Preface:

This is the sixth 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 2014, 2009, 2003, 1998, and 1987.

The major changes to this edition include the following:

• non-rectangular TC 44 are no longer limited to diesel fuel only. They are permitted for the transport of other dangerous goods, similar to TC 406 and equivalent tanks;
• revised requirements for tanks with an intermediate bulkhead;
• emergency shutoff marking requirements for manually activated remote shutoff device;
• minimum two chock blocks required when using chock blocks to prevent unintended vehicle movement; and
• revised dangerous goods table sorted by UN number.

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 B620:20, Highway tanks and TC portable tanks for the transportation of dangerous goods, is the reference document for design, construction, testing, and inspection requirements.

This Standard has been developed in compliance with Standards Council of Canada requirements for National Standards of Canada. It has been published as a National Standard of Canada by CSA Group.

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. Where there is an inconsistency between this Standard and a referenced publication other than the TDG Act or Regulations, the requirements of this Standard prevail. Application of a referenced publication should be made only with careful consideration of this Standard's reference to that particular publication.

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
This Standard does not apply to TC 106, TC 110, CTC 106, CTC110, DOT 106, DOT110, ICC106, and ICC110 tanks. Requirements for these tanks are provided in TP14877. (See Clause 6.6.)

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 (non-mandatory) to define their application.

1.8
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.
Note: Units for pressure refer to gauge pressure unless otherwise noted.