1. What is a Pipe Pressure Rating Calculator?

Definition: This calculator determines the maximum internal pressure a pipe can withstand using Barlow's formula.

Purpose: It helps engineers, plumbers, and pipeline designers ensure pipes are properly rated for their intended operating pressures.

2. How Does the Calculator Work?

The calculator uses Barlow's formula:

Where:

• \( P \) — Pressure rating (psi)
• \( S \) — Allowable stress (psi)
• \( t \) — Wall thickness (inches)
• \( D \) — Outside diameter (inches)

Explanation: The formula calculates the hoop stress in a thin-walled pipe under internal pressure.

3. Importance of Pressure Rating Calculation

Details: Proper pressure rating ensures pipeline safety, prevents failures, and helps select appropriate pipe materials for specific applications.

4. Using the Calculator

Tips: Enter the material's allowable stress, pipe wall thickness, and outside diameter. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is allowable stress (S)?
A: The maximum stress the pipe material can withstand, typically 50-80% of the material's yield strength for safety.

Q2: Does this work for all pipe materials?
A: Yes, but you must use the correct allowable stress value for your specific material (steel, PVC, copper, etc.).

Q3: What's the safety factor in this calculation?
A: The safety factor is built into the allowable stress value, which is typically less than the material's actual yield strength.

Q4: When is Barlow's formula not appropriate?
A: For very thick-walled pipes (D/t < 10) or under external pressure, more complex formulas are needed.

Q5: How do I find allowable stress values?
A: Consult material specifications or engineering standards like ASME B31 for common piping materials.