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Indoor Radon Measurements
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Indoor Radon Measurements

RADON v.o.s. performs measurements of indoor radon concentration (OAR) using electret dosemeters and measurements of gamma dose rate (D).

The evaluation of measurement results is based on the criteria given by the Czech Law No. 18/97 ("Atomic Law") with respect to changes given by the Czech Law No. 13/2002, and by the Decree of the State Office for Nuclear Safety No. 307/2002 on Radiation Protection.

Electret dosemeters and exposure chambers type RM-200 and RM-1000 (produced by the firm Nuklearni technika, Prague) are used for indoor radon measurements. The system was verified by the State Metrological Centre Kamenna. One measuring unit consists of two exposure chambers with electret dosemeters.

The gamma dose rate is measured using the radiometer DC-3E-98 (produced by ZMA Ostrov nad Ohri). The instrument was verified by the Czech Metrological Institute Prague.

Evaluation criteria are given by § 6 of the Law No. 18/97, with respect to changes given by the Czech Law No. 13/2002, and by § 93 to § 97 of the Decree No. 307/2002. Reference values of exposure to radon and to radon progeny indoors are defined as criteria that indicates the need to decrease the exposure to radon and to other natural radionuclides. The reference values are given by § 95. They enable to decide if the protection of the building against radon penetration from soils, building materials and water is sufficient, or if a remediation action is required to decrease the indoor radon concentration.

The reference value for new buildings is 200 Bq.m-3 (Rn concentration in air) in living space.

The reference value for existing buildings is 400 Bq.m-3 (Rn concentration in air) in living space.

The indoor radon concentration varies during an annual climatic cycle and it depends on meteorological conditions and other influencing factors. The short-term measurements of radon concentration (OAR) are useful when the shortage of time does not allow to use the dosemeters with a one-year exposure period. The short-term measurements enable to estimate annual average values of OAR. The short-term measurements should be made under conservative conditions, when higher indoor radon concentrations are expected (lower ventilation, heating in operation, etc.).

The couples of electret dosemeters are placed into measured rooms for one week.

RADON v.o.s., Novákových 6, 180 00 Praha 8    e-mail :