Managing Threats to a Pipeline

We usually manage threats, and control the risk associated with pipeline operation by using prescriptive or ‘good’ practices; e.g., proven procedures, national standards, current regulations, and competent staff. The public would expect us to meet these ‘general requirements’ or ‘minimum requirements.

The problem with this prescriptive approach is that it may not identify new threats, and make be a more reactionary approach to risk management.

We now develop ‘integrity management programs’ that supplement our existing safety requirements. These programs use ‘risk-based management’ principles to improve safety. Risk-based management focuses on safety risks in ‘high consequence areas’ around pipelines where a failure will have a high impact (consequence), such as highly populated or frequented areas [1].

ASME B31.8S states:

‘This Code is a process code, which describes the process an operator may use to develop an integrity management program. It also provides two approaches for developing an integrity management program: a prescriptive approach and a performance or risk-based approach. Pipeline operators in a number of countries are currently utilizing risk-based or risk-management principles to improve the safety of their systems. Some of the international standards issued on this subject were utilized as resources for writing this Code. Particular recognition is given to API and their liquids integrity management standard, API 1160, which was used as a model for the format of this Code.

The intent of this Code is to provide a systematic, comprehensive, and integrated approach to managing the safety and integrity of pipeline systems.’.

A prescriptive integrity management process follows preset conditions that result in fixed inspection and mitigation activities and timelines. A more performance-based integrity management process utilizes risk management principles and risk assessments to determine prevention, detection, and mitigation actions and their timing

Prescriptive versus Risk-Based Approaches for Integrity Management

Prescriptive approaches involve detailed rules and regulations, which must be done. Risk-based approaches have a framework of rules with guidelines: they are more about managing and identify threats and risks first, then rank them and prioritizing actions accordingly. This is a more proactive approach.

These approaches can be summarised as [2]}

  • a ‘prescriptive approach’ when followed explicitly, provides all the inspection, prevention, detection, and mitigation activities necessary to produce a satisfactory integrity management program.; and,
  • a ‘performance’ or risk-based approach which uses more data and more extensive risk analyses, which enables the operator to achieve a greater degree of flexibility in order to meet or exceed the requirements of the standard specifically in the areas of inspection intervals, tools used, and mitigation techniques employed. An operator cannot proceed with the performance-based integrity program until adequate inspections are performed that provide the information on the pipeline condition required by the prescriptive-based program. The level of assurance of a performance-based program or an alternative international standard must meet or exceed that of a prescriptive program.

ASME B31.8S [2] states that using a ‘prescriptive-based’ process will produce a ‘satisfactory’ integrity management program, but… using a risk-based integrity management program will ‘meet or exceed’ the requirements of the standard. Hence, we need to move to a performance-based integrity management protocol.

Benefits of Risk-based Approaches

Risk-based management has several key characteristics that help to ensure safety:

  • it uses information to identify and assess risks;
  • prioritizes risks so that resources may be allocated to address higher risks first;
  • promotes the use of regulations, policies, and procedures to provide consistency in decision-making; and,
  • monitors performance.

References

  1. Anon., ‘Natural Gas Pipeline Safety: Integrity Management Benefits Public Safety, but Consistency of Performance Measures Should Be Improved’, GAO United States Government Accountability Office Report No GAO-06-946 to Congressional Committees. USA. September 2006.
  2. Anon., ‘Managing System Integrity of Gas Pipelines’, ASME B31.8S-2014. American Society of Mechanical Engineers. New York, USA. 2014.