Prevalence of CO2 from disused mineral mines and the implications for residential buildings: research

8 Expert Consultation

8.1 Consultation Methodology

Working with industry experts we considered the issues related to CO2 and mineral workings particularly in relation to the risk assessment process, mitigation measures and the verification and validation, the impact of construction techniques in relation to mine gas entry to residential developments and retrofitting of mitigation measure to existing properties.

The experts were selected on the basis of either being a known leader in a relevant field and/ or previous involvement in the development of relevant technical guidance or industry accreditation schemes. They were drawn from a range of sectors including environmental, engineering or specialist consultancies; designers, installers and verifiers of gas protection systems; a public sector ‘developer’; a home construction warranty and insurance provider; and a major house-builder. An additional specialist was interviewed at the request of HPS and Scottish Government due to their knowledge of the Gorebridge IMT case.

We selected a range of experts to cover the full breadth of these issues as it is unlikely that many individuals would be able to cover all areas. The research specification requested that we collect an answer to each question from at least three experts and obtain their reasoning for the response. We consulted a total of ten experts with a range of six to nine responses per question stated in the brief.

The main objective of consulting the industry experts was to gain independent expert opinion to understand if there may be a case for Scottish Building Regulations to be updated or supplementary guidance to be provided. This is in order to minimise the likelihood and mitigate the risks of similar incidents to Gorebridge occurring in the future.

The interviews covered three main areas of interest, these being:

• An assessment of the effectiveness and limitations of the current mine gas risk assessment and mitigation design process and identification of any possible improvements
• The effect of different residential construction techniques on mine gas migration
• Any suitable mitigation measures that could be implemented for existing properties found to be affected by mine gas, as opposed to demolition of the properties.

The industry experts were consulted independently and sent in advance a series of questions, shown below as drawn from the Gorebridge IMT report, to serve as discussion topics.

8.2 Conflicts of interest

Scottish Government stressed the importance of obtaining unbiased views and avoiding those who have vested interests. However, where this was not possible, all vested interests were declared by the experts. A small number of the industry experts we approached declined our invitation to participate because of a conflict of interest in relation to a pending court case.

8.3 Arrangements for interviews

We conducted the interviews in late November/early December 2018, which were led by RSKW’s Project Lead Andrew Gunning and supported by Dr. Tom Henman as technical specialist. The interviews took place by phone and lasted between one and two hours. They were carried out individually and followed a repeatable format structured around the three main areas of interest, as identified above, but also included supplementary questions where appropriate.

The industry experts that were consulted are noted in Table 8-1 Expert Consultees below. Each consultee was asked to respond to the IMT Building Standards questions shown in Table 7‑2 IMT Questions to Building Standards Stakeholders. Their responses are collated within Annex 4.

Table 8‑1 Expert Consultees