Pipe Thickness Calculation Formula

Pipe 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 the Pipe Thickness Calculation?

Definition: This calculator determines the minimum required wall thickness of a pipe based on internal pressure, diameter, material strength, and joint efficiency.

Purpose: It helps engineers and designers ensure pipe systems can safely contain internal pressures without failure.

2. How Does the Calculator Work?

The calculator uses the formula:

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

Where:

\( t \) — Required wall thickness (meters)
\( P \) — Internal pressure (Pascals)
\( D \) — Outer diameter (meters)
\( S \) — Allowable stress (Pascals)
\( E \) — Joint efficiency factor (0-1)

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

3. Importance of Pipe Thickness Calculation

Details: Proper thickness calculation ensures pipe safety, prevents ruptures, optimizes material usage, and complies with engineering standards.

4. Using the Calculator

Tips: Enter the internal pressure, outer diameter, allowable stress (typically 60-80% of yield strength), and joint efficiency (default 0.85 for welded joints). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is joint efficiency?
A: A factor (0-1) accounting for welded joint strength. 1.0 for seamless, 0.85 for welded with radiography, 0.7 for welded without radiography.

Q2: How do I determine allowable stress?
A: Consult material specifications or codes like ASME B31.3. Typically 60-80% of material yield strength at design temperature.

Q3: Does this include safety factors?
A: The allowable stress (S) typically includes safety factors. Additional factors may be needed for specific applications.

Q4: What about corrosion allowance?
A: This calculation gives minimum thickness. Add corrosion allowance (typically 1-3mm) to the calculated value.

Q5: Is this formula for thin or thick-walled pipes?
A: This is the Barlow formula for thin-walled pipes (D/t > 10). For thick-walled pipes, use Lame's equations.