On the surface, or on paper at least things appear fine. There is plenty of guidance – British Standards, CIRIA and CL:AIRE documents. There have been advances in ground gas monitoring technology which enable measurements to be taken in space and time. And risk assessment modelling has advanced too, enabling practitioners to come up with more informed answers.
So, what is the problem? At Environment Analyst’s recent Brownfield Land Scotland Conference earlier this month there was a round table on ground gas assessment, monitoring and verification and there along with discussions around the conference, including a presentation on the Gorebridge case (see below) where CO2 escaped into residential buildings – it is obvious things aren’t A1 OK.
In fact, it opened a can of worms. Attendees pointed to the quality of the work – and concluded not all the steps needed are being done correctly enough of the time.
Some of the causes included lack of inspection by Building Control, lack of training by supplier or contractor operatives, passing on of responsibility between, consultant, contractor, supplier and client, loosely worded contracts, lack of adequate training for CLOs and EHOs; and lack of resources to check whether the guidance, validation and verification has been carried out correctly.
Some of the solutions mooted included mandatory gas risk mitigation measures. Not everyone agreed – a similar mixed answer was elicited in RSK’s Gorebridge report - and that if gas risk assessment process is followed and implemented correctly then mandatory mitigation would be unnecessary and could be counter-productive and use unnecessary resources.
Others said a minimum level of protection would address uncertainties and create a ‘level playing field’. While a hybrid solution – and a sensible compromise would be a minimum standard backed up by a risk assessment.
Other solutions included inspections by an independently verified third party - suitably qualified persons, where problems could be caught at verification stage. But this is no easy answer given the experience of the waste industry.
And what about the housebuilders? Isn’t part of the problem something to do with the quality of their products. Attendees thought that the importance of ground gas measures in developers’ eyes had been downgraded – a tick box exercise for planning – and not something in its own right. And therefore, something not worth the investment in terms of training and quality procurement.
The ground gas protection industry has a big job to do to raise its importance in the eyes of the government and clients. If not, it is relying on more disasters like Gorebridge to get system change.