The Australian pipeline design code AS 2885 is largely a risk-based standard, and its safety management study process is admirably suited to the needs of the Australian industry. However it is a unique process that has been developed in Australia and is not used anywhere else in the world. Successfully benchmarking it against other risk assessment methodologies would put the basis of the Australian approach on a footing that would be more difficult to challenge should a major pipeline disaster result in a public enquiry. And if the comparison reveals shortcomings in the AS 2885 process then there will be a sound basis for addressing those shortcomings to improve the process.
The APIA Research and Standards Committee and the Energy Pipelines CRC commissioned studies to compare the AS 2885 SMS process against two alternative methods:
• Reliability-based analysis.
• Quantitative risk assessment based on historical failure rates.
Each study looked at the same four pipeline segments spanning a variety of urban locations in which the consequences of a major pipeline failure would be very serious. Each of the four segments had previously been through the AS 2885 safety management study process and found to present a level of risk that was borderline tolerable. The objective of the studies was to determine whether the alternative risk assessment methods also found a level of risk that was similarly borderline tolerable.
This paper will present the results of the comparison studies, showing that all three methods produce broadly similar outcomes for risks that are close to the borderline between tolerable and intolerable. This is a welcome endorsement of the AS 2885 SMS process and reinforces its validity as a method for assessing and managing pipeline safety.