Formulas

Metric Conversions

American
Pounds per square inch (psig)
Pounds per square inch (psig)
Pounds per square inch (psig)
Gallons per minute (GPM)
Gallons per minute (GPM)
Degrees Fahrenheit (ºF)
Inches Mercury at 60°F
Inches (")
Inch pounds (in•lbs)
Foot pounds (ft•lbs)
Cv

 

 

Metric
Kilograms per contimeter squared (kg/cm2)
Kilopascals (kPa)
Bar
L/min.
Cubic centimeters per minute (cc)
Degrees Centigrade (°C)
Millibar (mbar)
Millimeters (mm)
Newton meterse (N•m)
Newton meterse (N•m)
Kv

 

 

Conversion Formula
psig x 0.0703 = kg/cm2
psig x 6.895 = kPa
psig x 0.069 = bar
GPM x 3.79 = L/min.
GPM x 3785 = cc/min.
5/9 (°F -32) = °C
" Hg x 33.8 = mbar
" x 25.4 = mm
in•lbs x 0.113 = N•m
ft•lbs x 1.356 = N•m
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)