measurement of radioactivity in the environment that describes spot measurement methods for determining the activity concentration of short-lived radon-222 decay products in the air and for calculating the potential alpha energy concentration.
ISO 11665‑3 gives indications for performing a spot measurement of the potential alpha energy concentration, after sampling at a given place for several minutes, and the conditions of use for the measuring devices. This measurement method is applicable to air samples with potential alpha energy concentration greater than 5 nJ/m3.
The measurement method in ISO 11665‑3 is applicable for a rapid assessment of the potential alpha energy concentration. The result obtained cannot be extrapolated to an annual estimate potential alpha energy concentration of short-lived radon-222 decay products.
ISO 11665‑3 on measurement of radioactivity in the environment is useful for:
Radon present in soil enters buildings via diffusion. Over time, radon concentration in indoor air can increase, posing a health hazard for occupants of the building. Indoor radon activity concentration depends on radon activity concentration in the underlying soil, the building structure, the equipment (chimney, ventilation systems, among others), the environmental parameters of the building (temperature, pressure, etc.) and the occupants’ lifestyle.
To limit the risk to individuals, a national reference level of 100 Bq.m-3 is recommended by the World Health Organization. ISO 11665‑3 deals with spot measurement methods.
ISO 11665‑3 provides a spot measurement method to reduce the risk to the overall population. Building codes should be implemented that require radon prevention measures in buildings under construction and radon mitigating measures in existing buildings. Radon measurements are needed because building codes alone cannot guarantee that radon concentrations are below the reference level.
ISO 11665-3
EN ISO 11665-3