Author(s): S Wilson, S Oliver, H Mallett, H Hutchings, G Card
Date: 2007
ISBN (13 digit): 978-0-86017-665-7
ISBN: 0-86017-665-7
Pages: 202
Publisher: CIRIA

Description: Following the high profile gas explosions at Loscoe and Abbeystead during the 1980s, a number of reports were published in the 1990s on the measurement of soil gases, the assessment of risk such gases may present along with the measures that can be employed to mitigate such risks.

With government policy encouraging redevelopment on brownfield sites including those sites where there is a potential for elevated concentrations of potentially hazardous soil gases to be present, the lack of clarity in the existing guidance has become more apparent.

This report provides up to date advice on all of these aspects. The guidance it contains consolidates good practice in investigation, the collection of relevant data and monitoring programmes in a risk based approach to gas contaminated land.

Keywords: pollution prevention, environmental good practice, contaminated land, urban regeneration, ground investigation and characterisation

Contents: Summary, Foreword, Acknowledgements, List of figures, List of tables, List of boxes, Glossary, Abbreviations, 1 Introduction, 1.1 Background, 1.2 Legislative framework, 1.4 Methodology, 1.5 Audience, 1.6 Structure of the report, 2 Hazardous gases, 2.1 Introduction, 2.1 Common sources of hazardous gases, 2.3 Physical and chemical hazards, 2.4 Nature of hazards, 2.5 Factors influencing the generation of soil gases/vapours, 2.6 Factors influencing the migration and behaviour of gases/vapour, 2.7 Ingress into buildings, 2.8 Ingress into other structures, 2.9 Summary, 2.10 Further information, 3 Development of initial conceptual model and preliminary risk assessment site characterisation, 3.1 Overview of risk assessment, 3.2 Desk study, 3.3 Initial assessment of risks, 3.4 Summary, 3.5 Further information, 4 Methods of non-intrusive and intrusive investigation, 4.1 Setting the objectives of the ground investigation, 4.2 Investigation techniques, 4.3 Number and location of monitoring/sampling points, 4.4 Construction of monitoring/sampling points, 4.5 Summary, 5 Monitoring methodologies, 5.1 Types of instrumentation appropriate for monitoring 5.2 Selection process, 5.3 Monitoring methodologies 5.4 Flux box measurements, 5.5 Number, frequency and duration of monitoring, 5.6 Presentation of data, 5.7 Summary 6 Sampling methodologies, 6.1 Types of equipment appropriate for sampling and analysis, 6.2 Methodology, 6.3 Analytical techniques to identify the source of gas and hazardous properties, 6.4 Summary, 7 Interpretation of results, 7.1 Background, 7.2 Understanding the collected data, 7.3 Refining the conceptual model, 7.4 Additional phase II site investigation, 7.5 Summary, 8 Assessment of risk, 8.1 Introduction, 8.2 Risk assessment process, 8.3 Methane and carbon dioxide, 8.4 Assessing vapours from hydrocarbon contamination, 8.5 Considering protection in risk assessment, 8.6 Radon, 9 Remedial options, 9.1 Setting remedial objectives, 9.2 Philosophy for gas protection, basic concepts, 9.3 Passive and active systems of gas control (interpretation of the migration pathway), 9.4 details of systems available, 9.5 Monitoring and alarms in buildings, 9.6 Summary, 10 Post development monitoring, 10.1 Construction monitoring, 10.2 Existing guidance, 10.3 Future changes to the development and impact on soil gas regime, 10.4 Risk perception issues, 10.5 Practical aspects of the long-term verification monitoring, 10.6 Recommendations for post construction/post-remediation monitoring, 10.7 Verification/completion reporting, 11 Recommendations for research, 12 References, Appendices, Bibliography