Benji,
I feel like this is a trick question, lol. Assuming you put the proper design pressure to each equipment type, and you sized each valve and then sized the mainline (making sure that the 16 valves running at a time accounted for the worst case amount of flow at a time)...what does the Critical Analysis say your required pressure is?

Good morning Jake!

No trickery intended! I have just never really thought or worried about what it means to size the mainline as multi-valve because I have never needed so many valves running simultaneously.

I have done all the above (proper pressure, etc.), and when sizing the mainline the critical analysis says I need a minimum of 70 psi at the POC. It just seems low to be able to run 16 valves at a time.

So then I looked at the run time analysis, noted the first valve group that would turn on, and sized the mainline again with only the first valves group selected in the sizing. The critical analysis pressure was 63 psi. Again, seems really low.

Thanks for your help!

Cheers!

Benji

Benji,
Remember, Flow and Pressure are two different things. When making sure to account for the proper availability in a system, the amount of water you are supplying is the important part of running multiple zones at a time. The pressure will be consistent through the system based on the worst case zone's pressure it needs to account for, which doesn't mean a collective sum of pressure based on how many zones will be running at a time. Yes, with more flow demands, you will see an increase in pipe size to account for the friction loss increase, but you will still have a critical station to which the system needs to account for from a pressure standpoint.

I hope that makes enough sense, and would love to hear any other input from the masses!