When we tested our windows in 2009 we knew very little about how NAFS would come in to play in the future of our window company. Since then, NAFS has been implemented in the Canadian Building Code and is meant to harmonize Canadian and American testing standards for windows and doors. These standards exist to make sure windows are strong enough to stand up in the environment in which they are installed.
In Canada, NAFS 08 must be used in conjunction with the Canadian Supplement – CSA A440S1-09. The Canadian Supplement provides additional requirements for compliance in Canada, figuring out the specific standards that windows must meet, through use of geographic, climatic and terrain parameters.
There are different testing methods used in Canada including differences in:
Air leakage testing and water penetration resistance are two differences that greatly improve performance requirements for windows and doors.
In the Canada, air leakage testing is required for both air infiltration and air exfiltration (in the US, only air infiltration testing is required).
In the Canada, water test pressure is separate from design pressure, which allows manufacturers to test for higher water pressures.
NAFS does not deal with energy ratings such as U Factor, Solar Heat Gain Coefficient, Condensation Resistance and Visible Light Transmittance. Instead it relates to the physical performance of windows, doors, and other openings. The primary test procedures are for air infiltration, and exfiltration, water penetration and structural capacity.
NAFS levels the playing field when comparing products, forcing everyone to meet the same standards. To achieve these standards, window manufacturers are required to retest their products to show they comply. NAFS does not have a single minimum rating system anymore but classifies fenestration products in Performance Class, Performance Grade, and Gateway Performance.
There are four Performance Classes:
Performance Grade is a single numeric grade given based on Design Pressure which represents how a window performs in each of the following tests. As well, the Performance Grade is determined by geographic location, building height, terrain conditions and serviceability.
In each Performance Class has a set of requirements, these are minimum test sizes and pressures that each product must meet to qualify for a Performance Class.
The first thing you will notice is that each class has a higher minimum Performance Grade, design pressure, structural test pressure and water penetration resistance test pressure than the class before. The classes are ranked with R having the least stringent requirements, followed by LC, CW and AW.
This time when we tested our windows, we made our windows larger than required for class R, and within the size specifications for Class LC, which is the same as Class CW. Our goal was to have our windows qualify for Class LC as we wanted to have the option of having our windows installed not only in single family homes, but also multi-family dwellings. Our windows surpassed the LC class when tested and qualified for class CW with excellent Performance Grades.
The results from our windows are as follows:
Not all provinces of Canada choose to comply with the NAFS standards. Some choose to use older Building Code and only require windows tested to the older CSA 440 requirements. You may not think this will affect you in Saskatchewan, however, should you purchase windows made in a province that does not comply, and bring them to Saskatchewan to install into your home, be aware that when applying for your building permit, it will state that NAFS 08 compliant windows and doors are required. Whether or not your building inspector enforces it is at his or her discretion.