Fixture Units?

Terry St.James_2

Can anyone help me out a little here? I need to know how many "fixture units" a 1" copper line can handle. can't seem to locate it in any of my books.

Ken_8

You referring to the NSPC?

National Standard Plumbing code for DWV sizing?

If so, 1" is too small for even a small lav. sink.

Smallest drain is one and a half inches nominal pipe diameter.

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Weezbo

Depends....

could go with 1/2 =4 .3/4 =16, 1=32 ........... or get really fancy and figure pressure and developed length.....
potable isnt too critical. there is some degree of lee way as it is sorta unlikely someone will turn everything on at once. say you had two and a half bath home 2200 sq ft...maybe after calculations it says you need 26 fixture units however you have a 3/4 inch lateral running to your home,,you could use a 3/4 X1 adaptor at the meter tap off the hose bib right away take off a couple toilets and it would still be fine,

Weezbo

Drainage?

dwv is different deal... one inch for like drink dispensors? drip pan conversion to indirect drain waste vent?

Ken_8

Yeah. The Wheeze and I

are confused.

You asking about feedwater, waste pipe size or venting or a hot water system for heating?

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Geo_2

1'

That's what I got...33 for 1 or 2 family units

mph

2000 UPC fixture units

At 46 to 60 PSI, the 2000 UPC allows 39 units for up to 80' in total length. Longer runs drop the number of units (36 for 100', 25 for 200', etc).

Jeff

Terry St.James_2

Sorry you guys...seems I left a little information out of the question. It is a water line...a riser. Changing the risers in an apartment building. I am having trouble telling co-workers and the boss too that the riser is way too small.
The water feeds 2 bathrooms per floor(back to back washrooms)...3 fixtures(so the bathroom group equals 6 fixtures x 2 per floor)...also 8 floors up. Giving a total of 96 fixtures units. The old line was galvanized and undersized too...it was 1 inch. They want to replace it with one inch copper...I am trying to tell them it needs
1 1/2 inch copper. So...that is why I am asking...can't seem to locate the fixtures units...on 1"...1 1/4"...1 1/2" copper..at 100psi and say roughly...80 to 100 feet straight up (water line).

Weezbo

You are starting to make me think....

thats a few more variables:))) minor technicalities as i call them...the hot water might fly in one inch...however i kinda think that id opt out for a 1/2"return line off the top loop(battery of fixtures)to a recircu pump for immediate hot water at the fixture. 100 feet Up aint quite the same deal as 100 feet on the flat...Appendix a is a close approximation of where to go with that system.
You have some lash ups where the water supply to the building is X" and thats it and there aint no getting it changed any time soon...depending on the jurisdiction the inspector may allow what you had going on the cold water side..if so then i have a nother couple ideas,dont try to overcome the lack of volume with pressure...it wont work.
and....even though you only have one inch feeding it you can go to the next pipe size up as a trunk line from the meter... it is also possible to use a tank to suppliment volume to a certain extent. there are other variables you havent mentioned...:)

Terry St.James_2

it's a cold water line....hot is done...a year so before..not sure why they didn't do the cold also...
There are no other variables...it is quite simple,a cold water riser.
Just can't locate my listings on fixture units.

Larry Weingarten

erosion

Perhaps you could mention erosion corrosion to your co-workers. If the line is too small, the water moves too fast, eroding the line. It gets worse at fittings. Noisy too, and you have just the right conditions for water hammer. They/you could be repiping again in a few years, or... it might be less expensive in the long run to install the right size. Or you could use PEX. That would tolerate high flow better than copper. You have lots of good reasons for actually sizing the line.

hot_rod

Flush tanks or flushmeters?

This handy wheel, from the PHCC, shows 1-1/2" at about7.6 fps and 8.5 psi/ 100 foot pressure drop.

You could run gpm calcs on Siggys HDS software also.

hot rod