Place the pump in pressure mode for the following high-rise scenarios: 1) standpipe riser is not PRV'd and the fire is over the 10th floor; 2) the standpipe riser IS PRV'd and the building exceeds 10 stories.

Place the pump in pressure mode for the following high-rise scenarios: 1) standpipe riser is not PRV'd and the fire is over the 10th floor; 2) the standpipe riser IS PRV'd and the building exceeds 10 stories.

• A. Only scenario 1
• B. Only scenario 2
• C. Both scenarios
• D. Neither scenario

Answer: (C)

In high-rise standpipe work, the goal is to keep a reliable, usable pressure at outlets on every floor as flow varies. Pressure mode achieves this by keeping a relatively constant discharge pressure, so when firefighters open a valve and draw more water, the pump maintains that pressure instead of letting it drop. If the standpipe riser isn’t PRV’d, there’s nothing to regulate downstream pressure, so elevation head becomes a bigger issue the higher you go. Without pressure mode, opening a hose line on the 10th floor or higher can cause a significant pressure drop due to height and friction losses. Using pressure mode offsets that loss by boosting the system pressure to maintain adequate flow to upper floors. If the standpipe riser is PRV’d, the valve limits pressure to a safe level, which helps protect lower portions of the system. But as the building exceeds 10 stories, the extra head from height and continued friction still challenge the ability to deliver sufficient pressure at the top. Pressure mode helps the pump sustain the necessary pressure for upper floors even while the PRV clamps pressures at other points. So, in both scenarios, keeping the pump in pressure mode ensures firefighters have adequate, dependable pressure at higher elevations.

In high-rise standpipe work, the goal is to keep a reliable, usable pressure at outlets on every floor as flow varies. Pressure mode achieves this by keeping a relatively constant discharge pressure, so when firefighters open a valve and draw more water, the pump maintains that pressure instead of letting it drop.

If the standpipe riser isn’t PRV’d, there’s nothing to regulate downstream pressure, so elevation head becomes a bigger issue the higher you go. Without pressure mode, opening a hose line on the 10th floor or higher can cause a significant pressure drop due to height and friction losses. Using pressure mode offsets that loss by boosting the system pressure to maintain adequate flow to upper floors.

If the standpipe riser is PRV’d, the valve limits pressure to a safe level, which helps protect lower portions of the system. But as the building exceeds 10 stories, the extra head from height and continued friction still challenge the ability to deliver sufficient pressure at the top. Pressure mode helps the pump sustain the necessary pressure for upper floors even while the PRV clamps pressures at other points.

So, in both scenarios, keeping the pump in pressure mode ensures firefighters have adequate, dependable pressure at higher elevations.