Spring tension huh?
Seeing as how every pumper made in the US for a decade (@50,000) gas a preset suction relief and do you suppose the relief valve uses crappy steel where as the other uses good steel for their spring? Or do you suppose it isn't really an issue? I talked to two pump guys and they don't replace many springs. If is a really big dangerous issue, we could have a TIA out of NFPA in a few weeks stopping the use of relief valves, ie around the pump foam systems.
Odds are it isn't really an issue. I bet more relief valves than not are never ever used.
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Thread: relief valve setting
10-19-2000, 07:05 PM #21LHS*Firehouse.com Guest
10-26-2000, 09:38 PM #2222R1Firehouse.com Guest
We preset relief valves at 150 PSI. Shut off for the valve is kept in "open" position. Valves are pressure tested and activated a number of times each week at station check. In addition to the NFPA intake relief valve on the newer of our two engines, we also have external "Jaffrey" relief valves on both units which are preset at 150 PSI. We do a lot of mutual aid inline pumping in this area, and this is the "standard" for us. Note that the Jaffrey is not a redundency on the truck with the NFPA internal relief, since we also have a butterfly valve between the NFPA relief and the suction intake. If we shut this valve, the outside Jaffrey will still relieve pressure over 150 PSI to protect the 4 inch incoming line from over pressurizing. I find the idea that the spring would get a "memory" if kept partly compressed doesn't make sense to me...it would be like having to jack up the front of your car when you are not using it so the front coil springs don't get a "memory". And cranking it all the way to its highest pressure will defeat the purpose of the valve (just shutting it off will accomplish the same thing). It is there as a safety and should not be put out of service.
10-27-2000, 12:09 PM #23cob1028Firehouse.com Guest
I believe that Hale recomends that you back the relief valve control (the hand crank) off all the way to keep the brass nut from stripping out. This practice also prevents the relief spring from taking a set. I have found that most depts. leave the valve setting at aprox.150 to 160 psi and work the relief from there depending on how many hand lines they have layed out. Hope this helps.
10-27-2000, 12:51 PM #24FireFJayTFirehouse.com Guest
I would say that the most imporatnt thing to remember is that this is a fire truck. The citizens paid for it and you need to get use out of it. Cycle it everyday. Leave it shut or open but continually excercise it. Many, many fires and have not seen one relief valve fail.
"No matter what rank I have attained, I am, at heart, a Firefighter First"
11-01-2000, 08:01 PM #25KG LockwoodFirehouse.com Guest
Being that we also use TFT's we start out @ approx. 120 psi on the handlines & adjust accordingly from there.
I'm a little unsure on the debate on the spring theory-but it does make sense that the spring would create a memory over time.
And if it's going to fail it'll fail on the preverbal big one-just when you need it the most.
11-07-2000, 11:07 PM #26EnjineCaptainFirehouse.com Guest
This is not just theory. I have had some experience with the pilot valve spring developing a memory and having to take the truck out of service to have it repaired.
Furthermore, turning off the PRV does not accomplish the same thing. The tension on the spring is created when you turn the valve handle. Turning off the PRV does not relieve this pressure.
I'm glad to hear from any of you.
"This isn't what we do, it's who we are!"
Prevent Harm, Be Safe, Be Nice - A. Brunancini
11-29-2000, 01:11 AM #27FAE767Firehouse.com Guest
The relief valve is primarily a safety device. And, as an observer of firefighter behavior, if is not kept in a mode where safety is most likely to be the default effect (ON), it will not be used.
Why have it at all if it is not used? I have seen this to be the case with the PRV many, many times.
Any time more than one line is charged it should be on and set. If it is preset to the most commonly used discharge pressure, it will be there when needed, by default.
Your apparatus needs maintenance, and this item should be no different than any other wear item, like brakes. It will need periodic service, testing, springs, o-rings, screens, etc.
If safety is paramount, preset it, excersize it to keep it from seizing-up, and maintain it! If you don't, no one else will!
11-29-2000, 02:24 AM #28snowballFirehouse.com Guest
Our dept. has an S.O.P. for our handlines set
at 120 to 140 pounds. Every engineer on morning check-out checks the prv to make sure
that pressure is correct, thus excersising
the valve. Due to our budget we do most of our own maintenance and repairs and I personally have not seen a prv develop a memory although spring steel can. We haven't had a problem yet but I probably just jinxed
myself. snowball out!!
12-04-2000, 12:55 AM #29fire127797Firehouse.com Guest
The policy on our department is to close the PRV fully the back it off 1 to 2 turns at the end of every pumping operation. If the pressure relief valve becomes stuck for any reason you will still be able to make pressure at the next call. When on scene the PRV is set to the highest discharge pressure, usually the initial attack lines. If the PRV is preset, 160 psi for example, and the valve sticks, ot would be impossible to supply a higher pump pressure if needed.
12-07-2000, 11:01 PM #30FireMedic38Firehouse.com Guest
Pressure relief valves are designed to protect those on the nozzle from receiving too much pressure. It is our practice to excersize the relief valve each morning during our engine checks. The valve is then set to the lowest pressure handline which will be used. In our case it is a 2.5" with a smooth bore. We use a pressure of 80 psi. All handlines can be used at this pressure but the valve pressure will need to be increased if a smaller diameter handline is pulled.
12-18-2000, 06:31 PM #31MichrehfFirehouse.com Guest
After learning, reading and learning more! I have found that the more you require a PO to do under working fire conditions the more likely small issues or often not used issues won't get done. I have adopted a daily check of the spring and working the mechanism. After the check, I place it at 150psi and leave it on.
Michael R. Rehfeld
Baltimore County, Maryland
IAFF Local 1311
01-17-2001, 06:58 PM #32Jon StrittmatterFirehouse.com Guest
At our dept. We leave the preasure relief set at 150psi and it is 'worked' up and down once a week when equipment checks are done. At the time of an incident, the "engineer of the day*" will set acording to the needs at that time.
note*We don't have a "engineer", everybody on the dept. must know how to run the engine, we never know who is going to show..
01-18-2001, 06:46 PM #339C7Firehouse.com Guest
Ours are set at 150-160 psi. They are checked several times per week.
You asked for my opinion, now you have it. Any similarity to another opinion, living or dead, is purely coincidental.
01-25-2001, 12:04 AM #34fireman_387Firehouse.com Guest
Just had this discussion in an officers meeting yesterday. An LT doesnt like hearing the pump wind while the guys are setting the relief.
As a consensus we decided that we would leave it to the driver since he is responsible for the truck.
We set ours at 200
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