Engineering Practice Guide
The AS/NZS 2885 series of standards – often just called 'the Standard', or “AS2885” by participants in the industry – is a vital and crucial part of the high pressure pipelines speciality in Australia. AS/NZS 2885 is the foundation on which the high pressure pipelines sector provides assurance to itself, policy makers, regulators and the wider community that the pipelines that carry very hazardous materials at high pressure (i.e. hydrocarbons, hydrogen, CO2 and other fluids) are safe, environmentally benign and reliable.
AS 2885 is one of the most advanced, if not the most advanced, standards for high pressure pipelines in the world, because it remains at the cutting edge of technology, both in terms of safety and in efficient use of resources. A project is currently underway to revamped the series to address the real possibility of fluids other than hydrocarbons flowing through our pipelines at high pressure.
AS 2885 is considered to be ‘single and sufficient’ for design, construction, maintenance and operations of pipeline systems carrying fluid at high pressures, because it is comprehensive in the matters that need to be covered by pipeline technical regulation and there is no need for the State technical regulators to make further or additional technical regulations.
This status was adopted by the Council of Australian Governments in its communiqué of 25 February 1994 in which it agreed to adopt AS 2885 to achieve uniform national pipeline construction standards by the end of 1994.
Accordingly, all State legislation except for Western Australia recognise this and have not added further requirements over AS 2885.
It is therefore vital that engineers who work in the pipelines industry are familiar with the AS 2885 Standard and each of the parts, knowing how to apply them, or knowing who to call on to assist them in applying them.
AS 2885 provides an authoritative source of fundamental principles and practical guidelines for use by responsible and competent persons or organisations. It is also applicable in New Zealand.
The Standard has seven parts:
- AS/NZS 2885.0: General requirements
- AS/NZS 2885.1 Design and construction
- AS/NZS 2885.2: Welding
- AS/NZS 2885.3: Operation and maintenance
- AS/NZS 2885.4: Submarine pipeline systems
- AS/NZS 2885.5: Field pressure testing
- AS/NZS 2885.6: Pipeline safety management
The Standard is published by Standards Australia and is regularly reviewed by a body of experts drawn from industry and professional associations and from State and Territory regulators who form the ME-038 Technical Committee. The ME-038 Technical Committee also has responsibility for the related Standards:
- AS 4822 External field joint coatings for steel pipelines;
- AS/NZS 1518 External extruded high-density polyethylene coating systems for pipes; and
- AS/NZS 3862 External fusion-bonded epoxy coating for steel pipes.
The AS 2885 development and revision processis a particularly robust process because it includes members from a full range of industry sectors, including the State regulators.
What is in a Standard?
A Standard provides designers, builders and engineers with mandatory and informative criteria for designing, constructing, testing and operating a product, piece of equipment or structure. Standards are written primarily from a safety perspective, and are often referenced by legislation and may be used as evidence in court actions dealing with public liability and workplace health and safety.
Standards consist of rules, requirements, principles, and factors that must be taken into account when undertaking the design, construction, testing or operation of a product or activity. In the case of AS 2885, the pipeline system is our product, and operating the pipeline system is an activity governed by the AS 2885 suite.
Standards are not instruction manuals for untrained persons or a complete design specification, and require a certain minimum level of background knowledge and understanding.
Why does Australia have its own Standard for high pressure pipeline systems?
Energy resources in Australia are typically remote from load centres, particularly the historic development and usage of methane gas and petroleum oil. The loads were (and still are by world standards) small and the energy value is relatively low. The land between the energy source and the load centre is generally sparsely populated. These factors combine to make it difficult to justify development of high pressure transmission pipelines unless the capital cost can be amortised over a long project life. It was this fact that led the Australian pipeline industry to depart from traditional North American and European pipeline designs, in the 1970s and 1980s.
To reduce capital costs, the Australian pipeline industry adopted higher strength line pipe steels and reduced wall thickness and increased operating pressures (initially 7 MPa, then 10.2 MPa, and 15.3 MPa) to increase the gas quantity transported per unit of steel. Combined with newly developed pipe coatings, joint coatings, and construction methods, they formed the need for development of Standards relevant to Australian conditions.
Differences between AS 2885 and the US Standard
AS 2885, was first published in 1987. While still looking much like the American Standard, this Standard introduced significant departures from the previous documents including:
- Application to transmission pipelines only (pressures greater than 1,050 kPa).
- Application to gas and liquid hydrocarbons (onshore).
- Definition of a single design factor for determining the pressure design thickness of the pipe.
- Definition of a third-party protection factor (to recognise the purpose of the mandatory design factors that the earlier standards applied to class locations other than broad rural).
During the 1990s, AS 2885 went through a range of developments, and it was separated into several parts. Between 2007 and 2018, the series was expanded to include the “General Requirements” in Part 0, and “Pipeline Safety Management” in Part 6, to cover the risk management aspect of pipelines in one document.
AS 2885 seeks to manage issues of safety through risk management techniques, focussed on the integrity of the pipeline. Keeping the pipeline safe from interference keeps the people and the environment safe from the pipeline..
This means that protection measures are based on a thorough assessment of sources of risk (identification of threats) along the whole length of the pipeline. This has two benefits:
- threats specific to the location and the pipeline are identified and are eliminated wherever possible, and the protection measures (‘controls’) properly reflect the threats specific to that pipeline and location; and,
- protection measures (controls) are sufficient, but not excessive thus minimising the cost of risk elimination or risk management.
In summary, this approach provides a high level of assurance about safety, but at the lowest sustainable cost.
AS 2885 requires that each identified threat be controlled by a combination of design solutions,and physical and procedural methods to reduce the likelihood of that threat causing damage to a risk level that is as low as reasonably practicable (ALARP). AS2885.6 (“Part 6”) of the Standard requires extensive investigation to identify, document and control each threat, and to undertake regular reviews to ensure that the identified threats are current and the controls applied are effective.
The depth of detail and the level of documentation required by the AS 2885.6 Safety Management Study (formerly the risk assessment process) is significant.
The AS 2885 Safety Management Study (SMS) requires validation by a workshop of stakeholders. Validation requires the entire Safety Management Study to be reviewed and the stakeholders to work to form the opinion that all threats are identified, the controls applied are effective, the risk of any threats that are not controlled is not higher than intermediate, and that any risks assessed as intermediate are reduced to as low as reasonably practicable (ALARP).
The safety management study (which includes a formal risk assessment process) forms the basis of safety and operating plans for the ongoing safe management of a pipeline.
Unlike other standards that apply mandatory requirements for the pipe wall thickness according to location and population density, AS 2885 requires the Pipeline Licensee to demonstrate that the pipeline is safe in each location in which it is installed. This requires the Licensee (and its designer) to consider many factors, each of which influences the required wall thickness (such as resistance to penetration) and to select wall thickness at each location accordingly. The Standard has a mandatory requirement for the Licensee to demonstrate that the pipeline will not rupture in populated locations.
The scope of the Standard is restricted to the pipeline (significantly because of the emphasis on thin walled pipe). Consequently, it has nominated that connected station piping be designed to an appropriate pressure piping standard such as AS 4041 or B31.3.
Themes in AS 2885
Several broad themes are clearly identifiable in the Australian Standard that are generally either, not present, or less clear, in other standards. These tend to distinguish the Australian Standard from the other pipeline standards.
Other standards typically provide only general statements about their purpose. While they do point to issues of safety, integrity, environmental protection and security of supply, their treatment within the standards is not particularly clear. AS 2885.0 provides a clear statement of the basis of the AS 2885 series, and sets out the fundamental principles of:
- Safety, environmental protection, security of supply;
- Consideration of all planned and accidental loads over the complete life cycle;
- The basis of approval; and
- The key role of approved safety and operating plans.
In addition, each major section of AS 2885 has a Basis of Section clause stating its overall purpose and intent, and guiding principles.
Principles in AS 2885
The Australian Standard is characterised by a set of principles that add to its uniqueness:
- Ensuring the protection of the general public, pipeline operating personnel and the environment.
- Explicitly recognising that continuity of supply is an important secondary community safety issue.
- Requiring suitably qualified, experienced and trained people who take responsibility for their actions in writing.
- Designing against actual threats and failure modes.
- Auditing design and operations processes.
- Ensuring transparency, repeatability and traceability.
Responsibility and approvals
AS 2885 gives responsibility for decisions under it to the pipeline Licensee. The pipeline licensee is defined as the entity held accountable for the pipeline system under relevant legislation. There need not be an actual license, and the licensee might not be the license holder. It is the entity held accountable for the pipeline system. Significant decisions require designated approvals, which must be made consciously by the Licensee and may include obtaining approval from the relevant State regulator.
Approval applies to important matters related to safety, engineering design, materials, testing and inspection. The Standard also requires that accountability rests with a competent person or entity on behalf of the Licensee and that they must document approvals in writing.
These clear definitions of the Licensee’s responsibility and a competent person/entity have at least two benefits. The first is that critical decisions will be made with a high level of awareness of their significance. The second is that regulators are responsible only for those approvals and decisions that can and should be made by regulators. In other words, the accountability lies with the party who is best placed to understand and manage the desired outcomes sought by the Standard. The role of the technical regulator is to ensure the Standard has been properly applied through adherence to the required processes.
Other standards do not make the process of decision-making, accountability and approval so clear.