Radon

Radon is a colorless, odorless and tasteless noble gas. Radon is found everywhere in nature. Like other noble gases, radon hardly forms any chemical compounds and is soluble in water and fat.

The earth's crust has contained radioactive, extremely long-lived uranium since the earth was formed. Over the course of time, radioactive secondary products such as radium-226 are formed under the emission of alpha, beta and gamma radiation. This radium-226, which is present practically everywhere in the earth's crust, decays into radon-222 under the emission of alpha radiation. It is constantly being regenerated in the soil and released into soil pores and soil air.

Radon diffuses through the ground to the surface and escapes into the atmospheric air. Radon-222 has a half-life of 3.82 days. During this time, radon breaks down into other radioactive decay products that are no longer gaseous but solid (heavy metal).

Radon and its secondary products Po-218 → Pb-214 → Bi-214 → Po-214, which are relevant from the point of view of radiation protection, are formed in the air and accumulate mainly in aerosols.

Attention danger!

These radioactive aerosols are transported into the human lungs with the air we breathe. Here they attach themselves to the sensitive lung tissue and continue to decay. They damage cell tissue and human DNA and can cause lung cancer.

• Radon and its radioactive derivatives have been shown to increase the risk of lung cancer. The duration and level of exposure determine the risk.
• Studies across Europe prove ....
• Radon in homes causes 5% of lung cancer deaths, which correpsonds to about 1,900 deaths per year.
• Radon is the second most important risk factor for lung cancer, after smoking!
• Smoking and Radon mutually reinforce each other.
• Radon represents the greatest risk of developing lung cancer for lifelong non-smokers.
• For every 100 Bq / m³ of long-term Radon concentration, the risk of lung cancer increases by about 16%.
• There is no indication of a threshold below which Radon would not be dangerous.

Radon escaping from the ground can penetrate and accumulate practically anywhere where moisture can also enter buildings.

Radon risk areas are those areas with an increased level of radon above a reference value.

Reference should be made to maps in the BRE Report - BRE 211 and via : https://www.ukradon.org/information/ukmaps as to determining the level of risk to your building.

For Northern Ireland: Please refer to Public Health England inidicative atlas for Northern Ireland https://www.gov.uk/government/publications/radon-indicative-atlas-for-northern-ireland and in Republic of Ireland http://www.epa.ie/radiation/radonmap/

While terminology may vary within the different regional building regulations, guidance document maps will give the level of associated risk and determine the required level of radon protection either “basic” or “full”.

“Basic” protection means you need to lay a ground floor radon membrane and “full” protection means that in addition, you need to make provision for underfloor depressurisation by installation of a sump or subfloor ventilation.

For details on depressurisation, please refer to BRE 211.

• Reference / guide value

The guideline for reference value in the UK and Ireland is 200 Bq/m³ indoors. If this value is exceeded, reduction measures should be taken. In the UK and Ireland the average value of the radon concentration in the air near the ground is approx. 10 Bq/m³.

Attention!

According to current information from the Federal Office for Radiation Protection (BfS) & World Health Organization (WHO), protective measures are recommended from an annual mean of 100 Bq / m³.

• Reference value, Guide value, no limit value

A reference value is limit that must not be exceeded. Protective measures do not make sense if they are exceeded. The reference value is used to evaluate radon concentrations.

A reference value is not a limit ! There are significant differences:
A limit is a value that must not be exceeded.

A reference / or guideline value is a value which should be followed and adhered to in order not to act negligently or grossly negligent under any circumstances.

Because radon is of natural origin, the radiation source cannot be removed and a risk can be detected even with naturally occurring radon concentrations.

A limit value only makes sense if the extent of radiation level can be controlled and the amount of radioactive material can be adjusted, exposure can be controlled and protective measures can be taken.

If a limit for radon concentrations in buildings were defined, measures would have to be taken there. Consequently, restrictions on use or renovation measures in private buildings would be absolutely necessary. Measures required by defining a limit value are not considered appropriate by international radiation protection experts. It was agreed that there should only be one reference value for radon.

Under the Safety, Health and Welfare at Work Act 2005, employers must identify hazards in their workplace which includes radon, assess the risk and eliminate or reduce and control the risk. In addition, Section 8(2)(d) of the Act requires that the employer ensures, so far as it is reasonably practicable, the safety and the prevention of risk to health at work of his or her employees relating to the exposure to ionising or other radiations.

Nuclear track detectors have become established for long-term measurement of interior radon occurrence. They register the radon concentration over a defined time. No measurement effect is lost. According to the Radiation Protection Commission, it is recommended to perform assessment measurements with nuclear trace detectors over a period of twelve months. Alternatively, a measurement can also take place over three months in spring or autumn.

Our tip:

Setting up radon measuring devices is comparatively simple.

• Measuring times of 12 months are recommended due to strong fluctuations in indoor radon.
• Advice on measuring radon can be found via https://www.radon.org/ or http://www.epa.ie/

Due to basement walls being in contact with the surrounding ground, the radon levels in a basement can be considerably higher than that of a standard house. All basements are at risk regardless of location within a higher risk area or not.

Where newly consructed or an existing basement conversion, the waterproofing should be designed to protect against radon and the ingress of groundwater. Remmers MB 2K can be used as a combined product for this application.

Tninsg to know about the protection against radon
The gas permeability of a sealing material depends both on its material composition and on the properties of the penetrating gas. Noble gases such as radon, diffuse particularly well as single atoms through porous substances. In particular, the half-life (the period of time after which half of the originally present quantity of the isotope has been decomposed by radioactive decay) of radon must be taken into account (3.82 days). The radioactive decay takes place within the components if the diffusion time of radon atoms through the materials to be diffused is several half-lives. The decay products that form are then no longer gaseous and are bound in the building material, i.e they do not reach the ambient air and are therefore harmless to humans.

Radon-tight materials must be at least three times as thick as the diffusion length of radon, according to a proposal that has now been accepted by scientists*.

* Keller, G .; Hoffmann, B .; Feigenspan, Th .: "Radon permeability and radon exhalation of building materials", Science of the total environment 272 (1-3), pp. 85-89 (2001), doi: 10.1016 / S0048-9697 (01) 00669-6