# Thread: Friction loss with synthetic hose

1. ## Friction loss with synthetic hose

I was wondering if anyone has a friction loss chart, or a formula that shows friction loss for synthetic hose. I know that because of the improvements in lining, there is less friction loss than with the old rubber lined cotton hose. I am primarily looking for 1 3/4 and 2 1/2. Thanks!

2. Friction Loss Formula: FL=C(Q*Q)L
FL = Friction Loss in PSI
C = Friction loss coefficient (Standard & manufacturers values in chart below)
Q = Flow rate in hundreds of gpm
L = Hose length in hudreds of feet

For double jacketed, rubber lined fire hose C is:
1.75" C=15.5
2" C=8
2.5" C=2

Now, here's some synthetics. They use one or all of a combination of slipperier liners, jackets & liners that expand when charged to increase the inside diameter above nominal, or thinner/intergrated liners to again increase the inside diameter over similiar size hose made with older technologies:

Angus Red Chief, Hi-Combat 1.75 C=9.6
Ponn Supreme 1.75" C=10.5
Ponn Supreme 2" C=6.6
Angus Chief 2" C=3.9
Angus Chief, Hi-Combat 2.5" C=1.2

As you can see just from these numbers, the newer hose has about 1/3 to nearly 1/2 less friction loss than the "charts"

With hose you already own or can test, best thing to do is use it and do your own tests.

But when buying new hose, look at the "C" values, they can help you weed out the rubber-lined low bid hose from the better hose these companies also make.

Often new hose with the same nozzle and engine pressure can move your flow out from 150' to 200' or 250' and that's a good improvement if your trying to make high-flow 1-3/4" lines for residential fires where 150' are sometimes a bit too short to reach the far side.

My full spreadsheet in Excel form is available at
http://www.mortlake.org/Miscfire/FireInfo/fireinfo.htm

Matt

3. Hey Matt,

I couldn't get that zip to save. I would love to have a look at it, is there another way to get it?

4. mcaldwell and others:

If the zip isn't working (I get that complaint from time to time, don't know why!), email me at mkivela@mortlake.org and I can email you the zip file or the *.xls unzipped version.

Both files are well under 100k, so there not bad sending via email.

Matt

5. Dalmation90.....What about NEIDNER Hose?

Also...did you know that the reason Hi-Combat has a lower FL coefficient for 1.75" hose is that despite the fact it is marketed as 1.75" it is acutally 1.96" inside diameter.....or so I have been told.

6. I add in hose that I have manufacturer's provided "C" for or that I was able to back-calculate the value of "C" from their published figures.

So it's no slant against Niedner. I also don't have numbers for Ponn Conquest, which is my personal favorite for general purpose attack lines. On my recommendation, we use Niedner's lightweight hose in our Stairpacks for it's lower weight & tighter packing than Conquest.

If someone has references they send me (company datasheet via fax, pdf, etc -- I want something "published" not just word-of-mouth via email) I'd be happy to add them to the FireInfo spreadsheet.

7. Thanks for the replies. Anybody else know any coefficients for other synthetic hose?

8. Dalmation90...was not implying you were using a slant against NEIDNER. I was just curious if you had their figures.

You have any insight on the issue of some manufacturers hose being closer to 2" ID as opposed to the marketed 1.75" size? It is my understanding they do this to give a lower friction loss to make their product more attractive.

9. I know on attack lines, Ponn Conquest is one that does this.

As long as the hoses pack like other hoses their nominal diameter, it's not a big deal. Maybe you have a small amount of extra weight to lug when charged, but most people aren't dragging 150' or 200' of charged 1.75", at least not on the initial attack -- you stretch, charge, and advance 10/20/30'.

Ponn gets it's performance in Conquest from two things. First, the polyethlyene liner is slipperier than rubber. Second, it's molded into the inner jacket -- so it's not taking up internal space like a rubber lining does. Same hose on the outside, but a wider, slipperier inside.

On the Supply line side, Angus has for decades used the expansion trick. Hi-Vol 4" when charged is 4.2", and 5" goes to 5.2". It packs like other company's 4" & 5" did, so it's a fair term for it. But under pressure, it grows to improve hydraulics. More weight when charged, but not enough to make a practical difference.

But you always gotta weigh trade-offs. Light weight, tight packing. Better hydraulics, medium weight. Heavy weight, cheapest. Gotta figure out what you're looking for.

10. According to the Ponn Supreme website, friction loss appears to be a lot less than a 10.5 coefficent.

G-5 Friction loss per 100'attack hose
GPM: 150 180 200 220 240
1-3/4" 16 20 25 29 30
2" 10 12 18 10 23
All tests conducted with a 15/16 straight bore nozzle.

Thats more like a coefficent of 7ish. Seems like the only way to find out what the friction loss is, is to test if yourself. Everybody has different numbers.

11. Got some numbers for 2.5 Conquest? I have 500 feet and haven't had a chance to flow it yet. Thanks. Looks like a typo on the 2" Conquest. Showing 10 psi at 220 when it reads 18 for 200 gpm. Extrapolate 20 for 220 rather. Thanks for the effort. Roc

12. Citadel:
I would encourage you to FLOW test the hose and MEASURE the loss yourself instead of depend on a FL chart.

Monday up in Vermont we tested 4 different types of hose and found the following.

GPM - 230
Length - 2-50' sections - total 100 feet

Jafline 1 3/4" - 60-psi per 100 feet for 230-gpm

Angus High Combat 1 3/4" - 100-psi per 100 feet for 230-gpm

Snap-tite Ponn Conquest 1 3/4" - 30-psi per 100 for 230-gpm

Snap-tite Ponn Conquest 2" - 25-psi per 100 for 240-gpm.
The 2" was tested at a higher flow by mistake and they ran out of time to do the test again.

I have not found a significant gain with Conquest in the 2 1/2" size unless your going to be flowing 400+ through it. Below 350-gpm most of the quality brands have close too the same FL numbers.

I DONT SELL HOSE! Only nozzles, and during these tests we did not tell the hose which brand of nozzle was being used.

All testing was done with a UL listed and calibrated flowmeter, an inline pressure gauge at the inlet of the first section of hose and another inline pressure gauge at the end of the hose attached to the nozzle. A pre-determined flow was established and used for each test (except with the two inch.)

He who markets the most needs to! Note that the High Combat had over three times the FL of the Conquest, and it cost about three times as much Not sure how anyone can justify the cost based on what we saw Monday. I know, you will never wear the hose out....only the pump!

Hope this helps in your search.

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