Execution controls · AWS D1.1 Clause 7
What weather, cleaning and tack-weld instructions belong in a WPS?
A procedure with correct material, joint and parameters can still be unusable if the job instruction omits conditions that affect actual welding. State how the crew will check the welding environment, prepare and clean the surfaces, and qualify and incorporate tack welds. Use the applicable code and project conditions rather than a generic “weld per AWS” note.
Check the conditions at the actual weld
| Condition | Action before welding | Evidence to record |
|---|---|---|
| Wind for gas-shielded GMAW/FCAW-G and other affected processes | Shield the work; Clause 7.11 limits wind velocity at the point of weld to 5 mph [8 km/h]. Gas flow setting alone does not prove protection. | Point-of-weld wind check or the effective enclosure/protection method. |
| Cold, wet, rain or snow | Do not weld when the point-of-weld ambient is below 0°F [−20°C], surfaces are wet or exposed to rain/snow, or conditions are otherwise unsuitable. A heated enclosure can change the point-of-weld condition. | Local temperature and surface condition, plus enclosure or heating arrangement when used. |
| Preheat table shows 0°C | Still apply the independent Clause 7.11 environmental and surface requirements and the actual preheat/interpass instruction. | Temperature and surface checks before the pass; do not use a table value as permission to weld wet steel. |
Specify what is cleaned and when
Before welding, remove loose or thick scale, thick rust, excessive moisture, oil, grease and other harmful surface matter under Clause 7.14. Do not weld over a crack, tear or entrapped-sand defect. The code has conditional allowances for tightly adherent scale or rust and certain coatings, so a broad “all rust is acceptable” or “all coatings are prohibited” rule is inaccurate. A cyclically loaded beam flange/web preparation has its own stricter scale-removal condition.
Clause 7.29 also requires cleaning between passes and before restarting an interrupted crater: remove slag and brush the weld and adjacent base metal. Clean the completed weld. Spatter removal can depend on the inspection and finishing requirement; state the project-specific disposition. A usable WPS names the method and check point instead of merely saying “clean as needed.”
Treat tack welds as welds with a traceable route
Clause 7.17 requires tack welds to use a qualified or prequalified WPS and qualified personnel. If a tack remains in the finished weld, use filler meeting the final weld requirements, clean it, and treat the ends as the applicable multilayer detail requires. Record whether tacks are incorporated or removed, who places them, the governing procedure and how they are inspected or prepared before continuation.
There is a narrow continuous-SAW remelt condition for certain single-pass tacks. Do not turn that exception into a general permission to skip preheat or qualification for all tack welds.
Convert a vague note into a reviewable instruction
For a hypothetical gas-shielded FCAW job outdoors with incorporated tacks, “protect weld and clean” leaves three decisions open. A reviewable instruction identifies wind protection at the weld point, the method for verifying that the surface is dry and at the required temperature, the specific cleaning before each pass, and the tack WPS/personnel plus final-weld treatment. It then points to the controlled drawing and project inspection requirements for any stricter condition. No unverified project measurement should be filled in as if observed.
Code basis and limits
This guide uses AWS D1.1/D1.1M:2025 base edition plus registered July 28, 2026 base-edition errata; AMD1 is excluded. Relevant fabrication provisions are Clauses 7.11, 7.14, 7.17 and 7.29. The contract edition, load category, drawing and project site rules govern where they add conditions. This page is an instruction-writing aid, not evidence that a specific site was suitable or a tack was qualified.
Include the process, drawing, load category, site conditions and tack-weld plan with the technical request.