Split Copper Water Line

[froddan]

I would like to install a double shower head in a shower and I was told that it requires a 3/4" water supply to do this.

The shower currently has 1/2" copper pipe, but 3/4" pipes run only about 5 feet away from where the shower is.

The pipe to the shower curently is 1/2" and it "tees off" in a 'T' from a 3/4", which continues to another bathroom.
I was thinking of changing the split from a 1/2" to a 3/4" and run this line all the way to the shower.

Is there a limit on how many times a line can be split and extended without loosing too much water pressure?

The water pressure at my house is 60 psi, I'm not sure if that is normal, but it seems perfectly fine for other sinks and showers in the house.

 

[Jadnashua]

Two heads should work with a 1/2" rough-in valve. Any more and you'd definately want 3/4". Most 1/2" valves can flow the 5 gpm okay.

 

[Sponsor]

 

[Winslow]

if the outlet on the valve is 1/2 then changing the supply wouldn't matter unless it was a long run of piping. If you plan on running both showerheads at the same time and they are both large panhead showerheads then you might want to upgrade to a 3/4 valve.

 

[froddan]

So if I understand this correctly, it is the inlet on the valve that actually matters.

The 1/2" copper pipe is currently running about 5 feet from the 3/4" to the shower.
Yes, I intend on running the two shower heads at the same time.

I guess a drawing would make it easier to give further advice...

 

[Geniescience]

if you draw out the whole house plumbing, and show all the restrictions in the flow path, you might get valid information back, about how much water will flow out of two shower heads. Restrictions are elbows, and lengths of straight pipe too.

Many people have another problem, a reduced flow when other taps are open elswhere in the house. This is not related to your pressure number of 60, because once water is flowing, that magic "static" pressure number is no longer valid. Moving water, dynamic flow, has another pressure number, called dynamic pressure. Flush all toilets simultaneously (need helpers) while all taps are open but one, and then measure the time it takes to fill a big big container like a 5 gal, and compare that to the time it takes to fill a 5 gal "on a good day", and you'll see that even the two measures of time-to-fill might not be the same. That would be because dynamic pressure reduces as time goes on.

I'll bet your have plenty of water in dynamic pressure to operate two normal shower heads sold in stores today. Since you haven't mentioned that a flushed toilet causes a problem in flow in other taps.

David

 

[froddan]

Thanks for the replies!
Because alot of the pipes are covered, I am not exactly sure of all the details of the elbows, and other restrictions.

What I do know is that from the main line, there are hot and cold pipe of 3/4" size that run about 7 feet to one bathroom with a tubshower, sink and toilet, where it branches off to the bathroom with the shower I am remodeling.

Currently the 3/4" pipes branch off to 1/2" pipes and they feed a shower (currently one head, which will change to two separate shower heads) one sink and one toilet.
The distance of the 1/2" pipe from where the 3/4" pipes end to the shower is about 5 feet.

I am basically trying to figure out if I will have good pressure if both shower heads even if they are running at the same time with the 1/2" pipe or if I have to/should/might as well/ upsize to 3/4" pipes to the branch.
Attach is a simple drawing of what I'm thinking...

Thanks for any advice!