Formula Used
Barlow thin-wall equation: P = 2 × S × t / Do
Mean diameter equation: P = 2 × S × t / Dm
Lamé thick-wall equation: P = S × (b² - a²) / (b² + a²)
Here, P is burst pressure. S is adjusted material strength. t is effective wall thickness. Do is adjusted outside diameter. Dm is mean diameter. a is inner radius. b is outer radius.
How to Use This Calculator
- Select the unit system for your data.
- Enter tube outside diameter and nominal wall thickness.
- Enter copper tensile strength for the correct alloy and temper.
- Add corrosion allowance, tolerance loss, and ovality allowance.
- Set joint efficiency and temperature derating.
- Select a formula method and safety factor.
- Press Calculate to view results above the form.
- Use CSV or PDF buttons to export the calculation.
Example Data Table
| Example |
OD |
Wall |
Strength |
Derating |
Safety Factor |
Use Case |
| Small hard drawn tube |
0.625 in |
0.040 in |
45000 psi |
100% |
4 |
General screening |
| Annealed service tube |
22 mm |
1.0 mm |
220 MPa |
85% |
5 |
Heated service |
| Worn inspected tube |
1.125 in |
0.050 in |
30000 psi |
90% |
6 |
Conservative review |
Copper Tube Burst Pressure Guide
What Burst Pressure Means
Copper tube can carry high pressure, but the limit depends on geometry and material condition. Burst pressure is an estimated failure pressure. It is not the same as normal working pressure. This calculator uses tube diameter, wall thickness, strength, temperature derating, joint efficiency, corrosion allowance, and wall tolerance. These options help model real service conditions instead of a perfect new tube.
Why Wall Thickness Matters
Hoop stress rises as pressure tries to split the tube lengthwise. A thicker wall lowers that stress. A larger diameter raises it. Small changes in wall loss can strongly reduce the result. For that reason, the calculator subtracts corrosion allowance and manufacturing tolerance before solving pressure. It also lets you add ovality, because an out of round tube may have a weaker section.
Choosing a Formula
The Barlow method is common for thin wall tubing. It works best when diameter is much larger than wall thickness. The Lamé option is useful when the tube behaves more like a thick cylinder. The calculator also reports the diameter to thickness ratio. Use that value to decide which model is more suitable. When in doubt, compare both outputs and apply a conservative safety factor.
Material and Temperature Effects
Copper strength changes with alloy, temper, work hardening, brazing, and heat exposure. Annealed tube is weaker than hard drawn tube. Temperature can further reduce allowable stress. Enter a derating factor below one hundred percent when the tube works hot. Joint efficiency also matters. Soldered, brazed, flared, or welded connections may fail before the straight tube wall.
Using Results Safely
The burst result is an estimate for analysis and comparison. The allowable pressure divides burst pressure by your selected safety factor. Real systems also need pressure cycling checks, code compliance, fittings review, valve ratings, installation quality, inspection history, and pressure relief devices. Do not use a calculated burst value as a direct operating limit. For critical systems, follow the applicable plumbing, refrigeration, gas, hydraulic, or process piping standard. Ask a qualified engineer to review the design before testing. Always hydrotest carefully behind protective barriers and release stored pressure slowly. Record assumptions clearly, so later audits can repeat the calculation. Keep units consistent. Save export files locally.
FAQs
What is copper tube burst pressure?
It is an estimated pressure where the tube wall may fail. It depends on diameter, wall thickness, strength, wall loss, and temperature conditions.
Is burst pressure the same as working pressure?
No. Working pressure must be much lower. It should include safety factors, code limits, fatigue checks, fittings, joints, valves, and service conditions.
Which formula should I choose?
Use Barlow for thin wall screening. Use Lamé when the diameter to thickness ratio is low or thick wall behavior may matter.
What strength value should I enter?
Enter the tensile strength for the exact copper alloy, temper, and condition. Annealed copper usually has lower strength than hard drawn copper.
Why include corrosion allowance?
Corrosion, erosion, and wear reduce effective wall thickness. Since pressure capacity depends strongly on wall thickness, even small loss matters.
What does joint efficiency mean?
Joint efficiency reduces strength for weaker seams, welds, brazed joints, soldered joints, or mechanical connections. Use one for seamless tube screening.
Can I use this for gas lines?
Use it only for preliminary engineering checks. Gas systems need code review, rated fittings, approved materials, pressure relief, inspection, and qualified design.
Why export CSV or PDF?
Exports help record assumptions, compare cases, document reviews, and share calculations with engineers, inspectors, or project teams.