Steam Pipes - Online Pressure drop Calculator
The pressure drop in a saturated steam distribution pipe line can be calculated in metric units as
dp = 0.6753 106 q2 l (1 + 91.4/d) / ρ d5 (1)
where
dp = pressure drop (Pa)
q = steam flow rate (kg/h)
l = length of pipe (m)
d = pipe inside diameter (mm)
ρ = steam density (kg/m3)
The Unwin formula can also be expressed in imperial units as
dp = 0.0001306 q2 l (1 + 3.6/d) / (3600 ρ d5) (2)
where
dp = pressure drop (psi)
q = steam flow rate (lb/hr)
l = length of pipe (ft)
d = pipe inside diameter (inches)
ρ = steam density (lb/ft3)
Use values for the specific volume corresponding to the average pressure if the pressure drop exceeds 10 - 15 % of the initial absolute pressure.
Note that for elevated velocities the Unwin's formula is known to give pressure drops higher than the actual.
Example - Pressure Drop in a Steam Pipe
A steam flow 4000 kg/h with pressure 10 bar (1000 kPa) and density 5.15 kg/m3 flows through a schedule 40 ND 100 steel pipe with inside diameter 102 mm and length 100 m. The pressure drop can be calculated as
dp = 0.6753 106 (4000 kg/h)2 (100 m) (1 + 91.4/(102 mm)) / ((5.15 kg/m3) (102 mm)5 )
= 36030 Pa
= 36 kPa
Steam Pressure Drop Calculator - Metric Units
Steam Pressure Drop Calculator - Imperial Units
Pressure Drop Diagrams - metric units
The diagrams below can be used to indicate pressure drop in steam pipes at different pressures. The calculations are made for schedule 40 pipe.
- 1 bar = 100 kPa = 10,197 kp/m2 = 10.20 m H2O = 0.9869 atm = 14.50 psi (lbf/in2)
- 1 kg/h = 2.778x10-4 kg/s = 3.67x10-2 lb/min
Steam - pressure 1 bar gauge
Steam - pressure 3 bar gauge
Steam - pressure 7 bar gauge
Steam - pressure 10 bar gauge
Related Topics
• Pipe Sizing
Sizing of steam and condensate pipe lines - pressure loss, recommended velocity, capacity and more.
• Steam and Condensate
Steam & condensate systems- properties, capacities, pipe sizing, systems configuration and more.
Related Documents
ASME/ANSI B36.10/19 - Carbon, Alloy and Stainless Steel Pipes - Dimensions - Metric Units
Pipe sizes, inside and outside diameters, wall thickness, schedules, weight and weight of pipe filled with water - Metric Units.
Pressure
Introduction to pressure - online pressure units converter.
Properties of Saturated Steam - SI Units
Saturated Steam Table with steam properties as specific volume, density, specific enthalpy and specific entropy.
Recommended Velocities in Steam Systems
The steam velocity in a steam distribution system should be within certain limits to avoid excessive wear and tear
Saturated Steam - Properties - Imperial Units
Steam table with sensible, latent and total heat, and specific volume at different gauge pressures and temperatures.
Saturated Steam - Properties for Pressure in Bar
Saturated Steam Table with properties like boiling point, specific volume, density, specific enthalpy, specific heat and latent heat of vaporization.
Sizing Steam Pipes (kg/h)
Steam is a compressible gas where pipe line mass flow capacity depends on steam pressure.
Sizing Steam Pipes (lb/h)
Steam is a compressible gas where the capacity of a pipe line depends on the size of the pipe and the steam pressure.
Steam & Condensate Equations
Steam consumption and condensate generation when heating liquid or gas flows
Steam Flow - Orifices
Steam flow through orifices - for steam pressures ranging 2 - 300 psi
Steam Flow Rate vs. Pressure Drop - Schedule 40 Pipe
Flow rate (lb/h) and pressure drop per 100 feet of pipe.
Steam Heating Systems - Design
An introduction to the basic design of steam heating systems.
Steam Pipes - Max. Flow and Pressure Drop
Pressure drop and maximum allowable flow in steam pipes.
Steam Pipes - Pressure Drop vs. Steam Flow
Steam pipes and pressure drop diagrams - imperial and metric units.
Steam Pipes - Sizing
Sizing of steam pipe lines - major and minor loss in steam distribution systems.