Older and wiser: APA manages its ageing infrastructure

With an interest in over 12,000 km of transmission pipeline infrastructure, aged from 1 to 54 years old, and an interest in over 23,000 km of distribution networks across Australia, APA Group is experienced in using technology to keep its infrastructure working soundly. Of particular interest is how pipelines that are approaching their original design life can be maintained to remain productive and to continue to be operated safely and reliably.

As owner and operator of some of Australia’s oldest gas transmission pipelines, including one of Australia’s first high pressure natural gas pipelines – the Roma to Brisbane Pipeline – the company has the expertise to maintain its older pipelines to the same high standard as all pipelines in Australia.

Keeping old pipes healthy

APA emphasises the necessity of regular inspection and maintenance to ensure security of supply, safety of the public and the longevity of individual pipeline assets.

The company has teams dedicated to assessing the current condition of each pipeline based on data collected from assessments such as intelligent pig surveys, coating defect surveys, inspections and cathodic protection records. These processes ensure speedy identification and correction of any issues that arise.

APA Group Manager Operations Stephen Ohl says “A major asset management activity is to conduct regular integrity and fitness for purpose assessments so as to determine that the asset is OK to continue to operate for a further 20, 30, 40 years or more.”

The maintenance of ageing pipelines can become a juggling act for companies as they have to weigh up the costs of repairing older assets against the cost of replacement or even abandonment. The maintenance of ageing infrastructure can come at a cost to companies as inspections may be more frequent, maintenance expenses increases as pipelines get older and equipment needs to be replaced and more inspection and repair work needs to be carried out.

However, in relation to intelligent pigging inspections, Mr Ohl points out that the frequency with which a pipeline should be pigged is determined more by its condition than its age. “A newer pipeline with known coating damage issues may need to be inspected more frequently than an older pipeline where it is known that the coating is in good condition.”

Urban encroachment

One difficulty with older pipelines is their increasing proximity to urbanisation. As rural land becomes transformed into new suburbs, companies have to work harder to ensure the safety of the encroaching public as well as the protection of the pipeline.

As Mr Ohl explains “Dial before You Dig, proactive pipeline awareness programs and early engagement of developers and councils all help to manage the amount of encroachment near the pipelines.”

Recent technology benefits all pipelines

The pipeline industry continues to invest in research to improve both the construction of new pipelines as well as the maintenance and integrity of existing pipelines. As APA points out, there have been obvious benefits for the construction of new pipelines with the use of higher strength steels, new and improved pipeline coatings and increases in pipeline operating pressures. Improvements in technology have also created benefits for existing pipeline infrastructure.

Intelligent pigs today typically have a much better defect definition capability compared to what was available 20 years ago. This means more accurate defect assessment and improved efficiency as defects can be accurately classified, excavated and repaired as required rather than having to excavate a large number of defects just to determine if they need to be repaired or not.

In addition, supervisory control and data acquisition (SCADA) systems are continuously improving the way information is gathered and managed. “SCADA systems allow real time monitoring of process and integrity conditions which provides good records for integrity reviews, as well as reducing manual onsite monitoring activities,” Mr Ohl says.

APA Queensland Manager of Transmission Operations Peter Benham highlights the jump in technology since the company’s Roma to Brisbane Pipeline was constructed in 1969. “The original Roma to Brisbane Pipeline was a very simple operation with one gas inlet and two gas outlets with very limited remote monitoring and no remote control. Since the construction of the first compressor station in 1981, the SCADA system has developed and grown to the point where it monitors and controls over 5,000 data points between Wallumbilla and Brisbane,” Mr Benham says.

Since the pipeline commenced operations, six compressor stations and looping have been added to the line. Despite this, the original mainline’s maintenance schedule has not been that affected by the expansion, which is a good sign for the pipeline’s longevity. “Changes are small and in the same area as existing facilities,” says Mr Benham.

It is important to assess each pipeline asset individually. As Mr Ohl explains, new technology and improvements help improve the maintenance and integrity management of older pipelines, however maintenance costs still continue to increase with pipeline age. Therefore, “justification processes based on risk assessment and benefit-verses-cost are used to determine which activities and improvements should be implemented to ensure the continued integrity and safety of older pipelines”.

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