CSA A123.21 standard protect you, as it meets the requirements of the specific elements in force in the National Building Code of Canada 2015 (NBCC) and earlier.

Using an assembly tested according to the CSA-A123.21 specifications and designed for the building you are working on, you ensure that you are in good standing with the NBCC and that the chosen system will respond effectively to the elements according to the specific criteria of your project such as:

• Building location
• Building geometry
• Building exposure
• Building openings
• Importance category (risk level)

So, with accurate results for your project and using the right materials with the right linked fixing method to each other, your risk level is greatly reduced.

CSA A123.21 Standard: his reason of being

It is important to note that since 2004 an interest group formed by researchers from the National Research Council of Canada (NRC) and involving most stakeholders in the roofing industry in North America exists. This group, SIGDERS (Special Interest Group on the Dynamic Evaluation of Roofing Systems), has developed a dynamic test protocol simulating actual and real cyclic and variable wind pressures.

Previously, designers had to use either their previous experiences or use empirical data available from manufacturers

The basis for these data was the requirements of an American insurance company known as the Global FM and their laboratory Factory Mutual (FM). Those data, better known as FM 1-90 or other and used by most Canadian professionals, represent the resistance to a static lifting pressure of 90 psi.

This practice was deemed insufficient, and the requirement for a dynamic calculation came into being in section 4.1.7 in 2005, thus provoking the urgency of designing a protocol dedicated to it. To counter this, dynamic calculation methods have been included in the Canadian Building Code in the user guide section and adjusted as the CSAS A123.21.

CSA A123.21 Standard: Its scope

This test method determines the pull-out resistance of wind-driven membrane roofing systems when subjected to dynamic wind load cycles.

The test methods are applicable to mechanically fastened or adherent membrane roof systems.

The roofing system comprises a bridging and a roofing membrane. It also includes components such as vapor barrier, thermal barriers or retarders, insulation, cover panel, etc. It is subjected to a dynamic load sequence that has been developed as a function of wind pressure records simulating the effects of wind on the membrane roof assembly.

Now that CSA A123.21 has become law in some Canadian provinces, many different interpretations are being conveyed for commercializing waterproof systems by different laboratories and manufacturers.

It is therefore essential to know the details of this new standard and to be able to use it adequately. To do so, should not hesitate to inquire about the test methods used, and to validate the relevance of the elements included in the documents presented. In addition, ensure that the laboratory is recognized by NRC and accredited to ISO-17025 for this type of test.

Central Roof Reference: all about the CSA A123.21 standard

Central Roof Reference is your reference portal for CSA A123.21 for the design and construction of Canadian roofs. Use our tool to determine which roofing assembly is right for your construction project.

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