Tank to Pump Flows

[jrcarespfd]

Anyone have experience with Hale's QPAK pump with a 4" tank to pump valve? The QPAK is rated at 1000 GPM max, but I'm convinced I can get 1500 gpm out of a tank with that setupo, but of course Hale won't tell me one way or another. They say "If you want 1500GPM order a 1500 GPM pump". I know that the rating of a fire pump is at 10' of draft with 20' of hard suction, and the closer you get to the water the more GPM you can do.
My calculations show that I should be able to do 1500 through a short section of 4" pipe, especially whe the water is sitting in the tank above the pump inlet... Any ideas??? Anyone have a QPAK and want to run an experiment for me?

[justinmcguigan]

i would be a bit hesitant to stand behind that claim, but i would not be overly surprised if you could suqeeze that much from your pump - but it would be a really tight squeeze. i know some guys who would be able to lend some real solid inut on this. i'll see what i can find and let you know.

Justin

[quint1officer]

I would think the only restriction is the tank to pump plumbing. Too many other variables to consider.

[HFD147]

Info from Hale

Hale's Application Guide for midship pumps lists the following flow rates: single 3" TTP is 550 GPM on a Q-Pak and a single 4" is 1000 GPM. A footnote states "Based on sufficient tank venting, sump and baffle design and having a full flow straight connecting line/valve". On a Q-Max (which has dual TTP ports) dual 3" TTP is rated at 1100 GPM, dual 4" TTP is rated at 1500 GPM. I don't believe you will see any more than the 1000 GPM flow out of the tank due to the physical limitations associated with the valve/piping size. Since NFPA addresses flow rates from tanks (1901-16.13.7) it would seem logical that Hale's engineering has come up with these flow rates based on actual conditions.

Sorry if it sounds like I'm "bursting your bubble", but it is what it is. There's no doubt that the 1000 GPM Q-Pak could do 1500 GPM off a good hydrant, but out of the tank is highly unlikely.

[fire0099881]

my question is, why would you want to be flowing over 1000 gpm off tank water?

[chiefengineer11]

Tank to pump line size

In a recent magazine article Dominic Colletti of Hale Pumps suggests that a 3" line is not enough to flow much above 500 gpm from the tank to the pump. This brought on some discussion between our truck committee chairman and me. Our new engine is at the point where the builder is ordering or has ordered most of its components, including its tank. To make any changes now would involve some very expensive change orders, so I don't want to unless it's truly necessary.

Due to very high hydrant pressures, we are setting the pump up so that all CAFS operations will be from tank (or in very rare instances, draft). We're using an automatic tank fill valve to do this. The manifold for the CAFS enabled discharges will have 1000 gpm capability. We do have a 3-1/2" tank to pump line specified. Chief Colletti (he has served as an assistant chief in another department in our county) suggests in his article that we might need a 4" line.

I did some number crunching of my own to see if 3-1/2" would be adequate. Using Hale's flow and friction loss charts, I found that friction loss in 3-1/2" at 1000 gpm would be 34 psi. If the tank to pump line were 1' long, the loss then would be 0.34 psi. That's less than the head pressure for 1' of water.

The tank to pump line in our current first out engine is 15" long, or 18" counting the waterway through the valve. I'm expecting that the new one won't be any longer. The loss there would be 0.51 psi, or the head pressure of just over 14" of water.

The truck is going to have an "L" shaped tank where the high part will be 43." I believe that we can set the automatic fill valve to maintain at least 15" of water. Based on that, I'm ready to tell the committee that we should not make any changes.

Before I do, does anyone see anything that I missed? Or, does anyone have a more accurate formula? Granted, if we weren't this far along, I'd probably make the change. But at this point, I want to avoid it. Any takers?

Stay safe out there, everyone goes home!

[HFD147]

The charts you used from Hale are friction loss charts for hose, not the same application as a tank-to-pump line. As stated previously, Hale's Vehicle Mounted Pump Application Guide lists the tank to pump flows for their pumps as 550 GPM for a 3" TTP line and 1000 GPM for a 4" TTP line (both with the disclaimer about adequate venting, sump and baffle design). You state you're getting a 3-1/2" TTP valve. This is the standard size for Waterous. Any chance that's the pump you're getting? Its unusual to see one on a Hale. I don't have engineering data on their TTP flows, but they are most likely around 700-800 GPM for the 3-1/2" valve. At any rate, Chief Colletti is absolutely correct: if you're expectation is to be able to flow 1000 GPM with this truck's CAFS, then you will need a 4" TTP line and valve.

If you work with your manufacturer, you may find the change might not be as expensive as you may think, given that it isn't built yet.

Hope this helps. Chief Colletti has been designing and operating these systems for years. The information he gave you is exactly on the mark.

[Engine305]

Tank To Pumps

Hello guys, I'm not much for the numbers crunching, but we have an E-One tanker pumper from 1990 that has a single 3" TTP that isnt worth a damn over 500 gpm. On my 1992 engine we went with a 2 1/2 " and A 3' line and she pumps over 1000 GPM. It might be easier for you to add another TTp line and run duals.

[chiefengineer11]

Hope this helps. Chief Colletti has been designing and operating these systems for years. The information he gave you is exactly on the mark.

Thanks for the input. Even though the chart I'm using is for hose, I'm going on the fact that biggest difference would have to be the quality of the interior surface and the number of places where hose is clamped to tubing, causing eddy currents and turbulence. Other than that, the cross sectional area of a given diameter is the same whether it be fire hose or metal tubing. There may be some difference in the losses, but they shouldn't be huge.

You're right about the pump, we're getting a CMU/Eclipse with an Advantus proportioner, and 3-1/2 is the standard tank to pump size. I'll contact Chief Colletti's counterpart at Waterous (he's a firefighter too), but I don't expect much difference between what the two of them say. After all, in reality we're dealing with basic physics here and the laws of physics are exactly the same in South Saint Paul as they are in Conshohocken.

E305, we had a '68 Hahn that had 2-1/2" tank to pump lines, 1 forward and 1 aft. The reason for doing it that way was that so that if you were parked on a hill (we have plenty), you could still get the full capacity of the tank. In those days there wasn't a direct connection to the back of the pump, you ran plumbing from the bottom of the tank and teed into a pony inlet. Not very efficient, but on level ground when we pulled both, the flow was half decent.

Stay safe out there, everyone goes home!

[npfd801]

Sam, there you go thinking again. It only gets us in trouble!

I think you're doing the right thing to call Waterous and get their opinion. And regardless of cost implications, I would get it changed if necessary now since you know you'll be keeping the rig for a good long while.

I also have a strong belief that while I'm sure your builder has ordered many if not all of the components for your rig, I would be willing to lay money down that your tank is nowhere near constructed, and for UPF or whomever to change what is required to go 4", wouldn't be much of an issue. I think the same argument applies for every other component that will be changed. Builders don't want tanks sitting around their facility for months waiting for the build slot for your truck. I would bet the tank isn't there longer than a few weeks before they set it, and the tank builder won't want it sitting around their facility either.

Besides, unless you specified some really wonky valve for the tank to pump line, even if they have the valve already - you know darn well they'll use it in a heartbeat on another rig.

It might be the salesman in me, but I firmly believe change orders are a fact of life any more in a rig. There will always be something overlooked, newly desired, who knows. The brand I sell for now spells out change order costs that you can expect to face as a rig nears completion, which I think is fair. The only thing that people need to realize is that this protects the builder from major changes. Adding a shelf, or step, etc. - you aren't going to get nailed. Deciding that the hosebed needs to carry another 1000 feet of 5 inch? That may be another story...

Have you decided when or if you'll be sliding through the area? I gimped up our local Toyne rep at a tower burn a couple weeks ago, I need to watch my back!

[chiefengineer11]

Sam, there you go thinking again. It only gets us in trouble!

Have you decided when or if you'll be sliding through the area? I gimped up our local Toyne rep at a tower burn a couple weeks ago, I need to watch my back!

Yeah, Joel, thinking always gets me in trouble. Thinking, then talking out loud is even worse. The trip is still up in the air. Your points, as well as those of HFD 147 and Eng 305 are well taken. I understand that the chassis is all but complete now. The pump should be done pretty soon. I don't know if the tank has been built yet, but it can't be that far off. I presume it's going to built in the Iowa facility. Check your e-mail.

Stay safe out there, everyone goes home!

[chiefengineer11]

The charts you used from Hale are friction loss charts for hose, not the same application as a tank-to-pump line. As stated previously, Hale's Vehicle Mounted Pump Application Guide lists the tank to pump flows for their pumps as 550 GPM for a 3" TTP line and 1000 GPM for a 4" TTP line (both with the disclaimer about adequate venting, sump and baffle design). You state you're getting a 3-1/2" TTP valve. This is the standard size for Waterous. Any chance that's the pump you're getting? Its unusual to see one on a Hale. I don't have engineering data on their TTP flows, but they are most likely around 700-800 GPM for the 3-1/2" valve. At any rate, Chief Colletti is absolutely correct: if you're expectation is to be able to flow 1000 GPM with this truck's CAFS, then you will need a 4" TTP line and valve.

If you work with your manufacturer, you may find the change might not be as expensive as you may think, given that it isn't built yet.

Hope this helps. Chief Colletti has been designing and operating these systems for years. The information he gave you is exactly on the mark.

Thanks, 147, 801 and E305 for your helpful and thought provoking comments. I spoke with Waterous Co. yesterday morning (11/27) on this, they expect that subject to given the disclaimers, we should expect 800 - 850 gpm.

They also pointed out that the anticipated refill rate through the automatic tank fill may not be that high since we're using a 2-1/2" standard flow fill valve. I did reply that our mains with beaucoup water at 180+ hydrant pressure does funny things. Their response was that as with the ability to get water out of the tank, baffling and venting play a major role in fill rates, also. No doubt we'll be putting CFP's tank to the test.

Stay safe out there, everyone goes home.

[firefighter1962]

First a few years ago, I left high school and enrolled in the school of hard knocks.

Has anyone considered?

• To flow 1000 gpm through a 4” pipe the velocity of the flow will be in the neighborhood of 25 ft/sec (17 mph)
• The most efficient way (path of least resistance) to get water into the pump is in a straight line from the steamer port(s)
• The tank to pump line is generally connected to a intake manifold through a flange perpendicular to the pump intake path, and the water must make this 90 degree turn before entering the pump
• Can the path of water take a 90-degree corner without losing velocity, and if so, by how much?
• Since the velocity of the water is one of the key determining factors for flow, are we still getting the desired 1000 gpm?
• On the intake side of the pump, we are still dealing with pressure except that it is negative from the pump’s point of view and positive from the atmosphere and head pressure point of view. Is the atmospheric pressure + head pressure in the tank enough to “push” the water at 25 ft/sec in the first place?
• How does the high flow in the pipe affect the Reynolds Number (turbulence in the water flow)? How does turbulent water flow (if there is one), affect the pumping properties?

All I know is that I am not educated to answer these questions, and need help from those that are.

My pea brain says if you crash a car into a brick wall at 100 mph, the pieces flying off sideways probably will not be going 100mph because the brick wall is going to absorb some of the energy. On the other hand, if you are driving in a straight line at 17 mph and crank the wheel sideways, you are probably not doing 17 mph any longer because it takes energy to do that.

I know that if I were going to depend on my tank supply to do the majority of the firefighting, I would err on the side of caution and make sure that I did not have a $30k CAFS boat anchor. Some form of twin tank supply lines may be the best option here, but the questions need to be answered by the people who make the big bucks.

Stay Safe

[chiefengineer11]

Some great thoughts, there, 1962. Actually, I went to the same school, with the exception that after my Navy days and before my trucking days, I spent 7 years at Univac engineering working directly under engineers, both mechanical and electronic. While that experience in no way shape or form qualifies me as an engineer, some of their thought processes followed me out the door when I left.

I truly believe that the numbers you've seen bounced around in this part of the from the names you've seen dropped come from some serious testing. Dominic Colletti, the Hale person who wrote the article that got me started on it is/has been a firefighter/chief officer. I have met many of his counterparts at Waterous and know that most of them are firefighters also. I feel certain in addition to structured testing, all of the pump manufacturers have derived the benefit of their peoples' fireground experiences.

The points that you raise are indeed valid, but I believe that they are factored into the equation. So I feel quite confident that we have a winning item. Talk to me again a year from now.

Stay safe out there, everyone goes home!