Sector window maximum area specification requirements

"Public **** building energy-saving design standards" GB50189-2005 Article 4.2.4: building each direction of the window (including transparent curtain wall) wall area ratio should not be greater than 0.70. When the window (including transparent curtain wall) wall area ratio is less than 0.40, the visible light transmission ratio of the glass (or other transparent materials) should not be less than 0.40. When it can not meet the provisions of this article. Must be in accordance with the provisions of section 4.3 of this standard for weighing judgment. This article is mandatory. Interpretation: The determination of the window-wall area ratio should take into account a variety of factors, the most important of which is the different regions of winter and summer sunshine (sunshine duration, total solar radiation intensity, sunlight incidence angle size), monsoon, outdoor air temperature, indoor lighting design standards, and the external window openings and building energy consumption and other factors. Generally ordinary windows (including the transparent part of the balcony door) have much worse thermal insulation performance than the external wall, and the larger the window-to-wall area ratio, the greater the heating and air conditioning energy consumption. Therefore, from the perspective of reducing building energy consumption, it is necessary to limit the window-wall area ratio.