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Preface
This is the eighteenth edition of CSA B51, Boiler, pressure vessel, and pressure piping code. It supersedes the previous editions published in 2009, 2003, 1997, 1995, 1991, 1986, 1981, 1975, 1972, 1969, 1965, 1960, 1957, 1955, 1951, 1945, and 1939.
In keeping with CSA's goal of harmonizing its standards with those of other countries to the greatest extent possible, CSA's Technical Committee on Boilers and Pressure Vessels and its Subcommittees have, in the course of developing this Standard, worked closely with the National Board of Boiler and Pressure Vessel Inspectors in the United States and with the American Society of Mechanical Engineers (ASME) committees responsible for producing the National Board Inspection Code and ASME's Boiler and Pressure Vessel Code.
There are three parts to this Standard:
Part 1 contains requirements for boilers, pressure vessels, pressure piping, and fittings. It is intended mainly to fulfill two objectives: first, to promote safe design, construction, installation, operation, inspection, testing, and repair practices, and second, to facilitate adoption of uniform requirements by Canadian jurisdictions.
Part 2 contains requirements for high-pressure cylinders for the on-board storage of natural gas, blends of natural gas and hydrogen (hydrogen blends), and hydrogen as fuels for automotive vehicles. It has been harmonized with International Organization for Standardization (ISO) Standard 11439:2013, Gas cylinders - High pressure cylinders for the on-board storage of natural gas as a fuel for automotive vehicles. In addition, the CSA Subcommittee responsible for developing Part 2 has consulted with the American National Standards Institute (ANSI) committee responsible for developing ANSI Standard NGV 2-2007, Compressed Natural Gas Vehicle Fuel Containers, and the draft American National Standard/CSA Standard for Compressed Hydrogen Gas Vehicle (HGV) Fuel Containers. The members of these two committees are dedicated to harmonizing their standards as far as circumstances allow.
Part 3 contains requirements for compressed natural gas and hydrogen refuelling station pressure piping systems and ground storage vessels. These requirements have been allotted a separate part of the Standard to emphasize the differences between them and the requirements in Part 1, thereby facilitating their application.
This Standard has undergone substantial technical and editorial revisions since the previous edition in 2009. Significant changes to Part 1 include the following:
(a) The following definitions have been added to Clause 3:
(i) air heater coil;
(ii) historical steam boiler;
(iii) owner;
(iv) pressure relief device (PRD); and
(v) thermal expansion relief valve.
(b) General requirements: Clauses 4.1.1, 4.1.4, 4.2.4, 4.2.8, 4.6.5, 4.7.1, 4.7.2 Note 1, 4.8.2, 4.8.3, 4.9.3 Note, and 4.10 have been updated, and Clauses 4.1.9, 4.1.10, 4.2.5, and 4.2.6 have been added.
(c) Boilers and related components: Clauses 6.2.1 and 6.7 have been updated, and Clauses 6.2.2 and 6.5.1 Note 3 have been added.
(d) Pressure vessels - applicable codes and standards: Clauses 7.1.2 and 7.1.4 have been added.
(e) Piping and fittings: Clause 8.1(c) has been updated.
(f) Repairs and alterations: Clause 11.5 has been added.
(g) Pressure relief devices: Clause 12 has been added.
(h) In-service inspection: Clause 13 has been added.
(i) Categories of fittings: Table 1 Note 2 has been updated.
(j) Maximum servicing intervals: Table 5 has been added.
(k) The sample forms in Annex D have been updated to include cast aluminum.
(l) Requirements for a crush test for manifold vessels have been added to Annex G (Clause G.3.7).
(m) Provisions applicable to overpressure protection devices have been revised (Annex H).
(n) Requirements for historical boilers have been added (Annex I).
(o) Requirements regarding the use of finite elements analysis (FEA) to support a pressure equipment design submission have been added (Annex J).
The users of this Standard should note that it is a recommendatory document only and does not have the force of law except where it has been officially adopted by a Canadian jurisdiction. Users should also note that adoption does not necessarily mean that the Standard has been adopted unchanged. For example, a jurisdiction may decide to make an informative annex normative.
In addition, owners and users of cylinders designed to the requirements of Part 2 should note that the safe operation of such cylinders requires, first, compliance with the service conditions specified by the manufacturer, and second, use of the cylinders only during the service life specified by the manufacturer. Each cylinder is marked with an expiry date, and owners and users are responsible for ensuring that a cylinder is not used after that date.
The Technical Committee intends to meet periodically to review this Standard and, if necessary, to revise it to meet changing conditions and maintain uniformity of practice throughout Canada.
The Technical Committee supports the use of the National Board Inspection Code. It is the responsibility of the user of this standard to be aware that applicable local regulations can take precedence over the requirements of that Code.
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B51-14, Part 1 - General requirements for boilers, pressure vessels, and pressure piping
Scope
1.1
Except as indicated in Clause 1.2, Part 1 of this Standard applies to all boilers, pressure vessels, pressure piping, and fittings, as provided for by the Act (as defined in Clause 3) and identified in Part 1 of this Standard.
Notes:
(1) It is possible that the size limitations specified in provincial or territorial statutes or regulations will differ from those specified in Part 1 of this Standard. The applicable regulatory authority should be consulted.
(2) The pressures specified in Part 1 of this Standard are gauge pressures above atmospheric pressure.
(3) This Standard applies to all boilers, pressure vessels, pressure piping, and fittings installed subsequent to its adoption.
1.2
Requirements for compressed natural gas cylinders and refuelling station pressure piping systems and containers are covered in Parts 2 and 3 of this Standard.
1.3
This Standard does not apply to
(a) pressure-retaining components in hydraulic elevators;
(b) pressure-containment devices for gas-filled switchgear and controlgear; and
(c) pressure vessels for the transportation of dangerous goods regulated by Transport Canada.
1.4
Where a clause in Part 1 of this Standard is at variance with a code or standard referenced in Part 1 of this Standard, the requirements of Part 1 of this Standard govern.
1.5
In this Standard, shall is used to express a requirement, i.e., a provision that the user is obliged to satisfy in order to comply with the standard; should is used to express a recommendation or that which is advised but not required; and may is used to express an option or that which is permissible within the limits of the standard.
Notes accompanying clauses do not include requirements or alternative requirements; the purpose of a note accompanying a clause is to separate from the text explanatory or informative material.
Notes to tables and figures are considered part of the table or figure and may be written as requirements.
Annexes are designated normative (mandatory) or informative (nonmandatory) to define their application.
1.6
The values given in SI (metric) units are the standard. The values given in parentheses are for information only. Nominal pipe sizes are expressed in non-dimensional terms.
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B51-14, Part 2 - High-pressure cylinders for the on-board storage of natural gas and hydrogen as fuels for automotive vehicles
Introduction
Part 2 of this Standard concerns high-pressure cylinders for the on-board storage of natural gas, blends of natural gas and hydrogen (hydrogen blends), and hydrogen as fuels for automotive vehicles. The use of gas cylinders is governed by the Act. Users and manufacturers should note the need to apply to the applicable regulatory authorities for approval of gas cylinders.
Scope
1.1
Part 2 of this Standard specifies minimum requirements for serially produced lightweight refillable gas cylinders, both original equipment and conversions, having a water capacity exceeding 20 L (0.71 ft3) but not exceeding 1000 L (35.3 ft3). Part 2 of this Standard applies only to cylinders for the on-board storage of high-pressure compressed natural gas and/or compressed hydrogen as fuels for automotive vehicles to which the cylinders are to be fixed. Cylinders may be of any material (steel, aluminum, or non-metallic) and constructed in accordance with any design or method of manufacture suitable for the specified service conditions.
1.2
The cylinders covered by Part 2 of this Standard are designated as follows:
(a) Type 1 - metal;
(b) Type 2 - metal liner reinforced with resin-impregnated continuous filament (hoop-wrapped);
(c) Type 3 - metal liner reinforced with resin-impregnated continuous filament (fully wrapped); and
(d) Type 4 - non-metallic liner with resin-impregnated continuous filament (all-composite).
1.3
The service conditions to which the cylinders are subjected are specified in Clause 4. Part 2 of this Standard is based on a working pressure settled at 15 °C (59°F), with a maximum filling pressure of 1.25 times the working pressure.
The service life of a cylinder is defined by the manufacturer and can vary with different applications. This Standard's definition of service life is based on filling a cylinder 750 times a year. The maximum service life of Type 2, Type 3, and Type 4 cylinders is 20 years. For all cylinders, a safe life design principle is used.
For metal and metal-lined cylinders, the cylinder life is based on the rate of fatigue crack growth. Ultrasonic or equivalent inspection of each cylinder or liner is necessary to ensure that there are no flaws that exceed the maximum allowable size determined by fracture mechanics. This approach optimizes the design and manufacture of lightweight cylinders for natural gas vehicle service.
For all-composite cylinders with non-metallic non-load-bearing liners, safe life is ensured by appropriate design methods, design qualification testing, and manufacturing controls.
1.4
Part 2 of this Standard does not cover Type 1 or Type 2 welded metal cylinders or liners.
1.5
Where a clause in Part 2 of this Standard is at variance with codes or standards referenced in Part 2 of this Standard, the requirements of Part 2 of this Standard govern.
1.6
Type 1 steel cylinders may be requalified for further service in accordance with the procedure described in Annex B.
1.7
In this Standard, shall is used to express a requirement, i.e., a provision that the user is obliged to satisfy in order to comply with the standard; should is used to express a recommendation or that which is advised but not required; and may is used to express an option or that which is permissible within the limits of the standard.
Notes accompanying clauses do not include requirements or alternative requirements; the purpose of a note accompanying a clause is to separate from the text explanatory or informative material.
Notes to tables and figures are considered part of the table or figure and may be written as requirements.
Annexes are designated normative (mandatory) or informative (nonmandatory) to define their application.
1.8
The values given in SI (metric) units are the standard. The values given in parentheses are for information only.
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B51-14, Part 3 - Compressed natural gas and hydrogen refuelling station pressure piping systems and ground storage vessels
Scope
1.1
1.1.1
The pressure piping systems covered in Part 3 of this Standard are systems used in compressed natural gas (CNG) and hydrogen refuelling stations
(a) between the termination of the utility's piping, usually at the meter, and the inlet to the compressor assembly if the design pressure exceeds 414 kPa (60 psi); and
(b) from the inlet to the compressor assembly through to the dispenser nozzle, except for the mechanical parts of the compressor and any subsystems designed for 414 kPa (60 psi) or less.
1.1.2
The ground storage vessels covered in Part 3 of this Standard are pressure vessels that are installed at CNG and hydrogen refuelling stations and intended to store CNG or hydrogen at pressure for delivery to vehicle fuel tanks.
1.2
Where a clause in Part 3 of this Standard is at variance with codes or standards referenced in Part 3 of this Standard, the requirements of Part 3 of this Standard govern.
1.3
In this Standard, shall is used to express a requirement, i.e., a provision that the user is obliged to satisfy in order to comply with the standard; should is used to express a recommendation or that which is advised but not required; and may is used to express an option or that which is permissible within the limits of the standard.
Notes accompanying clauses do not include requirements or alternative requirements; the purpose of a note accompanying a clause is to separate from the text explanatory or informative material.
Notes to tables and figures are considered part of the table or figure and may be written as requirements.
Annexes are designated normative (mandatory) or informative (nonmandatory) to define their application.
1.4
The values given in SI (metric) units are the standard. The values given in parentheses are for information only.
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