Water Handling & Portable Pump Operations Flashcards

When setting up a portable pump to draft water from a stream, 'priming' the pump refers to:

Answer: Removing air from the suction hose and pump housing to create the vacuum needed to lift water

Centrifugal pumps cannot self-prime — they cannot move air efficiently enough to create suction. Priming removes air from the suction line and pump casing so that atmospheric pressure can push water up from the source. A pump that cannot maintain prime will not deliver water regardless of engine RPM.

In a progressive hose lay, water is moved from a pump source to the fireline by:

Answer: Extending one hose length at a time while the pump is operating, advancing toward the fire

A progressive hose lay advances one section at a time while the system remains charged and operational. This allows firefighters to work progressively closer to the fire as suppression continues, without having to shut down or drain the entire system between extensions.

Friction loss in a fire hose refers to:

Answer: The reduction in pressure caused by water moving through hose against the inner wall

Friction loss is the pressure drop that occurs as water flows through hose — turbulence and contact with the hose walls dissipate energy. Friction loss increases with flow rate, hose length, and smaller hose diameter. Calculating or estimating friction loss is essential for determining whether nozzle pressure will be adequate at the end of a long lay.

A 'wye' fitting used in wildland hose lays is primarily used to:

Answer: Split one supply line into two separate hose lines for simultaneous use

A wye (Y-fitting) divides one incoming hose line into two outgoing lines, allowing a single pump to supply two separate attack crews or hose lines simultaneously. This is distinct from a siamese fitting, which combines two supply lines into one.

When operating a Mark 3 portable pump, the operator notices the engine is running but water delivery at the nozzle has dropped significantly. The FIRST thing to check is:

Answer: Whether the pump has lost prime due to air entering the suction line

A running engine combined with sudden loss of flow or pressure almost always indicates the pump has lost prime — air has entered the suction line (through a leak, low water level, or vortex at the intake) and broken the vacuum. Re-priming is the standard first response before investigating other potential causes.

The maximum practical lift height for most wildland portable centrifugal pumps drafting from a static water source is approximately:

Answer: 26 feet

Atmospheric pressure (approximately 14.7 psi at sea level) can theoretically push water up to about 33.9 feet. In practice, friction losses, altitude, and pump inefficiency reduce this to approximately 25–26 feet of practical lift for most portable pumps. Exceeding this distance results in cavitation and loss of prime.