Fire Engineering Training Community

Where firefighters come to talk training

We have set up a new Pumper/Tender with 1200 feet of 3 inch that is set up for a forward lay. I am asking to change the hose lay so that we can pull one or two lines to pump to the attack engine, in a reverse lay. I am being told by command, that a 3 inch line is adequate for a supply line and that if we need to supply the attack engine “we’ll do the best we can”.

My thinking is that it is better to hook to the hydrant with 50 feet of 6 inch LDH and pump the 3 inch then try to supply an attack engine by pulling from 600 feet of 3 inch at 65-70 psi static pressure, less elevation. When I referenced the phase II report from Charleston, NC (regarding the inadequacy of 2 ½ inch supply lines), the response was the extra ½ inch (going from 2 1/2 inch to 3 inch) makes a huge difference. :-0

My intent is to request a test where we fill a draft tank for time and see the results using both methods, but as the very FNG I don’t want to get a rep for demanding huge changes that have very small improvements in performance.

Am I missing something here or is my thinking correct.

Views: 285

Replies to This Discussion

Larry - I hope you get the answers your looking for. I would tell you that it is better for the pumper to be on the hydrant and supply those 3" lines. We use 31/2" supply lines for long distances but rarely do we foward lay without another pumper on the supply hydrant. Do you always use two 3" lines for supply? You don't mention your hydrant spacing.
You got to pump the 3". Ray is right. Unless you split the beds and use both 2 1/2" buds on the hydrant, you are looking at maybe 500 GPM. Now, if that is your Chief's mission statement as far as initial GPM for the attack lines, then it works great. If you only have small single family dwellings, great. If you are looking at larger structures, then be carefull. Now I know some guys will say that 3" put out a lot of fire before LDH came along, and I will say to that....yup. A lot of fire. Because the fire extended that much more. LDH is not all that is is said to be. I like 3". It is a good feeder line. But it has to be pumped.
Sorry, I didn't provide enough detail. We have 1000 to 1500+ gpm hydrants that are 1000 or less feet apart in the housing areas. There are a few houses with long driveways that are farther from the hydrants then we can reach after dropping all of our LDH.

We have a class A pumper, two wild land/quick attack pumpers and the tender. The tender is a Fouts Brothers 3000 gal with a 750 gpm pump, so for structure attack the tender and pumper are all we have.

Hope that this helps.
I may have missed the point, but if you are supplying the engine from hydrant pressure, use the LDH (6") if you are relaying from the tender to the engine the tender is the limiting factor. I say this because rule of thumb you can flow around 900 gpm through 3". If the tender will only flow 750gpm then it is limiting the relay. The line officers or personnel may be more familiar with their first due and what the target hazards flow rate might be. If there are any flows above 750gpm, then you need to look at other options. Do you have a good amount of 6" on the rig?

Are you looking to load the bed differently? Meaning, is it in a forward configuration now and you want to reverse it? Do you run a single bed of 1200' or dual beds of 600' each?

Obviously dual supply lines gets you more water to the pump than a single. Not much argument there. And even with 5" LDH, real long lays (over 1000') dictate a relay pumper of some sort.

If you already have the dual beds or even a long single bed, you can always throw a double female or double male on the lay to facilitate laying in OR laying out. Put the opposite coupling in your hydrant bag and problem solved.

As for being the FNG, don't be afraid to ask the questions, but don't be the one that harps on it or complains. The senior guys at your department have reasons for doing what they do. If it works for your department then how is to say it is bad...

Be safe brother

We ran a test from the Tender to the Engine where we ran three 3 inch lines to an intake manifold. The Engine was pumping a smooth bore deck gun, a Blitz fire w/ smooth bore and a 2 ½ inch fog nozzle for a total of around 1100 gpm. We were at 20 psi residual on the intake of the tender.

It was a real short stretch but it gave us an idea of what we could get.
I want to set up two reverse lays of 600 feet and connect to either the Engines LDH or the Engine itself because nothing that we have will discharge from a large diameter discharge. It's a logistical nightmare!!! (not really)


Policy Page


The login above DOES NOT provide access to Fire Engineering magazine archives. Please go here for our archives.


Our contributors' posts are not vetted by the Fire Engineering technical board, and reflect the views and opinions of the individual authors. Anyone is welcome to participate.

For vetted content, please go to

We are excited to have you participate in our discussions and interactive forums. Before you begin posting, please take a moment to read our community policy page.  

Be Alert for Spam
We actively monitor the community for spam, however some does slip through. Please use common sense and caution when clicking links. If you suspect you've been hit by spam, e-mail

FE Podcasts

Check out the most recent episode and schedule of

© 2024   Created by fireeng.   Powered by

Badges  |  Report an Issue  |  Terms of Service