External drainage in a building refers to the external drainage system of the building. It refers to a rainwater drainage system without rainwater buckets on the roof and no rainwater pipes inside the building. It is divided into categories according to whether there are gutters on the roof. It is an ordinary external drainage system and a gutter external drainage system. Ordinary external drainage system, also known as grid trench external drainage system, consists of trenches and rainwater pipes.
External drainage in a building refers to the internal drainage system of the building, which refers to a rainwater drainage system with rainwater buckets on the roof and rainwater pipes for indoor drainage. This system is often used in multi-span industrial factories, as well as factories with shell-shaped roofs, zigzag roofs, and skylights where it is difficult to install gutters on the roof. For high-rise buildings with high requirements on building facades, buildings with large roofs and buildings in cold areas, when rainwater risers are not allowed to be installed on the exterior walls, internal drainage should also be considered.
Extended information:
The gutter exterior drainage system of the building exterior drainage system consists of a gutter, a rainwater bucket and a drainage riser. The gutter is set in the middle of the two spans and slopes to the end. However, rainwater buckets are arranged along the exterior walls. The rainwater falling on the roof collects into the gutter along the roof of the gutter, flows along the gutter to both ends of the building (gables, parapets), enters the rainwater bucket, and is discharged to the ground or rainwater well through the riser. Gutter external drainage systems are suitable for multi-span industries with a length not exceeding 100m.
Using the drainage method outside the gutter, there is no rainwater bucket on the roof, the drainage is safe and reliable, and there will be no roof leakage or water leakage from the inspection well due to poor construction. It also saves pipe materials and is easy to construct, which is beneficial to the factory building. Space utilization can also reduce the burial depth of rainwater pipes in the factory area. However, because the gutter has a certain slope and is long, and the drainage riser is outside the gable, there are also problems with thick roof cushion and increased structural load.
Reference materials:
Baidu Encyclopedia - Building external drainage system
Baidu Encyclopedia - Internal drainage system