Finding min psi or gpm
Finding min psi or gpm
(OP)
I am working on a project that requires the hydraulic calculation to have a 0.39/2600 density. I'm using HASS as my calc program and I can not input the density into the program. I need to get the minimum allowable end head condition in either psi or gpm. Heads are space 10x10 and are 5.6 k-factor.





RE: Finding min psi or gpm
Q= (area) * (Density)
Therefore,
P= [(ad) / k]^2
P= [(100sq.ft * 0.39gpm/sq.ft) / 5.6] ^2
P= 48.5 psig required at the most remote sprinkler.
I don't use HASS, but it should derive Q from this equation. Otherwise, re-arrange and calc it yourself.
RE: Finding min psi or gpm
Why not consider using a larger orifice sprinkler? 5.6 is pretty small to be pushing that kind of water through. Consider using an 8.0, 11.2, 14.0 etc. in your calcs. As you can see from the above calc, increasing the K factor (denominator in the pressure equation) will decrease the required end head pressure, while increasing the total flow required in GPM. Could make it possible to decrease pipe sizes, or even delete a fire pump.
RE: Finding min psi or gpm
RE: Finding min psi or gpm
Wow, good luck with that. Most of the older abandoned factories have a tank and pump set, is that the case here? The pressure is one thing, the onsite water storage is quite another.
I once tried to "find a home" for a displaced tire manufacturer; the fire protection was just one of the features that factored into the cost, but we looked at many many different existing spaces before finding one that worked for the sprinklers, and even then didn't get near the storage height they would have liked..
RE: Finding min psi or gpm
Ed Kramer
Kramer Design, LLC
RE: Finding min psi or gpm
RE: Finding min psi or gpm
RE: Finding min psi or gpm
Travis Mack
MFP Design, LLC
www.mfpdesign.com
RE: Finding min psi or gpm
RE: Finding min psi or gpm
RE: Finding min psi or gpm
When I was young and brash I would go for this sort of work but have since learned the owner will stack to whatever height he wants and when there is a fire they will come after me as the last one who "touched it".
Given it is an older building and pipe schedule nothing you do will work.
I would be happy to install a brand new system. New heads, new pipes, new everything.
RE: Finding min psi or gpm
Sometimes the customer is wrong.