From: Chris Scivyer
Principal Consultant
Building Technology Group
Watford, U.K.

I work for the UK Building Research Establishment and have been working in the Radon field for over 33 years. I attended the AARST Symposium many years ago in Denver and have conversed with many AARST members over the years.

The reason for contacting you now is that I have a project for which I need to demonstrate evidence of others having carried out similar work in the past. I have been asked by a client to deal with an issue relating to C02 vapour intrusion from past mining into a house in the UK. I have suggested that a sub-slab depressurisation system as used for radon might be appropriate. However in this case we are thinking that we would pressurise the system rather than depressurise. This has been used in only a handful of cases in the UK for radon but has been successful in reducing radon levels.

Many years ago I visited Spokane to look at radon solutions. At the time SSD systems were often used with the fan pressurising the ground beneath the building rather than depressurising the ground. This was because glacial deposits in the ground were very permeable and pressurisation worked better than depressurisation. I just wondered if this approach is still used in the Spokane area or in other parts of the USA and if so roughly how many systems might have been installed over the years. What I am hoping is that if it is used for radon it may also have been used for dealing with C02 vapour intrusion in the USA?

I have written to various bodies and mitigation companies in the Spokane area to see if they can help me but thought that AARST might be able to give me a National perspective. A web search for C02 vapour intrusion has come up with little information.