Question about Hydraulic Calculations

[Lostino]

Hello All

I have a question regarding doing the manual hydraulic calculations. I have a case where the area has three identical branch lines and one node on another branch line (which is the most remote). Now when I start from that node and into the cross main, I get a certain Q and a pressure. When I do the first branch line, I get another Q and P .

Now here is the problem, since the pressure on the branch line is much higher than the line of the solitary node (due to higher flow since there are multiple nodes) when I try to balance the two points on the cross main, the actual flow from the BL decreases !

To try to make it clearer:

K (branch line) = Qbranch/(Pbranch^0.5)
Q(balanced) = K(branch line) x P(from solitary node line)

so I end up with a Q balanced lower than the original Q of the branch line

Does that make sense? What is my mistake?

I know that it is difficult to understand what I mean without actually showing it on a drawing and on calcs but if somebody understood I appreciate a reply.

Thanks

 

[SprinklerDesigner2]

I think I understand.

Always k-factor the branch line or segment demanding a lower pressure than balance it to the higher pressure branch line or segment.

 

[Lostino]

Makes sense.

Thanks for your reply. Much appreciated.