A440.2-98

1. Scope 1.1 This Standard applies to (a) all windows covered by CSA Standard A440, including (i) vertical sliding windows; (ii) horizontal sliding windows; (iii) tilt-and-turn windows; (iv) casement windows, both fixed and operable; (v) projecting (awning/hopper) windows, and (vi) fixed windows, including fixed-window sidelights and transom windows; (b) sliding glass doors covered by CGSB Standard CAN/CGSB-82.1; (c) skylights with flat glazings; (d) curtain walls; and (e) doorlites, including a doorlite frame to attach glazing to a door slab. Note: Unless otherwise specified, the term "window" is used to apply to all the products listed in Clause 1.1. 1.2 This Standard specifies both measurement and calculation methods for establishing the following window properties for both residential and commercial applications: (a) overall coefficient of heat transfer (U-value); (b) solar heat gain coefficient (SHGC); and (c) visible light transmission (VLT). Note: These window properties are established for specific indoor and outdoor conditions and will vary slightly under actual conditions. The values obtained by the methods specified are considered to provide an acceptable basis for comparing performance in use. 1.3 This Standard specifies a method for determining an energy performance rating for windows under heating conditions in residential applications that come under the Model National Energy Code of Canada for Houses. The Energy Rating (ER) includes factors for (a) solar heat gain; (b) heat loss by conduction, radiation, and convection; and (c) heat loss by air leakage. 1.4 The ER allows for a comparison of different window products on the basis of their effect on the annual energy supplied by the house heating system. The Er calculation assumes vertical installation in a typical residence and is based on average conditions for solar radiation incident on windows facing the four cardinal compass directions (north, east, south, and west) and for representative climate zones in Canada. 1.5 CSA Special Publication Z440.3 is a user guide to this Standard. It provides data and instructions for determining an ER for Specific locations, orientations, and window sizes (ERS) and an ER for residential cooling (ERC). 1.6 This Standard does not apply to (a) fixed glazing cast into precast concrete panels; (b) greenhouse windows; (c) non-flat glazing; (d) hinged doors; and (e) glass blocks. Note: Although these products have not been considered in the development of this Standard, simulation procedures given in the Standard could be used to evaluate the U-value and the SHGC of these products. 1.7 This Standard does not address the ability of windows to retain thermal and optical properties and air tightness over time and under conditions of use.