In India, bricks as building materials are mainly prepared by clay using the deposited sediments of rivers, and the radionuclide contents in bricks and brick-making clays should vary with origin and geological condition. Primordial radionuclides in building materials are one of the sources of radiation hazard in dwellings made of these materials. It is important to measure the natural radioactivity due to gamma rays from building materials and consequently to determine the dose rate from these materials. This helps to important precautionary measures whenever the dose rate is found to be above the recommended limits. The aim of this work was to measure the specific activity concentration of 226Ra, 232Th and 40K in bricks and brick making clay from Namakkal, Tamilnadu, India using gamma ray spectrometer. The radiation hazard of the total natural radioactivity in the studied brick and clay was estimated by different approaches. From the analysis, it is found that these bricks may be safely used as construction materials and do not pose significant radiation hazards.
