Superseded standard

Standards die in two ways, and the difference matters. A superseded standard has a successor: the new edition or replacing document is now current, and the old one remains published for reference. A withdrawn standard has been removed without replacement — its subject no longer standardised, or absorbed elsewhere. Both remain applicable to what was built or contracted under them: a facility designed to the edition in force at the time is not made non-compliant by later editions, and in-service assessment is generally against the original basis unless law says otherwise.

The problems run in both directions. Forward: new submissions citing superseded editions — usually inherited from a copy-pasted specification or an unmaintained master document — which is among the most common findings in formal review, and among the most mechanical to make. Backward: automatic "always use the latest" updating in mid-project, which silently breaks a frozen design basis and can invalidate completed calculations. The discipline is the same in both cases: every citation carries an edition, and every edition decision is deliberate.