Supply line sizing for master bath dual lavatory + toilet

I've looked up the fixture units for lavatories and gravity feed toilet for Virginia in Table 2903.6 at:

http://www2.iccsafe.org/states/virg.../Chapter 29_Water Supply and Distribution.pdf

This table define the fixture units for each lavatory at 0.5 and toilet at 2.2 for a total of 3.2 fixture units; can I supply all three fixtures off of a single 1/2" copper branch off of a 3/4" copper line? House pressure is regulated to 80PSI.

Thanks in advance.

PC

PS: The folks at JohnBridge forums say hi!

 

In your link look at TABLE P2903.7. Maximum of 3 water supply fixture units for 1/2 distribution pipe.

 

Stuff - Very good, thanks for the quick response! Can't belive I missed that, must have been a "can't see the forest for the trees" thing.

 

Followup question - what is the fixture unit so high for a toilet? For example a shower is 1.0 fixture units but the toilet is 2.2. Seems odd.

 

In table 2903.6, it says that a toilet and bathroom sink combined is 2.5 wsfu of cold, 0.5 of hot, and 2.6 wsfu if combined.

 

Good point. I sometimes can't see the forest for the trees either.


As for why it is so high, look at TABLE P2903.1 to see that you are required to supply a one piece toilet at 6 gallons per minute! My guess is that it has something to do with making sure that the shutoff valve closes properly. Hopefully someone else has a real answer.

Terry's chart is a bit more realistic - https://terrylove.com/watersize.htm

 

Interesting, thanks for pointing this out Reach.

Since I have dual lavatories; adding the 0.5 for the second lav bring the total to 3 which can all be supplied with a single 1/2 branch per P2903.7 with 80PSI source

Certainly seems reasonable since a full bath group, toilet, lavatory, tub w/wo shower is listed as 2.7 for cold line in 2903.6.

Thanks again for your assistance.