1. What is Pipe Stress Calculation?

The pipe stress calculation determines the hoop stress in a cylindrical pipe under internal pressure. This is crucial for ensuring the pipe can withstand operational pressures without failure.

2. How Does the Calculator Work?

The calculator uses the pipe stress equation:

Where:

• \( P \) — Internal pressure (psi)
• \( D \) — Pipe diameter (inches)
• \( t \) — Pipe wall thickness (inches)

Explanation: The equation calculates the circumferential (hoop) stress in thin-walled pressure vessels, which is the dominant stress for pipes under internal pressure.

3. Importance of Pipe Stress Calculation

Details: Proper stress calculation ensures pipe integrity, prevents failures, and helps in material selection and thickness determination for safe operation under design pressures.

4. Using the Calculator

Tips: Enter pressure in psi, diameter and thickness in inches. All values must be positive numbers. The calculator assumes thin-walled pipe theory (D/t > 20).

5. Frequently Asked Questions (FAQ)

Q1: What is the difference between hoop stress and longitudinal stress?
A: Hoop stress is twice the longitudinal stress in cylindrical pipes under internal pressure. This calculator computes hoop stress.

Q2: What are typical allowable stress values for steel pipes?
A: Varies by material grade, but common carbon steels might have allowable stresses around 15,000-20,000 psi at room temperature.

Q3: When is thick-walled pipe formula needed?
A: When diameter-to-thickness ratio (D/t) is less than 20, more complex thick-walled formulas (Lame's equations) should be used.

Q4: How does temperature affect pipe stress?
A: Higher temperatures typically reduce allowable stress values and may introduce thermal expansion stresses not accounted for in this calculator.

Q5: What safety factor should be used?
A: Depends on application, but common safety factors range from 2-4 for static pressure applications. Consult relevant codes (ASME B31.3, etc.).