Certification, Testing and Standards
With the rapid growth in window technology improvements, a number of organizations and industry associations have been trying to sort out performance standards and certification procedures, both for industry and for the protection of consumers.
The Insulating Glass Manufacturers Alliance (IGMA) certification program requires manufacturers to meet quality control standards and the CGSB edge seal standard (CAN/CGSB 12.8). All IGMA-certified products bear the following information: IGMA logo, along with a date, the company name and the place of manufacture. This information is normally stamped into the spacer bar between the glazings or etched onto the glass.
CSA Standard A440
The Canadian Standards Association (CSA) has established the CSA-A440 standard. It is called an omnibus standard because it applies to windows constructed from diverse materials. It describes how to measure and rate a window's airtightness, watertightness, wind resistance, condensation resistance, forced entry resistance, ease of operation, and other requirements. It also sets out minimum requirements for all components and their materials, from hardware, insect screens or weatherstripping, to finishes, adhesives and thermal performance. In addition, all windows must be designed to allow on-site reglazing.
The CSA-A440 rating is a minimum to start with when purchasing new windows.
The Canadian Energy Rating (ER) System
A window's ER rating is a measure of its overall performance, based on three factors: 1) solar heat gains; 2) heat loss through frames, spacers and glass; and 3) air leakage heat loss. A number is established in watts per square metre, which is either positive or negative, depending on heat gain or loss during the heating season.
U-Value
A U-value indicates the rate of heat transfer. The lower the U-value number, the slower it transfers heat from a warm area to a cold area. Equivalent R-Values have been given to help you understand the U-values. An R-Value is the inverse of a U-value and indicates the resistance to heat transfer. The higher the R-Value number, the more insulative the product is. The R-Values given are in imperial units. Neither the U- or R-value account for heat energy from the sun (solar gain).
See also The ABCs of Windows
