Gas Pipeline Systems
This seventh edition of CSA Standard Z184 (now CAN/CSA-Z184), Gas Pipeline Systems, supersedes previous editions published in 1968 and 1973 (entitled Gas Transportation and Distribution Piping Systems); and in 1975, 1979. 1983. and 1986 (entitled Gas Pipeline Systems).
This Standard is part of the Pipeline Systems and Materials segment of CSA’s transportation program.
This edition differs from the sixth edition mainly as follows:
(a) Clause 4, Materials has been revised to reflect the increased pipe-body-absorbed energy requirements contained in CSA Standard CAN/CSA-Z245.1. The table of limitations for acceptable alternative materials has been expanded to cover pipe and components, and the limitations are now more comprehensive.
(b) Clause 5, Design has been extensively revised in format and content. There is now consistency between design pressure and the intended maximum operating pressure, and the term “maximum allowable operating pressure” has been eliminated. The format of the design formula and the associated factors in the formula have been revised, and the concept of a hydrostatic test factor has been eliminated. It has been clarified that the true design stress is to be used in all combined stress calculations. The requirements for pipe-type and bottle-type holders have been simplified, with most being treated as pressure vessels to CSA Standard B51. The material on flexibility and stress analysis for restrained and unrestrained-piping has been rewritten to provide clearer and more complete guidance on the treatment of combined stresses.
(c) Clause 6. Joining has been significantly revised in respect to the subject of essential variables. The consequences of changes in welding variables are now expressed in tabular form for ease of application; there are separate requirements for manual and mechanized welds, and for welds to be subjected to- acceptance standards based on engineering critical assessment. More comprehensive information has been provided on the design of welded joints between items of different thickness. Some essential elements of low hydrogen welding practices have been enumerated. More detailed information is given on the removal of weld cracks, including requirements for the repair of cracked circumferential welds. Requirements for field joining by explosion welding have been added.
(d) Clause 7, Construction has been revised to include requirements on bends, mitres, and elbows, which were previously contained in Clause 5.
(e) Clause 8, Pressure Testing of Steel Pipeline Systems has been completely revised to reflect the changes in pressure design contained in Clause 5. The relationship between design pressure, strength test pressure, and maximum operating pressure has been clarified.
(f) Clause 9, Corrosion Control has been revised to include a requirement for coating to comply with the requirements of the applicable CSA Standard, where one exists.
(g) Clause 10, Operating, Maintenance, and Upgrading has been revised to give clearer guidance on the repair of arc burns, gouges, grooves, and gouged dents, and the acceptability limits of plain dents have been revised. The requirements for maintenance welding have been extended, particularly in respect to welding on in-service pipelines.
(h) Appendix E, Examples Illustrating the Application of the Rules for Reinforcement of Welded Branch Connections has been revised to conform with the changes in Clause 5.
(i) Appendix H, Recommended Practice for Joining Plastic Pipe Using Solvent Cement Technique has been deleted because solvent cement joining techniques are no longer used in the gas industry.
This Standard contains basic reference data and formulae pertaining to design, supplemented by specific requirements where necessary, to obtain a uniform interpretation of the design requirements. It refers to unsafe pipeline practices that are prohibited and sets out warnings where caution must be exercised. In addition, this Standard contains a bibliography (Appendix A) listing applicable reference standards organizations that may be of interest to users of this Standard.
This Standard is intended to establish essential requirements and minimum standards for the design, installation, and operation of gas pipeline systems. It is not a design handbook and the exercise of competent engineering judgement is a necessary requirement to be employed concurrently with its use.
The requirements of this Standard are adequate under conditions normally encountered in the gas industry. Requirements for abnormal or unusual conditions are not specifically provided for, nor are all details of engineering and construction prescribed. It is intended that all work performed within the scope of this Standard shall meet or exceed the safety standards expressed or implied herein.
As with all new editions, it is to be expected that changes may have to be made from time to time based on new experience or technology, or both. When necessary to do so, amendments will be made by the Committee and published in accordance with CSA practices.
This Standard was prepared by the CSA Technical Committee on Oil and Gas Industry Pipeline Systems under the jurisdiction of the Standards Steering Committee on Oil and Gas Industry Systems and Materials and was formally approved by these Committees. It has been approved as a National Standard of Canada by the Standards Council of Canada.
This Standard covers the design, fabrication, installation, inspection, testing, and safety aspects of the operation and maintenance of gas pipeline systems including gathering lines, transmission lines, compressor stations, metering and regulating stations, distribution lines, and service lines.
The Scope of this Standard, as shown in Figure 1.1. includes the following:
(a) gas storage vessels of the bottle-type or closed pipe-type fabricated or forged from pipe or fabricated from pipe and fittings, and gas storage lines; and
(b) the conditions of use of the elements of the pipeline systems described in Clause 1.1, including, but not limited to, pipe valves, fittings, flanges, bolting, gaskets, regulators, pressure vessels, pulsation dampeners, and relief valves.
Note: Designers are cautioned that, while some sections apply to other gases, this Standard was prepared as a minimum standard for the design, construction, and operation of gas distribution and transmission systems as portrayed in Figure 1.1.
This Standard does not apply to
(a) design and fabrication of pressure vessels that are covered by appropriate pressure vessel codes;
(b) piping with metal temperatures above 230°C or below —70°C;
(c) piping beyond the outlet of the customer's meter set assembly;*
*For such piping, see CAN/CGA-BI49.1.
(d) piping in oil refineries, natural gasoline extraction plants. gas treatment plants (except main gas stream piping in dehydration and all other processing plants installed as parts of gas pipeline systems), gas manufacturing plants, industrial plants, or mines;
(e) vent piping for waste gases of any kind operating at or near atmospheric pressure;
(f) wellhead assemblies, including control valves and casing and tubing in gas or oil wells;
(g) proprietary items of equipment, apparatus, and instruments;
(h) heat exchangers;
(i) oil and liquid products pipeline systems;
(j) prefabricated units that employ plate and longitudinal welds rather than pipe;
(k) liquefied natural gas pipeline systems; and
(l) offshore pipeline systems, except offshore compressor stations.
This Standard is intended to establish essential requirements and minimum standards for the design, installation, and operation of gas pipeline systems. It is not a design handbook and the need for exercising competent engineering judgement is a necessary requirement to-be employed concurrently with its use.
The requirements of this Standard shall be applicable to the operation, maintenance, and upgrading of existing installations; however, it is not intended that such requirements be applied retroactively to existing installations insofar as design, construction, and established operating pressures are concerned.
Where any requirements of this Standard are at variance with the requirements of other standards or codes incorporated by reference into this Standard, the requirements of this Standard shall govern.
It is not the intent of this Standard to prevent the development of new equipment or practices, or to prescribe how such innovations should be handled.