If MAWP changes due to alteration, what action is required?

If MAWP changes due to alteration, what action is required?

• A. Repaint the vessel
• B. Re-stamp per NBIC
• C. Replace with a new vessel
• D. Recalculate but no stamping

Answer: (B)

When a vessel is altered in a way that changes its pressure-retaining capability, the official proof of what pressure it may safely operate at must be updated. The MAWP is the maximum pressure the vessel is stamped to withstand for a given temperature, and alterations can alter that value. Because of this, the vessel must be re-evaluated and re-stamped in accordance with NBIC to reflect the new MAWP and any other updated data on the nameplate. Repainting or replacing the vessel does not address the certification of its pressure-containing capability, and recalculating without updating the stamping leaves the official record inconsistent with the vessel's actual rating, which is not acceptable under code requirements.

When a vessel is altered in a way that changes its pressure-retaining capability, the official proof of what pressure it may safely operate at must be updated. The MAWP is the maximum pressure the vessel is stamped to withstand for a given temperature, and alterations can alter that value. Because of this, the vessel must be re-evaluated and re-stamped in accordance with NBIC to reflect the new MAWP and any other updated data on the nameplate. Repainting or replacing the vessel does not address the certification of its pressure-containing capability, and recalculating without updating the stamping leaves the official record inconsistent with the vessel's actual rating, which is not acceptable under code requirements.