Allowable external pressure is obtained from which source?

Allowable external pressure is obtained from which source?

• A. UG-28
• B. ASME B31.3
• C. API 650
• D. Differential pressure tables

Answer: (A)

Allowable external pressure is determined by the ASME Code rules for unfired pressure vessels, specifically in UG-28. That section provides the criteria and formulas to prevent buckling when a shell is subjected to external pressure, taking into account geometry (outside diameter, wall thickness, radius of curvature, end support), material properties (modulus, yield), and any stiffening details. It’s the dedicated source for calculating how much external pressure a vessel can safely withstand. The other options don’t provide the governing method for this situation: B31.3 is the process piping code and doesn’t define external‑pressure buckling limits for vessels; API 650 covers welded tanks with its own set of rules; and differential pressure tables aren’t used to establish the allowable external pressure for vessel buckling.

Allowable external pressure is determined by the ASME Code rules for unfired pressure vessels, specifically in UG-28. That section provides the criteria and formulas to prevent buckling when a shell is subjected to external pressure, taking into account geometry (outside diameter, wall thickness, radius of curvature, end support), material properties (modulus, yield), and any stiffening details. It’s the dedicated source for calculating how much external pressure a vessel can safely withstand.

The other options don’t provide the governing method for this situation: B31.3 is the process piping code and doesn’t define external‑pressure buckling limits for vessels; API 650 covers welded tanks with its own set of rules; and differential pressure tables aren’t used to establish the allowable external pressure for vessel buckling.