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As individuals, every year we are exposed to many different types of radiation from both natural and man-made sources, including cosmic radiation that reaches us from space as well as routine medical devices such as X-ray machines. However, a much more elusive source comes from radon gas that is responsible for the majority of radiation exposure by far – in the UK accounting for an estimated 50% of yearly exposure.
Radon gas is all around us and results from the decay of another radioactive element – uranium. These deposits are found within the Earth and just like many other more popular radioactive elements have been around for eons. What makes radon remarkable from the other radioactive substance is that just like other hazardous gases it has the typical hallmarks: it’s odorless, colorless, tasteless and therefore difficult to detect by the human senses – as a result you may not know how much you are inhaling.
What are the Risks?
According to the Agency for Toxic Substances and Disease Registry from the U.S. Public Health Service, there are around 150 atoms of radon per milliliter of air. Therefore, avoiding complete exposure is simply impossible, yet, this doesn’t mean we are at risk of developing cancers and other diseases associated with radon exposure.
The risks associated with radon exposure are related to the amount you are exposed to. The typical radon concentration outside is around 10 Bq/m3. The U.S. Environmental Protection Agency (EPA) recommends radon levels at home below 148 Bq/m3. For instance, in the case of lung cancer, the WHO highlights that the risk of the disease increases 16% per 100 Bq/m3 of radon exposure.
As well as the amount of radon you’re exposed to, your risk is also determined by a range of other important factors too, such as age and the length of exposure. Radon deposits also very dependant on location and increased exposure has been linked to areas with particularly high deposits.
Testing your Home for Radon
Unlike other pathogenic substances such as asbestos, carbon monoxide, lead, and cigarette smoke, there is no solid evidence that low-level radon exposure is a substantial hazard when isolated from cigarette smoke. As a result, sparse legislation has resulted, meaning the EPA has largely relied on fear tactics to overplay the significance of the limited evidence produced to date.
Regardless, there is no denying that radon does cause cancer and as the government and EPA have been powerless to draw up any new laws, it is largely up to homeowners themselves to determine the risks. First thing first, you ought to check the levels of radon present in your home, this can be achieved easily and affordably using a digital radon testing detector.
Radon Mitigation Systems
Once you have determined your radon levels and come to the conclusion that you need to take some form of action, you will need to decide which method to opt for in order to mitigate or remove radon from your home. This can be a costly exercise, but there are quite a number of mitigation techniques that are relatively inexpensive and since they also help to increase the energy efficiency of your home they’re also a worthwhile investment.
Sealing your home to keep Radon out –
Taking the necessary steps to ensure radon gas entering your home is limited to the greatest extent is perhaps the most cost-effective method. This includes cheap and effective measures such as caulking cracks in floors, sealing openings to drains and draught-proofing your home.
As well as helping to reduce levels of radon in your home, these measures also help increase the energy efficiency of your home, meaning you won’t need to use your heating as much and the heat you do have will stay inside your home for longer. For more information on how to effectively draught-proof and insulate your home and employ other energy-saving tactics, check out our blog for more info.
Removing Radon from your Home –
Since the main source of radon is from the earth beneath your home, the main target of mitigating radon is the foundations of the property i.e. the basement, or slab – concrete installed at ground level, or the crawl space – a shallow space underneath the first floor. The type of mitigation system you install is largely dictated by the type of foundation your home has.
These methods work on the principle of depressurization. Since the air pressure in the majority of buildings is lower than the external ground, it is possible for gases to be drawn into the property. Depressurization helps to reduce the pressure beneath the foundations by causing a negative pressure beneath the foundation. The result is that gases are drawn from underneath the home to the outside of the building and away from your homes venting.
For homes with a basement or slab foundation:
Sub-slab depressurization also referred to as active sub-slab suction is a method used to reduce the air pressure below the concrete slab relative to the air pressure indoors by utilizing a fan powered vent which sucks air from beneath the concrete foundation.
This is one of the most common approaches and entails installing suction pipes through the foundation of the property, or alternatively directly underneath. This involves boring holes into the soil or slab and removing some soil to create an area for effective suction to take place. Typically just one or two pipes are required, which are then connected to a fan that draws the gas vapors to the outside.
For homes with a crawl space:
Sub-slab ventilation is the go-to option in properties that have a crawl space with bare soil since the soil permeability is often so high that it’s impossible to maintain a pressure gradient beneath the building to achieve negative pressure.
This method utilizes a very similar set-up to sub-slab depressurization, but instead of installing pipes it utilizes existing property pipework such as drains or sump holes that act to draw radon vapors from the building to the external environment. In order to maintain the pressure gradient, plastic sheeting is laid over the earth floors.
Passive vs. Active depressurization
In some instances, a fan isn’t required and instead, passive ventilation is pursued with the use of additional vents being fitted. Instead of the pipes being connected to a fan that actively draws radon vapors out, the pipework is vented to the exterior of the building and relies on natural air currents to expunge gas from beneath the building.
The passive effect operates on the law that higher pressure gases ascend via the route of least resistance to the lower pressure exterior air. However, since air currents are not consistent, this configuration is most suitable in circumstances where vapor infringement is very limited, but still a potential cause for concern.
If you live in a particularly cold or seasonal climate, then ensuring pipework such as drains and slump and water pipes are well insulated is essential to reduce heat loss.