Making Non-ASME Stamped Vessels Legal—and Safe—in the U.S.

In U.S. plants, the default assumption is simple: if it’s a pressure vessel, it was built and stamped to ASME Section VIII, Division 1. That’s what most state laws require, and it’s the baseline most owner/operators work from. When equipment is not U-stamped, you’re typically looking at an exception process—often called a “State Special”—to secure installation or continued operation.

This post distills a recent conference paper into a field-ready playbook. We’ll unpack the regulatory context, then walk through two case studies: (1) importing CE-marked (PED) vessels and (2) securing approval for an older, non-code flare drum that now sees higher pressure. Along the way you’ll see what evidence actually convinces a state board and chief inspector, and how to set yourself up for a smoother approval.