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Gas supply - Monitoring and reporting of Distribution Networks

Iron Mains replacement programmes 2006 - 2013



Changes in industry structure

National Grid Gas plc

North West

East of England

West Midlands

North London

Northern Gas Networks Ltd

North of England

Scotland Gas Networks plc


Southern Gas Networks plc

South of England

Wales & West Utilities Ltd

Wales & West


Monitoring and reporting arrangements

DNOs are required to report quarterly and annually to HSE on their progress with their approved programmes. This applies to annual programmes and those programmes lasting more than one year. These are minimum reporting requirements and HSE may require further information where necessary.

Quarterly reports

Annual reports

Exception reporting

Risk profiles


Enforcement action

HSE Hazardous Installations Directorate
Gas & Pipelines Unit, December 2005

[1] Mains replaced through condition and diversion policies do not contribute to the replacement targets under the approved programmes.

[2] A gas in buildings event is where gas from a leaking main has entered property and reached a concentration level of 20% of the lower explosive limit (LEL).