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

4 Report Objectives

4.1 Summary of IMT Building Standard Related Questions

The following list is a summary of the key building standard related questions highlighted by the Gorebridge IMT report (for the full questions, see Table 7‑2 IMT Questions to Building Standards Stakeholders):

• Is the current mine gas risk assessment process adequate?
• Is the current risk assessment process fit for purpose particularly in terms of taking account for future potential changes?
• Is there sufficient emphasis in the current mine gas risk assessment process on the potential for other interventions?
• Are current mitigation processes sufficiently precautionary?
• In determining the need for mitigation measures, is the current scope for interpretation of the guidance open to developers at present appropriate?
• Are ventilated solums more appropriate?
• Is the drive to improve the energy efficiency/air tightness of modern properties a potential factor contributing to the retention of mine gas emissions in a property?
• Would the simplest and most appropriately precautionary solution be to require mandatory gas risk mitigation measures in all new residential and similar developments in former coalfields?

4.2 Objectives

The main aims and objectives were detailed within the Scottish Government tender documents. In summary the aims for this project are to:

• Understand details of any similar past incidents in Scotland;
• Identify other organisations which provide guidance on mine gas mitigation, understand what that guidance is and if they intend to review that advice;
• Determine if different, modern construction techniques no longer offer the same levels of protection on residential properties for mine gas mitigation issues;
• Consider and investigate if there are any other applicable and suitable mitigation measures that could be utilised on existing properties; and
• Consider the eight building standards related recommendations in the Gorebridge IMT report.

These aims and objectives have been addressed by fact finding carried out by a literature review, stakeholder engagement and consultation with experts followed by an analysis of the findings. In that analysis, which is presented in Section 9, we have considered the following points:

• What retrofitting works (e.g. gas membranes and/or ventilation/pressurisation) can be carried out to existing properties that would give certainty to successfully ‘managing’ the presence of CO2?
• Given that it is assumed that CO2 would take the path of least resistance, is it possible to create paths in affected buildings that would result in escape routes for the gas?
• High levels of CO2 may eventually become exhausted, are there any ways of determining how and when that might happen? Would there be any way of accelerating such a process?
• What are the implications for existing properties surrounding a new-build development if gas membranes are deployed (e.g. is there a need for venting trenches surrounding the site or buildings to prevent gas migration)?
• What are the maintenance requirements for any potential mitigation arrangements?