# 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.

## 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.

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

$$\large{ v = \frac { 1.25 \; Q }{ A_c } }$$     (Velocity)

$$\large{ A_c = \frac { \pi \; d^2 }{ 4 } }$$     (Area Cross-section)

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

Symbol English Metric
$$\large{ d }$$ = ID of the pipe $$\large{in}$$ $$\large{mm}$$
$$\large{ v }$$ = velocity of condensate in the pipe $$\large{\frac{ft}{sec}}$$ $$\large{\frac{m}{s}}$$
$$\large{ Q }$$ = flow rate of the condensate $$\large{\frac{ft^3}{sec}}$$ $$\large{\frac{m^3}{s}}$$
$$\large{ \pi }$$ = Pi $$\large{3.141 592 653 ...}$$
$$\large{ v_{combined} }$$ = combined velocity and area $$\large{\frac{ft}{sec}}$$ $$\large{\frac{m}{s}}$$
$$\large{ A_c }$$ = area cross-section of the pipe $$\large{in^2}$$ $$\large{mm^2}$$

To use this formula, you need to know the condensate flow rate and the desired Keep 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.

## 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.

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

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

$$\large{ v_{adjusted} = v_{slope} \; \left( 1 + \frac{ L_{eq} }{ L_{pipe} } \right) }$$     (Adjustment Velocity for Fittings and Valves)

Symbol English Metric
$$\large{ d }$$ = ID of the pipe $$\large{in}$$ $$\large{mm}$$
$$\large{ Q }$$ = flow rate of the condensate $$\large{\frac{ft^3}{sec}}$$ $$\large{\frac{m^3}{s}}$$
$$\large{ \pi }$$ = Pi $$\large{3.141 592 653 ...}$$
$$\large{ v_{adjusted} }$$ = final adjusted velocity $$\large{\frac{ft}{sec}}$$ $$\large{\frac{m}{s}}$$
$$\large{ v_{slope} }$$ = velocity adjusted for slope $$\large{\frac{ft}{sec}}$$ $$\large{\frac{m}{s}}$$
$$\large{ v }$$ = velocity of condensate in the pipe $$\large{\frac{ft}{sec}}$$ $$\large{\frac{m}{s}}$$
$$\large{ \theta }$$ = angle of slope $$\large{deg}$$ $$\large{rad}$$
$$\large{ L_{eq} }$$ = equivalent length of fittings and valves $$\large{ft}$$ $$\large{m}$$
$$\large{ L_{pipe} }$$ = equivalent length of pipe $$\large{ft}$$ $$\large{m}$$