pressure pipe

The pressure pipe of a sewage lifting station is a pipe used to pump sewage or wastewater from lower-lying areas, where there is no natural gradient towards the sewer, into higher-lying drainage pipes or sewer systems. The water is conveyed by the pump using pressure and velocity, which means that pressure pipes must meet certain requirements. 

The pressure pipe of the sewage lifting plant must be routed above the backwater level via the base of the backwater loop. No other connections may be made to the pressure pipe; vent valves are not permitted. Pressure pipes from lifting stations must not be connected to downpipes, but always to the ventilated main drainage pipe or collector. Where pressure pipes enter chambers, effective energy dissipation must be ensured, e.g. by means of a pressure relief chamber. 

A shut-off valve must be installed on the pressure pipe side downstream of the backwater preventer. For wastewater lifting systems in accordance with EN 12050-2 or EN 12050-3, the shut-off valve may be omitted if the pressure pipe is < DN 80. If there is no valve in the pressure pipe, the backwater preventer must have a venting device or some other means of drainage must be provided.

According to standard DIN EN 12056-4, the pressure pipe must be able to withstand at least 1.5 times the maximum pump pressure. Nevertheless, the forces acting on the pipe should be carefully assessed, as other factors may require a pipe material with an even higher load-bearing capacity. Some such factors are: 

• Pressure surges 
• Soil loads 
• Temperature effects 
• Test and flushing pressures 
• Long-term behaviour and warranty periods