CSA B72:20 (R2025) ✓ Most Recent

Preface:

This is the third edition of CSA B72, Installation code for lightning protection systems. It supersedes the previous editions published in 1987 and 1960.

The major changes to this edition include the following:
a) The Standard has been updated and expanded in order to harmonize lightning protection standards within North America.
b) The requirements for the various components that make up a system have been consolidated into their own sections (e.g., air terminals, conductors), and ANSI/CAN/UL 96:2016 has been incorporated as the component standard
c) Further requirements regarding specialized structures and classes have been included following the base requirements in the initial sections.
d) New requirements have been added under Class IV installations, covering a number of specialized structures, including buildings constructed of structural metallic systems, telecommunications equipment, and rooftop helipads.
e) A new clause has been added on protection for solar arrays.
f) The informative annexes have been expanded into four annexes. Further guidance has been provided for inspection and maintenance of lightning protection systems, the risk analysis has been updated to conform to current best practices, and an annex on surge protective devices has been added.

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 covers the protection from lightning of
a) recreational, residential, institutional, medical, agricultural, industrial, commercial, military, and telecommunications buildings and structures;
b) tall, slender structures such as smokestacks, silos, tanks, towers, masts, and poles;
c) immobile property such as equipment, tents, fences, trees, and solar arrays; and
d) high-risk structures with dangerous contents such as explosives and flammable goods.

1.2
This Standard covers the protection from lightning of structures housing electrical generation, transmission, and distribution systems, as well as structures housing communication systems, but not the equipment or installation requirements for such systems.

1.3
This Standard does not cover installation requirements for early streamer emission systems or charge dissipation/charge transfer systems. No recognized standards body or testing agency exists for Canadian installations of these devices.

1.4
This Standard also contains non-mandatory sections devoted to the nature of lightning and the general principles upon which lightning protection is based, so that the user of the Standard will be able to assess the need for lightning protection in the case of any given structure (see Annexes A through D).

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 (non-mandatory) to define their application.

1.6
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. See more