The assessment of radiological hazard due to external and internal indoor exposure was investigated for 26 raw granites collected from different granite quarries in Ranyah (KSA). The activity concentrations of 226Ra, 232Th and 40K were measured by high-resolution gamma spectrometry. Four granites were classified as “anomalous” due to their relatively high radioactivity. The averages and ranges of their activity concentrations were 667 (305 - 1120), 320 (161 - 491) and 586 (282 - 893) Bq·kg-1, respectively. The corresponding ones for all remaining 22 granites were 45 (18 - 77), 39 (16 - 73) and 1178 (954 - 1531) Bq·kg-1, respectively. In accordance with new European Basic Safety Standards (BSS) directives requiring a uniform reference level for indoor external exposure to gamma rays of 1 mSv·y-1, all 22 granites may be used as bulk or ornamental building materials without any restrictions. Three anomalous granites should be subjected to control to be used as bulk materials. One anomalous granite was categorized as hazardous having an activity concentration index higher than 6. All four anomalous granites exceeded the level of newly adopted reference level of 300 Bq·m-3 for radon indoor exposure in case of poor ventilation. Two of them exceeded even for adequate ventilation. ·
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