Positive pressure air systems for protection of buildings from soil gas ingress – a case study

Phillip Crowcroft and Richard Stevens

Protection systems for properties affected by ground gas emissions have been evolving over a period of years, but retrofitting protection is more problematic than providing control in new buildings.
The case study reviews the use of positive pressure air systems in the context of controlling hazardous gas emissions from the ground beneath a building. The particular conditions at this site are described in terms of geology, hydrogeology and nature and extent of gas ingress into the property. A range of protection systems are considered and the selected method of air pressurisation described in detail.
Several methods of gas monitoring are used to demonstrate the success of the control systems, which have reduced measured methane concentrations in the building from percentage levels to a few parts per million.

3 (1) 1995

Updated: 09-Jun-2005