Revision control is unglamorous and it is where a surprising number of expensive site problems begin. Somebody works from an old drawing, builds it, and the cost of correcting it dwarfs whatever the administration would have taken.
What a register needs to do
A drawing register answers three questions at any moment: what is the current revision of each drawing, who has it, and what changed. If your register cannot answer all three quickly, it is a list rather than a control system.
Numbering that survives
Choose a numbering system and hold it for the whole project. It should encode discipline, level or zone, and drawing type consistently. Numbers should not be reused when a drawing is superseded, and gaps are preferable to renumbering. Renumbering mid project is one of the reliably terrible decisions in documentation.
Revisions and status are different things
Revision tracks change: A, B, C or 1, 2, 3. Status tracks purpose: preliminary, for planning, for tender, for construction. A drawing can be revision C for tender and revision D for construction, and conflating the two causes real confusion. Both belong in the title block and in the register.
Cloud what changed, and describe it
Every revision should carry a cloud around the change and a description in the revision table specific enough to be useful. "Updated as per client comments" tells a contractor nothing. "Door D12 changed to 1200mm wide, corridor wall relocated 200mm north" tells them exactly where to look.
Remove clouds from previous revisions, or a mature drawing becomes unreadable.
Issue deliberately
- Record every issue: what, to whom, when, and in what status
- Issue complete sets rather than loose sheets where possible, since partial issues are where mismatches breed
- Make superseded drawings clearly superseded, and remove them from shared locations
- Keep one authoritative location for current drawings, not several
The common failure modes
Emailing individual sheets so nobody knows the full current set. Multiple folders where a current drawing sits beside three old ones. Revisions made without incrementing the revision. Two people editing the same file in parallel. Each of these is prevented by discipline rather than software, though software helps.
Keep the archive
Superseded drawings should be archived, not deleted. When a dispute arises about what was issued when, the archive and the issue record are the evidence. Keeping them costs almost nothing and occasionally saves a great deal.
None of this is complicated. It requires someone to own it and a habit of updating the register at the moment of issue rather than later, because later reliably becomes never.