BY NOEL MAITLAND
It’s 3 a.m. fire is blowing out the windows of the private dwelling, and there are reports of people trapped. You’ve got the first handline in operation, and things are looking hopeful. Then comes that URGENT message that freezes every chauffeur’s blood: The nozzle team has lost water!
Do you know what to do?
I had an officer who taught me to always test the hydrant on a fire run, even if it’s for one of those annoying automatic alarms that always seem to turn out to be defective. Why? Because the time to find out the hydrant doesn’t work is when you DON’T need it! It’s the same with our vital, skill-improving training: It’s far better to make mistakes in the comfort of a firehouse drill than in our 3 a.m. Armageddon scenario.
So where do you start?
I’ve heard it said that when you lose water, you should start at the hydrant and check everything in turn—the hydrant, the intake line, the intake valve, the road-to-pump switch, and so forth. I couldn’t disagree more. Why waste time checking everything when a few seconds can give you an idea of the exact problem?
INTAKE, PUMP, AND DISCHARGE
The “water lifeline” consists of three parts: the intake side, the pump, and the discharge side. Three pressure gauges respectively monitor what’s going on in each part: the intake pressure gauge, the engine pressure or “master pressure” gauge, and the discharge gauge. Some apparatus might also have flowmeters for each discharge. Let’s look at what the readings of each gauge mean.
Intake pressure. If the hydrants in your area normally deliver 50 pounds per square inch (psi), that’s what your intake pressure gauge should read if you are on hydrant water. If it reads zero, the hydrant valve isn’t open, or the intake line is not connected on one or both ends, or the relevant intake valve is closed. Other scenarios that could result in a zero reading but that are more likely to result in a reading between zero and the normal pressure include the following: A foreign object is stuck in the intake line, the hydrant valve is not fully open, the pumper intake valve is not fully open, or the hydrant is open but providing insufficient flow to supply the discharge hoseline.
(1) Putting water on the fire is the number one priority at a structure fire. (Photos by Joseph J. Cassetta.) |
Master pressure.Your master pressure will equal intake pressure, plus the additional pressure created by the pump. So if the intake pressure is 50 psi and the master engine pressure is also reading 50 psi, the pump is producing nothing. The most likely cause is that the apparatus’s transmission is still in “road” or Neutral mode or the pump was not primed. If the pump is working but is supplying less pressure than expected, you may be attempting to feed more hoselines than the pump can supply.
Outlet pressure.Check this gauge last. If the outlet to a given hoseline is opened fully, the outlet gauge should show approximately the same pressure as the engine pressure gauge. If it does not, you have a problem at the outlet or in the hoseline you are supplying. A reduced pressure reading at the outlet side may result if the outlet valve is not open, a hose length has burst, the hydrant or pump is supplying too many lines, or the hydrant or pump is supplying multiple lines with no automatic pressure governor and no compensating throttling-up by the chauffeur.
PROBLEMS AND REMEDIES
You can lack water at the beginning of an operation, or you can initially have a good water flow and then lose it. In the second instance, it means that something has changed in the operation, and you must determine what it is. To do this, you must understand what was happening when you initially started water. The engine company chauffeur must communicate with his nozzle team or the officer of the appliance he is supplying to confirm that water supply is adequate and then note the gauge readings at that time. If there is a substantial difference at some later time, then you have a problem that must be diagnosed, communicated, and corrected.
Now let’s look at some specific scenarios:
If you had been pumping successfully through a given number of lines and this situation occurred when you started another line, chances are that the most recent hoseline overburdened the hydrant. Have the nozzle team on that line back out and shut down until you have a successful water relay. In the meantime, the other hoselines should be able to get enough water for a successful attack.
Another possibility is that you are not getting any hydrant water or are not maximizing it. Make sure the hydrant is connected to the apparatus and that the hydrant and intake valves are fully open.
(2) Will the chauffeur know what to do if you lose water at your next fire? |
If you have completely lost water at the pump, once you get a sufficient water supply, you must start water again. Throttle back or set the pressure preset to “Idle,” reprime the pump, increase the throttle or press the preset, and open the outlet valve again.
- All three gauges read zero or the intake gauge reads okay, but pump and outlet pressures are zero and you have failed to get water initially. First, check the pumps. Is the panel “pump” light unlit? If so, go back to the apparatus cab and make sure the parking brake is on. Some apparatus won’t go into pump unless the parking brake is set. After verifying that the brake is engaged, shift the apparatus transmission into Neutral and move the road-to-pump switch to “road.” Now reverse the procedure: Move the road-to-pump switch to “pump,” and reengage the transmission. There should be a noticeable change in engine sound, and indicator lights in the cab and at the pump panel should show that the pump is engaged. When the apparatus is in pump gear, go through the motions of starting water: Throttle back or set the pressure preset to “Idle,” pull the tank-to-pump valve, reprime the pump, increase the throttle or press the preset, and open the outlet valve again. Once you are sure water is started, you must get hydrant water into the apparatus. Make sure the hydrant is connected to the apparatus and that the hydrant and intake valves are open.
- Intake, pump, and outlet pressure gauges all read as they should, but the outlet flowmeter reads zero. There is an obstruction in your outlet line. Most likely, there is a severe kink in the line or several kinks. It’s also possible that the nozzle team has unknowingly shut the nozzle. You must notify personnel that this is the problem so that all hands will check for and correct any kinks in the line. Also remind the nozzle team to ensure that the nozzle is open.
- Burst length in the outlet line. If this happens, there will often be a dramatic increase in that line’s flowmeter; the flow in the line is now completely uncontrolled. What the pressure gauges will show largely depends on whether or not the apparatus has an automatic pressure governor. If it does, the governor will attempt to maintain pressure in the outlet line, and the engine will race. If the engine/pump is able to compensate for the lost pressure, the engine and outlet pressures will hold steady. If the pump is unable to compensate, the engine and outlet pressures will decrease. If the apparatus doesn’t have an automatic pressure governor, you can expect the engine and outlet pressures to decrease.
Note that automatic pressure governors can minimize pressure reductions at the master pressure and outlet pressure gauges. If the pressure governor and pump are capable of compensating for a hydrant/intake line problem or a hole in the outlet line, then the master and outlet pressures will not decrease; instead, you will hear the engine rev louder as it spins the pump faster to compensate. If the loss of water is of such magnitude that the governor can’t compensate, you will hear the engine rev and see a loss of pressure at the pump and the outlets. Also note that the pressure governor will never compensate directly for difficulties on the intake side. If not enough water is getting from the hydrant into the apparatus, the intake pressure gauge will show a decreased reading or go to zero, regardless of what the pressure governor does.
When a loss-of-water situation occurs, four things must happen: recognition, communication, diagnosis, and problem solving. In studying and practicing the scenarios above, engine company chauffeurs will greatly improve their competence in diagnosing water-loss problems, and sometimes they will also be able to solve the problem themselves. We must also train to rapidly recognize and communicate an actual or impending loss-of-water situation. Often, the nozzle team will communicate a lack of water. Sometimes the chauffeur will notice a developing problem, such as dropping pressures on all gauges after water is started in an additional line, and will notify the officers in charge of all attack lines. The chauffeur must also stay in communication after diagnosing the problem. A burst length or severe kinking issue, for example, requires that he immediately inform the incident commander and all units so that all available hands can solve the problem.
Losing water is one of our primary enemies in the battle to fight fires successfully and come out alive. The time to start training on water loss problems is now.
NOEL MAITLAND is a lieutenant and 15-year veteran of the Fire Department New York, assigned to Division 15, Brooklyn.
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