Gate valve size for Pendent and upright sprinklers in one shop. 1

[Miangoni]

Dear all,
I have to install fire sprinklers in a shop in shopping mall and there is gypsum board false ceiling in the shop. There is the requirement to also install upright sprinklers above false ceiling. The area of the shop is 180 square meters so there will be 16 pendent and almost 15 upright sprinklers connected to single gate valve. There is already 2.5" gate valve provided but mall design engineer asked me to change the gate valve size to 3" because 2.5" size is not sufficient for pendent and upright sprinklers.
My question is that, whether I should consider gate valve size for 15 sprinklers (2.5") or I should also add upright sprinklers to increase the size of gate valve to 3".
Because pendent and upright layers are serving the same vertical area and one of my seniors once told me that when it is needed to cover same vertical area with different layers, the gate valve size should be considered for single layer.

Waiting for quick reply

 

[TravisMack]

What do your hydraulic calculations indicate? Or are you trying to pipe schedule this. Pipe schedule is pretty much done away with in the US, but some areas outside of US still do pipe schedule.

Travis Mack
MFP Design, LLC

http://www.mfpdesign.com

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[Miangoni]

Regardless of pipe schedule and hydraulic calculations, If we have to connect the two different layers of sprinklers with same gate valve, should we consider both layers for pipe size? Because both layers of sprinklers are covering the same shop (one layer for pendent and other layer for upright sprinklers separated by gypsum board ceiling in between).
by the way, pipe schedule design is required there.

 

[SprinklerDesigner2]

You have two separate layers but one floor so the single shutoff valve is sufficient.

 

[TravisMack]

I believe your response indicates a deficit in experience. That is why I asked in the manner I did. Calculation wise, you only consider one level. However, there is a pipe schedule for above/below a ceiling. That is precisely why my answer was in two parts. Adding the extra sprinklers if you are doing pipe schedule could require an upsize in the supply pipe, which would lead to a larger control valve. Review your pipe schedule tables for above/below ceilings. If you calculate the system, you may not need to upsize the valve.

So as you can see, the method of sizing the pipe (calculations vs pipe schedule) does have an impact to the sizing.

Travis Mack
MFP Design, LLC

http://www.mfpdesign.com

"Follow" us at

https://www.facebook.com/pages/MFP-Design-LLC/92218417692

 

[Miangoni]

Dear TravisMack,
Thanks for clarifying the concept.
Actually pendent sprinklers are already existing in the shop. I have to install upright sprinklers only.