CSA B51:24

1 Scope 1.1 Equipment within scope Except as indicated in Clause 1.2, this Standard applies to all pressure equipment including a) boilers, pressure vessels, pressure piping, and fittings, as provided for by the Act (as defined in Clause 3) and identified in this Standard; and b) compressed natural gas and hydrogen refuelling station pressure piping systems and storage pressure vessels. Notes: 1) It is possible the size limitations specified in provincial/territorial statutes or regulations will differ from those specified in this Standard. The applicable AHJ should be consulted. 2) The pressures specified in this Standard are gauge pressures above atmospheric pressure. 3) This Standard applies to all boilers, pressure vessels, pressure piping, and fittings installed after its adoption. 1.2 Exclusions This Standard does not apply to a) pressure-retaining components in hydraulic elevators; b) pressure-containment devices for gas-filled switchgear and controlgear; c) high-pressure cylinders for the on-board storage of hydrogen as fuel for automotive vehicles (see CSA/ANSI HGV 2); d) high-pressure cylinders for the on-board storage of natural gas as fuel for automotive vehicles (see CSA/ANSI NGV 2); and e) pressure vessels for the transportation of dangerous goods regulated by Transport Canada. 1.3 Variances with CSA B51 Where a clause in this Standard is at variance with a code or standard referenced in this Standard, the requirements of this Standard will govern. 1.4 Exemptions in Canadian jurisdictions A synopsis of some exemptions in Canadian jurisdictions is provided in Annex R. 1.5 Clause numbering between B51:19 and B51:24 Annex Ucompares the location of clauses between the 2019 and 2024 editions of this Standard. 1.6 Terminology 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 (non-mandatory) to define their application. 1.7 Units of measurement The values given in SI units are the units of record for the purposes of this Standard. The values given in parentheses are for information and comparison only. Nominal pipe sizes are expressed in non- dimensional terms.