# 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 10^{6}q^{2}l (1 + 91.4/d) / ρ d^{5 }(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/m^{3})

The Unwin formula can also be expressed in imperial units as

dp = 0.0001306 q^{2}l (1 + 3.6/d) / (3600 ρ d^{5})^{ }(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/ft^{3})

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/m ^{3}* 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 10^{6}(4000 kg/h)^{2}(100 m) (1 + 91.4/(102 mm)) / ((5.15 kg/m^{3}) (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/m*^{2}= 10.20 m H_{2}O = 0.9869 atm = 14.50 psi (lb_{f}/in^{2})*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

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### 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.