Preface This is the second edition of CSA B342, Selection and use of UN pressure receptacles, multiple-element gas containers, and other pressure receptacles for the transport of dangerous goods, Class 2. It supersedes the previous edition published in 2009. This Standard was prepared as a related Standard to CSA B341-15, UN pressure receptacles and multiple-element gas containers for the transport of dangerous goods, with the intent that it will become part of the Government of Canada’s Transportation of Dangerous Goods Regulations through adoption by reference. In the development of this Standard, the Subcommittee reviewed and made extensive use of the United Nations’ Recommendations on the Transport of Dangerous Goods — Model Regulations, 18th rev. ed. (2013) (\"UN Model Regulations\"). It should be noted that members of the Subcommittee participated in developing and evaluating the ISO standards that are included in the UN Model Regulations. This Standard takes into account proven experience and recent technical advances. The following requirements have been included in this Standard for consistency with North American practices: (a) a five-year periodic inspection and test period for UN pressure receptacles in carbon dioxide service and for UN composite cylinders; (b) when UN pressure receptacles are required to be equipped with one or more pressure-relief devices, the pressure-relief device system(s) needs to be capable of preventing rupture of normally filled UN pressure receptacles that are subjected to a fire test; (c) UN pressure receptacles filled with a refrigerated liquefied gas or a liquefied flammable gas need to be transported in an upright position unless they are designed for horizontal service; and (d) the use of UN composite cylinders constructed in accordance with ISO 11119-3:2002, Gas cylinders of composite construction — Specification and test methods — Part 3: Fully wrapped fibre reinforced composite gas cylinders with non-load-sharing metallic or non-metallic liners, is not authorized for toxic gases with an LC50 less than 200 mL/m3. Scope 1.1 This Standard specifies requirements for the selection, use, handling, and filling of UN pressure receptacles, multiple-element gas containers, and other pressure receptacles for the transport of dangerous goods included in Class 2, gases. 1.2 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.