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Background - Radon

Map of the UK
Radon Map -
England & Wales
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The radioactive gas Radon is a hazard in many homes and workplaces. Breathing in radon is the second largest cause of lung cancer in the UK resulting in up to 2000 fatal cancers per year. Naturally occurring, it is particularly prevalent in granite and limestone areas but not exclusively so. Radon levels vary not only between different parts of the country but even between neighbouring buildings.

The principal areas of the country in which radon is a problem are the granite areas of Cornwall and Devon, and the limestone areas of Derbyshire, Northamptonshire, North Oxfordshire, Lincolnshire, and Somerset, however there are many other areas in England and Wales affected by radon.

Concentrations in the open air are very low. However radon that enters enclosed spaces, such as buildings, can reach relatively high concentrations in some circumstances. Radon from the ground is drawn into buildings through cracks and gaps because the atmospheric pressure inside the building is usually slightly lower than the pressure in the underlying soil.

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Background - Landfill Gas/Ground Gas

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Landfill Gas

Landfill gas occurs when the organic content of household waste is broken down by bacteria into Methane (CH4) and Carbon dioxide (CO2). The production of landfill gas is a recent problem as the organic waste content of landfills has increased since the introduction of the first Clean Air Act in 1956. Before this, most domestic waste was burnt and so landfill sites contained a high proportion of ash, a material that does not generate large quantities of landfill gas. It should also be noted that it is not just domestic waste landfills that produce gases, industrial and demolition waste landfills may also have the potential to generate large quantities of landfill gas.

Both Methane and Carbon dioxide are odourless and colourless and it is only the presence of trace gases that produces the distinctive landfill gas odour. There are many hundreds of types of trace gases but most do not usually represent a health hazard following normal atmospheric dilution.

Ground Gas

Ground gas is mainly composed of Methane and Carbon dioxide and presents similar risks to that of landfill gas. Ground gas can be formed by natural or man-made means. The following are common sources and their typical components:

  • Peat bogs and mosslands (CH4, CO2)
  • Uranium bearing rocks such as granites (Radon)
  • Carbonate rocks such as limestone and chalk (CO2)
  • Organic rich rocks such as coal measures (CH4, CO2, H2S)
  • River and lake sediments (CH4, CO2, H2S)
  • Made ground (ground that has been formed by the activities of man and can consist of natural or man made materials) (CH4, CO2, H2S, VOCs and any other gas)
  • Farmland
  • Sewers

Precautions need to be taken for Methane as it may give rise to a variety of hazards if it migrates to, and accumulates in, a property or confined spaces. If generated in sufficient quantity the gas may form an explosive mixture with air. It can also act as an asphyxiant and in particular circumstances it may be toxic.

Carbon dioxide is an asphyxiating gas and causes adverse health effects, unconsciousness or even death at relatively low concentrations (at approximately 5% by volume in air).

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Ground Gas/Radon Mitigation in Basements

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Where existing basements occur in areas at risk of Radon (refer to map link at top of this page) then suitable measures need to be taken to reduce the amount of Radon entering the property through the basement. For more detailed information please refer to BRE Guidance 343 - Guide to Remedial Measures in Existing Dwellings (available from BRE book shop - see useful links below) which identifies following methods of reducing the amount of radon entering the basement:

In areas shown as light grey on the maps, then an appropriately installed waterproofing system would generally suffice. However in areas with high radon levels, then the installation of a Platon cavity drain system along with a Triton Radon Sump and/or Positive Pressure Fan would be appropriate. It is always recommended to monitor the basement Radon levels after installation to ensure the installed measures are more than adequate.

A typical example of the Triton/Platon cavity drain system is shown in the diagram below with additional information given in the Triton Gas and Waterproof Membrane data sheet.

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In new build basements, and in accordance with current Building Regulations Part C, a ground investigation survey should be carried out to identify the presence of ground gases including Radon and other contaminants - both solid and liquid. Appropriate measures should also be taken to limit their effect on the basement and the remainder of the property. Please refer to The Building Regulations 2000 Part C - Approved Document Basements for dwellings, published by the Basement Information Centre. (This document is available from the publications section of the Basement Information Centre website - see useful links below.)

Reference should also be made to BS8102 (2009) - Protection of structures against water from the ground. (This can also be purchased via the Basement Information Centre website - see useful links below.)

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Platon Radon Stop 400

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Platon Radon Stop 400 prevents air leaks from the ground and provides a safe and effective protection against dangerous concentrations of Radon and other ground gases from penetrating a building. Radon Stop acts at the same time as a robust and solid damp proof membrane.

It is a non-reinforced polythene film with high strength and flexibility. The film is supplied in 4M widths and is installed with overlaps which are sealed with sealer and butyl sealing tape. A complete system of components is supplied including preformed details for sealing around pipes and for strengthening corners.

The film is used as a ground gas and damp proof membrane in slab on ground construction. It can be laid under the concrete slab (protected in the upper insulation layer) or laid direct on the concrete slab.

Full installation instructions are provided in the product literature which can be downloaded below.

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Triton TT Vapour Membrane

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A ready blended coating that once cured, provides a waterproof Radon, Methane and Carbon Dioxide barrier. Triton TT Vapour Barrier can be retro-applied as a waterproof and gas-proof membrane to concrete, masonry and brick substrates or as an alternative to sheet membranes in new construction. It can be applied by airless spray, roller or brush to walls, floors and soffits.

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Platon Multi

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A cavity drain membrane designed for internal use as a structural waterproofing membrane as well as a gas barrier. Platon Multi is BBA approved and impermeable to water, gas and water vapour. A key application is the upgrading of contaminated floors.

Platon Multi can be dry lined on walls, screeded, or finished with a dry board system on floors. Particularly suitable for floors in industrial buildings, as it will transfer loading through screed layers to the underlying concrete floor. Platon Multi can be used in conjunction with other Platon membranes and the Triton Aqua Channel and Pump system.

Gas Barrier Data Sheet - Platon Membranes
Download (1.3Mb)

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Radon Sump & Fan Kit

Triton’s Radon Sump & Fan Kit comprises:

  • Ground Gas Fan
  • Perforated Preformed Sump
  • Sealing Gaskets
  • Platon Sealer and Tapes
  • Connectors

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Radon Monitoring Kits

Triton’s Radon Monitoring Kits are supplied with a stamped return envelope so customers can post the detectors back for analysis. Results are then emailed back to the customer in the form of a certificate. Triton supplies 7-day or 3-month detectors in single or double packs. They are supplied with full instructions for use. The detectors are supplied in radon-proof bags (which should be re-used to return the detectors) and should be stored in the freezer if measurement is not to be started immediately. The detectors can be stored in the freezer for a maximum of six months.

The 7-day measurement period gives a result stating whether the radon exposure level is high or low, whereas the 3-month period will give a measure of the average radon level in a property.

Size: Radius 2.25cm, Height 2cm, Weight 12g

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Positive Pressure Units

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Positive pressure units are designed to eliminate moisture from the home by a constant circulation of gently pressurised, clean air. Installed in either the loft of a house or a hallway cupboard in a flat, the gentle pressurisation of the property expels any stale, humid air through natural ventilation points which are present in even the most insulated buildings.

Up to four humidity sensors can be fitted around the home all connected back to the main units described below to ensure total control. The air is delivered to the property through a centrally located inlet grille on the landing or hallway ceiling or a wall grille for properties without lofts.

Running costs: Both the units described below are rated at 7 watt slow and 14 watt fast. Assuming electricity costs of 12 pence per unit, and that the units might be used for an average of one hour per day, running costs would equate to just 3 pence per day/21 pence per week.

Triton Positive Pressure Unit - No Loft

A cupboard mounted unit for properties without lofts. Low wattage with 2-speed manually operated switch. Extract speed 55 litres/second on fast speed or 44 litres/second on slow speed. Noise level (at full speed) is just 20dBA.

Triton Positive Pressure Unit - Loft

A loft mounted unit for installation in properties with loft space. Low wattage with 2-speed manually operated switch. Extract speed 55 litres/second on fast speed or 44 litres/second on slow speed. Noise level (at full speed) is just 25dBA.

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Useful Links

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For further technical and
sales information
please call us on
020 8310 3929
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CAD Drawing:
Typical Cavity Drain &
Radon Sump Detail
Download

CAD Drawing:
Sealing Radon Extraction
through Platon Cavity
Drain System
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