Ground Gas Protection Liverpool
Experts In Solutions For Ground Gas Membrane Verification
UK is facing a rising problem from harmful, naturally occurring ground gases and vapours. It is vital that the presence of ground gases and the risks associated with them are assessed and mitigated to protect the structure and its users.
Natural gasses or historical usage may cause gases to be present at a site.
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.
The gases and vapours listed above can cause cancer if they are not used in sufficient quantities. They may react chemically with concrete or plastic building materials and cause damage to the structure of the building. 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.
In accordance with CIRIA C735, an independent ‘Gas protection verification plan’ is required. It is important to follow a solid design and construction process in order to implement the gas protection measures. Once construction has passed independent verification, handover paperwork should be prepared. This should include any necessary measures during the remaining construction phase, such as to prevent damage and during maintenance and operation.
It is recommended that specialist advice is obtained in the assessment of the ground gas data and at the risk assessment phase. These are the most important documents you need to know and to 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+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 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.
Leading experts in ground gas membrane installation validation and integrity testing in Liverpool and across Scotland
How does ground gas happen?
Why has ground gas become such a problem
Ground gases were not considered a danger to buildings or users in the past. Also the requirement for more new homes has led to the increase of development on previously developed sites, (Brownfield sites) as finding new sites to develop on has become increasingly difficult. Brownfield sites however can often contain pollutants affecting the ground and 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.
Assessment of ground gas risk
The potential for a risk from ground gases and vapours is firstly assessed at desk stage, with ground investigation or assessment designed accordingly if risks of ground gases are identified then measurement using monitoring wells in boreholes will normally be used as part of the investigations. 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.
After the investigation is complete, an interpretation of the measurement data can be used to determine whether ground gases or vapours are at risk.
Protection from below ground gasses
Ground gas protection is an extremely specialised operation. GeoShields Ground Gas specialists have the required knowledge, experience and skill levels.
Ground gas protection is often achieved by ventilation and ground membranes in construction. This provides primary and secondary protection against the ingress of gases. A foundation-based ground gas protection system is unlikely to be practical if you’re already a homeowner. Ventilation is therefore the most important factor. Ventilation can use a combination of natural ventilation for suspended floors, improved underfloor ventilation and the introduction of mechanical ventilation systems so that the harmful ground gases can be safely controlled and vented away from the property. In every case, validation of the construction methods and their installation is necessary.
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's the impact of not doing something?
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. As low as 5% can make methane flammable.
The property may be deemed too dangerous for mortgage lenders.
What is Ground Gas Membrane?
Ground gases are dangerous and buildings need to be protected. This protects the structure’s integrity as well as anyone inside it. Protection is usually in the for of a ground gas membrane.
Ground gas protection membranes are usually constructed from polymers but also include other materials such as aluminium. This allows them to be lightweight, flexible and formable. They can stop gas from getting into buildings and the ground.