Deviation request (concession)

Specifications meet reality ahead of time too: a material unavailable in the specified grade, a vendor's standard design that differs from the datasheet, a tolerance the chosen method cannot hold. The deviation request (in some systems, concession or waiver) puts the departure on the table before it happens — describing the requirement, the proposed departure, the justification and the technical assessment — for the owner or designer to accept, reject or accept with conditions. Approved, it becomes a documented, bounded exception; the timing is the entire difference between asking and confessing.

Two disciplines keep the instrument honest. The first is scope: a concession applies to the case it describes — this batch, this unit, this once — and treating one as precedent quietly rewrites the specification without anyone deciding to. The second is the register: concessions accumulate, and their aggregate is a fact about the asset that the handover documentation must carry. A facility's real specification is the written one as amended by every concession granted along the way — which is only knowable if someone kept the list.