天沟结构的紧急溢流口的计算可考虑两种方式。对于装于天沟旁边的紧急溢流口的计算,基本上与平顶屋顶的紧急溢流口的计算相同。**不同的是对于天沟结构的紧急溢流口,堰必须装在雨水斗上方10厘米的地方。
尽管我们有现成的计算表和上面提及的计算基础,在计算末端的紧急溢流口时还要注意以下几点
• Both front ends of the gutter must be equipped with an emergency overflow aperture.
天沟的两端必须都要留有紧急溢流口
• These apertures must be mounted in such a way that the whole gutter width is covered; the top must be kept open
这些紧急溢流口必须能覆盖整个天沟的宽度并保持敞开
• The weir must be mounted at least 5 cm and maximum 10 cm above the following outlet aperture (depending on the distance between the outlet and the front end or the longitudinal slope).
堰必须装在相邻雨水斗开孔处上方5厘米到10厘米的地方(根据该雨水斗与末天沟末端的距离或纵向坡度而定)