Pipe Pressure Drop

The tables in this section provide the air pressure drop in pounds per square inch for a 100 foot length of Schedule 40 Steel Pipe. For lengths other than 100 feet, the pressure drop is proportional to the ratio of difference in lengths.

Example:

For 50 feet of pipe, the pressure drop will be approximately one-half the value given in the table.

For 300 feet of pipe, the pressure drop will be approximately three times the value given in the table.

1/8" Schedule 40 Pipe - 0.269 actual I.D.
Free Air (SCFM)	Line Pressure (PSIG)
Free Air (SCFM)	40	50	60	70	80	90	100	110
1	1.08	0.86	0.72	0.62	0.54	0.48	0.43	0.39
2	3.88	3.10	2.59	2.22	1.94	1.72	1.55	1.41
3	8.22	6.57	5.48	4.69	4.11	6.65	3.29	2.99
4	-	-	9.33	7.99	6.99	6.22	5.60	5.09
5	-	-	-	-	10.57	9.39	8.45	7.69
6	-	-	-	-	-	-	-	10.77

1/4" Schedule 40 Pipe - 0.364 actual I.D.
Free Air (SCFM)	Line Pressure (PSIG)
Free Air (SCFM)	40	50	60	70	80	90	100	110
1	0.24	0.19	0.16	0.14	0.12	0.11	0.09	0.09
2	0.86	0.68	0.57	0.49	0.43	0.38	0.34	0.31
3	1.81	1.45	1.21	1.03	0.91	0.80	0.72	0.66
4	3.08	2.47	2.06	1.76	1.54	1.37	1.23	1.12
5	4.66	3.73	3.11	2.66	2.33	2.07	1.86	1.69
6	6.53	5.22	4.35	3.73	3.26	2.90	2.61	2.37
8	-	8.89	7.41	6.35	5.56	4.94	4.45	4.04
10	-	-	-	9.60	8.40	7.47	6.72	6.11
12	-	-	-	-	-	10.46	9.41	8.56

3/8" Schedule 40 Pipe - 0.493 actual I.D.
Free Air (SCFM)	Line Pressure (PSIG)
Free Air (SCFM)	40	50	60	70	80	90	100	110
1	0	0	0	0	0	0	0	0
2	0.19	0.15	0.13	0.11	0.09	0.08	0	0
3	0.40	0.32	0.26	0.23	0.20	0.18	0.14	0.14
4	0.68	0.54	0.45	0.39	0.34	0.30	0.25	0.25
5	1.02	0.82	0.68	0.58	0.51	0.45	0.37	0.37
6	1.43	1.15	0.96	0.82	0.72	0.64	0.52	0.52
8	2.44	1.95	1.63	1.39	1.22	1.08	0.89	0.89
10	3.69	2.95	2.46	2.11	1.84	1.64	1.34	1.34
15	7.81	6.24	5.20	4.46	3.90	3.47	2.84	2.84
20	-	10.63	8.86	7.59	6.65	5.91	4.83	4.83
25	-	-	-	-	10.04	8.93	7.30	7.30
30	-	-	-	-	-	-	10.23	10.23

1/2" Schedule 40 Pipe - 0.622 actual I.D.
Free Air (SCFM)	Line Pressure (PSIG)
Free Air (SCFM)	40	50	60	70	80	90	100	110
3	0.10	0.10	0.08	0	0	0	0	0
4	0.17	0.17	0.14	0.12	0.11	0.09	0.08	0.08
5	0.26	0.26	0.21	0.18	0.16	0.14	0.13	0.12
6	0.36	0.36	0.30	0.26	0.22	0.20	0.18	0.16
8	0.61	0.61	0.51	0.44	0.38	0.34	0.31	0.28
10	0.92	0.92	0.77	0.66	0.58	0.51	0.46	0.42
15	1.95	1.95	1.63	1.40	1.22	1.09	0.98	0.89
20	3.33	3.33	2.77	2.38	2.08	1.85	1.66	1.51
25	5.02	5.02	4.19	3.59	3.14	2.79	2.51	2.28
30	7.04	7.04	5.87	5.03	4.40	3.91	3.52	3.20
35	9.36	9.36	7.80	6.69	5.85	5.20	4.68	4.26
40	-	-	9.99	8.56	7.49	6.66	5.99	5.45
45	-	-	-	10.55	9.32	8.28	7.45	6.78
50	-	-	-	-	-	10.06	9.06	8.23

3/4" Schedule 40 Pipe - 0.824 actual I.D.
Free Air (SCFM)	Line Pressure (PSIG)
Free Air (SCFM)	40	50	60	70	80	90	100	110
5	0.08	0	0	0	0	0	0	0
6	0.11	0.09	0.07	0	0	0	0	0
8	0.19	0.15	0.12	0.11	0.09	0.08	0.07	0
10	0.28	0.23	0.19	0.16	0.14	0.13	0.11	0.10
15	0.60	0.48	0.40	0.34	0.30	0.27	0.24	0.22
20	1.02	0.81	0.68	0.58	0.51	0.45	0.41	0.37
25	1.54	1.23	1.03	0.88	0.77	0.68	0.62	0.56
30	2.16	1.73	1.44	1.23	1.08	0.96	0.86	0.78
35	2.87	2.29	1.91	1.64	1.43	1.27	1.15	1.04
40	3.67	2.94	2.45	2.10	1.84	1.63	1.47	1.34
45	4.57	3.65	3.04	2.61	2.28	2.03	1.83	1.66
50	5.55	4.44	3.70	3.17	2.77	2.47	2.22	2.02
60	7.78	6.22	5.18	4.44	3.89	3.46	3.11	2.83
70	10.34	8.27	6.89	5.91	5.17	4.60	4.14	3.76
80	-	10.59	8.83	7.57	6.62	5.88	5.30	4.81
90	-	-	10.98	9.41	8.23	7.32	6.59	5.99
100	-	-	-	-	10.00	8.89	8.00	7.27
125	-	-	-	-	-	-	-	10.99

1" Schedule 40 Pipe - 1.049 actual I.D.
Free Air (SCFM)	Line Pressure (PSIG)
Free Air (SCFM)	40	50	60	70	80	90	100	110
50	1.66	1.33	1.11	0.95	0.83	0.75	0.66	0.60
60	2.33	1.86	1.55	1.33	1.16	1.03	0.93	0.85
70	3.09	2.47	2.06	1.77	1.55	1.37	1.24	1.12
80	3.96	3.17	2.64	2.26	1.98	1.76	1.58	1.44
90	4.92	3.94	3.28	2.81	2.46	2.19	1.97	1.79
100	5.98	4.79	3.99	3.42	2.99	2.66	2.39	2.18
125	9.04	7.23	6.03	5.17	4.52	4.02	3.62	3.29
150	-	10.13	8.44	7.24	6.33	5.63	5.07	4.61
175	-	-	-	9.63	8.42	7.49	6.74	6.13
200	-	-	-	-	10.78	9.59	8.63	7.84
225	-	-	-	-	-	-	10.73	9.75

1.25" Schedule 40 Pipe - 1.380 actual I.D.
Free Air (SCFM)	Line Pressure (PSIG)
Free Air (SCFM)	40	50	60	70	80	90	100	110
50	0.42	0.34	0.28	0.24	0.21	0.19	0.17	0.15
60	0.59	0.47	0.39	0.34	0.30	0.26	0.24	0.21
70	0.78	0.63	0.52	0.45	0.39	0.35	0.31	0.29
80	1.00	0.80	0.67	0.57	0.50	0.45	0.40	0.37
90	1.25	1.00	0.83	0.71	0.62	0.56	0.50	0.45
100	1.52	1.21	1.01	0.87	0.76	0.97	0.61	0.55
125	2.29	1.84	1.53	1.31	1.15	1.02	0.92	0.83
150	3.22	2.57	2.14	1.84	1.61	1.43	1.29	1.17
175	4.28	3.42	2.85	2.44	2.14	1.90	1.71	1.55
200	5.47	4.38	3.65	3.13	2.74	2.43	2.19	1.99
225	6.81	5.45	4.54	3.89	3.40	3.03	2.72	2.48
275	9.87	7.89	6.58	5.64	4.93	4.39	3.95	3.59
300	-	9.27	7.73	6.62	5.80	5.15	4.64	4.21
325	-	10.75	8.96	7.68	6.72	5.97	5.38	4.89
350	-	-	10.28	8.81	7.71	6.85	6.17	5.61
375	-	-	-	10.01	8.76	7.78	7.01	6.37
400	-	-	-	-	9.87	8.77	7.89	7.18
450	-	-	-	-	-	10.91	9.82	8.92
500	-	-	-	-	-	-	-	10.84

1.5" Schedule 40 Pipe - 1.610 actual I.D.
Free Air (SCFM)	Line Pressure (PSIG)
Free Air (SCFM)	40	50	60	70	80	90	100	110
50	0.19	0.16	0.13	0.11	0.10	0.09	0.08	0
60	0.27	0.22	0.18	0.16	0.14	0.12	0.11	0.10
70	0.36	0.29	0.24	0.21	0.18	0.16	0.15	0.13
80	0.46	0.37	0.31	0.27	0.23	0.21	0.19	0.17
90	0.58	0.46	0.39	0.33	0.29	0.26	0.23	0.21
100	0.70	0.56	0.47	0.40	0.35	0.31	0.28	0.26
125	1.06	0.85	0.71	0.61	0.53	0.47	0.42	0.39
150	1.49	1.19	0.99	0.85	0.74	0.66	0.60	0.54
175	1.98	1.58	1.32	1.13	0.99	0.88	0.79	0.72
200	2.53	2.03	1.69	1.45	1.27	1.13	1.01	0.92
225	3.15	2.52	2.10	1.80	1.57	1.40	1.26	1.15
275	4.57	3.65	3.04	2.61	2.28	2.03	1.83	1.66
300	5.36	4.29	3.58	3.06	2.68	2.38	2.15	1.95
325	6.22	4.97	4.15	3.55	3.11	2.76	2.49	2.26
350	7.13	5.71	4.75	4.08	3.57	3.17	2.85	2.59
375	8.10	6.48	5.40	4.63	4.05	3.60	3.24	2.95
400	9.13	7.30	6.09	5.22	4.57	4.06	3.65	3.32
450	-	9.08	7.57	6.49	5.68	5.05	4.54	4.13
500	-	-	9.20	7.88	6.90	6.13	5.52	5.02
550	-	-	10.97	9.40	8.23	7.31	6.58	5.98

Pipe Pressure Drop

1/8" Schedule 40 Pipe - 0.269 actual I.D.

Free Air

(SCFM)

Line Pressure (PSIG)

1/4" Schedule 40 Pipe - 0.364 actual I.D.

Free Air

(SCFM)

Line Pressure (PSIG)

3/8" Schedule 40 Pipe - 0.493 actual I.D.

Free Air

(SCFM)

Line Pressure (PSIG)

1/2" Schedule 40 Pipe - 0.622 actual I.D.

Free Air

(SCFM)

Line Pressure (PSIG)

3/4" Schedule 40 Pipe - 0.824 actual I.D.

Free Air

(SCFM)

Line Pressure (PSIG)

1" Schedule 40 Pipe - 1.049 actual I.D.

Free Air

(SCFM)

Line Pressure (PSIG)

1.25" Schedule 40 Pipe - 1.380 actual I.D.

Free Air

(SCFM)

Line Pressure (PSIG)

1.5" Schedule 40 Pipe - 1.610 actual I.D.

Free Air

(SCFM)

Line Pressure (PSIG)