On a steel project, the costly shop drawing mistakes are rarely found on the drawing. They are found on site, when the first column is lifted into place and the holding-down bolts are not where the steelwork expects them to be.
The shop drawing approval process exists to catch that mistake while it is still a line on a sheet. It is the structured exchange in which a detailer’s drawings are checked against the design intent, coordinated with other trades, and released for fabrication. This guide explains how it works on New Zealand steel projects, who reviews what, what approval does and does not mean, and how to keep it off the critical path.
Key Takeaways
- The shop drawing approval process checks a detailer’s drawings against the design intent and other trades’ work before any steel is cut, drilled, or welded.
- Approval is often limited to design concept and general arrangement, while the accuracy of dimensions and fabrication detail stays with the contractor and fabricator.
- The process is a loop of submission, review, comment, revision, and resubmission, and clear drawing registers, clouded revisions, and agreed status definitions keep it short.
- Shop drawings sit alongside the building consent, and any change to the consented design needs a minor variation or amendment before the work proceeds.
- Staged submissions, early holding-down bolt drawings, and model-based coordination are the most reliable ways to protect the programme.
What the Shop Drawing Approval Process Is For
Design drawings show what the building must achieve. Shop drawings show how each piece will be made and fitted, and what a set of shop drawings includes for steelwork typically runs to member marks, dimensions, connection details, weld and bolt specifications, and finishes.
The approval process is the checkpoint between those drawings and the workshop floor. It confirms that the detailer has read the design correctly, that the drawings reflect the requirements of every discipline involved, and that nothing is cut, drilled, or welded until the people accountable for the design have had a chance to object. On a well-specified steel package, that checkpoint is a formal hold point, which means fabrication cannot start until written approval is given.
What Approval Does and Does Not Cover
Approval is narrower than the word suggests. The model structural steelwork specification from Steel Construction New Zealand (SCNZ), written to align with AS/NZS 5131, limits the design engineer’s review to design concept and general arrangement and keeps the accuracy and adequacy of the shop drawings with the contractor. Contracts vary, so the review clause in your own specification is the one that counts.
AS/NZS 5131, the standard for structural steelwork fabrication and erection, treats shop detailing documentation as a defined requirement, covering its scope, its production, and its review. It does not say who does what. Those responsibilities are left to the contract documents, which is why “approved”, “reviewed”, and “accepted” can mean different things on different projects.
In practice, a review stamp is not a guarantee of dimensional accuracy. The detailer and fabricator still own their own checks, and proposed changes to the documented design need separate approval. The SCNZ specification asks for that before the shop drawings are submitted, rather than leaving a reviewer to spot a substitution buried in the drawings.
The Shop Drawing Approval Process, Step by Step
Names and responsibilities shift with the contract, but on New Zealand steel packages the sequence generally runs as follows:
- Confirm the design basis: collect the latest issued structural and architectural drawings, the specification, and answered requests for information (RFIs), and note the AS/NZS 5131 construction category and any exposed-steel requirements
- Agree the submission programme: decide which packages will be submitted, in what order, and how long each review will take
- Model and detail: build the 3D model, coordinate it with the other disciplines, and produce general arrangement drawings, marking plans, fabrication drawings, and connection details
- Check internally: verify member sizes and grades against the structural drawings, confirm weld and bolt information, resolve clashes, and cloud every change
- Submit with a transmittal: issue the package through the contractor, or directly to the engineer where the contract allows, with each drawing identified by number, revision, and status
- Review and comment: the engineer, architect, and contractor each check their own scope, and comments come back as one consolidated mark-up with a status
- Revise and resubmit: the detailer closes out every comment, clouds the changes, increments the revision, and resubmits until the drawings are accepted
- Release for fabrication: once written approval is given, the approved revision goes to the workshop and the register of approved revisions is kept for as-built and handover records
Steps 5 to 7 repeat until the drawings are accepted, and each extra cycle adds review time to the critical path. The aim is to settle questions in the model and in the first round of comments, not through repeated resubmission.
What Reviewers Check and Why Drawings Get Returned
Each reviewer checks the drawings against their own part of the design. The structural engineer looks at member sizes and grades, connection types against the documented details, weld and bolt requirements, holding-down bolt layouts, bracing, and anything flagged as a departure from the design. The architect looks at exposed steel, visible connections, finishes, and interfaces with cladding and linings. The contractor checks coordination with other trades, access, and the construction sequence.
Drawings are commonly returned for a short list of reasons:
- Drawings based on a superseded revision, or an RFI answer that was never incorporated
- Changes to the documented design that were not raised separately for approval
- Missing or inconsistent weld, bolt, coating, or camber information
- Holding-down bolt or base plate details that do not match the concrete setting-out
- Unresolved clashes with services, cladding supports, or adjacent structure
- Unclear revision control, such as unclouded changes or drawing numbers that were not maintained
Most of these are preventable before submission. A short internal checklist and a model-based clash check remove many of them before a reviewer ever sees the drawing.
Where the Process Meets Building Consent and Handover Records
Shop drawings are generally produced after building consent is granted and typically sit outside the consent documentation, but what is built must still match the consented design. If review turns up a change that departs from the consented plans, such as an alternative connection or a different member, it has to be raised with the building consent authority. A minor variation covers a change that does not deviate significantly from the consented plans and specifications; anything larger needs an amendment, and MBIE’s minor variations guidance explains where that line sits. Either approval should be in place before the affected steel is fabricated.
The same drawings support the later stages. The SCNZ specification asks fabricators for a data report at completion that, for higher construction categories, includes a drawing list with revision numbers, the shop drawings, and as-built drawings. A clean register of approved revisions is what makes that handover, and the sign-off that follows it, straightforward.
Keeping the Approval Process Off the Critical Path
Submit in Packages, in Construction Order
One large submission forces reviewers to treat the whole structure as a single decision and delays the first piece of steel. Splitting the work into fabrication shop drawing packages that follow the construction sequence lets early items be approved while later ones are still being detailed. Holding-down bolts and base plates usually go first, because cast-in bolts must be set and checked before the concrete is poured, followed by primary frames, secondary steel, bracing and connections, then stairs and handrails.
Coordinate in the Model Before Drawings Go Out
Many reviewer comments are coordination problems that a federated 3D model can surface earlier: a beam that clashes with a duct, a cleat that fouls a cladding support, or a connection that cannot be bolted because there is no access. AS/NZS 5131 recognises model-based delivery, listing preparation of a project BIM brief or BIM management plan, where required, among the responsibilities to be assigned, and the SCNZ specification states a preference for 3D models as a design and detailing deliverable.
Close Comments Cleanly
One consolidated set of comments, a drawing register showing current revisions, and agreed status definitions reduce much of the back-and-forth. Keep drawing numbers stable and respond to each comment by reference, so the reviewer can confirm closure without re-checking the whole drawing. Confirm any verbal or emailed approval in the register before the drawing is released to the workshop.
Frequently Asked Questions
How long does shop drawing review usually take?
The review period is set by the contract or specification, not by a fixed industry rule. The SCNZ specification, for example, allows two weeks for the design engineer’s review in its generic text, and projects adjust that to suit. Package size, the number of reviewers, and the completeness of the submission have the biggest effect, so confirm the review period in writing before programming fabrication.
Can fabrication start before shop drawings are approved?
In the SCNZ specification, shop drawings are a hold point before fabrication begins, and hold points are released in writing. Steel ordering has its own hold point, the steel source list, so material can sometimes be ordered earlier, but that is at the contractor’s and fabricator’s risk. Cutting and drilling should wait for written approval of the drawings, because that is where rework starts.
What do review statuses such as “approved with comments” mean?
Status wording varies between projects, so confirm what each one permits in the specification. As a general pattern, “approved” allows fabrication to proceed, “approved with comments” allows it once the comments are incorporated (sometimes with a resubmission for the record), “revise and resubmit” means fabrication must not start, and “rejected” means the drawing needs to be redone. Whichever scheme is used, record the status in the drawing register so the workshop only receives approved revisions.
Do stairs, balustrades, and other specialist items follow the same process?
Generally yes, because they interface with the main steel and affect fixings, tolerances, and finishes. Items designed by a specialist supplier typically also need their supporting design documentation submitted with the drawings, and the contract should say who reviews it. Where a specialist item connects to the primary structure, the engineer will want to see the loads it applies before approving the connection.
Treating Shop Drawing Approval as a Control Point, Not a Formality
The shop drawing approval process works when everyone understands what it is: a structured check that the detailer has read the design correctly, that the disciplines are coordinated, and that nothing is fabricated on an unresolved question. It does not replace the detailer’s and fabricator’s own checking, and it does not remove the need to keep the building consent in step with what is built. Projects that stage their submissions, coordinate in the model, and keep a clean register of approved revisions tend to spend less time in the review loop and less money on rework.
If you need shop drawings prepared for review and approval, with the 3D model coordination behind them, Citotech’s detailing team can produce fabrication-ready packages for your project. Reach out with your drawings and programme to talk through how the submissions should be staged.
