Preface
This is the fourth edition of CSA A440.2/A440.3, Energy performance of windows and other fenestration systems/User guide to CSA A440.2-04, Energy performance of windows and other fenestration systems. It supersedes the previous editions published in 1998, 1993, and 1991.
Scope
1.1
This Standard applies to
(a) all windows covered by CAN/CSA-A440, including
(i) vertically sliding windows;
(ii) horizontally 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 sidelites and transom windows;
(b) sliding glass doors covered by 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 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 transmission (VT).
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 incident solar radiation on windows facing the four cardinal compass directions (north, east, south, and west) and for representative climate zones in Canada.
1.5
CSA A440.3 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 retention of thermal and optical properties and airtightness by windows over time and under conditions of use.
1.8
In CSA Standards, shall is used to express a requirement, i.e., a provision that the user is obliged to satisfy in order to comply with the standard; should is used to express a recommendation or that which is advised but not required; and may is used to express an option or that which is permissible within the limits of the standard; and can is used to express possibility or capability.
Notes accompanying clauses do not include requirements or alternative requirements; the purpose of a note accompanying a clause is to separate from the text explanatory or informative material.
Notes to tables and figures are considered part of the table or figure and may be written as requirements. Legends to equations and figures are considered requirements. Annexes are designated normative (mandatory) or informative (nonmandatory) to define their application.
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