Update No. 1 was published as notification that this is now a National Standard of Canada This PDF includes Update No.
This is the first edition of CSA A123.21, Standard test method for the dynamic wind uplift resistance of mechanically attached membrane-roofing systems. The requirements of this test method are based on research and testing carried out at the National Research Council.s Institute for Research in Construction (NRC/IRC) for a North American roofing consortium known as the Special Interest Group for the Dynamic Evaluation of Roofing Systems (SIGDERS). This consortium includes manufacturers and trade associations. See Annex B for a list of participants.
This test method determines the wind uplift resistance of mechanically attached membrane-roofing systems subjected to dynamic wind load cycles. The roofing system consists of a deck and roofing membrane. It also includes components such as air/vapour barriers or retarders and insulation. 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.
Testing under this method is limited to mechanically attached, reinforced membrane systems having a fastener row separation not greater than 2896 mm (114 in) and a fastener in-line spacing not greater than 610 mm (24 in). Note: Environmental temperatures can affect the choice of membrane material and installation. Membrane manufacturers can be consulted to confirm the applicability of a proper design.
The values given in SI (metric) units are the standard. The values given in parentheses are for information only.
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. Legends to equations and figures are considered requirements.