PISA Tubing Catalog

The working pressures of stainless steel tubing are calculated based on the methodology established in ASME B31.3 (Chemical Plant and Petroleum Refinery
Piping Standard).

The formula for calculating the working pressures of low thickness tubing (where the thickness e <D / 6) is the following:

P = 2Se / (D-2ye)

P = Recommended working pressure, with a 4: 1 safety factor
S = Allowable stress (lb.in2) according to ASME B31.1 (for 316 it is 80,000 psi, a value to which applied a 4: 1 safety factor gives a value of 20,000 psi).
D = Maximum outside diameter OD (in inches)
e = Minimum wall thickness (in inches)
y = Coefficient according to ASME B31.3 (Table 304.1.1, for 316 = 0.4 when e <D / 6).

The formula for calculating the working pressures of thick thick tubing (where the thickness e is equal to or greater than D / 6) is as follows:

P = 2Se / (D - 2e) ((D - 2e) / (2 (D - e))

P = Recommended working pressure, with a 4: 1 safety factor
D = Maximum outside diameter OD (in inches)
S = Allowable stress (lb.in2) according to ASME B31.1 (for 316 it is 80,000 psi, a value to which applied a 4: 1 safety factor gives a value of 20,000 psi).
e = Minimum wall thickness (in inches)

If you need more precise information for your tubing project, contact us so that one of our consulting engineers can help you with everything you may need so that you have the best result in your execution.