Preface
This is the first edition of S520, Design and construction of low-rise residential and small buildings to resist high wind.
This Standard is considered suitable for use for conformity assessment within the stated scope of the Standard. A cost-benefit analysis has, however, not been done, so the total economic burden and the benefit of compliance with this Standard are not known.
CSA Group acknowledges that the development of this Standard was made possible, in part, by the financial support of the Standards Council of Canada.
This Standard was prepared by the Technical Committee on High Wind Safety for Low-Rise Residential and Small Buildings, under the jurisdiction of the Strategic Steering Committee on 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.
Scope
1.1 General
This Standard contains best practice guidance for the design and construction of low-rise, wood-frame buildings to withstand high winds corresponding to EF-2 tornado-level wind speeds, assumed to be associated with a reference velocity pressure of 1 kPa. The guidance in this Standard is based on, and written to, supplement the requirements specified in Part 9 of the National Building Code of Canada (NBC) (see Clause 0.4).
1.2 Applicability and limitations
The guidance in this Standard has been developed primarily for new wood-frame building construction. The resistance to high wind speeds up to an EF-2 level requires adherence to all provisions and recommendations in this Standard.
1.3 Alterations and additions
This Standard can be applied to major alterations and additions to existing buildings where the entire continuous vertical and lateral load path can be upgraded with all primary structural requirements. For alterations and additions to existing buildings where the entire continuous vertical and lateral load path cannot be upgraded, users should start with the non-structural measures provided in Clauses 11 through 14. For more information, see Clause 0.3.
1.4 Conflicting requirements
In cases where a requirement or method in another standard that is referenced in a regulation conflicts with recommendations in this Standard, the regulatory requirements take precedence. For more information, see Clause 0.5.
1.5 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.
