Consensus means general agreement by all interested parties. Consensus includes an attempt to remove all objection and implies much more than the concept of a simple majority, but not necessarily unanimity. It is consistent with this meaning that a member may be included in the Committee list and yet not be in full agreement with all clauses of this Standard.

This Standard makes use of current American Standards such as ASME B31.3, Process piping, as well as Australian Standards. This has been done where practicable to align with international practices to provide flexibility in design and to enable current proven computer programs for the above Standard to be used to satisfy the design requirements of this Standard (see Clause 1.6). BS 806, Specification for the design and construction of ferrous piping installations for and in connection with land boilers was originally used as the basis for much of this Standard and even though BS 806 has been withdrawn the parts of this Standard where BS 806 was used are still considered valid and relevant and have been retained. BS 806 was superseded by the European Standard EN 13480, Metallic industrial piping.

Comparison of this Standard with ASME B31.1, Power piping and ASME B31.3 shows that for the same pressure and application, piping to this Standard may be thinner than piping to the two American Standards at low to medium temperatures. These two American Standards have been consulted as a major source of material.

The extension of scope in this edition to embrace room-temperature-safe fluids brings into contrast three different traditions of steel pipe engineering which exist side by side in Australia. All are successful in their particular scope of application.

The first tradition is that of power and process piping using steam and other hazardous fluids. This tradition is noted for higher safety factors, thick pipe, and the greater use of pre- and post-weld heat treatment and sophisticated quality assurance.

Another tradition is the non-code tradition for room temperature safe fluids. This is more influenced by the third tradition than by the first. It uses thick or thin pipe and rarely applies postweld heat treatment and only uses limited quality assurance.

The third pipe tradition is that of petroleum and natural gas pipelines. This tradition uses lower safety factors, thin pipe, rarely applies preheat and rarely uses postweld heat treatment but has adequate quality assurance.

The extension of scope that joined tradition 1 and 2 (and possibly tradition 3 in special cases) presented the Committee with a difficulty in preventing unnecessary increases in costs for the present non-code piping systems in Australia while maintaining safety. The more conservative requirements of tradition 1, and ASME B31.3 are not appropriate for applying these features to room-temperature safe fluids in modern low carbon equivalent pipe steels. Hence a four-tier pipe classification system is introduced to ensure adequate safety, performance and economy of piping systems for the wider range of industrial applications from critical pipe used in power stations to low hazard piping found in small industrial plant. In summary this edition will generally permit thinner steel pipe to be used for a given pressure than previously. Also there is a change to some of its pressure testing equations for steel pipe. The traditional value of 1.5 P applies for steam and water piping for steam boilers only.

Australian, American, and European material and component Standards which are used to a considerable extent in Australia have been listed. This Standard now provides for a wider range of materials than previously covered. A basis for specifying non-metallic pressure piping is given by reference to ASME B31.3 but with provision for substitution of equivalent Australian Standards.

The Standard follows in principle other Standards forming part of AS/NZS 1200, Pressure equipment, in providing guidance for owners, designers, manufacturers, inspection bodies and users in the form of minimum engineering requirements for the safe design, fabrication, installation, testing, and commissioning of pressure piping based on world-wide advances and experience. It also provides basic requirements and references for welding qualification, non-destructive testing, operation, maintenance and in-service inspection.

The principle objective of this Standard is to provide clear uniform national requirements which will result in reasonably certain protection of the general public, persons installing and operating the piping, and of adjacent property and environment, which give economic piping, and which show where a margin for deterioration may be necessary to give adequate and safe service life. Additional requirements may be necessary to prevent damage from unusual conditions, third parties and abnormal forces.

The Standard provides an authoritative source of important principles, data, and practical guidelines to be used by responsible and competent persons. It is not practicable nor indeed desirable for the Standard to specify every aspect of piping design and fabrication. It is neither an instruction manual nor a complete design or construction specification. The Standard does not replace the need for appropriate experience, competent engineering judgement, and the application of fundamental engineering principles.

Acknowledgment is gratefully made to the American Society of Mechanical Engineers and the British Standards Institution for the considerable assistance provided by the above referenced national Standards.

Statements expressed in mandatory terms in notes and footnotes to tables and figures are deemed to be requirements of this Standard.

The terms ‘normative’ and ‘informative’ have been used in this Standard to define the application of the Appendix to which they apply. A ‘normative’ appendix is an integral part of a Standard, whereas an ‘informative’ appendix is only for information and guidance.