Formulas


Metric Conversions

America Metric Conversion Formula
Pounds per square inch (psig) Kilograms per centimeter squared (kg/cm2) psig x 0.0703 = kg/cm2
Pounds per square inch (psig)
Kilopascals (kPa) psig x 6.895 = kPa
Pounds per square inch (psig) Bar psig x 0.069 = bar
Gallons per minute (GPM) L/min. GPM x 3.79 = L/min.
Gallons per minute (GPM) Cubic centimeters per minute (cc) GPM x 3785 = cc/min.
Degrees Fahrenheit (°F) Degrees Celsius (°C) 5/9(°F-32) = °C
Inches Mercury at 60°F Millibar (mbar) "HG x 33.8 = mbar
Inches (") Millimeters (mm) " x 25.4 = mm
Inch pounds (in•lbs) Newton meters (N•m) in•lbs x 0.113 = N•m
Foot pounds (ft•lbs) Newton meters (N•m) ft•lbs x 1.356 = N•m
Cv Kv Cv x 14.28 = Kv

Cv Factor


"Cv" flow factor is the number of gallons of water that pass through a given orifice area in one minute at a pressure drop of one psig.

"Kv" flow factor is the number of liters of water that pass through a given orifice area in one minute at a pressure drop of one bar.

 

Flow Calculations

Basic Formula for System Designing

 

Flow Estimate

Q = 2.449 VD2

Where:
Q = gallons per minute
V = velocity, feet per second
D = inside diameter, inches

Pipe Diameter Estimate

Velocity Estimate

Pressure Loss Due to Friction

Hazen & Williams Formula

Where:
Q = gallons per minute,
fluid with specific gravity 1.0
C = velocity, feet per second
D = inside diameter, inches

Hazen & Williams calculator

Approximate Burst Pressure of Tubing or Pipe


BP = W x T
           ID

Where:
BP = burst pressure, psig
W = wall thickness, inches
T = tensile strength, psi
ID = inside diameter, inches

For additional application assistance contact Entegris.
 

Fitting Pressure Drop Calculation


Le = K x ID

K = configuration constant
ID = fitting inside diameter, feet
Le = equivalent tubing length

K values (same size ends)

90° Elbow                                      K = 30
45° Elbow and Sweep Elbow      K = 16
Tee (flow through run)                K = 20
Tee (flow through branch)          K = 60

Fitting pressure drop calculator
 

Material Tensile Strength


FEP = 3000 @ 23°C (73°F)
PFA = 3600 @ 23°C (73°F), 1800 @ 250°C (482°F)
Tefzel® = 6500 @ 23°C (73°F), 3000 @ 93°C (200°F), 1300 @ 149°C (300°F)