Ground Gas Assessments

 

Ground Gas Solutions

At Roberts Environmental we are experts in Ground Gas Assessments, making us well placed to advise you on any implications this might have on the potential future development of a site.

Ground Gas Assessments are a typical requirement in Planning Applications and it is the experience of Roberts Environmental that where a potential gas hazard has been identified, the Local Authorities are becoming more stringent with regards to the scope of gas protection and validation that they will accept.

Ground gas ingress into buildings can be a significant issue for new developments and has the potential to arise from natural or man-made ground conditions including mining. Ground gas also includes Radon which affects the UK to varying degrees.

Ground gas ingress can cause harm to both health and property, by displacing oxygen causing asphyxiation or poisoning, and by creating a potentially flammable/explosive atmosphere particularly in confined spaces.

In Loscoe Derbyshire in 1986, gas migrating from a recently capped landfill in coal measures caused an explosion which demolished a bungalow and severely injured the two occupants (Ref: CIRIA C665, 2007).

Ground Gas Solutions

The Process

Stage 1

The first stage involves undertaking a Desk Based Review which typically includes:

  • A review of mapping sources (historical, geological)
  • Collecting anecdotal information regarding the site and surrounding area
  • Reviewing regulatory databases including the Local Authority Planning Portal and;
  • Undertaking regulatory consultation (where a potential source of ground gas is identified).

Stage 2           Stage 2 involves on site ground investigations as follows:

  • Undertaking an intrusive ground investigation, which would involve drilling boreholes to allow for installation of gas monitoring wells.
  • Undertaking monitoring visits, the number and frequency will depend upon the gas generation potential of the source and the sensitivity of the development.
  • Carrying out a Ground Gas Risk Assessment using methodologies outlined in CIRIA C665.
  • Classifying the site according to its Characteristic Situation.
  • Providing recommendations with regard the scope of gas protection required.

Stage 3       The final stage completes the process and includes:

  • Installation of gas protection
  • Inspection of the protection system
  • Review of information to ensure the system is fit for purpose
  • A validation ground investigation report is then submitted to the Local Authority for review and approval.
Ground Investigation Services

Outcomes

The client has reassurance that they will not be exposed to any significant residual liability if and when the site is transferred to another owner.The future owner occupier has reassurance that they are not taking on residual liability and agreed sale value is reflected in the condition of the property.

Any future occupants have reassurance that their health and the structural integrity of the property in which they occupy is not at significant risk from ground gas.

Mortgage providers and Insurance companies are provided reassurance that the property provides suitable guarantee for a loan and/or does not represent a significant insurance liability.

The Local Authority is provided with reassurance that their Public Health and Building Control responsibilities have been addressed and the site is suitable for its intended use.

For further information about how we can help you with Ground Gas Assessments please contact a member of the team on 0191 230 4521