P-811.3 Minimum Water Supply Sizes to Flushometers

The maximum number of water closet flush valves allowed to be supplied from a single source shall conform to the schedule of pipe sizes and water pressures listed in Table P811.3.

TABLE P-811.3 —
MINIMUM WATER SUPPLY SIZES TO FLUSHOMETERS^a

First Floor Above Groundb
Pneumatic Tank or Underground Main Pressure Using Iron Pipe	Ferrule Size
	1"	1-1/2"	2"	3"	4"	6"	8"
30 psi		1 (200')	2	12	50	180	450
40 psi	1 (25')	1 (400')	4	24	80	220	450
50 psi	1 (50')	1	7	40	110	220	450
60 psi	1 (75')	2	7	40	110	220	450
70 psi	1 (100')	3	7	40	110	220	450
First Floor Above Groundb
Pneumatic Tank or Underground Main Pressure Using Copper Tubing	Ferrule Size
	1"	1-1/2"	2"	3"	4"	6"	8"
30 psi		1 (250')	3	15	55	200	450
40 psi	1 (30')	1 (500')	6	30	110	220	450
50 psi	1 (65')	2	9	40	110	220	450
60 psi	1 (100')	3	9	40	110	220	450
70 psi	1 (135')	4	9	40	110	220	450

Note a: Numbers shown in parentheses designate maximum allowed distance of fixtures from pneumatic tank or underground main.

Note b: See Section P-811.3.2

If the distance from the fixture to the pneumatic tank or underground main is in excess of 500 feet, deduct 10 psi from the tank or main pressure.

For each floor above the first floor, deduct 10 psi from the tank or main pressure.

Two urinals shall be counted as one water closet.