Trunnion Ball Valve Body Wall Thickness

Shell wall thickness design for fixed-shaft ball valve body per ASME VIII-1 cylinder formula with 1.5x hydrotest pressure verification.

Open Calculator →

Core Formula:
t₁ = 1.5P_n · d₁ / (2S − 1.2P_n) + C
t₂ = 1.5P_n · d₂ / (2S − 1.2P_n) + C

Where:
• P_n = rated pressure (MPa), 1.5P_n = hydrotest pressure
• S = allowable stress = 2/3 σ_s (2/3 of yield strength)
• d₁ = bore diameter (flow passage), d₂ = body cavity ID
• C = corrosion allowance (mm)
• Actual t ≥ max(t₁, t₂) → PASS

Why This Calculator

ASME VIII-1 Formula

Classic thin-wall cylinder formula t = PR/(S-0.6P) adapted for valve body with proven reliability.

Dual-Section Check

Separate minimum thickness for flow passage bore d1 and body cavity diameter d2.

1.5x Hydrotest

Design pressure set to 1.5x rated pressure per standard hydrostatic test requirement.

Auto Pass/Fail

Instant judgment: actual wall thickness tBody vs. calculated minimum for both sections.

Corrosion Allowance

Built-in corrosion margin C ensures long-term service life under operating conditions.

Yield-Based S

Allowable stress S = 2/3 sigma_s directly from material yield strength per ASME VIII-1.

How It Works

Enter Parameters

Input rated pressure class, design pressure, material yield strength, bore and body diameters.

Compute Allowable Stress

S = 2/3 * sigma_s is calculated automatically from the yield strength input.

Calculate Minimum Thickness

t1 (bore) and t2 (body cavity) computed per ASME VIII-1 cylinder formula with 1.5Pn.

Verify Actual Thickness

Compare actual wall thickness tBody to both minimums; pass/fail displayed instantly.

Who Is It For

Valve Design Engineers | API/ASME Compliance Teams | Quality Inspectors | Manufacturing Engineers

Key Highlights

ASME VIII-11.5x HydrotestAuto JudgmentDual Section

Ready to Calculate?

Enter your design parameters and get instant verification results.

Open Calculator →