# Thread: 2 1/2 to 1 3/4

1. ## 2 1/2 to 1 3/4

Why dont we set a 300 ft of 2 1/2 with a 1 3/4 preconnected? Why do we always put a Gated Y on the 2 1/2?

Why dont we set a 300 ft of 2 1/2 with a 1 3/4 preconnected? Why do we always put a Gated Y on the 2 1/2?
I have never seen the set-up you are talking about. You need to always keep your options open. Having the "gated y" gives you the option to add and/or extend lines without stopping water flow (at least for very long).

3. We use the following setup:

1) Three sets of preconnects that are 200 foot 1 3/4 hose each.

2) One preconnect that is 300 foot of 2 1/2 hose.

3) One preconnect that has 200 foot of 2 1/2 hose with a gated Y that has 100 foot of 1 3/4 connected to it.

One of the uses for our last setup is that we get an extra 100 foot of hose that allows us to reach fires that might be difficult to access. Once we get more manpower they can take our second pack of 100 foot of 1 3/4 and connect it to the Gated Y and assist the initial attack team.

I think that another reason for this setup is that the 200 foot of 2 1/2 hose might have less friction loss than two 200 foot section of 1 3/4, but I'm not sure how much benefit that really yields.

And of course the main reason is this:

Because we have always done it this way

4. We would not put a gated Wye on a 2-1/2 in hose. We consider the max flow of a 2-1/2 inch to be 300gpm, and the max flow on a 1-3/4 to be 200 each. Therefore, two 1-3/4 hand lines will theoretically outflow the 2-1/2 inch supply.

We only use the gated Wye on a 3 inch to supply two 1-3/4 hand lines.

But, that's just us. Your mileage will vary.

5. We run 400' 2 1/2" line to a gated wye with 2 1 3/4" 100 foot lengths. We flow 160gpm from each 1 3/4" line. No idea why anyone would limit their 2 1/2" flow to only 300, but as said....your mileage may vary.

6. Originally Posted by MarcusKspn

And of course the main reason is this:

Because we have always done it this way
Good one,

If there is one statement that better exemplifies the fire service, I've never heard it.

Hose loads should be based on the requirements of your response area, and as such should vary to meet those needs..

7. I can't remember what magazine I saw it in, but I did see something they called a "day line" it was a 2 1/2 in line with a smoothbore nozzle attached. Attached to the smoothbore was an 1 3/4 line with a combo nozzle. The way it was supposed to work was if upon arrival the 1 3/4 line could handle it it was deployed normally. If they were presented with a large body of fire beyond the capabilities of the 1 3/4 then they would disconnect the 1 3/4 and use the 2 1/2. Also the 2 1/2 nozzle was tied open to prevent its accidental closing.

8. My department uses the same setup, with a 2 1/2" and a wye with 100' of 1 3/4" pre-connected for garden apartments and other long lays. The back-up line is supposed to be set-up by the other company bringing their hi-rise packs.

I have a question, and I also posted it in the wildfire forum.

There was discussion of using a small forestry wye (1 1/2 to (2) 1 1/2") because of the lighter weight. Most of us don't think it will work (but we are new guys and don't count). I imagine it is possible to flow enough (360 gpm) through it, but the friction loss will be excessive. Does anyone have info of flowrates / friction loss for that size appliance?

9. Originally Posted by tfd181
My department uses the same setup, with a 2 1/2" and a wye with 100' of 1 3/4" pre-connected for garden apartments and other long lays. The back-up line is supposed to be set-up by the other company bringing their hi-rise packs.

I have a question, and I also posted it in the wildfire forum.

There was discussion of using a small forestry wye (1 1/2 to (2) 1 1/2") because of the lighter weight. Most of us don't think it will work (but we are new guys and don't count). I imagine it is possible to flow enough (360 gpm) through it, but the friction loss will be excessive. Does anyone have info of flowrates / friction loss for that size appliance?
I don't have any friction loss numbers with me here @ my "real job" but I would think that if your dept is looking to move to the smaller wye just because of weight issues - I think they should look into some of the newer lighter weight equipment that is already out there in the "appropriate" sizes rather than looking to downsize..

We have a "long lay pack" with 100' of 1-3/4" with a "Lightweight Leader Line Wye" ( http://www.edarley.com/finditem/20781 ) on our primary engine.

The overall weight of 100' of hose w/ a nozzle on it is such that you can't tell if this wye is on the pack or not when you're carrying it.

food for thought

10. In my area we call this set up a leader line. Which consists of your 2 1/2 with a smooth bore nozzle and the end of the nozzle has 1 1/2 threads which we have 100 ft of 1 3/4 with a break apart nozzle on that. This set up gives us 3 choices of fire streams with only leading out 1 line, and if I remember right 2 1/2 redlines at 400 GPM. My 3 cents

11. Originally Posted by tfd181
There was discussion of using a small forestry wye (1 1/2 to (2) 1 1/2") because of the lighter weight. Most of us don't think it will work (but we are new guys and don't count). I imagine it is possible to flow enough (360 gpm) through it, but the friction loss will be excessive. Does anyone have info of flowrates / friction loss for that size appliance?
I did some real quick math and the friction loss for 1 3/4" hose @ 360gpm would be about 200psi/100ft. You would exceed your max pressure of 250psi well before you completed your hose lay. Forestry firefighters use these hose sizes and appliances because their gpms are much lower, usually around 25-50gpm for each nozzle. Also the critical velocity of 1 3/4" is around 175-200gpm, depending on brand and/or construction. After you exceed that flow volume there is so much churning in the line from the speed the water has to travel it effects the quality of stream. Also, your friction loss rises so quickly you hit the point of diminishing returns. We pumped a SB nozzle on a 1 3/4" line to over 200GPM in training and you could see the quality of stream change from the churning.

Does anyone use a water thief for what we're talking about? We have both on the truck and it's down to the company's preference. I like the WT because you can go back to a 2 1/2" line if things get big on you or you can extend any size line. Our 2 1/2" preconnect has a nozzle and we bring the appliances with us if we're going to make a long lay like what we're talking about here. The only reason is that we can reach the majority of our fires with our preconnects so we're set up for that. I worked for a more rural dept where it was common to have structures that the engine could not get close enough to so they had to lay to it with MDH and wye from there already set up (the 2 1/2 was in a dead load for length flexibility), it worked great. If it works, it's the right answer. I would always want to be able to reduce down to at least two lines though.

Why dont we set a 300 ft of 2 1/2 with a 1 3/4 preconnected? Why do we always put a Gated Y on the 2 1/2?

"WE" don't why your FD operates that way...

13. Originally Posted by Fokker416
Does anyone use a water thief for what we're talking about?
I'll sell you the one on my engine, heck I'll give you twenty to take it...

http://www.elkhartbrass.com/files/aa...og-e-04-03.pdf

Figure 3 is that I am blessed with. Sorry I can't send you the manpower to move it.

Why dont we set a 300 ft of 2 1/2 with a 1 3/4 preconnected? Why do we always put a Gated Y on the 2 1/2?
F.D.N.Y. and many other depts. do it just the way you describe. Except the 2 1/2 is usually 500ft with 300ft of 1 3/4 in a static bed. You pull as much hose as you need in any situation and disconnect from the bed and attach to a discharge. As was stated previously, having a wye on 2 1/2 defeats the purpose because the flow of 2 1 3/4 lines exceeds the flow of the 2 1/2.

15. I am not sure but I think that it may have alot to do with friction loss. Most 1.75 hose has 1.5 couplings with a much higher friction loss that 2.5 hose.

Use the 2.5 to move the water at greater distances then put the 1.75 or 1.5 at the end for better handling.

16. ## 2-1/2" to 1-3/4" Operation

We call this operation 2-1/2 to bundles.

The duce and a half is set up with a set of stack tips on the end. We can pull off any amount of hose that we need. Our 1-3/4" linse are set up as bundles with the nozzle in the middle, they are 100' in length. (called a Metro Pack) On the end of one of the bundles is a 2-1/2" to (2) 1-1/2" gated wye.

We can start knocking down the fire with the Duce and a half, remove the stack tips leaving the ball valve only, and than attach our 1-3/4"s for finishing up.

We also use the same bundle in our transverse hose bed with 500 addational feet of 1-3/4". It is only connected to a discharge when the desired length of hose has been taken to the fire ground. (No longer than 300' total, Friction loss at 200 gpm becomes to much)

Why dont we set a 300 ft of 2 1/2 with a 1 3/4 preconnected? Why do we always put a Gated Y on the 2 1/2?
Partner if you haven't learned by now the fire service is 200 years of tradition unimpeded by progress. Because we have always done it that way is the standard answer for just about any question that involves some type of change.

Now. In theory 2 1 3/4" lines through the gated wye can outflow a 2 1/2" supply. Unless you restrict the flow of the 1 3/4. You restrict the flow to save the 2 1/2. Just because you can put 350 gpm through 2 1/2 doesn't mean it's good for the hose, couplings, pumper or your men that have to advance said hose

These numbers are just for illustration and should not be taken as serious calculations. Please don't crucify me for them

18. Originally Posted by lexfd5
I'll sell you the one on my engine, heck I'll give you twenty to take it...

http://www.elkhartbrass.com/files/aa...og-e-04-03.pdf

Figure 3 is that I am blessed with. Sorry I can't send you the manpower to move it.
Holy crap lex!! I didn't mean one of those abominations. I meant a 2 1/2 that splits to two 1 1/2 and one 2 1/2, not one of the LDH manifolds.

http://www.elkhartbrass.com/files/aa...og-e-04-01.pdf

figure 1 in this pdf.

It's probably double the weight of a common wye, but it's not a bear at all to handle and you can extend your 2 1/2 easily.

19. ## Use of a water thief to extend 2 1/2 & 1 3/4 lines

fokker416: Our dept has been using 3" W/ 2 1/2" couplings to feed a water thief since 1948. We continue this today for the following reasons. First, if you subscribe to Warren Kimball's system of backing up lines with one of equal or larger size, the thief can get you a 2 1/2" backup when you commit both 1 3/4" lines. Secondly, our SOP says to pump the 1 3/4" with TFT's at 180 psi, and all engines have 4 or 5 - 1 3/4" Pc's and 2 - 2 1/2" PC lines 200 ft long. The 2 1/2" needs to be supplied at 130, and are gated down to hit the SOP.
Advancing a leader line 200 ft of 3" and attaching a water thief will supply 2 - 1 3/4" 200' long at 150 gpm and the 200' of 2 1/2" line at about 110 psi of nozzle pressure. Thus no adjustment in master pump discharge is needed, just keep on pumping at 180 psi on both the PC's and the leader line.

Extending the 3" leader to 300 ft will still supply about 115 gpm on the 1 3/4's and slightly under (95 psi NP) on the 2 1/2" line. that gets you 500 ft from the engine and still flowing 450 gpm with all lines operating.

Yes, some of us "Old Guys" are still using water thiefs to good advantage.

Kuh Shise - Just and old German BS'er

20. Originally Posted by KuhShise
fokker416: Our dept has been using 3" W/ 2 1/2" couplings to feed a water thief since 1948.

Yes, some of us "Old Guys" are still using water thiefs to good advantage.

Kuh Shise - Just and old German BS'er
Guys have been doing this since the wayback days and it has worked? Rats. Since I'm not an old guy yet I can't do it because it wouldn't be "progressive".

I had that conversation with a guy from a nearby dept. "We don't do that because we're a progressive Department" (different firefighting subject btw).

"But it works rather well" I replied.

"But we're a progressive department".

"Congratulations on that dude, let me know how it works out for you."

21. We have 200' of 3" with a gated wye on our rigs. If this is needed, we use our standpipe pack which is two 100' sections of 2" with a 5/16" tip nozzle to connect to the wye.

This gives us the option of one 200' 2" line or two 100' 2" lines off the wye (with a second nozzle off the rig).

We used to use 1 3/4" pre-connects to work off the wye, but the 2" gives us a little more flow with a bit less friction loss...

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