Code Minimum vs WPS — Which Is Stricter Wins
AWS D1.1 sets minimum Requisitos; your WPS, Documentos contratuais, and the Engineer can add restrictions — never relax them. When a customer claims D1.1 prohibits something your WPS allows, the answer almost always traces to §1.5.1: the Engineer specifies stricter, and contract documents propagate it to the WPS.
The Hierarchy: Code Floor, Contract Documents, Then WPS
AWS D1.1 is structured as a floor, not a ceiling. Per §1.4, the code was specifically developed for welded steel structures using carbon or low-alloy steels 1/8 in [3 mm] thick or greater with a minimum specified yield Resistência of 100 ksi [690 MPa] or less. Within that scope, the code defines the minimum requirements for design, Fabricação, qualification, and Inspeção. Anything stricter must come from somewhere else.
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 is the legal mechanism by which a project becomes stricter than D1.1 alone.
Per §1.5.2, the Contratante is responsible for WPSs, qualification of Soldagem 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 hierarchy resolves disputes in this order: contract documents first, code second, WPS third. The WPS is a derived document — it must satisfy whichever is stricter, the contract or the code, on every parameter.
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 Eletrodo, a non-Norma 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 Cláusula 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:
| Term | Force | Who can change it |
|---|---|---|
Shall (§1.7.1.1) |
Mandatory unless specifically modified in contract documents by the Engineer. | Engineer only, via contract documents. |
Should (§1.7.1.2) |
Recommended practice considered beneficial; not a requirement. | Anyone; ignoring it is not a code violation by itself. |
May (§1.7.1.3) |
Optional procedure or practice usable as alternative or supplement. | Contractor freely, except where Engineer approval is specified. |
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:
- Code requirements that are applicable only when specified by the Engineer.
- All additional NDT that is not specifically addressed in the code.
- Extent of verification inspection, when required.
- Weld Critérios de aceitação other than that specified in Clause 8.
- CVN toughness criteria for Metal de Solda, Metal de Base, and/or HAZ when required.
- For tubular and nontubular applications, whether the structure is statically or cyclically carregado.
- Which welded joints are loaded in tension.
- All additional requirements that are not specifically addressed in the code.
- 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 Inspetor.
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.
| Source | What it adds | Where it lives |
|---|---|---|
| Owner specification | Project-specific NDT percentages, AESS Visual standards, environmental class. | Section 05 12 00 or equivalent Especificação division. |
| Engineer-of-Record contract documents | Weld Aceitação criteria beyond Clause 8, CVN requirements, fatigue Categoria constraints. | General notes on structural drawings; §1.5.1(1)–(9) items. |
| Building code reference | AISC 360 / IBC / AASHTO requirements that bring in additional NDT or inspection. | The applicable building code, referenced via the contract. |
| Fabricator's quality manual | In-house tighter tolerances, more conservative Pré-aquecimento, mandatory documentation steps. | The Fabricante's WPS and quality manual. |
| WPS qualification limits | Essential variable bounds that may be tighter than the code's default range per Tabela 5.5. | The qualified WPS document itself. |
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 EPS pré-qualificada. The owner's third-party inspector observes Cordão oscilante 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, Temperatura Interpasse, NDT extent, and every other prescriptive parameter D1.1 sets. Code minimums, contract additions, then the WPS that satisfies whichever is stricter.
D1.1 is a floor, not a ceiling. The Engineer adds requirements to the contract; the Contractor writes the WPS to meet contract plus code. When a customer cites the code as prohibiting something the WPS allows, ninety percent of the time they are reading a "shall" that the contract modified — or a "should" they have inflated to mandatory. Read the source documents in hierarchy order before escalating.
— CWI auditor field observation, code-vs-WPS shop disputes
Frequently Asked Questions
Both can be technically correct, and that is the source of the dispute. AWS D1.1 sets minimum requirements — what shall, should, and may provisions apply across structural welding. The WPS sets the project requirements, which can never relax a shall but often add restrictions on top. Per D1.1:2025 §1.7.1.1, every shall is mandatory unless specifically modified in the contract documents by the Engineer. Per §1.5.1, the Engineer may add to, delete from, or otherwise modify code requirements to fit a specific structure — and those modifications must be incorporated into contract documents. Read three things in order: the contract documents, the project specification, and the WPS. The customer is usually citing what they think the code says without checking what the contract actually requires. The hierarchy resolves the dispute every time.
Yes — explicitly. AWS D1.1:2025 §1.5.1 states the Engineer shall be responsible for the development of the contract documents that govern products or structural assemblies produced under this code, and 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. The Engineer is the only party with this authority — the Contractor cannot relax a code requirement on their own initiative, and they cannot ignore an Engineer-imposed addition either. §1.5.1 lists nine specific items the Engineer shall specify in contract documents, as necessary, and as applicable: (1) code requirements applicable only when specified by the Engineer, (2) additional NDT not specifically addressed in the code, (3) extent of verification inspection when required, (4) weld acceptance criteria other than 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 not specifically addressed in the code, and (9) for OEM applications, the responsibilities of the parties involved.
Per D1.1:2025 §1.7.1, these three words have specific meanings that drive the entire code's enforceability. Shall (§1.7.1.1) marks a mandatory requirement — the provision applies unless specifically modified in contract documents by the Engineer. Should (§1.7.1.2) recommends practices that are considered beneficial but are not requirements; ignoring a should is not a code violation by itself, though the Engineer can elevate it to mandatory in contract documents. May (§1.7.1.3) allows optional procedures or practices that can be used as alternatives or supplements to code requirements. Some may options require Engineer approval before use; others can be used freely by the Contractor. The practical consequence: when a customer claims the code prohibits a practice your WPS uses, the first question is shall, should, or may, followed by is the contract document modifying it. That two-step lookup resolves most disputes.
Per D1.1:2025 §1.5.1, only the Engineer has authority to modify code requirements, and only by incorporating those modifications into contract documents. Per §1.6, all references to approval in D1.1 mean approval by the Authority Having Jurisdiction or the Engineer. The Contractor (per §1.5.2) is responsible for WPSs, qualification of welding personnel, contractor's inspection, and performing work in conformance with the code and contract documents — but cannot unilaterally relax or modify code provisions. The Inspector (per §1.5.3) verifies that work meets the contract documents and may flag deviations but does not have authority to grant exceptions. This is why customer disputes about whether D1.1 prohibits something almost always trace back to a contract-documents review, not a code-only argument: the contract is where the modifications live.
The contract documents win, and the WPS must be revised. AWS D1.1:2025 §5.2.1 requires that all prequalified WPSs be prepared by the Contractor as written documents, with welding parameters within the ranges specified by Table 5.5. But §1.5.2 makes the Contractor responsible for performing work in conformance with both this code and the contract documents — so if a contract document imposes a stricter requirement than D1.1 (for example, lower interpass temperature, additional NDT, or Charpy V-Notch toughness on weld metal), the WPS must reflect that. A WPS that meets D1.1 but violates the contract is non-compliant for the project. In practice, fabricators issue a project-specific WPS that rolls up the code minimum plus all contract additions in a single document, so the welder reads one set of parameters and there is no ambiguity at the joint.
Reference data from AWS D1.1/D1.1M:2025. Not affiliated with the American Welding Society.