Radioactivity of granites: truth or myth

More and more often, buyers who are engaged in repairs or construction of a house put the issue of material safety first, since the main global trend in our time is maximum naturalness and environmental friendliness of materials.

Today, much is said about the environmental friendliness and radioactivity of granite, and whether this material is suitable for indoor use. This is due to some prejudices and rumors in relation to granites, in connection with which people have a question, how safe is granite, and whether it is worth installing countertops in the kitchen or window sills in living rooms. These rumors need to be sorted out, but first, it is necessary to clarify what radioactivity is and what classes it has.

Radioactivity

Radioactivity is radiation, the emission of rays by any body, for example the Sun (solar radiation) or another source. Radioactivity can be natural and artificial. Natural radioactivity has existed for billions of years, it is present literally everywhere. Radioactive materials have been part of the Earth since its birth, so it is obvious that any person, as an element of this Earth, is slightly radioactive: in the tissues of the human body, one of the main sources of natural radiation are potassium-40 and rubidium-87. Artificial radioactivity is the result of human activity. This includes all materials and processes created by man - X-rays, oil, gas and other fossil fuel production, the use of phosphate fertilizers, ore mining and processing, nuclear weapons testing, nuclear energy and industry.

Radioactivity Classification

The radioactivity classification of building materials is presented in Becquerels per kg (Bq/kg). Becquerel is a unit of measurementactivity radioactive source. One becquerel is defined as the activity of a source in which one radioactive decay occurs on average per second.

Construction materials containing radioactive substances are divided into application classes (the higher the class, the higher the radioactivity):

Class I - radioactivity content of no more than 370 Bq/kg. Materials of this class can be used in all types of construction without restrictions;

Class II - radioactivity no more than 740 Bq/kg. Materials belonging to this class can be used for external cladding and finishing, for the construction of industrial buildings and for road construction within populated areas;

Class III - radioactivity no more than 1500 Bq/kg. Materials for road construction, underground structures and communications, and for the construction of other objects, the time spent by people in which is no more than 50% of the working day.

For most common granites (more than 200 deposits), which are mined in Ukraine, the level of radioactivity falls under the first class, i.e. the materials can be used for all types of construction. For example, such a popular type of stone as gabbro has a value of 27.6 ± 0 Bq/kg, Ternovoye deposit - 144.7 ± 11.5. There are Ukrainian granites that belong to the 2nd class of radioactivity. For example, Kapustinskoye deposit is only 6 Bacquerels higher than the 1st class norm - 375.9 ± 21.4 Bq/kg, Tokovskoye deposit has a value of 736.1 ± 41.5 Bq/kg, Tanskoye - 552.3 ± 0 Bq/kg.

That is, in the main, granites belonging to the first class (all types of construction without restrictions) are used for the manufacture of kitchen countertops. The radiation content in granite is so small that it cannot compete with other natural sources of radiation. It is also necessary to take into account the short-term nature of human interaction with this material.

And, of course, it is necessary to mention one of the main factors “against” the concept of granite radioactivity – this is the growing competition. Manufacturers of individual and composite substitute goods, as their growth slows down and their own market becomes saturated, must constantly think about maintaining the growth rate. The “native” market is no longer so attractive, and this fact forces them to enter the field of natural materials producers. This is why, from time to time, such “throws in” about the great harm of granite in human life appear.