The Title Block Revision Block
Every structural steel shop drawing should have a revision block in the title block area showing: revision letter (A, B, C), date of revision, brief description of what changed, and initials of the person who made the revision. The current revision is the highest letter in the revision block. If a drawing in a binder shows Rev A in the title block and the revision register shows the current issue is Rev B, the drawing in the binder is superseded.
The Revision Register — Your Ground Truth
The revision register is the authoritative document that lists every drawing, its current revision, the date that revision was issued, and all prior revisions with their dates. Before fabricating any member, the shop should check the revision register to confirm the drawing in hand matches the current registered revision. A drawing register that is updated in real time — not weekly — is the only reliable system.
Digital Drawing Management for Revision Control
Digital drawing management systems (Procore, e-Builder, Aconex, or even a controlled SharePoint folder) solve many revision control problems by making it impossible to access a superseded revision without a specific override action. The current revision is the only active file; prior revisions are archived with a clear superseded flag. When all project parties — fabricator, detailer, GC, EOR — work from the same digital system, the 'which revision?' question becomes answerable in seconds.
Physical Distribution Controls on the Shop Floor
Digital systems protect the drawing file server; physical controls protect the shop floor. Every drawing binder and workstation print should be stamped with the issue date and revision letter in a color that stands out from the drawing linework — red is standard. When a new revision is issued, the distribution protocol must physically collect all copies of the prior revision from every location where it was in use: the layout table, the CNC machine operator's station, the fitting floor, and the welding bay. Collecting and marking old revisions 'SUPERSEDED — VOID' before distributing new ones is the only reliable physical control.
How Revision Letters and Numbers Are Assigned
Industry convention uses sequential uppercase letters for shop drawing revisions — the original issue is often Rev 0 or the drawing is simply issued without a revision designation, with the first revision being Rev A. Some firms use numeric revisions (Rev 1, Rev 2); others use a combination system where letters indicate major revisions and numbers indicate minor clouds. Whichever system is used, it must be consistent across the entire project drawing set. Mixed systems — some drawings using letters, others using numbers — are a setup for confusion. The AISC Code of Standard Practice does not mandate a specific revision designation system but requires that revisions be clearly identified.
Revision Clouds as a Navigation Tool
Revision clouds — the curved lines that surround changed areas on a revised drawing — are not just a documentation requirement; they are a navigation tool. When a new revision arrives on a drawing the shop has already seen, the cloud tells the shop floor precisely what changed without requiring a full re-read of the drawing. Clouds should be accurate — surrounding only the area that actually changed — and the revision triangle or delta symbol at the cloud should match the revision letter in the title block. A drawing with clouds from three different revisions still visible tells the reader the history of changes, but the most recent revision's clouds are the only ones that matter for the current production decision.
Confirming Revision Status Before Cutting or Drilling
The practical implementation of revision control is a two-step check before any production operation begins: first, verify the revision letter on the drawing in hand against the revision register; second, verify that the CNC file loaded on the machine carries the same revision identifier as the drawing. AISC standard practice holds the fabricator responsible for using the current approved revision — not the EOR or the detailer. A fabricator who cuts from a superseded drawing owns the rework cost unless they can demonstrate that the new revision was not properly communicated through the agreed distribution channel.
EOR Approval Status and Revision Coordination
Revision control cannot be separated from approval status. A revised drawing that has not been through EOR approval and received an 'Approved' or 'Approved as Noted' stamp is not yet authorized for fabrication — even if it is the most current revision in the register. The revision register should track not just the current revision letter, but also the approval status of that revision. Only drawings showing both the highest revision letter and an approved stamp should be released to the production floor. Projects that track these two dimensions simultaneously — revision currency and approval status — have the fewest superseded-drawing incidents.