Fire-pumps are typically listed by an
approval institute and can be driven either by an electric motor or diesel
engine. In a fire installation there can be one or more fire pumps put into
operation as a duty assist (50%) – and standby pumps.
The fire-pump delivers the water via the
pipe-system to the fire sprinklers to suppress the fire. Fire pumps are powered
either by an electric motor or a diesel engine or sometimes by a steam turbine.
The number of fire-pumps installed depends on the occupancy hazard (LH, OH or
HH) and specific fire installation standard. Some known can be seen in the
table to the right.
Where twin electric fire pumps are
installed, there is a requirement for a secondary power source. This can be
from a separate feed to the nearest electricity sub-station, or from a
generator located on site. A mains changeover facility should be incorporated
into the design to allow for switching to this alternate power source in the
event of a mains supply failure.
The fire pump starts when the pressure
in the fire sprinkler system drops below a certain set-point. If one or more
fire sprinklers are exposed to heat above their design temperature, and opens,
the sprinkler system pressure drops and the pressure switches gives a signal
and the duty pump starts. If the duty-pump, for any reason, does not start, the
standby pump will start, usually from a secondary pressure switch.
Types of pumps used for fire service
include: end suction, horizontal split case, vertical split case, vertical
inline and vertical turbines.
Most fire-pumps are
listed for fire pump application, which means they are tested and certified by
accredited laboratories and listed by authorized institutions such as VdS, UL,
FM, LPCB etc.
Fire system with a
diesel engine and an electric motor.
Fire system with a
diesel engine and an electric motor.
