Birmingham Ground Gas Protection
Experts In Solutions For Ground Gas Membrane Verification
UK residents are facing increasing problems from dangerous, naturally occurring below-ground gasses 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.
The naturally occurring gases methane is carbon dioxide, nitrogen, and radon. However, these gases can also be found in soil in elevated concentrations relative with normal atmospheric gasses.
Sites with a history of heavy industrial use, landfills, or spillage of petrol, oil, or solvents can produce dangerous gases such methane and carbon dioxide.
Each of the gases and vapours mentioned above have different properties. Some are asphyxiating, flammable and potentially explosive. Others can be toxic and, over many decades, can cause cancer. Some can chemically interact with concrete and other plastic building materials, affecting its structural integrity. They can be found in buildings and other structures above and below ground.
These are the different types of gases
- 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.
A ‘Gas Protection Verification Plan’ independent of CIRIA C735 is required. A robust design and construction process should then be followed to install the gas protection measures and the requirements of ‘verification plan’ implemented. After construction passes independent verification, handover documentation should then be prepared. It should detail any steps required during the construction process to prevent damage as well as for the operation and maintenance of the building.
Specialist advice is highly recommended during the assessment and risk assessment phases of ground gas data. Below are some important documents to keep in mind and reference:
- 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+A1 2019 offers recommendations on ground-gas site characterisation and the selections of solutions to design integral gas protective mechanisms for new buildings. This is done in order to prevent methane and carbon dioxide from entering and maintain a safe interior environment. It provides a way to demonstrate that potential or actual carbon dioxide and methane risks have been mitigated.
Call our Birmingham team today to book your gas protection systems verification inspection
How does ground-gas occur?
Why is ground gas becoming a problem?
In the past ground gases where not perceived as a risk to users and the buildings themselves. As it is becoming increasingly difficult to find suitable sites for development, there has been an increase in the number of brownfield sites. However, brownfield sites can contain soil and ground pollutants.
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. Existing buildings can be monitored using static measurement methods and diffusion tubes. Depending on the nature and severity of the risk, monitoring programmes can last from days to months.
Once the investigation has been completed, the analysis and interpretation of measurement data will reveal whether there are ground gases or vapours.
Protection against below-ground gases
Ground gas protection can be a complex operation. GeoShields Ground Gas Specialists have the necessary knowledge, experience, and skills.
Ground gas protection is often achieved by ventilation and ground membranes in construction. This provides primary and secondary protection against the ingress of gases. If you are already a homeowner living in a property then foundation based ground gas protection will most likely be impractical. Ventilation is therefore the most important factor. The best ventilation is a combination natural ventilation for suspended floors, underfloor ventilation, and mechanical ventilation systems. This will allow harmful ground gases to be safely controlled and vented from the property. In all cases validation of the construction and the installation techniques is important.
There are some situations where gases and vapours may pose risks because they are a byproduct of soil or groundwater contamination. This can be mitigated by remediating the source of contamination.
What could be the effect of doing nothing?
The impact of not responding to the potential ground-gas risk depends on the type and extent of the ground gas. Some ground gases can affect your health, others may cause damage to the building’s integrity. Radon can cause lung cancer. Carbon Dioxide can cause asphyxiation and can be deadly. Methane, Volatile organic compounds, and Methane can all be explosive/flammable. Low levels of Methane (5%) can make it flammable.
The property may be deemed too dangerous for mortgage lenders.
What is Ground Gas Membrane?
Due to the hazardous nature of ground gasses, buildings should be protected to ensure safety and integrity. 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 prevent gas from flowing into the building from the ground.
Call our Birmingham team today to book your gas protection systems verification inspection
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