Hale CSD - Manual (Page 7)

Definitions
Absolute pressure - The sum of gauge pressure and atmospheric pressure.
Approved - Acceptable to the "authority having jurisdiction".
Authority having jurisdiction - Refers to the organization, office or individual responsible for "approving" equipment, an
installation or a procedure.
Compound gauge - A gauge reading pressure from zero to maximum in pounds per square inch (psi) and vacuum from 0 to
30 inches of mercury (Hg).
Discharge manifold - An enclosed housing, connected to the discharge side of pump case and used to distribute water to
several outlets.
Draft- Pumping condition using hard suction hose immersed in standing water which is below the pump inlet connection.
Dynamic suction lift - The sum of the vertical lift and the friction and entrance loss due to the flow through the suction
strainers and hose.
Engine governor - A device installed on the engine designed to limit maximum RPM, often used incorrectly to describe
pump-engine governor or pump pressure control device.
Inlet screen - A device inserted in the pump inlet connection to restrict debris or other objects from entering the pump.
Mechanical seal- A device to replace the packing box; it does not normally require periodic maintenance.
Net pump pressure - The sum of the discharge pressure and the dynamic suction lift when testing at draft, or the difference
between the discharge pressure and the suction pressure when testing from a hydrant or other source of water under
positive pressure.
Packing box - Pump shaft sealing device to seal the pump from the atmosphere and to seal internal water pressure.
Incorporates packing or mechanical seal that is replaceable.
Primer - Device used to lower pressure in suction manifold of pump to induce water flow.
PSI - Pounds per square inch - Standard unit of pressure used in the fire service; eventually will be replaced with the Pascal
metric system.
PSIG - Pressure as read on the pressure gauge.
Pump case - Synonymous with volute but does not always have a volute shape with varying area to enhance constant water
velocity.
Pump outlet- An opening connected to the discharge manifold allowing water to exit during pump operation. Pump shift- A
device to engage and disengage a fire pump.
Service tests - Tests made occasionally (at least annually) after the pump has been put into service to determine if
performance is still acceptable.
Siamese - A device used to divide water flow from one large hose to two or more smaller hoses, often used to describe the
discharge manifold used on front mounted fire pumps.
Single stage pump - Fire pump using a single impeller to induce water flow.
Steamer connection-Refers to pump suction nipple or main inlet connection.
Suction nipple - Pump inlet connection usually with male hose threads.
Vertical lift- The vertical distance from the surface of the water to the center of the pump suction inlet.
Volute - Pump case wrapped around an impeller as a collector and having varying areas to maintain constant water velocity.