CSA Group CSA S37:24 National Standard of Canada Antennas, towers, and antenna-supporting structures

Preface

This is the ninth edition of CSA S37, Antennas, towers, and antenna-supporting structures. It supersedes the previous editions published in 2018, 2013, 2001, 1994, 1986, 1981, 1976, and 1965.

The following are the major changes to this edition:

a) the addition of dynamic response to wind for tall, guyed masts and multi-sloped self-supporting

towers in Clauses 6.9 to 6.11;

b) the inclusion of the oscillation and fatigue analysis in Clause 5.13;

c) the inclusion of a method to calculate vortex shedding response due to higher modes of vibration in Clause 5.13.2.3;

d) the updated ice map in Figure 1 and updated climatic data in Table E.1;

e) the inclusion of drag coefficients, Cd, for perforated shrouds in Table 1;

f) the updated earthquake loads and analysis in Clause 5.12;

g) the inclusion and update of the fatigue resistance calculation in Clause 7.9, replacing Annex N of the previous edition;

h) the addition of Clause 7.3.4.4 to provide factored resistance formulas for HSS members with slotted through plates;

i) Clause 7.5.5 has been updated for bolt tensioning requirements;

j) Clause 7.5.7.4 has been updated and a formula for prying action included;

k) commentary Annexes have been updated and consolidated into Annex S; and

l) the inclusion of additional recommendations for tower condition assessment (Annex D).

A commentary on this Standard can be found in Annex S.

CSA Group acknowledges that the development of this Standard was made possible, in part, by the financial support of Bell, Hydro-Québec, Rogers Communications Canada, Telus, CBC, NorthWesTel, and Vidéotron.

This Standard was prepared by the Technical Committee on Antenna Towers, under the jurisdiction of the Strategic Steering Committee for Construction and Civil Infrastructure, and has been formally approved by the Technical Committee.

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.

Notes:

1) Use of the singular does not exclude the plural (and vice versa) when the sense allows.

2) Although the intended primary application of this Standard is stated in its Scope, it is important to note that it remains the responsibility of the users of the Standard to judge its suitability for their particular purpose.

3) This Standard was developed by consensus, which is defined by CSA Policy governing standardization — Code of good practice for standardization as “substantial agreement. Consensus implies much more than a simple majority, but not necessarily unanimity”. It is consistent with this definition that a member may be included in the Technical Committee list and yet not be in full agreement with all clauses of this Standard.

4) To submit a request for interpretation of this Standard, please send the following information to [email protected] and include “Request for interpretation” in the subject line:

a) define the problem, making reference to the specific clause, and, where appropriate, include an illustrative sketch;

b) provide an explanation of circumstances surrounding the actual field condition; and

c) where possible, phrase the request in such a way that a specific “yes” or “no” answer will address the issue.

Committee interpretations are processed in accordance with the CSA Directives and guidelines governing standardization and are available on the Current Standards Activities page at standardsactivities.csagroup.org.

5) This Standard is subject to review within five years from the date of publication. Suggestions for its improvement will be referred to the appropriate committee. To submit a proposal for change, please send the following information to [email protected] and include “Proposal for change” in the subject line:

a) Standard designation (number);

b) relevant clause, table, and/or figure number;

c) wording of the proposed change; and

d) rationale for the change.

1 Scope

1.1 General

This Standard applies to structural antennas, towers, antenna-supporting structures, and roof- and wall-mounted structures including their components, such as guys and foundations. It covers the structural design, fabrication, and erection of new structures and the modification of existing structures.

1.2 Exclusions

This Standard is not intended to apply to

a) attachment antennas and arrays or assemblies of such antennas; or

b) towers that support attachment antennas, extending less than 15 m above grade, including the height of any structure on which they are mounted.

1.3 Unusual designs and antennas

This Standard covers the requirements for most structural antennas, antenna towers, and antenna-supporting structures, but it is recognized that structures that are unusual with regard to their height or shape, or with regard to the shape and size of individual members, or that are located on sites having unusual topographical, geological, or climatic conditions might not be adequately covered. In such cases, appropriate engineering principles providing a level of reliability at least equivalent to that provided by this Standard should be applied.

1.4 Other design approaches

A rational design based on theory, analysis, and engineering practice that is acceptable to the owner and regulatory authority may be used in lieu of the design procedures or materials described in this Standard. In such cases, the design should be prepared by an engineer qualified in the specific method and knowledgeable about the materials to be used, and should provide a level of safety and performance that is not less than that implicit in this Standard.

1.5 Local, provincial, and federal regulations

Responsibility for observing all applicable local, provincial, and federal regulations is not relieved by compliance with 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.