# Thread: friction loss, new driver

1. ## friction loss, new driver

Believe it or not, I have been told I'm am driving the quint even without having a hydraulics course. I am having to remember friction loss calculations from basic training 8 years ago as well as info I dug up on the internet on my own time. Two questions, Fl=CxQsquaredxL,, what is C for 1 1/2 inch. Second question, suppose I lay two 2 1/2 inch lines into a standpipe and have no idea how much length of interior piping there is, it's a fire on the third floor and now they are reducing to a 1 1/2 inch handline off the pipe that they took up. I never cared before, until last week when another shift had this fire. So three floors up, no idea how long, and reduced to a 1 1/2 fog, what's the friction loss? Same scenario, thirty floors up, should I ever go downtown, now what?

2. Well to answer your question. C= the coefficient which you will have to know or be able to access the chart.

The bigger answer is to throw all that stuff you are worried about in the trash ans make or find yourself a cheat sheet.

Every company here has a chart with all the diameter hoses we carry, lengths in 50' increments and the type of nozzle along with some more stuff.

Go to the size hose your are using, the length, the nozzle, and presto.....the pump pressure is in the square.

Some stuff is easy to remember. Elevation loss or gain, fog vs. solid stream pressures, ballpark gpms for solid bore diameters. Don't worry about the rest

K.I.S.S.

3. Pumping todasy is really not roket science....

Most departments have pretty easy SOPs for pressures.
50 psi at the panel for truck to truck nurse supply. 150 PSI at the panel for the standpipe or sprinkler system. 100-150 PSI for the handlines. 200 PSI for boosters, etc etc. Friction loss calculations are great but just ask your officers what the standard pressures and standard adjustments (such as one we use here 20 psi for each 50' of 1.75" beyond 200") are for your agency. Once you know them, that will cover 95% of your situations.

4. If you use primarily preconnects, remember the pump pressures or mark them on your guages. We run 110 and 120 for our two preconnects. if I have to extend or shorten them I have a laminated pump chart I created for the rig in my engineers compt as well.

If you have target flows (ex. 150 GPM, 250 GPM) remember the FL for each size hose. 35 Psi/100' 1 3/4" for 150 GPM and 12 PSI/100' for 250 GPM 2 1/2" line. If you have other flows, its easy to remember 3 or 4 numbers for the 100' FL rather than those stupid useless calculations.

Pump FDC's at 150 PSI unless otherwise marked. The engine crew should have an inline pressure guage to regulate the standpipe outlet pressure for an effective stream. All stuff you have to practice and figure out first, before a fire. Basically for a standpipe op. you regulate the flow to the line at the outlet, not by doing math at the pump for variables you can't even determine. Thats something the FDNY taught me a while back.

I modified an old PDP chart I made fro my old VFD to make it more generic. Simple Excel document. The colors correspond to the valve handle tag colors and the column thats colores shoes the length of each line for the preconnects (200').

5. Originally Posted by gfireboy10
Believe it or not, I have been told I'm am driving the quint even without having a hydraulics course. I am having to remember friction loss calculations from basic training 8 years ago as well as info I dug up on the internet on my own time. Two questions, Fl=CxQsquaredxL,, what is C for 1 1/2 inch. Second question, suppose I lay two 2 1/2 inch lines into a standpipe and have no idea how much length of interior piping there is, it's a fire on the third floor and now they are reducing to a 1 1/2 inch handline off the pipe that they took up. I never cared before, until last week when another shift had this fire. So three floors up, no idea how long, and reduced to a 1 1/2 fog, what's the friction loss? Same scenario, thirty floors up, should I ever go downtown, now what?
c= coefficient

1.5" c= 24
1.75" c= 15.5
2" c= 8
2.5" c= 2
3' c=0.8
4" c=0.2
5" c=0.08

These are theoretical values.Not all hose will perform to these numbers.
For true flows the only way is to test using a flow meter.

As for supplying a standpipe or sprinkler system 150psi at the pump.

Cheers,

Don

6. Originally Posted by don120
c= coefficient

1.5" c= 24
1.75" c= 15.5
2" c= 8
2.5" c= 2
3' c=0.8
4" c=0.2
5" c=0.08

These are theoretical values.Not all hose will perform to these numbers.
For true flows the only way is to test using a flow meter.

As for supplying a standpipe or sprinkler system 150psi at the pump.

Cheers,

Don
Don't forget what is considered to be the "street" coefficients:

1.5" - 24
1.75" - 15
2.5" - 2
3" - 1
4" - /5
5" - /10

Keep in mind that none of this is rocket science. The easiest thing to do is find out from the people on the line if they are getting enough pressure or too much. Being a company officer myself, I have no problem letting my PO know whether I am getting enough or too much...

7. Our trucks have a chart on the inside door of the radio cabinet near the pump controls. Check to see if something like that is available or can be made availble. It makes things quite a bit simpler for our department.

8. Originally Posted by KTorak
Our trucks have a chart on the inside door of the radio cabinet near the pump controls. Check to see if something like that is available or can be made availble. It makes things quite a bit simpler for our department.

Ours are here too. Not used much if at all. Some of the seasoned guys either have them memorized or have charts of their own with their gear. they gave us little plastic cars from Pok with the info on them, currently mine sits in my FD workshirt(a.k.a jobshirt, New Yorker, what have you) . What to do with it?

9. You can know all the hydraulic formulas in the world and still be a sh**ty pump operator. I drove and pumped for over a year before I had an FAE class. The most important thing about being a pump operator is being able to stay cool and handle a situation when things dont go right. Cuz when something messes up it will be at the worst time. You always want to start over if something is not right at the panel. As far as figuring friction losses for your preconnects you should know what those are. Like has been said before get a cheat card, laminate it and keep it with you so u can get in the ballpark for firction loss. Alot of pumping is thumb up tumb down in the real world. So as long as u keep your head and get it close you will be ok.

10. It's unfortunate you have been put in this situation. Get yourself an IFSTA pump operator manual and take some notes from it. CQ2L is good on paper but you really need a field guide which after some practice you will remeber your friction losses and be able to determine apprpriate pressures for different operations.

The other way to do it is this:
Have a radio for contact with guys inside and watch the guys outside. If you get the thumbs up...increase the pressure....thumbs down......drop it....flat hose going into the bldg with guys inside needing water.......well lets hope the city has good attourneys when you tell the Judge you had no training on the equipment.

11. Back when I drove the pump/engine I made myself laminated flip cards. It may take time but you could pre-figure out your most common hose lays. In a couple hours you can have all the info you need at your finger tips.

12. If a guy has 8 years in a department and no training on the apparatus, it's the officers' fault.

This should be common knowledge among all crew members. The officer needs to make it clear what he wants pumped--which means he has to have some idea of how much water he wants and how the hose performs.

Fact is, it's up to each individual firefighter to keep himself sharp. We all fail in that regard, yours truly included. That's why we have officers.

13. Yes...the officer should know what he wants, but. It is the pump/engine operators job to KNOW how to get what the officer wants. I tell the pump/engine operator that we are pulling what and HE NEEDS TO KNOW WHAT TO DO WITH THE PUMP. I do not tell him anything about FL and or psi that is his job. If I change tips then I tell the pump/engine operator what I am doing. I will tell him how many sections of hose we have out and/or what floor we are going to and he does the rest. In fact...a good pump operator will tell the officer what he is going to get out of what. He will keep the officer advised to the water situation.

It is a Team effort...The officer should know and do his job and the pump/engine operator should know and do his job. They can and should help and advise each other but they should be able to do their own jobs.

As stated before make up some flip cards for your apparatus and practice.

14. __________________

15. Ther is a different pressure required for standpipes vs. sprinklers. Typically, sprinklers are pumped at 150 psi at the pump. This provides the capacity of the pump and the engine rpm's will change based on the number of fused sprinkler heads. Standpipes require a regular computation of the hose layout on the fire floor. You can use a standard number for the risers and floors, but you must also know what lines are deployed on the fire floor. If you have hose packs of two sizes (2.5" and 1.75") how all those lengths are used makes a significnat difference in the required pressure on the fire floor. You have to remember that the companies may hook up on the floor below the fire, but they still require the pressure for the floor they are operating on to overcome the head pressure in the system between floors.

16. The formulas used in all the manuals are great if you have time to sit down, pull out the calculator, and do the math. As stated above they will get you in the ball park for your pump pressure. In order to get good at where to set your pump so you don't limp hose your crew inside, your entire company must practice as a team.

17. Standpipe / highrise operations with 1 3/4 line and a fog nozzle (100 PSI required) is a setup for a underpumped line and putting crews at risk. At mimimum use a lower pressure version fog nozzle, usually requiring 50 PSI, or better yet, as the good fellows at FDIC like to preach, 2.5 line and solid bore tips. An Automatic nozzle will give you a good shape stream at a lower pressure at the cost of GPMs, but it is the GPMs that put out the fire. If you're not use to what a properly pumped line feels like it is easy to be misled into thinking you have an adequate line when you don't.

18. The ol' hand method works pretty well, too.

19. Noz, are you talking about something with a 2-1/5? I tried to learn something about that, I think it related flow to psi? I think somehow it stepped through each finger showing something, and each web showing something else.
Unless you're just saying increase the psi until the hose is solid, then disregard my last.

20. Noz, are you talking about something with a 2-1/5?
Well, there is one for 2 1/2" hose, as well...but I never use it. I tend to use the gallons flowing method for 2 1/2" in the field. There is a hand method for 1 3/4" and 1 1/2" hose. We only used 1 3/4" and the method is pretty simple. You just start with your left thumb and number your fingers 1-5. You then assign each digit a gpm amount, starting with 100 gpm and increasing 25 gpm each time you go up a digit, ending with 200 gpm on your little finger. The next step is to assign coefficients to each digit. I use all 12's...some use 12 for the thumb and 9 for each additional digit. I think all 12's comes closer to theoretical results, myself. For example, if you were flowing 125 gpm in a section of 1 3/4" hose, you would go to your second digit (pointing finger) which is the one assigned to 125 gpm. Multiplying 2 x 12 gives you 24 psi friction loss per each 100' of 1 3/4" hose flowing 125 gpm. Need to flow 150 gpm from your 1 3/4" hose? Simply go to digit #3 (my favorite finger), which is the 150 gpm designation. Multiply 3 x 12 and you come up with a friction loss of 36 psi per 100' of 1 3/4" flowing 150 gpm. I could post a pic if you'd like, but it's pretty much IFSTA basics. Of course, don't forget to calculate for elevation loss/gain, appliances, and nozzles.

21. fantastic noz, thank you! I saw something like that in fire engineering, but couldn't understand how they explained it. I'll definitely remember that. thanks again!!

22. One thing that I teach and several of my fellow instructors as a quick referance that works well is the following:

For 1 3/4" lines:

125 GPM (car fires) 20 psi
150 GPM 30 psi
175 GPM 40 psi

200' 1 3/4" FL= 60 psi plus nozzle pressure

2 1/2" lines:

Take the first 2 numbers of your GPM flow and subtract 10.

250 GPM.....25 minus 10= 15 psi FL

Also don't forget to add 25 psi for master stream devices.
And 25 psi for any appliance when flowing over 350 GPM's.

There is also another quick street calc for determining GPM's for smoothbore master stream devices. If you'd like that posted let me know.

23. ## Coefficients

The coefficient for 1.5" is 24

The list of coefficients I have looks like this:
3/4" (Booster Line) 1,100
1" 150
1.5" 24
1.75 w/ 1.5 couplings 15
2.5" 2
3" w/ 2.5" couplings .8
4" .2
5" .08

However, my B.C. just told me that the State did some recalculations with 1.75" and came up with 10 as a coefficient........ or it could have been 1.5"

When you have time, make a "cheat sheet" with the flows of your nozzles you will save yourself a lot of time. P.M. me and I will get you a copy of my "cheat sheet." It is pretty easy and very thorough.

24. ## Correction........

Sorry,
A correction on my last post here........

Coefficient for 1.75" is 15.5

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