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

In 2017 the NHS Lothian Incident Management Team investigated reported cases of ill health affecting residents of a recently built local authority housing estate. This research is looking for similar incidents and considers implications for building standards.


Annex 2 – Table of Standards and Guidance

Summary of published and planned technical guidance and standards on ground gas assessment and mitigation

Item No. Title/Report No. Author/ Publisher Publication Date Type Status Summary of scope of guidance[1] Applicability to mine gas?

1

Construction of new buildings on gas-contaminated land, BRE Report 212

Building Research Establishment (BRE)

1991

Guidance

Reference sources but largely superseded by later guidance.

Ground gas risk assessment (RA) and mitigation design. Contains basic technical advice on the design of gas-protection measures for new buildings on land affected by hazardous gases such as methane.

Not covered explicitly.

2

Ventilation Principles and Designing for Natural Ventilation, Code of Practice, BS 5925:1991

British Standards Institution (BSi)

1991

Standard

This British Standard gives recommendations on the principles which should be observed when designing for the natural ventilation of buildings for human occupation.

Not covered explicitly.

3

Methane: Its occurrence and hazards in construction, R130

CIRIA

1993

Guidance

Methane properties, sources, hazards and migration. Reviews all aspects of methane generation and associated hazards, including factors relevant to methane generation and migration, and circumstances in which methane may present a threat to the built environment.

Focus on methane but other gases inc. CO2 considered. Landfill primary focus but coal mining areas considered.

4

The measurement of methane and other gases from the ground, R131

CIRIA

1995

Guidance

Reference source but largely superseded by later guidance.

Measurement and monitoring methods

Focus on methane but other gases inc. CO2 considered. Landfill primary focus but coal mining areas considered.

5

Protecting development from methane, R149

CIRIA

1995

Guidance

Mitigation design methods. Contains similar but more detailed advice than BRE 212. Includes case studies of practical design measures in different applications. Provides a categorisation scheme for sites that have different gassing regimes.

6

Methane investigation strategies, R150

CIRIA

1995

Guidance

Site investigation and monitoring methods

7

Interpreting measurements of gas in the ground, R151

CIRIA

1995

Guidance

Ground gas investigation and assessment. Includes advice on the interpretation of results of ground gas

investigations, including the effect of

factors as temperature and pressure, fluctuating groundwater levels, etc.

8

Risk assessment for methane and other gases from the ground, R152

CIRIA

1995

Guidance

Reference source but largely superseded by later guidance.

Ground gas RA. Sets out a risk assessment procedure that incorporates both qualitative and quantitative assessment techniques. The quantitative methodology uses fault-tree analysis to predict the probability of an unacceptable outcome (such as an explosion) by assigning probabilities to various components of the source–pathway–receptor relationship (e.g., the potential for gas generation and/or migration, failure of a membrane, presence of an ignition source, etc.).

Focus on methane but other gases inc. CO2 considered. Landfill primary focus but coal mining areas considered.

9

Methane and other gases from disused coal mines: the planning response. Technical Report

Dept. of Environment

1996

Technical report

No longer available

Aimed at identifying a suitable planning response to reduce mine gas emission risks in respect of new development, without placing unnecessary constraints on land use. The principal objective was to provide advice suitable for use by planners, developers, land and property owners, insurers and others.

The study has relevance to the detection, investigation and treatment of mine gas emissions affecting existing development.

10

Passive Venting of Soil Gases Beneath Buildings: Volume 1 (Guide for Design) and Volume 2 (Computational Fluid Dynamics Modelling: Example Output)

Dept. of Environment, Transport and the Regions (DETR)

1997

Technical bulletin

Reference source but largely superseded by later guidance.

Mitigation design. Sets out a methodology to assess the risks to buildings posed by soil gases, and to design appropriate passive gas venting measures.

Referred to as a source, but not covered explicitly.

11

Gas protection measures for buildings. Methodology for the quantitative design of gas dispersal layers. Proceedings of the Fifth International Conference – Polluted and Marginal Land

Owen, R. and Paul, V.

1998

Published paper

No longer available, but referenced in other guidance.

Mitigation design

Not known as no longer available.

12

Reliability and risk in gas protection design, Ground Engineering, February 1999 and Ground Engineering News Section of Ground Engineering, March 1999 (this contains points of clarification that must be read in conjunction with the February paper)

Wilson, S. A. and Card, G. B.

February/ March 1999

Published paper

No longer available, but referenced in other guidance.

Mitigation design, building on CIRIA report R149

Not known as no longer available.

13

Protective measures for housing on gas-contaminated land, BRE 414

BRE

2001

Guidance

Reference sources but largely superseded by later guidance.

Mitigation design. A practical guide to good practice for the detailing and the construction of passive soil gas protective measures for new and existing residential development. It does not contain advice on the design of passive or active protective measures for specific gas regimes, nor does it provide information on active gas protective systems or external in-ground protective measures.

Includes methane and carbon dioxide from sources including coal measures and/or underground mine workings.

14

Model Procedures for the Management of Contaminated Land. Contaminated Land Report Number 11 (CLR11)

Environment Agency

2004

Guidance

Reference

Overarching guidance on assessment and remediation of land contamination.

Includes consideration of ground gas sources but not specifically mine gas.

15

Assessing risks posed by hazardous ground gases to buildings, C665

CIRIA

2007

Guidance

Reference

Good practice guidance covering methods of investigation, the adequacy of monitoring, the methods of risk assessment and the selection of options for remediation.

Includes methane and carbon dioxide from sources including coal measures and/or underground mine workings.

16

Guidance on Evaluation of Development Proposals on Sites where Methane and Carbon Dioxide are Present

NHBC

2007

Guidance

Current but due to be updated in 2019.

Good practice guidance covering methods of investigation, adequacy of monitoring, risk assessment and suitable design of protection measures for residential developments. Developed NHBC ‘traffic light’ risk assessment approach for low rise housing.

Covers methane and carbon dioxide only, including mine gas related sources.

17

The Local Authority Guide to Ground Gas

Chartered Institute of Environmental Health

2008

Guidance

Current. This is being updated with interim issue of Ground Gas Information Sheets by EPG.

This document provides practical guidance for Environmental Health, Contaminated Land and Building Control Officers along with others who need to undertake, manage or review ground gas assessments and design appropriate protection measures.

Yes, covered explicitly.

18

The VOC Handbook. Investigation, Assessing and Managing Risks from Inhalation of VOCs at Land Affected by Contamination, C682

CIRIA

2009

Guidance

Current

Good practice guidance on the investigation, assessment and remediation of risks associated with VOCs.

Limited to VOCs which may be present within mine gas.

19

A Pragmatic Approach to Ground Gas Risk Assessment. CL:AIRE Research Bulletin RB17

CL:AIRE

2012

Technical bulletin

Current

This Research Bulletin proposes a pragmatic approach to ground gas assessment for low risk sites using data that can be collected quickly and at low cost.

Not intended for sites affected by mine gas sources.

20

BS8576:2013. Guidance on investigations for ground gas – permanent gases and volatile organic compounds (VOCs).

BSi

2013

British Standard

Current. BSI committee EH4 reviewed whether BS8576 required revision earlier in 2018 and decided that it was not necessary at present. The next review will be c. 2023.

Good practice guidance covering site investigation and monitoring methods for ground gases and volatile organic compounds (VOCs), with particular reference to development sites and the risks posed by gassing sites to neighbouring land and developments.

Covers methane and carbon dioxide, including from mine gas sources.

21

Good practice on the testing and verification of protection systems for buildings against hazardous ground gases, C735

CIRIA

2014

Guidance

Current

Good practice guidance for the designer, installer, verifier and regulator on the verification and integrity testing of gas protection systems.

Not covered explicitly but is applicable to sites affected by mine gas sources.

22

Radon: Guidance on protective measures for new buildings, BR211

BRE

2015

Guidance

Current

Mitigation design. This report gives guidance for reducing the concentration of radon in new buildings, extensions, conversions and refurbishment projects to reduce the risk to occupants of exposure to radon.

Limited to radon which may be present within mine gas.

23

The utility of continuous monitoring in the detection and prediction of worst-case ground gas concentration, RB13

CL:AIRE

2011

Technical bulletin

Current

Ground gas RA. Technical bulletin that aims to show how the impact of temporal variability in gas concentrations and flow and uncertainties can be reduced by continuous monitoring, thereby reducing uncertainties in ground-gas risk assessment.

Incudes an example case study for old mine-workings.

24

Remediating and mitigating risks from VOC vapours from land affected by contamination, C716

CIRIA

2012

Guidance

Current

Good practice guidance covering remediation and risk mitigation for VOCs.

Limited to VOCs which may be present within mine gas.

25

Guidance on Managing the Risk of Hazardous Gases when Drilling or Piling Near Coal

Coal Authority, HSE and others

2012

Guidance

Current

This document is stated to be designed and published in order to provide guidance with respect to hazardous gases for the safe drilling and piling through Coal Measures up to a maximum depth of 200m.

Yes. Gases considered include methane, hydrogen sulphide, carbon dioxide and carbon monoxide but also less common gases such as hydrogen. It also includes oxygen deficient air.

26

BS8485 Code of practice for the design of protective measures for methane and carbon dioxide ground gases for new buildings

BSi

2015

British Standard

Originally published in 2007 and fully updated in 2015. Under review. A1 2019 currently in prep.

Code of practice covering gas risk assessment and mitigation design. It is intended to be used by designers of gas protection measures and by regulators involved in the assessment of design solutions. It recognizes that there are a number of factors requiring consideration which affect the sensitivity of a development to the effects of ground gas, and that there is a range of design solutions available for different situations. The framework, developed in line with CLR11, provides designers with information about what is needed for an adequate ground gas site investigation. It also provides an approach to determine appropriate ground gas parameters that can be used to identify a range of possible design solutions for protection against the presence of methane and carbon dioxide on a development site. The framework is not prescriptive, and professional judgement may be made as to the acceptability of risk and whether there might be benefit in undertaking a more rigorous site assessment or adopting conservative measures in design. Emphasis is placed on the justification and recording of risk assessments and design decisions throughout the process.

Yes. Both mine workings and mine gas sources and pathways are considered

27

User Guide for the BGS methane and carbon dioxide from natural sources and coal mining dataset for Great Britain, Open Report OR/11/054

British Geological Survey (BGS)

2011

Guidance

Current

This report presents a description and review of the methodology developed by BGS to produce an assessment of the potential hazards from methane and carbon dioxide from natural sources and coal mining. The purpose is to enable those licensing this dataset to have a better appreciation of how the dataset has been created and therefore a better understanding of the potential applications and limitations that the dataset may have.

Yes

28

Risk based approach to development management: Guidance for developers

Coal Authority

2017

Policy document

Current. Next revision scheduled for December 2018

Presents a risk-based approach developed by the Coal Authority for safe development in former coal mining areas and consultations required.

Yes

29

Piled foundations and pathways for ground gas migration

Wilson, S., Mortimer, S., Journal of Environmental Geotechnics

November 2017

Published paper

Reference

This paper discusses the different types of pile construction and considers how they may or may not influence gas migration.

Not specifically but applicable to assessment of mine gas.

30

Complete Continuous Monitoring in Underfloor Voids, TB16

CL:AIRE

December 2017

Technical bulletin

Current

This bulletin explains a best practice approach using complete continuous monitoring to assess the performance of ventilated voids.

Not specifically but applicable to assessment of mine gas.

31

Ground Gas Monitoring and ‘Worst-Case’ Conditions, Technical Bulletin TB17

CL:AIRE

2018

Technical bulletin

Current

Guidance on critical barometric pressure conditions that influence gas monitoring results and provides a framework to risk assessors to determine when they have sufficient gas monitoring data to evaluate risks with confidence.

Not specifically but applicable to assessment of mine gas.

32

Retro-fitting of gas protection measures, CIRIA report TBC

CIRIA

TBC

Guidance

In prep.

New research project commencing late 2018/early 2019.

Not specifically but applicable to assessment of mine gas.

Contact

Email: sarah.waugh@gov.scot

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