Ground Gas Protection Manchester
Experts In Solutions For Ground Gas Membrane Validation
UK is facing a rising problem from harmful, naturally occurring ground gases and vapours. To protect both the structure and its users, it is crucial that ground gases are identified and managed.
A site could have natural gasses, or they may be the result of an historical use.
Naturally occurring gases include methane, carbon dioxide, nitrogen and radon and many of these can be present within the soil at elevated concentrations relative to normal atmospheric gases.
Sites whose previous use was as a landfill, heavy industrial use, or where petrol, oil or solvents may have spilled can also generate hazardous gases such as methane, carbon dioxide, volatile organic compounds (VOCs) such as benzene and trace gas components such as hydrogen sulphide and carbon monoxide.
The gases and vapours listed above can cause cancer if they are not used in sufficient quantities. Some may also chemically interact with the concrete and plastic building materials, affecting the structural integrity of the building. They can be found in buildings and other structures above and below ground.
The different types of gases are;
- Radon
- Carbon Dioxide
- Nitrogen
- Methane
- Hydrogen
- Sulphide
- Volatile organic compounds (VOC)
Radon, carbon dioxide and methane gasses, as well as VOCs (Volatile Organic compounds such as hydrocarbons), pose a danger to your health. Therefore, new constructions must use the appropriate materials to keep them out.
According to CIRIA C735, a separate ‘Gas safety verification plan’ (or ‘Gas protection verification document’) is required. For gas protection, it is necessary to follow a robust design process and construct the building. After the construction has been verified, it is time to prepare handover documentation. This document should outline any additional measures that may be required, such as those necessary for preventing damage or during operation and maintenance.
It is strongly recommended that specialists be consulted during the assessment of groundgas data as well as the risk assessment phase. Here are some key documents you should know about and that you can refer to:
- BS 8485:2015+A1:2019 - Codes of practice for the design of protective measures for methane and carbon dioxide ground gases for new buildings.
- CIRIA C748:2014 - Guidance on the use of plastic membranes as VOC vapour barriers
- CIRIA C682:2009 - VOC Handbook
- CIRIA C735:2014 - Good practice on testing and verification of protection systems to buildings from hazardous gases
- BS 8102:2009 - Code of practice for protection of below ground structures against water from the ground
BS8485 2015 + A1 2019, provides guidelines on ground gas site classification and the choice for solutions for the design integral gas protective devices for new buildings. These measures are designed to prevent entry of carbon dioxide or methane, and provide an internal environment that is safe. It offers a process that can be used to demonstrate that risks posed by the potential or actual presence of carbon dioxide and methane have been addressed.
Call our Manchester team for further information on ensuring that the installation of your gas protection systems meets CIRIA 735 & BS8485
How does ground gas occur?
Why is ground gas becoming a problem?
Ground gases were not considered a danger to buildings or users in the past. In order to provide more homes, developers have begun to build on brownfield sites. It is now becoming harder to find sites suitable for development. Brownfield sites may contain contaminants that can affect the ground or soil.
Because of increased awareness about the dangers, the Environment Agency has created new legislation that is more strict in dealing with ground gas issues. It has been adopted across the country by local authorities.
It is important that you note that possible risk factors cannot be determined without a detailed ground gas investigation by a qualified ground gas surveyor.
Ground gas risk assessment
The risk from ground gases or vapours must be assessed first at the desk stage. If ground gas risks are identified, then borehole measurement will be performed. Diffusion tubes and other static measurement techniques are possible in existing buildings. Depending on the nature and severity of the risk, monitoring programmes can last from days to months.
After the investigation is completed, the interpretation and assessment of the measurement data will determine if there is any risk from ground gases or vapours.
Protection against below ground gases
Ground gas protection is an extremely specialised operation. GeoShields Ground Gas specialists have the required knowledge, experience and skill levels.
Mitigation of the harmful ground gases is usually provided by the use of ventilation and ground gas membranes during construction design, which provides both primary and secondary forms of protection for buildings from the ingress of gases and vapours. Foundation-based ground gas protection will not work if you are an existing homeowner. Ventilation is key. A combination of natural ventilation on suspended floors, better underfloor ventilation, or the introduction of mechanical ventilation systems can be used to ventilate. The harmful gases can then be safely controlled and vented out of the property. In all cases, it is important to verify the construction as well as the installation techniques.
Some cases in which the dangers posed by gases or vapours are due a by-product more severe soil and groundwater contamination can be mitigated through the remediation.
What could be the effect of doing nothing?
The effect of not reacting to potential ground gas risks depends on which type of ground gas was discovered. Some may affect your health while others can damage the integrity of the building. Radiant exposure can lead to lung cancer. Carbon Dioxide may cause death from asphyxiation. Methane (and other volatile organic compounds) can ignite and be flammable. Methane can be flammable at levels as low as 5%
Not only will it have serious consequences for your health, but also the possibility of fire, mortgage lenders may consider the property too dangerous.
What is Ground Gas Membrane exactly?
Ground gases are dangerous and buildings need to be protected. This protects the structure’s integrity as well as anyone inside it. Protection can be found in the form of a ground-gas membrane.
Ground gas protection membranes are typically made from polymers, but can also be made with other materials like aluminium. This allows them to be light and flexible while still being formable. They can stop gas from getting into buildings and the ground.
Call our Manchester team for further information on ensuring that the installation of your gas protection systems meets CIRIA 735 & BS8485
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