Pipelines

Pipeline being laid in the Surat Basin, southern Queensland.

Natural gas pipelines are built to strict standards in Australia.

They are made from high-grade steel that is impact-tested to withstand high levels of stress. The pipelines are usually buried.

Heavy-wall pipe is used where the risk of impact is considered highest, such as at water or rail crossings. High-grade coatings are used to prevent corrosion.

Australian Standard AS2885 applies to pipelines. Under this world-recognised standard:

• Pipelines must be buried to depths greater than those likely to be reached by common land use. For example, in areas of deep ripping cultivation, the pipeline is buried below 1200mm.
• Warning marker tape is buried above the pipe to ward off accidental damage while, above ground, marker posts are placed within sight of each other along the entire length of the pipeline.
• Emergency shutdown systems are required, with electronically controlled closure valves in strategic positions along the pipeline.
• Emergency crews must be trained to respond in the unlikely event of an incident and to work closely with the local emergency services.

Before filling with gas, the pipeline is pressure-tested with water to ensure it does not leak and is capable of operating at its design pressure.

Long design life

The pipeline will have a design life of about 40 years and with proper maintenance, it would be expected to operate even longer.

Once buried, pipelines are constantly monitored for pressure, temperature and external cathodic protection, a technique used to control the corrosion of metals and coatings. Valves along the pipeline can be operated remotely at any time to ensure integrity and safety.

Routine maintenance and inspections ensure the pipeline is operated safely.

Above ground, regular air and land patrols ensure that no unauthorised activities, such as deep digging, occur in the pipeline easement.

Landowners and other users of land above the pipeline receive education and information about their responsibilities.

Once work on a section of pipeline is completed, the site is tidied and topsoil is re-spread. The only visible sign of the Queensland Curtis LNG pipeline will be marker posts, as required under Australia gas and petroleum industry standards.