LOL.
That's the exact same example we got from the AHJ (which I found in my fire
department hydraulic text book). After looking at the example I think our
situation is a little more complex since our nozzle is at a fixed 60 degree
angle. So, if I remember my college physics correctly, we'll have a vertical
and horizontal reactionary force. But I'm pretty rusty so I’m looking for some
back-up and confirmation.
Jimmy Waite, CET
Design Engineer
[email protected]
mobile: 919.622.7030
3609 Bastion Lane | Raleigh, NC 27604 | : 919.212.2356 | :
919.212.2357 | www.piedmontfire.com
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Jeff Garrison
Sent: Monday, January 09, 2012 11:55 AM
To: [email protected]
Subject: Re: NFPA 15 - Nozzle Reaction
*Jimmy,*
*As an example.....*
**
*Calculating the Nozzle Reaction for a 1.25-inch-Bore-Diameter Nozzle
*The solid bore discharge formula is gallons per minute (gpm) = 29.71 D²
NP¹/². The formula can be rewritten to solve for the unknown, nozzle
pressure:
*Nozzle Pressure = NP psi = [(gpm)/(29.71 x D²)]²
*Where:
gpm = 400 gpm
bore diameter (D) = 1.25 in
*therefore:
*NP = [(400gpm)/(29.71 x 1.25²)]²
NP = 74.25 psi
*The formula for nozzle reaction (NR) for solid bore nozzles is NR = 1.57
D²NP
**therefore:
*NR = 1.57 x 1.25² x 74.25
NR = 182 lb reactive force
On Mon, Jan 9, 2012 at 11:29 AM, Jimmy Waite <[email protected]>wrote:
> We are working on a fixed water spray system that is cooling the exterior
> of
> a vessel at a soy bean processing plant. The AHJ is asking for reactionary
> force calculations per 6.3.2.8 of NFPA 15 ('07 ed.). We have contacted the
> nozzle manufacturer and NFPA and neither were able to provide any guidance.
> Has anyone out there come across this issue before? Does anyone have any
> good ideas of where to start? We do have a structural engineer that we're
> working with, but he is mainly evaluating the structure supporting the pipe
> and the vessel.
>
>
>
>
>
> Thanks,
>
>
>
> Jimmy Waite, CET
>
> Design Engineer
>
>
> <mailto:[email protected]> [email protected]
>
> mobile: 919.622.7030
>
>
>
> cid:[email protected]
>
> 3609 Bastion Lane | Raleigh, NC 27604 | ': 919.212.2356 | 6:
> 919.212.2357 | <http://www.piedmontfire.com/> www.piedmontfire.com
>
>
>
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