One of my plumbers is telling me I need to run a one inch copper pipe for both hot and cold supply lines as risers up the house. Then they would have half inch pipes coming off to each fixture. A one inch pipe creates a huge waste of water and heat. But they claim it is code. I can’t find anything that says this in the code book. What I can find is pressure requirements. So if I meet the flow rate and pressure minimums I should be OK no matter what size pipe I use? Does anyone know?
And if yes how do I test the (psi) and (gpm)?
From the NY code book page 31:
TABLE RS 16-7 MINIMUM RATE OF FLOW AND MINIMUM REQUIRED PRESSURE DURING FLOW FOR
SIZING INDIVIDUAL BRANCH SUPPLIES FOR PLUMBING FIXTURES
Flow Pressure, Flow Rate
(psi), (gpm)
Ordinary basin faucet ………………………… 8, 2.0
Sink faucet, 3/8 in. …………………………….. 8, 4.5
Sink faucet, 1/2 in. …………………………….. 8, 4.5
Bathtub ……………………………………………. 8, 5.0
Shower …………………………………………….. 8 5.0