Pressure Drop Calculation

PRESSURE DROP - COMPONENTS
PRESSURE DROP - METRIC UNITS PRESSURE DROP - IMPERIAL UNITS
Ball Valve No. of Ball Valve Pipe Length, L            
L - pipe length (m)
Pipe Length, L            
L - pipe length (feet)
Elbow No. of Elbow         Pipe Dia, D                   
d - inside diameter pipe (mm)
Pipe Dia, D                   
d - inside diameter pipe (inches)
Equal Tee No. of Equal Tee Free Air Flow Rate     
q - air volume flow at atmospheric conditions (FAD) (m3/min)
Free Air Flow Rate     
q - air volume flow at atmospheric conditions (FAD) (cfm)
Reducers Droplet No. of Reducers Pipeline Pressure     
p - initial abs. pressure (kg/cm2)
Pipeline Pressure     
p - initial abs. pressure (psi)
Total (psi) =           Total Pressure Drop(kg/cm2) = Total Pressure Drop(psi)=

Total (kg/cm2) =
Total Pressure Drop(kg/cm2) =
through Components
Total Pressure Drop(psi)=
through Components
   
   
   
Pressure drop in compressed air pipe line fittings can be expressed as equivalent length in meters of pipe line.
Equivalent Pipe Length (m)

Fitting
Nominal Pipe Size (mm)
15 20 25 32 40 50 65 80 100
Ball valve
0.175 0.28 0.35 0.455 0.56 0.7 0.98 1.26 1.68
90o elbow
0.25 0.4 0.5 0.65 0.8 1.0 1.4 1.8 2.4
Tee - run
0.2 0.3 0.4 0.5 0.7 0.85 1.1 1.3 1.6
Reducers Droplet
0.625 1 1.25 1.625 2 2.5 3.5 4.5 6
Example - Compressed Air Pipe Line and Equivalent Length
A 900 bend equals to a 0.6 m 50 mm pipe line.
Equivalent Pipe Length (ft)

Fitting
Nominal Pipe Size (inches)
1/2" 3/4" 1" 1  1/4" 1  1/2" 2" 2  1/2" 3" 4"
Ball valve
0.56 0.91 1.19 1.47 1.82 2.31 3.22 4.13 5.53
90o elbow
0.8 1.3 1.7 2.1 2.6 3.3 4.6 5.9 7.9
Tee - run
0.7 1 1.3 1.7 2.3 2.8 4.4 4.3 5.3
Reducers Droplet
2 3.25 4.25 5.25 6.5 8.25 11.5 14.5 19.75