Preface This is the fifth edition of CSA B621, Selection and use of highway tanks, TC portable tanks, and other large containers for the transportation of dangerous goods, Classes 3, 4, 5, 6.1, 8, and 9. It supersedes the previous editions published in 2009, 2003, 1998, and 1987. This Standard is one of a series of Standards that have been prepared for use in conjunction with the Transportation of Dangerous Goods Regulations. It should be noted that this Standard, by itself, does not have the force of law unless it is officially adopted by a regulatory authority. Since the Standard may be adopted into regulations with certain exceptions or additional requirements, it is recommended that the regulations of the relevant jurisdiction be consulted in order to establish the extent to which this Standard has been adopted. Where an industry practice differs from the requirements of this Standard, an application for a permit for equivalent level of safety may be requested from the regulatory authority. This Standard was prepared giving due consideration to current industry practices in North America, the US Code of Federal Regulations, Title 49, and the United Nations publication Recommendations on the Transport of Dangerous Goods: Model Regulations. CSA B620-14, Highway tanks and TC portable tanks for the transportation of dangerous goods, is the reference document for design, construction, testing, and inspection requirements. Scope 1.1 This Standard details the requirements for the selection and use, handling, filling, and unloading of highway tanks, TC portable tanks, and other large containers when they are used as a primary means of containment for the transportation of dangerous goods of Classes 3, 4, 5, 6.1, 8, and 9. 1.2 This Standard sets out certain minimum requirements for the selection of the appropriate means of containment for the transportation of dangerous goods. This Standard does not, however, prescribe selection of the materials of construction of the means of containment to ensure chemical compatibility with the dangerous goods. Consequently, it is essential to exercise competent technical and engineering judgment in conjunction with this Standard. 1.3 Where any requirement of this Standard differs from the Transportation of Dangerous Goods (TDG) Regulations, the requirements of the TDG Regulations apply. 1.4 This Standard does not apply to TC 56, CTC 56, and DOT 56 tanks. Requirements for these tanks are provided in CAN/CGSB-43.146. (See Clause 6.4.) 1.5 This Standard does not apply to TC 57, CTC 57, and DOT 57 tanks. Requirements for these tanks are provided in CAN/CGSB-43.146. (See Clause 6.5.) 1.6 In CSA Standards, \"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; \"may\" is used to express an option or that which is permissible within the limits of the standard; and \"can\" is used to express possibility or capability. 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 The values given in SI (metric) units are the standard. The values given in parentheses are for information only. Units for pressure refer to gauge pressure unless otherwise noted.

Preface This is the fifth edition of CSA B621, Selection and use of highway tanks, TC portable tanks, and other large containers for the transportation of dangerous goods, Classes 3, 4, 5, 6.1, 8, and 9. It supersedes the previous editions published in 2009, 2003, 1998, and 1987. This Standard is one of a series of Standards that have been prepared for use in conjunction with the Transportation of Dangerous Goods Regulations. It should be noted that this Standard, by itself, does not have the force of law unless it is officially adopted by a regulatory authority. Since the Standard may be adopted into regulations with certain exceptions or additional requirements, it is recommended that the regulations of the relevant jurisdiction be consulted in order to establish the extent to which this Standard has been adopted. Where an industry practice differs from the requirements of this Standard, an application for a permit for equivalent level of safety may be requested from the regulatory authority. This Standard was prepared giving due consideration to current industry practices in North America, the US Code of Federal Regulations, Title 49, and the United Nations publication Recommendations on the Transport of Dangerous Goods: Model Regulations. CSA B620-14, Highway tanks and TC portable tanks for the transportation of dangerous goods, is the reference document for design, construction, testing, and inspection requirements. Scope 1.1 This Standard details the requirements for the selection and use, handling, filling, and unloading of highway tanks, TC portable tanks, and other large containers when they are used as a primary means of containment for the transportation of dangerous goods of Classes 3, 4, 5, 6.1, 8, and 9. 1.2 This Standard sets out certain minimum requirements for the selection of the appropriate means of containment for the transportation of dangerous goods. This Standard does not, however, prescribe selection of the materials of construction of the means of containment to ensure chemical compatibility with the dangerous goods. Consequently, it is essential to exercise competent technical and engineering judgment in conjunction with this Standard. 1.3 Where any requirement of this Standard differs from the Transportation of Dangerous Goods (TDG) Regulations, the requirements of the TDG Regulations apply. 1.4 This Standard does not apply to TC 56, CTC 56, and DOT 56 tanks. Requirements for these tanks are provided in CAN/CGSB-43.146. (See Clause 6.4.) 1.5 This Standard does not apply to TC 57, CTC 57, and DOT 57 tanks. Requirements for these tanks are provided in CAN/CGSB-43.146. (See Clause 6.5.) 1.6 In CSA Standards, \"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; \"may\" is used to express an option or that which is permissible within the limits of the standard; and \"can\" is used to express possibility or capability. 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 The values given in SI (metric) units are the standard. The values given in parentheses are for information only. Units for pressure refer to gauge pressure unless otherwise noted.