1. What is a Pipe External Pressure Calculator?

Definition: This calculator estimates the external pressure at which a pipe may collapse using the approximate formula for thin-walled pipes.

Purpose: It helps engineers determine the maximum external pressure a pipe can withstand before collapsing, important for underwater or buried pipelines.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( P_{ext} \) — External collapse pressure (Pascals)
• \( E \) — Modulus of elasticity (Pascals)
• \( t \) — Pipe wall thickness (meters)
• \( D \) — Pipe diameter (meters)
• \( \nu \) — Poisson's ratio (dimensionless)

Explanation: The formula calculates the approximate external pressure that would cause a thin-walled pipe to collapse, considering material properties and geometry.

3. Importance of External Pressure Calculation

Details: Proper calculation ensures pipeline integrity under external pressure from soil, water, or other environmental factors, preventing catastrophic failures.

4. Using the Calculator

Tips: Enter the modulus of elasticity, wall thickness, pipe diameter, and Poisson's ratio (default 0.3 for most metals). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical Poisson's ratio for pipes?
A: For most metals, ν ≈ 0.3. For plastics, it typically ranges from 0.35 to 0.45.

Q2: Is this formula valid for all pipe materials?
A: This is an approximate formula best suited for thin-walled pipes. Thick-walled pipes require more complex calculations.

Q3: What safety factors should be applied?
A: Engineering standards typically recommend safety factors of 1.5-2.0 for collapse pressure.

Q4: How does pipe ovality affect collapse pressure?
A: Ovality significantly reduces collapse pressure. This formula assumes perfectly round pipes.

Q5: What's the typical modulus for steel pipes?
A: For carbon steel, E ≈ 200 GPa (200 × 10⁹ Pa). Stainless steel is typically 190-200 GPa.