Resistance and Equivalent Length of Fittings

Resistance and equivalent length of fittings in hot water heating systems

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The equivalent resistance length - head - of some common fittings in hot water piping systems can be found in the table below:

Equivalent Length (m or ft)
Fittings	Nominal diameter
	in	1/2	3/4	1	1 1/4	1 1/2	2	2 1/2	3	4	5	6
	mm	15	20	25	32	40	50	65	80	100	125	150
Contraction. sudden d / D=1/4	ft	0.8	1.0	1.02	1.5	2.0	2.5	3	4	5	6	8
Contraction. sudden d / D=1/4	m	0.25	0.3	0.35	0.45	0.6	0.75	0.9	1.2	1.5	1.8	2.5
Contraction. sudden d / D=1/2	ft	0.5	0.8	1.0	1.2	1.5	2	2	3	4	5	6
Contraction. sudden d / D=1/2	m	0.15	0.25	0.3	0.35	0.45	0.6	0.6	0.9	1.2	1.5	1.8
Contraction. sudden d / D=3/4	ft	0.4	0.5	0.6	1	1	1.5	1.5	2	2.5	3	3.5
Contraction. sudden d / D=3/4	m	0.12	0.15	0.18	0.3	0.3	0.4	0.5	0.6	0.8	0.9	1.1
Elbow	ft	1	2	2	3	4	5	6	8	11	13	17
Elbow	m	0.3	0.6	0.6	0.9	1.2	1.5	1.8	2.5	3.5	4	5.2
Elbow. long	ft	1	1.5	2	2.5	3	3	4	5	6	8	10
Elbow. long	m	0.3	0.45	0.6	0.75	0.9	1.0	1.2	1.5	1.8	2.5	3.0
Enlargement. sudden d / D=1/4	ft	1	2	2	3	4	5	6	8	11	13	17
Enlargement. sudden d / D=1/4	m	0.3	0.5	0.7	0.9	1.2	1.5	1.8	2.5	3.5	4	5.2
Enlargement. sudden d / D=1/2	ft	1	1.5	2	2.5	3	3.5	4	5	7	9	11
Enlargement. sudden d / D=1/2	m	0.3	0.45	0.6	0.75	0.9	1.1	1.2	1.5	2.1	2.7	3.5
Enlargement. sudden d / D=3/4	ft	0.3	0.5	0.5	1	1	1	1.5	2	2.3	3	3
Enlargement. sudden d / D=3/4	m	0.09	0.15	0.15	0.25	0.3	0.35	0.45	0.6	0.75	0.9	1.0
Entrance	ft	1	1	1.5	2	2.5	3	3.5	4.5	6	8	10
Entrance	m	0.3	0.3	0.45	0.6	0.75	0.9	1.1	1.4	1.8	2.5	3.0
Tee. run	ft	1	1.5	2.5	2.5	3	3	4	5	6	8	10
Tee. run	m	0.3	0.45	0.75	0.8	0.9	1.0	1.2	1.5	1.8	2.5	3.0
Tee. run reduced to 1/2	tf	1	2	2	3	4	5	6	8	11	13	17
Tee. run reduced to 1/2	m	0.3	0.5	0.7	0.9	1.2	1.5	1.8	2.5	3.5	4	5.2
Tee. branch	ft	3.5	5	6	8	10	13	15	18	24	30	35
Tee. branch	m	1.1	1.5	1.8	2.5	3	4	4.5	5.5	7.3	9	11
Valve. Angle	ft	8	11	15	18	20	27	32	40
Valve. Angle	m	2.5	3.5	4.5	5.5	6	8.3	10	12
Valve. Gate	ft	0.3	0.5	0.5	0.5	1	1	1.5	2	2.5	3	3
Valve. Gate	m	0.09	0.15	0.15	0.15	0.3	0.3	0.45	0.6	0.75	0.9	0.9
Valve. Globe	ft	13	16	26	35	40	55	65	80
Valve. Globe	m	4	5	8	11	12	17	20	24.5

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