Industry Insights

Low E Coatings

Rating Systems

Design Pressure Conversion to
Water Test PressureConversion as per NAFS-08––

• 15% for R, LC, CW
• 20% for AW
• Water Resistance Test Pressure is capped at 12.00 psf for the U.S. and 15.00 psf for Canada

Gateway Requirements

Performance Class	Minimum Design Pressure, Pa (psf)	Minimum Structural test pressure, Pa (psf)	Minimum Water Resistance Test Pressure Pa (psf)
R	15.0	22.5	2.90
LC	25.0	37.5	3.75
CW	30.0	45.0	4.50
AW	40.0	60.0	8.00

StructuralAir Infiltration
Structural Strength is the amount of pressure the window frame and sash will withstand under load. Strength affects the entire window’s performance and continues to affect its ability to perform year after year Glass deflection limit –– expressed as L/175 –– is for all glass holding members:

• Deflection limits are needed to ensure there is no damage to supported construction members
• Excessive deflection can compromise the integrity of the seal increasing air and water infiltration, which will increase energy use and costs
• Deflection limits are also needed for the occupant’s safety and comfort

The structural strength of aluminum windows resistance to deflection provides a better resistance to air and water infiltration caused by glass deflection

Life Cycle TestingLife Cycle requirements determine durability of products which help to ensure that windows and doors continue to perform and do not lose energy over the life of the product due to air and water infiltration.

Life Cycle TestingLIFE CYCLE TESTING VERIFIES AW PRODUCT DURABILITY

• One criterion of product quality is its ability to maintain required or expected performance levels throughout a reasonably long service life.
• Life cycle tests, described in AAMA 910, employ accelerated testing methods to model the normal wear that can be expected due to the typical number of basic operating cycles and locking hardware opening/ closing cycles experienced during the life of a typical AW class product. Loading conditions expected during washing, maintenance and the occasional, predictable misuse (such as improper operation or maintenance and excessive operating force) are also simulated.
• Air leakage and water penetration tests are conducted both before and after life-cycling and simulated misuse to evaluate any performance
  changes. In addition, there must be no damage to hardware and other components that would render the window inoperable.
  

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