UTL/Gas/TBT-UTL-002

Gas Main Installation Safety

Utilities & Network Infrastructure › Gas › Gas Main Installation Safety

Presenter		Project
Location		Date

Gas main installation involves laying new polyethylene or steel pipes to distribute natural gas through the network.
All gas main work must be carried out by operatives holding valid National Gas Emergency Service (NGES) competencies.
PE pipe butt fusion and electrofusion jointing require trained and certified operatives using calibrated fusion equipment.
Trench support is essential — gas main trenches are often in public highways with variable ground and adjacent services.
Live gas mains run parallel to new installations — accurate location and safe working distances must be maintained.
Gas purging procedures introduce natural gas into new mains, creating a temporary flammable atmosphere at vent points.
All ignition sources must be eliminated during purging and commissioning — including phones, radios, and vehicles.
Pressure testing of new gas mains uses compressed air or nitrogen — stored energy makes this a hazardous operation.
Traffic management on public highways must comply with NRSWA and Chapter 8 for all gas main works.
Reinstatement of excavations must meet the Specification for Reinstatement of Openings in Highways requirements.

Explosion risk	Gas escaping from damaged mains or during purging creates an explosive atmosphere — one ignition source can cause a fatal blast.
Public safety	Gas main work takes place in streets near homes and businesses — the public must be protected from excavation, gas, and traffic hazards.
Jointing integrity	Poor fusion joints on PE mains cause gas leaks that endanger entire neighbourhoods — only certified operatives may carry out jointing.

Don't

Hold valid gas network competencies before carrying out any gas main installation work.
Support all trenches in accordance with the method statement and ground conditions.
Locate and maintain safe distances from existing live gas mains along the route.
Use calibrated fusion equipment and hold current certification for the jointing method.
Eliminate all ignition sources during gas purging and commissioning operations.
Establish exclusion zones around purge vent points during commissioning procedures.
Pressure test completed sections to the specification before commissioning with gas.
Install compliant traffic management before opening any excavation in the highway.
Reinstate excavations to SROH specification to prevent road surface failures.
Carry a personal gas monitor throughout all gas main installation work.

DON'T carry out gas main installation without valid gas network competency qualifications.
DON'T work in unsupported gas main trenches in highways or variable ground.
DON'T machine dig within 500mm of a live gas main — hand dig within this zone.
DON'T operate fusion equipment without current certification and calibrated machines.
DON'T use phones, radios, or create sparks during gas purging operations.
DON'T allow anyone within the exclusion zone during gas purging and venting.
DON'T commission a gas main without confirmed pressure test results to specification.
DON'T start highway excavation without approved traffic management in place.
DON'T backfill with incorrect materials — reinstatement failures cause highway defects.
DON'T work on gas infrastructure without a calibrated personal gas monitor.

See also: Utility Works Safety Awareness | Gas Escape & Emergency Procedures

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