What is a pressure pipe?
A pressure pipe is a pipe that carries a liquid, gas or sludge under pressure, usually with the help of a pump. Unlike a gravity pipe, in which the medium flows by gravity alone, a pressure pipe is kept at an overpressure to drive the flow.
How does a pressure pipe work?
A pump at the start raises the pressure enough to overcome friction and head differences. The pipe must be designed for the working pressure, possible water hammer and external loads.
Pressure pipes are classified by medium and use:
- Water main — supplies every tap with adequate pressure
- Rising main — pumps wastewater up from low-lying areas
- District heating — pressurised pipes for hot water in city or district networks
- Fire mains — kept under pressure for immediate availability
- Industrial pipes — for process fluids, chemicals or compressed air
Application
- Building water services — from the stopcock under pressure to draw-off points
- Pumped sewage in low areas — bridging height differences to a pumping station
- Irrigation and sprinkler systems — pressure ensures even distribution
- Industrial process plants — for transporting liquids or gases
- Long-distance gas and oil transport — via pressure pipelines
Points of attention
- Pipe material must suit the medium and pressure (copper, plastic, cast iron or steel)
- Allow for water hammer when valves open or close quickly
- Use pressure-reducing valves where the network pressure is too high
- Pressure-test the line after installation according to standard
- Place air vents at high points and drain taps at low points
Related terms
- Drainage
- Drain tap
- Air vent
- Sewerage
- Building services
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