Radon?

[solo_innova]

I am renovating a bit.
In my laundry room, I have found that the walls are made of some kind of aerated concrete.
It's built in 1965 and I wonder if it's something dangerous or radioactive.
I am attaching a picture of the stone.
Grateful for a very quick response as I need to do some masonry work.
The color is a bit faintly bluish, not very visible in the photo.

 

[Humulus]

Yes, it is definitely so-called blue lightweight concrete - which emits radon gas. There are products from different manufacturers and the degree of radon emission varies, this can be checked with a gamma meter (a type of Geiger counter). If I were you, I would probably replace it if possible with a more health-friendly material.

 

[jon_h]

If it's only the walls in the laundry room that have blåbetong, then there's no danger. It's only when the whole or large parts of the house consist of blåbetong that it can reach dangerous levels. You can read more here.

 

[solo_innova]

I tore down the walls. So it will be wooden studs instead now!

 

[klaskarlsson]

If it's just the walls in the laundry room that have blåbetong in them, then there's no danger. It's only when the entire house or large parts of it consist of blåbetong that it can reach dangerous levels. You can read more here.

Now you're creating Expressen headlines, jon

"Dangerous" is not exactly the word:

"Someone who is on average exposed to gamma radiation of 0.20 microsieverts per hour over an entire year receives a radiation dose of 1 millisievert. Someone who spends 80 percent of the year in a room with 1.2 microsieverts per hour thus receives a radiation dose of 5 millisieverts. The risk at this dose is so low that the responsible authorities, when the issue of gamma radiation in blåbetong houses was prepared in the Radon investigation of 1979, found no reason for restrictions on housing. However, the authorities have determined that the maximum permissible gamma radiation in new buildings in rooms where people stay more than temporarily should be 0.3 microsieverts per hour (Swedish National Board of Housing, Building and Planning Regulations BFS 2006:12, BBR 12"

Completely safe is rather the word, but if you're still worried, you can remove it as much as possible

/K

 

[jon_h]

You're right, it wasn't the best choice of words.

 

[Humulus]

However, you completely miss what is potentially serious from a risk perspective with blue lightweight concrete... Namely, besides the mentioned gamma radiation, it emits Radon gas. It is the decay products of the Radon gas, the so-called radon daughters, that pose the greatest health risk. It must, if applicable, be measured with a separate measurement method.

Now you're creating tabloid headlines jon

Dangerous isn't the word directly:

"Someone who on average throughout an entire year is exposed to gamma radiation of 0.20 microsieverts per hour receives a radiation dose of 1 millisievert. Someone who stays 80 percent of the year in a room with 1.2 microsieverts per hour thus receives a radiation dose of 5 millisieverts. The risk at this dose is so low that when the issue of gamma radiation in blue concrete houses was prepared in the Radon investigation in 1979, responsible authorities found no reason for restrictions on living. However, authorities have determined that in order to prevent new buildings from being constructed with high gamma radiation material, the limit for the highest allowed gamma radiation in new buildings in rooms where people spend more than a temporary amount of time should be 0.3 microsieverts per hour (Boverket's Building Regulations BFS 2006:12, BBR 12."

Completely harmless is rather the word, but if one is still worried, one can remove it as much as possible

/K

 

[klaskarlsson]

However, you are completely missing what is potentially serious in terms of risk with blue lightweight concrete... Namely that, in addition to the aforementioned gamma radiation, it emits radon gas. It is the decay products of radon gas, the so-called radon daughters, that pose the greatest health hazard. It must, in such cases, be measured with a separate measurement method.

That's true. And here, you should conduct a measurement if you're worried to see if you're below or above 200 bq/m3. To address radon gas, however, ventilation is primarily the solution. That is, exhaust air is a good method, for example. You can also avoid drilling too many holes in blue concrete walls, thereby keeping the wallpaper or paint layer intact and reducing radon gas emission.

But it is still the case that the official recommendation for houses with blue concrete is to replace it if you are going to make alterations anyway, but you don't need to replace it due to radiation risk, as the radiation risk is not dangerously elevated. And regarding radon, you should do a measurement. Radon comes from multiple sources apart from blue concrete, such as ground radon, which is even more common, so a measurement is probably good in any case.

/K

 

[Lmob]

My basement, which is a walk-out basement, is built with such stone, built in '66. Checked with a Geiger counter, not too high values but still did a radon measurement with dosimeters. It was around 80-100. But as they said earlier, it's probably the ground radon that's the worst. If the whole house isn't built with blåbetong.

 

[Humulus]

The aerated concrete was manufactured in several different locations and with materials from various sources, resulting in the content of the uranium-bearing alum shale varying by as much as a factor of 5 (from about 20uSv - 100uSv). Your values indicate that you probably don't have much ground radon and not any of the "worse" types of aerated concrete either! Do you remember which gamma values you got? (center of the room or by the wall).

my basement, which is partly built into a slope, is built with such stone, constructed in '66. checked with a Geiger counter, not too high values but still did a radon measurement with dosimeters. was about 80-100. but as mentioned earlier, it's probably the ground radon that's the worst unless the whole house is built with aerated concrete

 

[Lmob]

I think it was around 18 at all outer walls, they are insulated with 5 cm blåbetong. I got 30 on an inner wall, but it's gone now due to an oil leak. I measured radon after the wall change. You were supposed to measure about 20 cm from the wall.
It was only a digital meter, no strip or anything, that's why I don't remember exactly.

 

[Humulus]

18 sounds like among the least gamma-emitting materials, that's good! That also explains your relatively low levels of radon. A bit curious about the measurement done 20cm from the wall, SSI's method description indicates right against the wall and preferably in the middle of it. Furthermore, one should take a value in the middle of the room (room center). We also normally measure with regular handheld instruments without strip or connection to PC.

I think it was around 18 at all exterior walls, they are insulated with 5 cm blue concrete. One interior wall I got 30 but it's gone now due to an oil leak. I measured radon after the wall change. You should measure about 20 cm from the wall. It was just a digital meter, no strip or anything, that's why I don't remember exactly

 

[UoC]

If you are not a smoker or a passive smoker, there is no major reason to get upset. SSI states in Radiation Protection News 1/2001 that:
"The group of cases that were exposed to environmental tobacco smoke at home seemed to account for the entire risk increase, while those not exposed to environmental tobacco smoke showed no risk increase with increasing radon concentration."
Looking at the charts on the SSI page, there is a significant risk for smokers/passive smokers, but for people who are never exposed to smoke, the risk increase is extremely small/not detectable. I do live in a blue concrete house with elevated levels, which went from 540 bq to 100 bq with the installation of FTX ventilation. We chose to conduct radon remediation for safety's sake, but I am quite convinced that it is not necessary from a health standpoint, although it was worth it from a ventilation standpoint.

/UoC

 

[somelvis]

However, you completely miss what is potentially serious from a risk perspective with blue lightweight concrete... Namely, that apart from the aforementioned gamma radiation, it emits Radon gas. It is the decay products of the Radon gas, the so-called radon daughters, that are the greatest danger from a health perspective. It must, when present, be measured with a separate measurement method.

Completely ridiculous to "replace a wall" in lightweight concrete because of radon. The houses with the highest radon levels are in 99.9% of cases not lightweight concrete houses but completely ordinary wooden houses with a crawl space. There, you can reach 5000 - 6000 becquerels without people even bothering to measure because "it's a wooden house". Ground radon gives many times higher values than radon from building materials. Radon gas from building materials is ventilated out through air exchange and becomes very low. An FtX unit retains the heat and provides a significantly improved indoor climate.

 

[midvinter]

We have blåbetong walls in a space and I measured and it was under 100Bq. (3-month measurement) I think it was 40... and then we had very poor ventilation.. which has now improved! So do a measurement to investigate if the blåbetong emits a lot of radiation or not.