CSA A440 / NAFS
The Canadian standard for windows, doors, and skylights that specifies performance requirements for air tightness, water tightness, wind resistance, and structural performance.
CSA A440 was Canada's national fenestration standard until it was harmonized with NAFS (North American Fenestration Standard) in 2011. Now referenced as NAFS-11 or NAFS-17 in Canadian building codes, it provides a common performance framework for windows and doors across North America.
Products are rated by Performance Grade (PG) which indicates the design pressure they can withstand. Higher PG numbers indicate better performance. The standard also defines performance classes: R (Residential), LC (Light Commercial), CW (Commercial), and AW (Architectural).