We set up a "real time" exercise at Joaquin Moraga Intermediate School. We
used a hydrant at the rear of the school which would likely not be
accessible by an engine in the winter when the ground was soft. The feed
main on the street is 16" so an engine pumping at the front of the school
would have little impact on the performance of the hydrant at the rear
of the school.
Our test evolution assumed engine companies would be attacking a fire in one
area of the school building using the hydrant on the street and our mission was
to deploy a ground monitor and 2½" safety loop using a single crew to protect the
uninvolved portion of the complex. (Since the hydrant behind the school had been upgraded to 2½" x 2½" x 4½",
it could supply two simultaneous hand lines, a monitor and a hand
line with 1¼" tip, or a monitor and two hand lines with 1" tips.)
Performance Objectives
Based on the flow test characteristics of the hydrant, we expected to deploy:
- A ground monitor flowing 600 GPM supplied by 4½" hose
- A 2½" safety loop flowing 325 GPM supplied by 150' of 2½" hose
Required pressures were 80 p.s.i. for the monitor and 50 p.s.i. for the safety loop. We had no difficulty
maintaining 600 GPM through the monitor. To supply the safety loop, we had to
restrict the hydrant discharge as to fully open the 2½" line ran the nozzle
pressure up to 70 p.s.i. with the monitor simultaneously flowing.
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Flowing from direct hydrant layout
Pressure Gauge Readings:
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Hydrant Static:
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116 psi
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Hydrant Residual:
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94 psi
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1½" Monitor Tip:
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79 psi
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1¼" Hand Line Tip:
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70 psi
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Flows Obtained
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1½" Monitor Tip:
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600 GPM
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1¼" Hand Line Tip (50 psi):
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315 GPM
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1¼" Hand Line Tip (70 psi):
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360 GPM
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