本文件规定了一种方法，用于测量表面正常和非正常辐射的开窗系统（例如，带或不带遮阳装置的完整窗户、门或幕墙）玻璃中心的太阳热增益系数。 本文件适用于门窗系统中的玻璃中心，可能包括: a） 各种类型的嵌装玻璃（例如，玻璃或塑料；单层或多层嵌装玻璃；有或没有低发射率涂层，以及充满空气或其他气体的空间；不透明或透明嵌装玻璃）； b） 各种类型的遮光装置（例如。 g、 百叶窗、屏幕、胶片或任何带有阴影效果的附件）； c） 各种类型的主动太阳能开窗系统[例如，建筑集成光伏系统（BIPV）或建筑集成太阳能集热器（BIST）]。 本文件不包括: a） 建筑构件的遮阳效果（例如屋檐、套筒墙等）； b） 带有悬挑结构（如雨篷等）或类似结构的开窗附件的遮阳效果； c） 开窗系统（如窗框等）中非玻璃构件的遮阳效果； d） 室内外空气泄漏引起的传热； e） 双层和耦合窗户的空气空间通风； f） 嵌装玻璃和其他开窗部件（如窗框等）之间接缝处的热桥效应。

This document specifies a method to measure the solar heat gain coefficient for the centre of glazing in fenestration systems (e.g. complete windows, doors or curtain walls with or without shading devices) for normal and off-normal irradiation on the surface. This document applies to the centre of glazing in fenestration systems which might consist of: a) various types of glazing (e.g. glass or plastic; single or multiple glazing; with or without low emissivity coatings, and with spaces filled with air or other gases; opaque or transparent glazing); b) various types of shading devices (e.g. blind, screen, film or any attachment with shading effects); c) various types of active solar fenestration systems [e.g. building-integrated PV systems (BIPV) or building-integrated solar thermal collectors (BIST)]. This document does not include: a) shading effects of building elements (e.g. eaves, sleeve wall, etc.); b) shading effects of fenestration attachments with overhang structures (e.g., awning, etc.) or similar; c) shading effects of non-glazing elements in fenestration systems (e.g. window frame, etc.); d) heat transfer caused by air leakage between indoors and outdoors; e) ventilation of air spaces in double and coupled windows; f) thermal bridge effects at the joint between the glazing and the rest of the fenestration parts (e.g. window frame, etc.).