1.0.1 This specification was formulated with a view to achieving advanced technology, safety and reliability, economy and rationality and guaranteed engineering quality of the siphonic drainage systems of roof.
1.0.2 This specification is applicable to the design, installation, acceptance and maintenance of the siphonic drainage systems of roof for the constructed, renovated and extended industrial and civil buildings.
1.0.3 The siphonic drainage systems of roof consist of siphonic roof outlet, pipes (spigot pipe, hanged pipe, stack, drainage pipe), pipe fittings and fastening system. The quality of each component shall meet the requirements of product standard separately.
1.0.4 The siphonic drainage systems of roof must be constructed according to design document and construction drawing, any change in the design must be agreed by the original design organization.
1.0.5 Design, installation and acceptance of the siphonic drainage systems of roof shall meet not only those specified in this specification, but also the requirements of relevant current national standard.
2 Terminology
2.0.1 Siphonic drainage systems of roof
The design for flow velocity and pressure of rainwater in piping according to the full-bore flow principle may effectively control and balance the roof rainwater drainage system. Generally, it consists of siphonic roof outlet, pipes (spigot pipe, hanged pipe, stack, drainage pipe), pipe fittings and fastening system.
2.0.2 Full-bore flow
Water filling piping up (proper air is allowed) and water flow movement may be described by Bernoulli's equation, and it is a flow state with obvious negative pressure in the piping.
2.0.3 Siphonic roof outlet
It is rain outlet for siphonic drainage systems of roof. It has functions such as air-water separation and anti-vortex, and the water depth in front of the rain outlet may be controlled effectively. When water level in front of the rain outlet gets stable at the design water depth, full-bore flow will be formed in the system.
2.0.4 Spigot pipe
It is the short connection pipe (also known as tail pipe) between siphonic roof outlet and hanged pipe. Water inflow and system resistance of rain outlet may be adjusted through changing diameter and length of spigot pipe.
2.0.5 Hanged pipe
