What is AISC 303 and why does it matter for welding procedure submittals?

AISC 303 is the Code of Standard Practice for Steel Buildings and Bridges, published by the American Institute of Steel Construction. It defines the standard business and contractual practices for structural steel fabrication and erection — including what submittals fabricators must provide, when, and in what form. When a project specification says structural steel shall conform to AISC 303, the shop's WPS submittal obligations are partly governed by that document alongside the welding code (AWS D1.1).

Does AWS D1.1:2025 require WPS approval from the engineer of record before welding starts?

AWS D1.1:2025 itself does not explicitly require EOR approval of WPS before welding begins — it requires that qualified WPS exist and be available. However, project specifications routinely add that requirement contractually. Language like 'no welding shall commence until WPS are reviewed and accepted by the engineer' is a contract condition, not a code condition. The distinction matters for scheduling: AWS D1.1 compliance alone does not guarantee a contract is satisfied.

How long should a fab shop allow for EOR review of WPS submittals?

AISC 303 addresses submittal review periods: the engineer is expected to return submittals within the time allowed by the contract, and the fabricator must allow adequate time before the scheduled start of fabrication. Most project specifications set a 14 to 21 business day review period for technical submittals like WPS. Shops should submit WPS packages as early as possible — ideally before shop drawings — to prevent welding from being delayed while waiting for EOR approval.

If an EOR stamps a WPS submittal as 'approved,' does that transfer qualification responsibility to the engineer?

No. AWS D1.1:2025 places qualification responsibility with the fabricator. EOR review and approval of a WPS submittal is typically a contract compliance check, not an independent qualification assessment. Most engineers include language such as 'review for general conformance only' on approval stamps. The fabricator remains responsible for using qualified procedures and for the correctness of the WPS contents.

AISC 303 and Structural Welding Submittals: What Fab Shops Must Know

AISC 303 Code of Standard Practice governs how structural steel contracts define WPS submittals and approval. Here is how it interacts with AWS D1.1:2025 for fab shops.

When a new structural project comes in and the project manager asks "when can we start welding?" the answer is not just "when the WPS is qualified." It is also "when the WPS submittal has been reviewed and returned by the engineer of record, if the contract requires that." Understanding what drives that review — and what AISC 303 says about it — keeps shops from scheduling conflicts that delay fabrication starts.

AWS D1.1:2025 is the welding code. AISC 303 is the contracting framework. Both are in play on most commercial structural steel projects, and they address different things. Knowing where one ends and the other begins prevents both missed submittal obligations and unnecessary hold-ups.

Rule library based on AWS D1.1:2025; verify against your governing edition.

What AISC 303 covers

The AISC Code of Standard Practice (AISC 303) establishes the standard customs and practices of the structural steel industry — what fabricators and erectors do by default when contracts are silent on a particular point, and what the parties' respective obligations are across the project lifecycle.

Section 4 of AISC 303 addresses submittals, defining the fabricator's obligation to submit shop drawings, erection drawings, and other required documents for review. While AISC 303 does not enumerate WPS as a specific submittal type the way it does shop drawings, project specifications that invoke AISC 303 frequently list WPS submittals in the submittal schedule.

Section 6 covers fabrication. AISC 303 requires that fabrication be performed in accordance with the contract documents, including applicable welding codes. The practical effect is that AISC 303 tells the parties how the contract runs; AWS D1.1 tells the welder how the weld is made.

For AISC 360-governed projects, the structural specifications often include a section on quality assurance that directly references both AISC 303 and AWS D1.1. See AISC 360 structural weld QC and AWS D1.1 for how the two documents overlap on quality program requirements.

The submittal obligation

On most commercial structural steel projects, the contract specification includes a submittal schedule — a list of documents the fabricator must submit, to whom, and when. WPS submittals appear on this list with their own action code (typically "review required" or "approval required") and a required submission date relative to the start of fabrication.

Required versus informational submittals: Some specifications treat WPS submittals as informational only — submit and proceed. Others require explicit engineer acceptance before welding begins. The distinction has scheduling consequences. A shop that submits WPS the day before planned arc strike and the contract requires EOR approval before welding has a problem.

What goes in the WPS submittal: A complete WPS submittal package typically includes:

All WPS documents to be used on the project, including prequalified WPS and tested WPS
PQR summaries for tested WPS (some engineers require the full PQR; others accept a WPS that cites the PQR number)
A WPS index cross-referencing weld types, positions, and member categories to WPS numbers
Welder qualification summary table for key welders, or a statement that WPQ records will be available on request

Prequalified WPS: Fabricators sometimes assume that prequalified WPS under AWS D1.1:2025 Clause 5 do not require submittal because they are inherently code-compliant. This is incorrect. Prequalified WPS still require documentation, still require a CWI signature, and still appear on the submittal schedule. They are "prequalified" in the sense that they do not require a test coupon and PQR — they are not exempt from contract submittal requirements.

What the EOR review covers

When an engineer stamps a WPS submittal, the scope of that review depends on what the contract requires and what the engineer chooses to do. In practice, structural engineers reviewing WPS submittals are checking:

Code compliance on face value: Does the WPS identify a process, base metal group, filler metal, position, and preheat range? Is it signed and dated? Does it appear to follow the format required by AWS D1.1?

Project applicability: Are the base metals on the submittal consistent with the materials specified on the structural drawings? Do the processes and positions match what the shop drawings show?

CVN requirements: If the contract specifies supplementary essential variables (CVN toughness requirements for demand-critical welds or low-temperature service), has the WPS addressed them? See CVN supplementary essential variables under AWS D1.1:2025 Table 6.8.

What the EOR review does not cover: Most structural engineers do not have the welding expertise or the time to independently verify that a tested WPS is properly supported by its PQR, that the preheat values are correct for the specific carbon equivalent of the specified steel, or that the essential variables in Table 6.6 are fully addressed. The fabricator cannot rely on an EOR approval stamp as confirmation that the WPS is technically correct — that responsibility stays with the CWI and QC manager.

Approval stamps and their limits

Project specifications typically define what each approval action code means. Common language:

"Approved" or "No exceptions taken": The document may be used as submitted. This does not mean the engineer has independently verified technical correctness.

"Approved as noted": Revisions are required. The WPS must be corrected and resubmitted before use, or specific noted corrections must be incorporated.

"Revise and resubmit": Substantive problems were identified. Welding may not start under this WPS until resubmission and re-review.

"Reviewed for general conformance only": A common protective notation engineers add to minimize implied liability. The submittal was checked for consistency with contract documents, not independently verified for code compliance in detail.

When a WPS comes back "revise and resubmit," the shop QC manager needs to understand why — not just mark it up and resubmit. Common EOR rejection reasons:

Process or base metal not matching the project specification
Preheat insufficient for the specified steel grade and thickness per Table 6.6 essential variables
CVN requirements not addressed when demand-critical welds are specified
WPS signed by an unidentified authority rather than a CWI
Tested WPS submitted without any reference to the supporting PQR

Structuring the submittal to avoid resubmittals

The goal is a first-pass acceptance. Resubmittals delay fabrication and erode schedule float.

Lead with a cover letter and WPS index: A one-page index that maps each WPS to the weld types it covers (e.g., "WPS-001: SMAW, Fillet, Horizontal, A36/A572, E7018, Preheat 50°F minimum") lets the reviewing engineer quickly confirm coverage without reading each WPS in full.

Attach PQR summaries for tested WPS: Even if the specification only requires the WPS, including a PQR cover sheet that shows the test results — tensile, bend, CVN if required — reduces the chance of a "not approved — basis of qualification unclear" return.

Address the project-specific requirements explicitly: If the specification requires that all WPS address the hydrogen control requirements of AWS D1.1:2025 (low-hydrogen electrode storage and conditioning procedures), add a note to the WPS or a project-specific addendum rather than leaving it for the EOR to look up. See electrode hydrogen designation and conditioning requirements for background.

Submit early: Submit WPS with or immediately after shop drawings. The review clock starts when the submittal arrives in the engineer's office. Submitting WPS the week fabrication is supposed to start all but guarantees a delay.

Common contractual traps

"No welding before WPS approval" and the submittal clock: If the specification requires WPS approval before welding and the engineer has a 21-business-day review period, the shop's effective welding start date is at least 21 business days after WPS submittal — often longer if the first submittal is returned for revision. Pre-bid schedule planning must account for this.

Multiple submittals for multiple weld categories: A project with demand-critical seismic welds, standard structural welds, and stainless steel connection welds under AWS D1.6 may require separate WPS submittals for each category, each on its own review cycle. Treating them as one package often results in the standard structural WPS being held while the seismic package is reviewed.

Subcontractor WPS: If a welding subcontractor is performing field welding, their WPS may require separate submittal in the prime contractor's name or with prime contractor endorsement. Contracts often require the prime to vouch for the sub's qualifications. See subcontractor WPS acceptance requirements under AWS D1.1.

Connecting to the audit-ready WPS library

A shop with a maintained WPS library — indexed, current, with PQRs filed against each tested WPS — can generate a project-specific WPS submittal package in hours rather than days. The welding procedure library at /pricing is structured for exactly this: a centralized library of WPS records that can be filtered, packaged, and exported by project.

Projects where WPS submittals arrive late, come back for revision, and delay arc strike are almost always shops that are assembling their WPS documentation from scratch for each project rather than maintaining a standing library. The cost of the library is paid back on the first project where it keeps fabrication on schedule.