Piping Wall Thickness Calculation

Wall Thickness Formula:

\[ t = \frac{P \times D}{2 \times S \times E} \]

Internal Pressure (P):

Outer Diameter (D):

Allowable Stress (S):

Joint Efficiency (E):

Wall Thickness (t):

1. What is Piping Wall Thickness Calculation?

Definition: This calculator determines the minimum required wall thickness for pipes under internal pressure using the standard ASME B31.3 formula.

Purpose: It helps engineers and designers ensure pipes can safely withstand operating pressures while optimizing material usage.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ t = \frac{P \times D}{2 \times S \times E} \]

Where:

\( t \) — Minimum required wall thickness (meters)
\( P \) — Internal design pressure (Pascals)
\( D \) — Outside diameter of pipe (meters)
\( S \) — Allowable stress of material (Pascals)
\( E \) — Longitudinal joint efficiency (0-1)

Explanation: The formula calculates the thickness needed to resist the hoop stress caused by internal pressure.

3. Importance of Wall Thickness Calculation

Details: Proper wall thickness ensures pipe integrity under pressure while preventing over-engineering that increases material costs.

4. Using the Calculator

Tips: Enter the internal pressure, outer diameter, material allowable stress, and joint efficiency (default 0.85 for welded pipes). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What units should I use?
A: The calculator uses SI units - Pascals for pressure/stress and meters for dimensions. Convert from psi/inches if needed.

Q2: What's a typical joint efficiency value?
A: 1.0 for seamless pipes, 0.85 for welded pipes with radiography, 0.7 for welded pipes without radiography.

Q3: Does this include corrosion allowance?
A: No, you should add corrosion allowance to the calculated thickness based on service conditions.

Q4: What about temperature effects?
A: The allowable stress (S) should be selected for the design temperature from applicable codes.

Q5: Is this valid for all pipe materials?
A: The formula works for ductile materials. Special considerations apply for brittle materials or very high pressures.