Preface

This is the second edition of CSA A123.21, Standard test method for the dynamic wind uplift resistance of membrane-roofing systems. It supersedes the first edition, published in 2004 under the title Standard test method for the dynamic wind uplift resistance of mechanically attached membrane-rooting systems.

Scope

1.1
This test method determines the wind uplift resistance of membrane-roofing systems when subjected to dynamic wind load cycles. The test methods are
(a) Method 1: mechanically attached membrane-roofing systems; and
(b) Method 2: adhered membrane-roofing systems.
The roofing system consists of a deck and roofing membrane. It includes components such as vapour barriers or retarders, insulation, cover board, etc. It is subjected to a dynamic load sequence that has been developed based on wind pressure records, simulating the effects of wind on membrane-roof assemblies.
Note: The roof membrane may be designated as the plane of air tightness.

1.2
Method 1: Testing in accordance with this test method is limited to mechanically attached, reinforced membrane systems having a fastener row separation not greater than 2896 mm (114 in) and fastener in-line spacing not greater than 610 mm (24 in).

Method 2: Testing in accordance with this test method is limited to roof components adhered as a means of resisting wind uplift, without the use of mechanical fasteners or ballast.

1.3
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; 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 (nonmandatory) to define their application.

1.4
The values given in SI (metric) units are the standard. The values given in parentheses are for information only.