PR-1712 – Process Safety Assurance – PDO

An explosion at the Longford gas plant occurred on 25 September 1998 resulting in two fatalities and a 19-day interruption in gas supply to the state of Victoria, Australia. An audit conducted by a corporate team six months prior to the explosion had determined that the gas plant was successfully implementing its process safety management system. However, a Royal Commission subsequently investigated the explosion and found significant deficiencies in the areas of

1. risk identification, analysis, and management;
2. training;
3. operating procedures;
4. documentation; and
5. communications.

These long-standing problems had not been detected by the prior audit.

Critical evaluation of the AI-PS management system is one element of learning from experience. This procedure covers formal methods for performing periodic Asset Integrity – Process Safety (AI-PS) framework audits, which should reduce risk by proactively identifying and correcting weaknesses in management system design and implementation.

Since 2010, PDO has implemented a dedicated program of level 2 (cross-directorate) and level 3 (asset verification) assurance for AI-PS. The initial program was based on the Center for Chemical Process Safety (CCPS) Guidelines for Risk-Based Process Safety. An external audit at the end of 2010 recommended that PDO established a risk-based AI-PS assurance procedure that was tailored to PDO business. The procedure was trialed in the 2011 AI-PS assurance program and was formalized in the first issue of this procedure in 2012.

The procedure defines the process for evaluating the implementation of AI-PS requirements in PDO, to ensure that they are in place and functioning in a manner that protects employees, stakeholders, the environment, and physical assets against process safety risks.