Pumping safety
Frank Janoch
Training Officer
Lake Conroe Volunteer Fire Department
Montgomery, Texas
In regard to “Advanced Pumping Skills: Tandem and Dual Pumping,” by Leigh T. Hollins (Fire Engineering, February 1996), the article is good, but he leaves out some very important steps in the dual-pumping setup.
His scenario using pumpers with gated inlets is okay, but remember that modern pumpers have intake relief valves set at about 150 psi, and the outlet of the valve should be capped when the pumper is receiving high-pressure inlet water. This is also true with pumpers having relief-type Storz inlet valves.
However, his scenario using pumpers without gated inlets needs to be changed. He states that the throttle on pumper A should be increased as the hydrant or inlet gate is being slowly gated down. This can be done, but it makes it much more difficult for a person to find the right time to remove the cap of the inlet to which pumper B is to connect its hose. The stream will diminish very little as the inlet pressure is lowered.
Should the cap be forced off pumper A, the person removing the cap is most likely to get it placed in his midsection by the force of the water from pumper A. One cannot rely on the gauges to determine when the cap should be removed. They may not be reading correctly, and when showing zero pounds there could be several pounds of residual pressure remaining. This pressure pushing against a large cap can cause a lot of force.
You may also force off the cap only to find that pumper A is now taking in air because the hydrant or the inlet gate was gated down too low or the gauge was showing zero when the pressure was actually below zero, thus causing the atmospheric pressure to hold the cap tight against the inlet threads. This will cause the fire stream from pumper A to diminish, and the nozzleman would not like that.
As the inlet pressure is lowered, the person who removes the cap on pumper A should try to turn the cap off but should not use too much force to move the cap. When the cap can be moved using very little force, it will come off easily and some water should come from the open inlet. It is also better to start the cap off using a rubber mallet to ensure that the cap is not stuck in place from being screwed on tightly.
Also, pumper A should notify all other pumpers at the scene not to change any setting or open or close any nozzle or valve. Should someone close a valve that affects the inlet pressure to pumper A just when the cap is removed, the remover will get the cap in his midsection. If a valve is opened just as the cap is removed, pumper A will take in air.
I have been teaching both of the above pumping arrangements, relay pumping, and all phases of fire pumping at Texas A&M University for 22 years. I have been in the fire service since 1957 and spent 28 years as fire chief of a two-pumper department; now I am the training officer of a three-station department with six firefighting apparatus.
Leigh T. Hollins responds: Thanks to Frank Janoch for pointing out several items of concern, specifically those that deal with a pump operator`s getting an intake cap “placed in his midsection.” I agree with most of his points, although I don`t feel some are as critical as he thinks. They are all good points. While writing the article, which is very technical, some simple steps–such as being careful when removing the intake cap–were left out to keep the number of steps to a minimum and avoid confusion. Other points were overlooked unintentionally, such as modern pumpers and some intake valves` having built-in intake pressure relief valves (not to be confused with discharge pressure-relief valves). See what I mean about trying to avoid confusion?
I would like to comment on two areas of your letter and state my concerns. One is that “modern pumpers and intake relief valves” would be a concern only when tandem pumping, not dual pumping.
I would not recommend that a relief valve “be capped.” I would suggest that a built-in or intake valve mounted relief valve be field adjusted to receive the higher intake pressures required for the procedure; this would be much safer.
The other area is, “Pumper A should notify all other pumpers at the scene not to change any setting or open or close any nozzle or valve.” While it is true that if another pumper at the scene opened or closed a valve or nozzle that was flowing “major” water, the residual hydrant pressure would be affected (assuming the other pumper was on the same water main), I don`t feel changing any setting, any nozzle, or any valve would be crucial–only those that would greatly affect residual hydrant pressure.
I would like to reference a very important word used in my article three separate times–“practice.” Most all apparatus are different in one way or another. The only way pump operators will become skilled and learn if two pumpers will be able to dual or tandem pump together without problems is through practice. Just be careful doing it, and watch that midsection!
