I wanted to start a discussion on pump operations, and maybe get some of the more experienced MPO's to chime in with tricks of the trade.

I have had Pump Operations training but am not very skilled or experienced on the pumps as I am usually the one with the nozzle in my hands.  I am Captain, and want to be able to refresh my knowledge of the skill and maybe learn something new as well.  I was trained on the older style pumps with actuall mechanical pump parts and valves, with none of the electrical components you see dominating the field today.

One of the things I forgot how to set was the relief valves?  Anyone want to walk through that?


How about pressures and volume; moving water through LDH.  We have a 2 1/2" discharge on our pumper with a 5" adaptor so we can pump through 5" hose, does this still produce the required volume?  I was instructed to increase PSI through this hose to achieve the desired results but I am getting arguments from other officers that this simply will not work.  Advice or input?

How about the hydrant assist valves?  How exactly does that work as I have never experienced using one before?  I see that they are used for hydrants with poor flows, but how exactly does it work?


Any other discussion about this topic is welcome and I hope we generate a good discussion about Pump Ops.  Stay safe all.

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Let me start by saying that you and I are probably about even on the pump skills, I can run the pump when necessary but much prefer the nozzle.  Having said that I do have a few questions/comments for you.


I'm having trouble figuring out what you're pumping to on a five inch line.  Are you relay pumping to another pumper?


Unless the pumper you're relaying to only has a 5" inlet I don't see what you're gaining by attaching the 5" line.  You will only get as much water as will fit through a 2 1/2" opening.  You probably gain a little in reduced friction loss so you might increase the volume by a small amount but you'll never make up the full amount that using a 5" outlet would give you. 


You also might see an overall loss if pumping uphill since you're pushing a greate volume (Weight) of water uphill at any given time then if you were using a 2 1/2" line and then using a reducing adapter at the far end.

Hope this helps and looking forward to seeing more on this topic


Receiving training on the older style pumping apparatus is by far the best training I've ever received.  When it's broken down into it's basics, the automatic controllers and governors on today's apparatus become much less of a mystery. 

The relief valve setting should be set to just above the desired pump operating pressure for the situation.  This prevents excessive pressure fluctuations from finding their way to the nozzle where it would be converted into nozzle reaction force to the hose team.  Maybe not as noticeable with a 1-3/4" hose, but the the team holding a 2-1/2" hand line will sure appreciate it.  If the situation changes, consideration should be given to adjusting the pump pressure and the relief valve. 

When setting the relief valve, you need to know your equipment on the apparatus.  For example, our engine has two identical pre-connected 1-3/4" crosslays with 400' hose each with a SOG that our nozzles are set to 95 GPM @ 100psi.  To get the expected flow from the nozzle, we need to make sure that there is 100 psi at the end of the hose (nozzle pressure).  Your operating pump pressure then becomes nozzle pressure + friction losses + elevation losses(gains).  Quickly calculate your friction losses for the size and length of hose and elevation losses/gains (approx. 5 psi per 10' elevation).  Increase your pump pressure to desired pressure and let it stablize if it overshoots.  Reduce your relief valve pressure until the light comes on, then increase it by 1/2 to a full turn.  Your relief valve is set!   Again adjustment will be required if the hose line requirements change.

For relay pumping operations, most often your goal is to provide volume instead of boosting pressure.  Using a 5" LDH reduces your friction losses for long runs of supply lines and "allows" for greater volume delivery.  However, it is difficult to achieve the full advantage of volume delivery from a single 2-1/2" to 5" LDH.  The target is to have an end supply pressure at the other pumpers intake of 20 - 30 psi.  If you have elevation increases, a 5" LDH may require more pressure to move that volume of water.  The theory in increasing the pump pressure, with no elevation increases, is the compensate for the resulting flow rate drop at the coupling for the larger diameter supply hose (pressure and volume remain constant, flow rate would drop).  If this is connected to a thirsty pump over a long distance with alot of discharge, it may not be sufficient to support it and an additional relay pumper would need to be considered.


Hope you find this helpful.



Brain, Scott said it all pretty well but the best way is to get one of the operators to take you out and run the pump. I could not sit here and tell you all the numbers and how our pumps operate but i could take you out and explain everything you need to know to run our pumpers and get the water pressure you need for what is going on. We have a manual style pump and a electronic control one just push a couple of buttons and away you go. I like the older myself. But the best way to learn is go out and do it. I have taking our trucks out 10 times a month or more just because we have had guys like you wanting to know how to pump with them and i would take a line in any burning building with anyone of these guys running the pump even though they are not the usual pump operators. They have taking there pump operators class but normally are on the line but i love when our guys want to train and stay fresh on things. Practice is always the best way. Keep up the good work at wanting to learn and stay safe.

I agree with Derek about getting out and practice. The issue with the manual relief valve was touched on and is pretty much what I would say too.


Having a 5" outlet on a 2 1/2" isn't going to really matter too much. Yes, there will be some friction loss, but being at the source, you don't have to worry too much about that and depending on what you are flowing, there should be no issues producing the required volume.


To further address another question, there are plenty of reasons to have an LDH coupling on a discharge, for relay pumping as mentioned, pumping into a monitor base with an LDH inlet, pumping into a manifold with multiple smaller lines off it, portable hydrant, pumping into an aerial ladder and so forth.


Hydrant assist valves have been awhile for me using them. We did have one on our frontline pumper when I was an intern. We also painted the outlets to make it easy to remember how to turn the valve for an operation. From what I recall (without doing research), you hooked the valve to a hydrant and you could have it set up to run water straight through the valve to the pump. A second pump could come to the hydrant and then connect a hose to the intake and discharge and basically act like a relay pump once the valve is diverted. This valve should help for a longer lay or going up hills etc where another hydrant may not be closer. The valve allows for psi to be boosted to overcome friction loss or elevation while limiting the amount of LDH out for such a relay operation.

5-inch hose is used for relay pumping to another pumper, to pump to a portable monitor equipped with a 5-inch intake, or to pump to an aerial ladder pipe if the truck intake is 5-inch.


My department does all three.


You can use 5-inch effectively with a 2-1/2 discharge, as the constriction is short.  You don't need a lot of pressure to move high volumes of water in 5-inch.  In this case, it's the volume that counts, not the pressure.

I'm having trouble figuring out what you're pumping to on a five inch line.  Are you relay pumping to another pumper?


My department is a small one, covering mostly farm and rural areas and we have no hydrant system.  Yet, if you go a few miles to our south, our mutual aid department is very large, covers a SUNY college, price chopper mall, Wal-Mart Plaza, numerous stores and shops, 3 schools and has a large population.  We are first due mutual aid to most of their district, and would have to supply their 95' Tower Ladder or first due engine, and they use primarily 5" LDH.  So we had to outfit our engine and our engine tanker with LDH hose and adapters.  Most of our MPO's have only run basic pump ops for single family dwelling fires and have not had the experience of working the pump for larger fires, supplying master streams and aerial trucks.  So myself and another experienced member who also just recently transfered to this department as I have, have experience in larger departments and are trying to get everyone caught up on pump ops so when we do get the call, they are ready and not looking incompetent.  I was talking about these issues with the other chiefs (not experienced in large scale pump ops) and they were arguing with me telling me it wasnt possible to feed the LDH through our 2 1/2" discharge, yet I have seen it done before in real practice and it worked.  So I wanted to brush up on things and ask all of you guys to throw in your advice and personal experiences so I can see just how much I have forgotten by being on the opposite end of the pumping operation for so long!!! LOL

Thanks for all of the responses so far, I appreciate them.


I believe most of the questions have been answered but I wanted to talk about the 2 1/2 to 5 adapter on a discharge.  It is best to place that adapter on a discharge on the pump panel that comes off the pump manifold as straight as possible to eliminate as much friction loss as possible in the internal piping of the pump.


As far as capacity of a 2 1/2 inch discharge, depending on internal friction loss,  and depending on pump capacity a gpm flow of well over 1000 gpm is possible.  Compare the 2 1/2 inch discharge to a 2 1/2 inch smoothbore nozzle tip.  At 30 psi the flow would be 1000 gpm, at 50 psi the flow would be 1300 gpm, at 80 psi the flow would be almost 1700 psi and at 120 psi the flow would be 2000 gpm.  The pressure is the pressure at the disccharge opening and obviously to flow 2000 gpm the pump has to have the ability to move that much water.

What about pump pressures for different appliances/nozzles, and any department specific protocols for running them at different situations?

I know when I took pump ops, the desired pressure for smooth bore nozzles was 50-60 PSI, and for adjustable fog nozzles it was at least 100 PSI for the desired stream to be effective.  What about the portable deck guns, or "Master Streams" like the Blitz Fire Portable Monitors?  Do they require the same pressures as the nozzle counterparts or do you give them extra for the reach and penetration needed, like 120-140 PSI.


Our SOP's are... add 5 PSI for any hose appliance, IE. gated Y, water thief, 2.5'' nozzle w/ a 1.75'' hose off of it.   As for nozzles, our master streams and fog nozzles are set at 100PSI at the tip, smoothbore nozzles are set to 50 PSI at the tip, and smoothbore master streams are set at 80PSI at the tip.  We have sheets made up of hose lengths, pressures, and friction loss per 100' of hose.  Also, as a cheater, we have each guage of each crosslay labeled as to what its supposed to be pumped at normally.

What about the portable deck guns, or "Master Streams" like the Blitz Fire Portable Monitors?


A master stream with a smooth tip, you are going to want to be about 80 to 90 PSI. Fogs are still 100.

Akron Assault nozzles are where it's at...50 PSI, period.  Assaults are break-apart nozzles that have removable fog tips.  Their standard 1-1/2 nozzles are 50 PSI/150 GPM fog with 185 GPM 15/16ths smooth bores.  Their 2-1/2 nozzles are 50 PSI/250 GPM fog tips with 165 1-1/8 smooth bores.


It took some retraining to get used to them but they are simple to use, simple to pump. and it has made our pump training a lot quicker and easier.

FL = C(Q Squared)L


In this case, for a 100-foot section of 2-1/2, FL = 2(10 squared) 1.

Filling out the numbers, that equals 200 PSI FL for the 50-foot section at the pump.  If you need to move 1,000 GPM through 100 feet of 2-1/2 and then 800 feet of 5 inch, you'll have 200 PSI of FL for the 2-1/2 and 0.02(100)8 for the 5 inch plus 60 PSI for the delivery.


That adds up to 200 PSI + 16 + 60, or 176 PSI as the Pump Discharge Pressure.  Not easy, but it can be done.


Now reduce the 2-1/2 length in question to 5 feet of piping from the pump to the discharge, and you only have 10 PSI of FL in the piping.  For the same 800 feet of 5-inch, you have 10 + 16 + 60 to move 1,000 GPM.  That's only 86 PSI, which is easy for a 1,000 GPM or larger pump in reasonably good shape.


Obviously, it makes it a little easier to plumb a 5-inch discharge with a larger diameter pipe.  Ours are plumbed with 3-1/2 inch piping and they work just fine.


The bottom line is that you don't have to move attack line pressures through 5-inch relays.

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