Roof Drain Pipe Slope

According to plumbing code drain pipe has to be sloped a minimum of 1 4 inch per foot and a maximum of three inches per foot or vertical.

Roof drain pipe slope.

All of your drain pipe with one exception must slope slightly downhill. Usually 1 8 per foot is plenty for drainage this is the same as the commonly recommended 1 slope. Larger lines such as 8 pipe actually require less pitch due to the larger circumference of the pipe. The secondary roof drains shall connect to a piping system in accordance with section 1101 12 2 2 1 or section 1101 12 2 2 2.

While vent piping generally runs straight to the building s roof in a vertical path drain and waste branch pipes must slope toward main drainpipes which slope toward main drain outlets. Drain pipe slope calculator. It is generally accepted that 1 4 per foot of pipe run is the minimum for proper pitch on a sewer line. How to use the calculator.

Drain waste and vent pipe hanger spacing support of drain waste and vent dwv pipes. The following diagram lays out the different terms that are used in the calculator. But there are other issues concerning pitch to keep in mind. The calculations below are meant for drainage from flat roofs where water are expected to spread over the entire flat roof during rain.

The roof drainage outlets and rainwater downpipes are calculated based on the design principles for gravity drainage systems established in ss525 2006 code of practice for drainage of roofs. Sanitary drainage systems the purpose of a sanitary drainage system is to remove effluent discharged from plumbing fixtures and other equipment. Calculating the slope of your drain pipe is easy. Cleanouts in draining systems cleanouts provides access to the sewer for rodding.

A slope of less than 1 4 inch per foot will cause constant drain clogs and a slope of more than three inches will allow the water to drain without the solids. The best type for the application depends on several factors such as the size and slope of the roof the desired appearance and how much regular maintenance the drain system might need. The term slope is also frequently used and has the same meaning as pitch. This drain pipe slope calculator will calculate the slope and total drop fall of a drainage pipe over a specified length of pipe.

Vent piping allows sewer gases to escape the system and admits air to regulate the system s pressure and prevent siphonage from drain traps. Roof drains for flat or low slope roofs come in a few standard types.