In tall buildings the pressure provided by a municipal
water system is generally not sufficient to provide adequate
pressure at the top of the building. As an example,
municipal water systems typically provide maximum
pressures in the range of 100 to 150 psi. This translates to
buildings of 20 to 30 stories. Above this height the building
will require a domestic water pressure booster system.
If a booster system is employed then the next issue to
address is how to supply a substantially varying flow rate
with relatively constant flow rate pumps. To accomplish
these tasks the industry has utilized several types of pressure
booster systems. They can be loosely categorized as
1. Open tank storage systems.
2. Closed tank hydropneumatic systems.
3. Tankless systems - constant volume pumps.
4. Tankless systems - variable volume pumps.
Open tank storage systems utilize an open atmospheric
tank located at the top of the building. These kinds of systems
are the simplest in terms of pump control. The pump
operation is controlled by a simple level control in the tank.
The tank volume and pump flow rate are typically sized to
prevent short cycling of the pump.