Low-Energy Foam Systems rely on which mechanism to entrain air at the nozzle?

Low-Energy Foam Systems rely on which mechanism to entrain air at the nozzle?

• A. The pressure of the water stream created by the fire pump
• B. An onboard air compressor
• C. Independent foam concentrate mixing
• D. The eductor's suction

Answer: (A)

Low-Energy Foam Systems rely on air being pulled into the water jet by the high-velocity stream from the pump. As water exits the nozzle, the turbulent, fast-moving jet creates shear and a region of low pressure around it, which entrains ambient air into the stream. This air mixes with the foam concentrate already in the nozzle to form the foam. The energy driving this entrainment comes from the water pressure produced by the pump, so no separate air compressor or eductor suction is required for the air entrainment at the nozzle.

Low-Energy Foam Systems rely on air being pulled into the water jet by the high-velocity stream from the pump. As water exits the nozzle, the turbulent, fast-moving jet creates shear and a region of low pressure around it, which entrains ambient air into the stream. This air mixes with the foam concentrate already in the nozzle to form the foam. The energy driving this entrainment comes from the water pressure produced by the pump, so no separate air compressor or eductor suction is required for the air entrainment at the nozzle.