Simplified Pipe/Pump Sizing Chart (Copper Tubing)

Pipe Size	BTUH	Friction Head Feet 100’ (straight pipe)	Friction Head Feet 100’ (allowance for fittings and boiler)	Gallons per Minute (GPM) at 20 degree Delta T
1/2”	17,000	4.2’	6’	1.7
3/4”	39,000	4.2’	6’	3.9
1”	71,000	4.2’	6’	7.1
1-1/4”	160,000	4.2’	6’	16.0
1-1/2”	240,000	4.2’	6’	24.0
2”	450,000	4.2’	6’	45.0
2-1/2”	750,000	4.2’	6’	75.0
3”	1,400,000	4.2’	6’	140.0
4”	2,900,000	4.2’	6’	290.0

In order for a pump to obtain the above GPM, the pump must be sized properly to overcome the friction head of 4.2-6 feet per 100’ of copper pipe.

Example: For water to move 7.1 gallons per minute through a 1” pipe that is 200’, the pump must be able to overcome the friction loss of 4.2’-6.0’ per 100’ (4.2’-6.0’ x 2=8.4-12.0 feet). The pump will need to be able to move 7.1 GPM with a 8.4-12 friction head.