1950s home - copper type/diameter?

[Redline]

I will be replacing a few of the branch lines this weekend on my home (St Louis, MO) and was curious to know what the reccomendation was for type of copper and diameter? These branch lines will be for outdoor faucets only, and will be tee'd off from a 1" OD main (i beleive it is galvanized?). It appears that most of the current branch lines are 3/4" but a friend said to use 1/2", so that is the reason I ask, also since I will be buying new copper, should I just up for the type L while im at it or is it just wasted money compared to M in this application?

Also, is there any logic to the location of a ball valve on the branch line, other than it being readily accessible?

Thank you.

 

[Gary Swart]

For the outside water, go with 3/4". You want all the pressure and volume you can get on those lines, and 1/2" will restrict the flow somewhat. No point in going with type L, type M is just fine although the dollar difference on a small job like yours wouldn't amount to much.

 

[Sponsor]

 

[Chassis]

FWIW I would go with 1/2". If you live in a typical city neighborhood with 0.25 acre lots, you will have enough water pressure for a hose-type sprinkler anywhere on your yard. If you live on a larger parcel, and you're using very long hoses, then 3/4" may be justified.

Again FWIW, I just replaced a sillcock which is fed by 3/8" supply line. Why 3/8"? Don't know, that's what was there. Too lazy to re-do the pipe back to the 1" main in the house. It delivers enough pressure and flow to drive the oscillating sprinkler with the longest amount of hose I have - 100' I think.

As far as ball valve, accessibility is key. Beyond that, I think it makes sense to have it close to where the branch originates. Most of the time this should be near the water meter where it comes in from the street/outside the house.

 

[Gary Swart]

Point I would make is this. The "savings" in $$$ going with minimum size 1/2" and the larger 3/4" would be peanuts, and if you ever want to run 3 or 4 sprinklers, you'll be SOL with 1/2" pipe. There's no reason not to go with the larger size other than trying to save a dollar or two. Go larger than necessary, and you'll have the capacity if it's ever needed. We read posts all the time on here about folks that are trying to overcome inadaquate sized pipes, poorly located drains, adding toilets in basements not properly prepared, etc.. We just don't always know what the future needs might be.

 

[hj]

pipe

If it is just for the hose faucet and will never be used for anything else, then 1/2" is adequate. The opening in the hose valve's seat is about a 1/4" to 5/16" in diameter and no matter what size the pipe is, that is all the water it will deliver. And the only difference between a 3/4" and 1/2" hose faucet is the size pipe it fastens to. The do not make the 3/4" one "bigger" than the 1/2" one.