ABSTRACT
Granites are among the natural materials that deserve attention in terms of potential contribution to external gamma radiation due to the presence of U, Th and K. Based on the data on granitic rocks collected by Sanjurjo-Sánchez & Alves (2017) were selected some sets of values that were used with the factors of Markkanen (1995) to calculate the exposition time to achieve the yearly effective dose of 1 mSv. The consequences on historical buildings use are discussed.
