Pipe Sizing for Condensate

on . Posted in Fluid Dynamics

Sizing a condensate pipe involves selecting an appropriate diameter to ensure efficient and effective drainage of condensate from a steam system.  One commonly used formula for sizing condensate pipes is based on the velocity of the condensate flow.  The goal is to maintain an acceptable velocity to avoid issues such as pipe erosion and ensure proper drainage.

 

Step 1 -  pipe Sizing for Condensate

pipe sizing for Condensate formulas

The value 1.25 is a factor that takes into account the fact that condensate flow is typically intermittent, and a slightly higher velocity is acceptable.

\( d = \sqrt{  1.25 \; Q \;/\; ( \pi \; v_{combined} \;/\; 4 )   }  \)     (Pipe Sizing for Condensate)

\( v =  1.25 \; Q \;/\; A_c \)     (Velocity)

\( A_c =  \pi \; d^2 \;/\; 4 \)     (Area Cross-section)

\( v_{combined} =  1.25 \; Q \;/\; ( \pi \; d^2 \;/\; 4 )   \)     (Combined Velocity and Area)

Symbol English Metric
\( d \) = Pipe Inside Diameter \(in\) \(mm\)
\( v \) = Pipe Condensate Velocity \(ft \;/\; sec\) \(m \;/\; s\)
\( Q \) = Condensate Flow Rate \(ft^3 \;/\; sec\) \(m^3 \;/\; s\)
\( \pi \) = Pi \(3.141 592 653 ...\) \(3.141 592 653 ...\)
\( v_{combined} \) = Area Combined Velocity \(ft \;/\; sec\) \(m \;/\; s\)
\( A_c \) = Pipe Area Cross-section \(in^2\) \(mm^2\)

 

To use this formula, you need to know the condensate flow rate and the desired velocityKeep in mind that other factors, such as the slope of the pipe, fittings, and valves, can also influence the sizing of the condensate pipe.  Additionally, consulting relevant engineering codes, standards, and guidelines, or working with a qualified engineer, is essential to ensure that the condensate pipe is properly sized for the specific conditions and requirements of your steam system.

 

Step 2  -  Pipe Sizing for Condensate with adjustment for Slope, Fittings, and Valves

pipe sizing for Condensate with adjustment for Slope, Fittings, and Valves formulas

The value 1.25 is a factor that takes into account the fact that condensate flow is typically intermittent, and a slightly higher velocity is acceptable.

\( d = \sqrt{ 1.25 \; Q \;/\; ( \pi \; v_{adjusted} \;/\; 4  )  }  \)     (Pipe Sizing for Condensate with Adjustment)

\( v_{slope} = v \; sin (\theta)  \)     (Adjustment Velocity for Pipe Slope)

\( v_{adjusted} =  v_{slope} \; ( 1 + ( L_{eq} \;/\; L_{pipe} ) \;)  \)     (Adjustment Velocity for Fittings and Valves)

Symbol English Metric
\( d \) = Pipe Inside Diameter \(in\) \(mm\)
\( Q \) = Condensate Flow Rate \(ft^3 \;/\; sec\) \(m^3 \;/\; s\)
\( \pi \) = Pi \(3.141 592 653 ...\) \(3.141 592 653 ...\)
\( v_{adjusted} \) = Final Adjusted Velocity \(ft \;/\; sec\) \(m \;/\; s\)
\( v_{slope} \) = Slope Adjusted Velocity \(ft \;/\; sec\) \(m \;/\; s\)
\( v \) = Pipe Condensate Velocity \(ft \;/\; sec\) \(m \;/\; s\)
\( \theta \) = Slope Angle \(deg\) \(rad\)
\( L_{eq} \) = Fittings and Valves Equivalent Length \(ft\) \(m\)
\( L_{pipe} \) = Pipe Equivalent Length \(ft\) \(m\)

 

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Tags: Pipe Sizing Condensate