2010 California Plumbing Code and calculating copper size??

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mcintoshmc

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Take a look at the attached. I was reviewing the 2010 California Plumbing Code, and I followed the formula they require.

Static pressure - minus .5 per foot of elevation from highest fixture to the meter. The I looked at table 6-6, and matched it to the long run from meter to remote fixture, and my numbers come up at over 60 PSI, 80 ft run, and 39 fixture units.

But as you can see, there are 3 options for 80 ft. and 39 FU's. How do I read this? I am re-piping with copper, and want to do it right.

Thanks.

copper.jpg
 
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1" water distribution with 3/4 main is good. You got 39 f.u. Wow, in my code 39 f.u. Is like a small commercial building lol. Bathroom group is like 4.2 or so and hose Bibb is 2, kitchen sink is 1.4.I think the average house around here is like 20 f.u. For a 3-4 bathroom. Interesting lol
 
You would take the smallest option. I've almost never been in a house with a 1" water distribution piping, 3/4 is almost always enough. But based on your f.u. 1" is what you need
 
Maybe I'm just a little tired or something, but am I reading that it is acceptable to size the water distribution larger than the service in some circumstances? If so, it seems to contradict our sizing methods. Y'know, once a service size has been determined the volume remains the same even if you increase the size of the pipe after the service. You would simply have 3/4" volume in a 1 1/4" pipe, 1" vol. in 2" pipe and so on...??
 
Caduceus said:
Maybe I'm just a little tired or something, but am I reading that it is acceptable to size the water distribution larger than the service in some circumstances? If so, it seems to contradict our sizing methods. Y'know, once a service size has been determined the volume remains the same even if you increase the size of the pipe after the service. You would simply have 3/4" volume in a 1 1/4" pipe, 1" vol. in 2" pipe and so on...??

Agreed, however in our code it has the same thing. 3/4 water service with 1" water distribution or 1 1/2 water service with 2" water distribution. It's very odd and I don't think in reality you would ever do that. But hey my code has 2 1/2" for DWV so I think they take minimums to a whole nother level lol
 
So, I have 1 inch coming in. I'm going to reduce to 3/4 to the water heater, and then run 3/4 throughout, but reduce 1/2 to the fixtures except for the h/c in shower, I'll keep that 3/4.

What I'm not sure of, is my sprinkler system in the back is fed from the spigot. I have nothing but long distance rotor heads. I have two zones, and 11 heads. Not sure, what size I should run to the spigot, so that I won't affect water pressure in the home while running.
 

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