Shop Drawings vs Approval Drawings: What Is the Difference?

“Shop drawing” is one of the most overloaded phrases in steel construction. Some specifications use it for every drawing the fabricator issues. Others mean only piece drawings. Approval drawings sit in the middle: they are issued so the engineer or owner can confirm that the fabricator understood the design before the shop is committed.

If you send piece drawings to a reviewer who wanted roof plans and typical details, the review will be slow and the comments will be the wrong kind. If you send only plans to a fitter, the shop cannot cut anything. The two deliverables have different readers.

This article separates the two sets, shows what usually belongs on each, and points to the steel approval drawing process for the submission sequence.

Approval drawings: confirm the story of the frame

An approval set should let a reviewer answer: Is this the right geometry? Are member sizes and grades consistent with the design? Are typical connections acceptable? Are bracing, crane beams and openings in the right place? The reviewer should not need to approve every clip angle to answer those questions.

• Cover sheet, drawing index and general notes
• Anchor-bolt / foundation plans if the fabricator is supplying that layout
• Roof and floor framing plans with marks and member sizes
• Key elevations and cross-sections
• Typical connection and bracing details
• Special details that affect design, such as moment splices or heavy base plates

Shop drawings: tell the shop how to make the piece

A shop drawing is read by a person standing at a saw, drill line, fitting table or CNC station. It needs cutting length, hole gauges, weld symbols, copes, finish and the piece mark that will be painted on the steel. It does not need a lecture on the wind load case.

Why teams mix the two

Software makes it easy to generate every part drawing on day one. That feels productive. It also dumps hundreds of sheets on a reviewer who cannot see the frame. The other failure mode is the reverse: a beautiful GA set with no path to fabrication data, so the shop invents missing hole locations.

A healthier split is: approval first on the sheets that change design risk, shop later from the same model. For PEB work, that approval package is highly standardised, which is why teams look at automating steel approval drawings.

Contract words to read twice

Before you argue about deliverables, read the specification definitions. Some owners require “shop drawings submitted for approval” and mean the GA package. Some require all piece drawings to be submitted. Some want electronic models. Your drawing list should quote that language so the team is not guessing.

A practical issue sequence

Issue approval plans and typicals. Collect comments. Update the model. Then generate shop drawings. If a late design change hits, decide whether it is an approval-level change (geometry, member size, typical) or a shop-only change (hole moved within a connection that was already approved).

A practical workflow

1. Read the specification definition of shop drawings and approval drawings.
2. Publish a drawing list that separates the two sets.
3. Issue the approval package with a transmittal and due date for comments.
4. Log comments and revise approval sheets.
5. Release shop drawings and fabrication data from the revised source files.
6. If a shop change affects strength or geometry, return it to approval, not only to the fitter.

Engineering tips

• Put the set type in the title block: APPROVAL or SHOP. Do not rely on file names.
• Keep typical details in the approval set even if they will later appear on shop sheets.
• Do not hide a design change on a shop drawing the reviewer will never see.

Common mistakes

Sending 400 part drawings for a first review

The reviewer will look at three of them and miss the bracing layout. Lead with plans.

Calling a design drawing a shop drawing

A design drawing does not have piece marks or hole gauges. The shop cannot fabricate from it without adding information that nobody approved.

Updating shop files but not the approval record

Then the as-built frame no longer matches the set the engineer stamped. That becomes a close-out problem.

Using one PDF for both audiences

A 90-page combined PDF is hard to review and hard to plot at the saw. Split the sets; cross-reference marks.

Checklist

• Title blocks identify APPROVAL vs SHOP
• Approval set can be reviewed without piece drawings
• Shop set can be fabricated without the design drawing open
• Marks are consistent across both sets
• Revision letters are independent but traceable
• Transmittal states which set is being issued
• Specification definitions quoted on the cover or notes

Frequently asked questions

Are erection drawings shop drawings or approval drawings?

They are usually part of the fabrication/erection package. Reviewers often want key erection plans in the approval set because they show bracing and sequencing that affect design. Piece-level erection notes stay with the shop/field set.

Can BIM replace approval drawings?

A model can support review, but most contracts still require stamped 2D sheets. If you review in a model, agree what will be issued as the record set.

Who approves shop drawings?

Often the fabricator’s own checker, plus any hold points the engineer set. Do not assume the engineer will review every piece drawing unless the contract says so.

Where does PEB approval fit?

PEB manufacturers typically issue a standardised approval package (plans, elevations, reactions, typicals) before production drawings. See the PEB approval drawing process.

Where this leaves the work

Keep the reader in mind. The reviewer needs the story of the frame. The shop needs the story of the piece. If a sheet tries to do both jobs, it usually does neither well.

When you are ready to structure the approval package itself, continue with what to include on a cover sheet and the submission checklist.