# 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.

### Imperial Units

The diagram is made for steam with pressure *100 psi* schedule 40 steel pipe. 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/in*^{2}) = 6,894.8 Pa (N/m^{2}) = 6.895x10^{-3}N/mm^{2}= 6.895x10^{-2}bar = 27.71 in H_{2}O at 62^{o}F (16.7^{o}C) = 703.1 mm H_{2}O at 62^{o}F (16.7^{o}C) = 2.0416 in mercury at 62^{o}F (16.7^{o}C) = 51.8 mm mercury at 62^{o}F (16.7^{o}C) = 703.6 kg/m^{2}= 0.06895 atm = 2.307 Ft. H_{2}O

### Metric Units

The diagram is made for steam with pressure *7 bar*. For other pressures - multiply the pressure drop with 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 = 10*^{5}Pa (N/m^{2}) = 0.1 N/mm^{2}= 10,197 kp/m^{2}= 10.20 m H_{2}O = 0.9869 atm = 14.50 psi (lb_{f}/in^{2}) = 10^{6}dyn/cm^{2}= 750 mmHg