man! Does anybody come in here? Anyway, I'm pondering hose layout.

Some places I've heard of use something like a couple lengths of 2.5 connected to a couple of 1.75. The way I understand it is this increases nozzle pressure over long layouts. I'm wondering if this might help out my department since we're going to have some industrial occupancies soon. I was thinking a split bed of this and one of straight 2.5. The problem is we don't have the kind of guaranteed water supply some of these places do. We have a few hydrants (flow unknown) and have to water shuttle in other places.

Oh yea, in case you didn't notice, i don't know shiite about hydraulics. It makes my head hurt.

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Replies to This Discussion

Yes, going from a larger diameter hose to a smaller on will increase pressure. and decrease friction loss with longer runs. However, I don't recall ever using a gated "y" in a low water enviroment.
Actually I was talking about one connection with a reducer between the different diameters. Either way I should wait until I get back and figure out what the flow rates are.

Is there a reference for determining something like this?
In my dept when we brake down from a 21/2 to 1 1/2 we always use a gated wye in case you want to shut down one line, great in low water cases. For the ref you're looking for look in pumping apparatus driver/operator handbook. What rates are you looking for? A 1 1/2 will flow 125 gpm 1 3/4 175 gpm 2" 200 gpm and a 2 1/2 25o gpm. Hope this helps.
If you are talking about the flow rates of the hydrants in your area, there is a tool for determining that. I cannot remember what it is called, but it is a guage of some kind. How do I know? My husband had to do the hydrant flow pressure test in his FireFighter 1 or 2 IFSAC Skills test. He'd never seen the tool till then! Fortunately for him, he's a brainiac and figured it out on the spot, because he had briefly read over the skill sheet before going to the testing site that day!
If you ask your public works dept they should be able to tell you what the flows are.
It's called a pitot tube and if you don't like to get wet you would use a device called a diffuser.

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