Gas Mains Tie-In and Live Service Connection — Safe Work Method Statement
Safe Work Method Statement for connecting new gas services or main extensions to live pressurised distribution mains, including excavation to the main, under-pressure tapping, squeeze-off of polyethylene mains, electrofusion, purging and reinstatement.
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Connecting to a live gas main is high risk construction work on several counts: it is work on or adjacent to pressurised gas distribution mains or piping, it creates a possible flammable atmosphere in the excavation, and it is usually done in a road or footpath with plant moving nearby. A SWMS is required, and the network operator will normally have its own work instructions and permit conditions that the SWMS must follow.
Work on the distribution network is controlled by the gas network operator. In most areas only the operator's own crews or contractors authorised by the operator can tap or tie in to a main, and a gasfitting licence on its own is not enough. Check the operator's requirements and your state or territory regulator before quoting the work.
The hazards specific to a tie-in are gas escaping during tapping, squeeze-off or cutting; ignition from static electricity on polyethylene pipe, sparks from tools or a vehicle; and gas building up in the trench, where it can also displace air. Static charge on PE pipe is a real ignition source: it builds up as gas flows and can discharge to a worker's hand or a tool. Cutting or breaking a metallic main without temporary bonding can expose workers to stray current. Other hazards include striking other services while excavating to the main, trench collapse, traffic, and purging gas into a new service where it can collect near buildings or ignition sources.
Your SWMS must cover service location and safe excavation, the gas monitoring arrangement and stop-work trigger, static control on PE, bonding on metallic mains, the tapping or squeeze-off procedure, the purge and venting method, and the emergency response to an uncontrolled release.
Customise this template with the network operator's permit or work order number, the main material, size and operating pressure, the tapping or fitting method, the BYDA enquiry reference, trench depth and support method, the traffic management plan, the gas detector make and calibration date, and the authorisation numbers of the workers.
Personal Protective Equipment
High Risk Construction Work Types
- •Work on or near pressurised gas distribution mains or piping
- •Work in an area that may have a contaminated or flammable atmosphere
- •Work on, in or adjacent to a road, railway or other traffic corridor in use by traffic
- •Work in an area with movement of powered mobile plant
Risk Assessment
1.Permits, traffic management and site set-up
| Hazard / Risk | Initial Risk | Control Measures | Residual Risk | Responsibility |
|---|---|---|---|---|
| Workers struck by traffic while working in the road or footpath | Catastrophic | Set up traffic control to the approved traffic management plan before any work starts, with signs, barriers and traffic controllers as required. Keep a buffer between the work area and live traffic. Wear high-visibility clothing at all times. | Moderate | Site Supervisor / Traffic Controller |
| Tie-in done without network operator authorisation or to the wrong main | High | Hold the operator's permit or work order on site and confirm the main location, material, size and pressure against it. Brief the crew on the operator's procedure for that pressure class. Do not start if the permit conditions cannot be met. | Low | Site Supervisor |
2.Locate services and excavate to the main
| Hazard / Risk | Initial Risk | Control Measures | Residual Risk | Responsibility |
|---|---|---|---|---|
| Striking the gas main or other services with an excavator | Catastrophic | Obtain a Before You Dig Australia (BYDA) enquiry and mark all services. Expose the main by hand digging or vacuum excavation within the tolerance zone set by the asset owner. Use a spotter for any mechanical digging near the marked main. | Low | Excavator Operator / Site Supervisor |
| Trench collapse onto workers at the main | High | Size the excavation to give working room around the main. Bench, batter or shore any excavation over 1.5 metres deep, and support shallower ones in poor ground. Keep spoil and plant at least 1 metre back from the edge. Provide a ladder or ramp for quick exit. | Low | Site Supervisor |
3.Gas monitoring and ignition control
| Hazard / Risk | Initial Risk | Control Measures | Residual Risk | Responsibility |
|---|---|---|---|---|
| Ignition of gas in or around the excavation | Catastrophic | Monitor the excavation continuously with a calibrated, bump-tested combustible gas detector during tapping, squeeze-off, cutting and purging. Stop work and withdraw from the excavation if readings reach 10% LEL or the lower limit set by the operator. Keep vehicles, generators, mobile phones and smoking outside the exclusion zone. Have two charged extinguishers at the excavation. | Moderate | Gas Fitter / Site Supervisor |
| Static discharge from polyethylene pipe igniting gas | High | Before cutting, squeezing or venting PE pipe, wrap the work area in wet cloth or hessian connected to an earth stake and keep it damp, or use the operator's approved anti-static method. Earth tools and fittings as required. Wear the anti-static clothing and footwear required by the operator. | Low | Gas Fitter |
| Stray current shock or arcing when cutting a metallic main | High | Fit a temporary bonding cable across the cut point on steel or cast iron mains before cutting or separating the pipe, and keep it in place until the new connection is completed. | Low | Gas Fitter |
4.Under-pressure tapping, squeeze-off and connection
| Hazard / Risk | Initial Risk | Control Measures | Residual Risk | Responsibility |
|---|---|---|---|---|
| Uncontrolled gas release from a failed fitting or tapping machine | Catastrophic | Use only fittings and tapping equipment approved by the operator for the main material, size and pressure. Inspect the tapping machine, seals and cutter before use. Fit and pressure test the tapping tee or saddle before tapping. Keep the escape route out of the trench clear and only the workers needed in the excavation. | Moderate | Gas Fitter |
| PE main damaged by squeeze-off or electrofusion done incorrectly | High | Use squeeze-off tools matched to the pipe size with stops set, at the minimum distance from fittings and joints set by the operator. Prepare and scrape pipe surfaces, clamp and fuse to the fitting's parameters, and do not move joints until the cooling time has passed. Mark squeeze-off points as required. | Low | Gas Fitter |
| Hearing loss and silica dust from saw cutting road surfaces | Moderate | Wet cut concrete and asphalt, wear hearing protection near saws and plant, and wear a P2 respirator where dust cannot be controlled with water. | Low | All Workers |
5.Testing, purging and commissioning the new service
| Hazard / Risk | Initial Risk | Control Measures | Residual Risk | Responsibility |
|---|---|---|---|---|
| Purged gas collecting near buildings or ignition sources | High | Purge the new service to a vent point outdoors, at least the distance from openings and ignition sources set by the operator, using a vent stack that directs gas upward. Monitor at the vent and around the site during purging. Stop when the operator's purge test shows gas has fully displaced air. | Low | Gas Fitter |
| Leaking joints left buried | High | Leak test all new joints and fittings at operating pressure with leak detection solution or a detector before backfilling. Record test results on the operator's job record. | Low | Gas Fitter |
6.Backfill, reinstatement and emergency response
| Hazard / Risk | Initial Risk | Control Measures | Residual Risk | Responsibility |
|---|---|---|---|---|
| Main damaged during backfill | Moderate | Bed and backfill around the main and new service with the material and marker tape the operator specifies. Compact in layers by hand around the pipe before using a compactor. | Low | Site Supervisor |
| Uncontrolled gas escape that cannot be stopped | Catastrophic | Brief the crew on the emergency plan before starting: stop work, eliminate ignition sources, evacuate upwind, set an exclusion zone, call the network operator's emergency line and 000. Do not re-enter the trench to try to stop a major escape. Practise the plan at the toolbox talk. | Moderate | Site Supervisor / All Workers |
Relevant Codes of Practice
Worker Acknowledgement
By signing below, I confirm that I have read, understood and agree to comply with this Safe Work Method Statement.