Pressure Vessel Calculator - ASME VIII Div 1 Thickness & MAWP Design
Calculate minimum required wall thickness & Maximum Allowable Working Pressure (MAWP) for cylindrical & spherical vessels per ASME Sec VIII Div 1 (UG-27).
Design Parameters
psi
in
°F
psi
in
Enter design parameters to calculate
Design and evaluate pressure vessels according to <strong>ASME Boiler and Pressure Vessel Code (BPVC) Section VIII, Division 1</strong>. This calculator helps engineers and designers determine the minimum required wall thickness for cylindrical and spherical shells under internal pressure, or calculate the Maximum Allowable Working Pressure (MAWP) for existing vessels. It implements the standard UG-27 formulas, accounting for joint efficiency, material allowable stress, and corrosion allowance.
How to Use Pressure Vessel Calculator
Calculate Minimum Wall Thickness
Determine the required shell thickness for a new vessel design.
1. Select Vessel Type
Choose between 'Cylindrical Shell' or 'Spherical Shell' based on your vessel geometry.
2. Enter Design Parameters
Input the Design Pressure (P) and Internal Radius (R). You can toggle between Radius and Diameter input modes.
3. Select Material & Stress
Choose a standard material (e.g., SA-516 Gr. 70) and enter the Design Temperature to automatically look up the Allowable Stress (S). Alternatively, enter a custom stress value.
4. Define Efficiency & Corrosion
Select the Joint Efficiency (E) based on radiography level (1.0 for Full, 0.85 for Spot, 0.7 for None) and specify the Corrosion Allowance (CA).
Calculate MAWP (Rating)
Determine the maximum safe pressure for an existing vessel.
1. Switch Mode
Change the 'Calculation Mode' to 'Calculate MAWP'.
2. Input Actual Thickness
Enter the measured or nominal thickness of the vessel wall in the 'Actual Thickness' field.
3. Review Results
The calculator will determine the MAWP based on the limiting stress (circumferential or longitudinal) after deducting corrosion allowance.
Calculator Features
ASME VIII Div 1 Compliant
Implements official UG-27 formulas for internal pressure design.
Dual Unit Support
Seamlessly switch between Imperial (psi, inches, °F) and Metric (MPa, mm, °C) units.
Material Library
Built-in allowable stress data for common pressure vessel steels with temperature interpolation.
Smart Validation
Automatic checks for thin-wall applicability limits and pressure ratios.
Complete Function List
- Cylindrical and Spherical shell support:
- Minimum Wall Thickness calculation:
- Maximum Allowable Working Pressure (MAWP) calculation:
- Automatic stress lookup for SA-516 Gr.70, SA-240 304, SA-516 Gr.60:
- Corrosion allowance consideration:
- Joint efficiency selection guide:
- Recommended standard plate thickness recommendations:
- Detailed breakdown of circumferential vs longitudinal stress results:
Common Calculations & Examples
Example 1: Cylindrical Shell Thickness Design
Problem: Calculate the required thickness for a drum operating at 300 psi with a 24-inch internal radius.
Steps:
- Select 'Cylindrical Shell' and 'Wall Thickness' mode.
- Enter Pressure (P) = 300 psi and Radius (R) = 24 inches.
- Select Material 'SA-516 Gr. 70' at 400°F (Allowable Stress S = 20,000 psi).
- Set Joint Efficiency (E) = 0.85 (Spot Radiography) and Corrosion Allowance (CA) = 0.125 inches.
Explanation: The calculator applies UG-27(c)(1) formulas. The circumferential stress governs the design, requiring 0.428" + 0.125" corrosion allowance. The result exceeds the longitudinal requirement of 0.336".
Example 2: Spherical Vessel MAWP Rating
Problem: Determine the maximum pressure for a sphere with 0.625" wall thickness and 36" radius.
Steps:
- Select 'Spherical Shell' and 'Calculate MAWP' mode.
- Enter Actual Thickness = 0.625 inches and Radius = 36 inches.
- Use Stress S = 20,000 psi and Efficiency E = 0.85.
- Set Corrosion Allowance = 0.0625 inches.
Explanation: First, the net thickness is calculated (0.625 - 0.0625 = 0.5625"). Applying the spherical MAWP formula P = 2SEt/(R + 0.2t) yields 469.6 psi.