High-Rise Water Boosting with a CDL(F) Multistage Pump: Worked Example

The building

• 25 floors, about 3 m each: top outlet about 75 m above the pump
• Peak demand for the zone: 16 m³/h
• Wanted pressure at the top outlet: about 15 m (0.15 MPa)
• Pipe and fitting losses at peak flow: about 10 m

The head

75 m lift + 10 m losses + 15 m at the top outlet = 100 m. If the pump draws from a tank with water above it, subtract that height; if it lifts from below, add it.

The pump

At 16 m³/h, the CDL(F) 16 family applies. The CDL(F) 16-80 gives 94 m, a little short; the CDL(F) 16-90 gives 106 m with an 11 kW motor and covers the duty.

In practice

• Booster sets usually use two or three pumps with a variable frequency drive, so one pump covers low demand quietly
• Very tall buildings are split into pressure zones so the lower floors are not over-pressurised
• Keep the pump’s own suction side flooded from the tank

Compare other stage counts in the CDL(F) selection table.