clause5.io/ Welding/ Code Minimum vs WPS

Code Requirements, Engineer Modifications, and the WPS

Under §1.7.1.1, code provisions using "shall" are mandatory unless specifically modified in contract documents by the Engineer. Start with the applicable code requirement, then identify any Engineer modification documented for the structure. The authority and documentation matter when deciding which requirements the WPS must meet.

Per §1.5.1, the Engineer is responsible for the development of the contract documents that govern products or structural assemblies produced under this code. The Engineer "may add to, delete from, or otherwise modify, the requirements of this code to meet the particular requirements of a specific structure." All such modifications must be incorporated into contract documents. This authority includes additions, deletions, and other modifications for the specific structure.

Per §1.5.2, the Contractor is responsible for WPSs, qualification of welding personnel, the Contractor's inspection, and performing work in conformance with the requirements of this code and contract documents. The "and" matters. A WPS that satisfies D1.1 but ignores a contract-document modification is non-compliant for the project, even if it would pass a code-only audit.

The WPS must reflect the applicable code requirements and the Engineer's modifications in contract documents. A stricter requirement may apply, but a blanket "stricter wins" rule would miss a documented deletion or other modification authorized by §1.5.1. The WPS itself does not authorize such a change.

When the Customer Says "D1.1 Prohibits…": Where Confusion Starts

The most common shop-floor dispute follows this pattern: a customer or owner's representative arrives on site, observes a welding practice (weave beads, a particular electrode, a non-standard sequence), and declares that D1.1 prohibits it. The Contractor disagrees because the WPS — properly written and qualified — explicitly allows it. Both parties dig in. The argument escalates.

Almost every time, the resolution lives in §1.7.1. The customer is misremembering a code term:

• If the provision uses "shall", it is mandatory unless the Engineer specifically modified it in contract documents.
• If the provision uses "should", it is recommended but not required, and the WPS may follow a different practice.
• If the provision uses "may", it is optional — the Contractor can use it freely unless the contract requires Engineer approval.

"D1.1 prohibits X" usually means one of three things in disguise: (1) the customer read a "shall not" without checking whether the contract modified it; (2) the customer read a "should" and inflated it to mandatory; or (3) the customer is citing a clause that does not actually exist in the edition the project was contracted under. The two-step lookup — which word, then which contract document — resolves the dispute in minutes.

What "Shall," "Should," and "May" Actually Mean

Per §1.7.1, three code terms carry the entire prescriptive force of D1.1:

This three-tier prescriptive force is the foundation of the entire code. Every dispute about whether D1.1 "requires" or "prohibits" a practice resolves to a "shall, should, or may" question first.

Per AWS D1.1:2025 §1.7.1.1: “Code provisions that use shall are mandatory unless specifically modified in contract documents by the Engineer.”

Who Has Authority to Modify D1.1: The Engineer's Role

Per §1.5.1, the Engineer is the only party authorized to modify code requirements, and only by incorporating modifications into contract documents. The clause is explicit about nine categories the Engineer shall specify in contract documents, as necessary, and as applicable:

1. Code requirements that are applicable only when specified by the Engineer.
2. All additional NDT that is not specifically addressed in the code.
3. Extent of verification inspection, when required.
4. Weld acceptance criteria other than that specified in Clause 8.
5. CVN toughness criteria for weld metal, base metal, and/or HAZ when required.
6. For tubular and nontubular applications, whether the structure is statically or cyclically loaded.
7. Which welded joints are loaded in tension.
8. All additional requirements that are not specifically addressed in the code.
9. For OEM applications, the responsibilities of the parties involved.

Per §1.6, all references to "approval" in D1.1 mean approval by the Authority Having Jurisdiction or the Engineer. Per §1.5.3.1, Contractor inspection is supplied by the Contractor and performed as necessary to ensure that materials and workmanship meet the requirements of the contract documents. Per §1.5.3.2, the Engineer determines whether verification inspection is performed; responsibilities are then established between the Engineer and the Verification Inspector.

The Contractor cannot unilaterally relax a code provision. The Inspector cannot grant exceptions. The Authority Having Jurisdiction can approve, but does not author, modifications. The single point of authority for "stricter than D1.1" is the Engineer, expressed in contract documents.

Five Common Sources of Stricter-Than-Code Requirements

When a project is stricter than D1.1, the additional requirements typically come from one of five places. Knowing where to look saves hours of dispute resolution.

The "customer says D1.1 prohibits" claim is most often a misread of a contract document requirement, not a code requirement. Verifying which source the restriction actually comes from is the fastest way to resolve the argument.

Worked Example: A Customer Dispute Resolved by the Hierarchy

Scenario. A fabricator is welding A572 Gr. 50 columns with E71T-1 FCAW per a prequalified WPS. The owner's third-party inspector observes weave bead technique on fill passes and stops the work, citing "D1.1 prohibits weaving." The Contractor's WPS specifies "stringer or weave permitted" and is signed and dated.

Resolution path. First, the Contractor checks §1.7.1 on weaving. D1.1:2025 does not contain a "shall not weave" provision in Clauses 5 or 7 for A572 Gr. 50 with FCAW within standard parameters. The "prohibition" the inspector remembers does not exist in the code itself.

Second, the Contractor reviews the contract documents per §1.5.1. The structural drawings include a general note: "All FCAW fill passes on cyclically loaded structures shall be stringer beads only." The columns in question are statically loaded, so the note does not apply. The code does not prohibit weaving here, and the contract does not modify it for this member type.

Outcome. The WPS allows weaving, the code does not prohibit weaving for this configuration, the contract does not restrict it for this member, and the work continues. The dispute resolved in 15 minutes by reading the source documents in hierarchy order: contract first, code second, WPS third. Without that discipline, the same dispute can stretch into a multi-day work stoppage and a contract claim.

The same hierarchy applies to preheat, interpass temperature, NDT extent, and every other prescriptive parameter D1.1 sets. Check the applicable code requirement and any Engineer modification incorporated into contract documents, then ensure the WPS reflects them.

Reference data from AWS D1.1/D1.1M:2025. Not affiliated with the American Welding Society.