Water Supply, Pumping Operations, and Fireground Support
Domain 7 covers what the aerial does after it is set: supplying the waterway, pumping within the appliance's rating, and supporting the fireground with elevated streams and access.
Rules
- Know the waterway's rated flow; the monitor, nozzle, and piping are not rated for unlimited gpm.
- Establish adequate supply first: hydrant, relay, or tanker shuttle. A 300-gal tank empties in about 30 seconds at 600 gpm.
- Pump discharge pressure = nozzle pressure + elevation (0.434 psi/ft) + friction loss + appliance loss.
- Set the relief valve or governor so shutting down one line does not overpressure the waterway.
- Monitor the aerial while flowing: reaction force, movement, swivel leaks, and changes at the tip.
- Pump-and-roll only within the manufacturer's limits and with the boom secured.
Worked example. A ladder pipe with an 80-psi nozzle, 60 ft above the pump, 30 psi of waterway friction, and 10 psi appliance loss: 80 + (60 × 0.434 ≈ 26) + 30 + 10 = 146 psi at the pump. If the supply is a 300-gal tank, that stream is not sustainable - establish the hydrant or shuttle before opening the nozzle.
Traps. Forgetting elevation pressure; running a master stream from tank water; leaving the relief valve set so the stream collapses when another line opens; cavitating the pump with a restricted intake; flowing while the boom is being repositioned.