Today we will tell you about one of our first property inspections – about 6 years ago. Our client wanted to buy an apartment. He was in the final stage of negotiations and right before signing a preliminary contract (Thanks God). He asked us to scan the object of his desires – a two-bedroom apartment, on the third floor, in a small apartment building. At first glance, there were no red flags. Sturdy, reinforced concrete construction and decent insulation. Low electromagnetic pollution, good insulation and window frames with little heat loss… everything looked like it could be the perfect home for this lovely family. Up until we pulled out the Geiger counter and started our inspection for elevated background gamma radiation on walls and ceilings. To our surprise, almost the entire interior of the home was made of plasterboard. In almost the entire area of walls and ceilings, the Geiger-Muller counter read between 0.380 and 0.420 µSv/h (micro Sieverts per hour).
Is an average of 0.400 µSv/h too much?
Typically, construction materials used in the interior, have a gamma radiation of 0.150 to 0.220, sometimes 0.250 µSv/h. Above 0.300 µSv/h … we saw for the very first time. We checked once again the places where the device recorded the highest values. Unfortunately, the results have been confirmed.
What does this value of 0.400 µSv/h mean and how does it affect people?
The equivalent of 0.400 µSv/h is close to 3.5 mSv/y (millisieverts per year). This is the permissible annual dose of radiation for miners in uranium mines in Canada and Australia. A norm that is accepted for workers in uranium mines is far from being considered safe for a residential place you inhabit 14 to 24 hours a day on average. Of course, we should specify that this is the background gamma at the source, that is, the wall, and not at the places where you will sleep, study, work and play.
For more precise results, we suggested using a personal dosimeter for several days, which counts the radiation received by the body and not emitted by the walls, thereby eliminating factors such as distance, clothing, etc. However, our client decided not to do a dosimetry study and take unnecessary risk and cancelled the purchase of the flat.
Verdict: One saved on time.