Pressure Drop in Steam Pipes

Steam pipes and pressure drop diagrams - imperial and metric units

Pressure drop in steam pipes can be estimated with the diagrams below.

steam pipe pressure drop diagram

The diagram is made for steam with pressure 100 psi. For other pressures use correction factors:

Pressure (psi)	0	5	10	30	60	90	100	110	150	200	250	300
Factor	6.9	5.2	4.3	2.4	1.5	1.1	1.0	0.92	0.70	0.55	0.45	0.38

1 lbs/hr = 1.26x10^-4 kg/s
1 psi (lb/in²) = 6,894.8 Pa (N/m²) = 6.895x10^-3 N/mm² = 6.895x10^-2 bar = 27.71 in H₂O at 62^oF (16.7^oC) = 703.1 mm H₂O at 62^oF (16.7^oC) = 2.0416 in mercury at 62^oF (16.7^oC) = 51.8 mm mercury at 62^oF (16.7^oC) = 703.6 kg/m² = 0.06895 atm = 2.307 Ft. H₂O

steam pipe pressure drop diagram metric units

The diagram is made for steam with pressure 7 bar. For other pressures use correction factors:

Pressure (bar)	0	1	2	4	5	6	7	8.5	10	12	14	20
Factor	6.9	3.67	2.51	1.55	1.31	1.13	1.0	0.85	0.74	0.63	0.55	0.39

1 kg/h = 2.778x10^-4 kg/s = 3.67x10^-2 lb/min
1 bar = 10⁵ Pa (N/m²) = 0.1 N/mm² = 10,197 kp/m² = 10.20 m H₂O = 0.9869 atm = 14.50 psi (lb_f/in²) = 10⁶ dyn/cm² = 750 mmHg