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Does high discharge pressures hurt the engine/pump?
One characteristic that always gets brought up in low pressure hose(low fricition loss characteristics)and low pressure nozzle discussions is the fact that they save wear and tear on the apparatus engine and pump. I don't think this is an issue. Any thoughts?
Replies to This Discussion
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Permalink Reply by Paul Shapiro on
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For some reason my last post was cut in have and I also did not get a chance to edit it. First I noted a mistake I made. I said that NFPA states that you cannot test hose higher than 300 psi. I meant to say that NFPA allows you to test hose higher than 300 psi and the manufacturers do as well. They state that the 300 psi is a minimum. Also NFPA states that pumps and the discharge and inke plumbing systems and valves be hydrostatically tested at a minimum of 500 psi. Again the minimum word. My department requires a 600 psi PDP and got the ok from Waterous to do so.
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Permalink Reply by Ben Waller on
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Paul,
Unless you're talking about a pump-and-roll engine, the driving 50 MPH comparison does not matter to a question about pumping RPMs vs another range of pumping RPMs.
For starters, there is NO wear on the pump when you're driving, since you're not in pump gear.
That's two reasons that driving speeds and RPMs are not pertinent to a pumping discussion.
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Just because a standard pump pressure is listed as a minimum doesn't make it either smart nor safe to exceed that pressure when testing hose.
Further, if you test hose with the engine instead of with a hose testing machine, you're unnecessarily stressing your engine's motor and pump. That's especially true if you're pumping it at pressures that exceed the basic hose testing standards.
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Permalink Reply by RsqRog on
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Hey you Old man,(Paulie) quit typing with them hammer heads you call fingers. I say pump it till it dont pump no more. As a professional fire apparatus operator until I was promoted, I had been trained (by the worlds greatest pump operator and street pilot) you pump until you either put the fire out, you run out of water, you run out of RPM's or something breaks. I pumped quite few BIG fires, never ran out of water, never broke anything, and on a few occasions ran out of RPM's But hey what do I know, i say just quit screwing around and BLAST IT......
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Respectfully Ben, I think the word MINIMUM would in fact indicate that its safe to exceed, and if its safe to exceed then its probably not so dumb either.
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I respectfully refer you to my previous post.
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Paul Spencer,
Apparently you believe that there is never any wear on any pump part no matter the RPMs?
I hope you're right. That would mean that fire pumps are now frictionless machines that will last forever.
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I think I know who this is Roger.
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Ben, its your choice as to what you want to test the hose too. I don't make the rules, I just follow them. Again I think you need to do more research if you don't agree to this.In fact go out and loo0k at your 1-3/4" and
2-1/2" and see what is labeled on the hose for the service test pressure. What ever number you find will probably say per NFPA.
I do agree that if you are driving that there is no wear on the pump. That is a no brainer. I was comparing engine RPMs to driving VS pumping.
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Why are you picking on Vegas. How about New York, Chicago, LA Frisco . need I go any further. There are alot of highrise out there.
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"I was comparing engine RPMs to driving vs pumping."
That's why I said that engine RPMs are not pertinent to a discussion that is entirely about pumping.
I agree that each department is going to test its hose in the manner it chooses. However, testing hose to unnecessarily high pressures increases the chances of hose failure and decreases safety for the people doing the hose test. I don't see either of those as being a good thing.
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Permalink Reply by Paul Spencer on
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@Ben, I have to apologize a bit. You have been ambushed slightly by accident. On a board like this you never really know who is posting. You have on one hand the most well known fire pump engineer/instructor in the American fire service who is known for some of the highest pressure pumping operations requirements throughout his career. I on your other side am changing the fire service with the strategy of "predictive maintenance". Fire pump wear ring wear is the primary example. An excellent technician looking at pump test reports can predict when a pump will fail in the future. Both of us are at the extreme edge of our subjects.
And my last post on the subject is wear ring wear is a factor of contaminate like sand in the water or erosion. It is a factor of how much water, not how much pressure. Respectfully, Spencer
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