What certifications should you require when hiring welders?
The correct certification to require depends on the application. Requiring AWS D1.1 Structural for a pipe welding role reflects a misunderstanding of how welding procedure qualifications work — and may filter out the right candidates while admitting the wrong ones. Start with the base material, thickness, and application, then determine which code and procedure qualification applies.
The most common industrial welding certifications and their correct applications:
- AWS D1.1 Structural: Structural steel fabrication and erection. Buildings, bridges, heavy equipment frames.
- ASME Section IX: Pressure-containing components — boilers, pressure vessels, process piping. Required in refinery, power generation, and chemical plant environments.
- API 1104: Pipeline welding. Oil, gas, and water transmission pipelines.
- AWS D1.8 Seismic: Structural steel in seismic zones. Required in California and other high-seismic markets for moment frames and special connections.
For a complete breakdown of welding certifications by industry and application, see the welding certifications glossary. For what welders earn by certification level, see the welder salary guide.
How do you verify a welder's certification is current and valid?
Certification cards can be forged or out of date. The only reliable way to verify an AWS certification is to check directly with the AWS certification database at aws.org. ASME certifications are maintained by the employer's weld procedure qualification records — ask to see the WPS (Welding Procedure Specification) and PQR (Procedure Qualification Record) documentation. A staffing agency that cannot tell you how they verify certifications is a significant red flag.
Before a welder begins work on pressure-containing equipment, verify:
- Current certification card with the issuing code and test date
- Continuity of qualification — AWS and ASME require re-testing if the welder has not used the process in the past 6 months
- The specific positions tested (1G flat, 2G horizontal, 3G vertical, 4G overhead) — certifying in one position does not automatically qualify a welder for all positions
- The specific base material and filler metal qualifications — a welder qualified on carbon steel is not automatically qualified on stainless or chrome-moly alloys
How do you assess welder skill beyond the certification card?
The certification card documents a test performed under controlled conditions. What matters operationally is the welder's actual performance in your specific environment. Three assessment tools used by procurement teams at major industrial facilities:
- Facility weld test: A short practical test on the base metal and in the position required for the actual work. This is the gold standard and should be required before any critical pressure-containing work begins.
- Structured reference check: Contact previous employers specifically about defect rates, RT/UT results, and whether they would rehire. General references are not useful.
- Visual inspection self-assessment: Ask the welder to describe what they look for when visually inspecting their own completed weld. The ability to self-inspect is a strong predictor of quality output.
What to ask a staffing agency before hiring welders through them
| Question | What a Good Answer Looks Like |
|---|---|
| How do you verify welding certifications? | Direct AWS lookup; WPS/PQR documentation for ASME; copies maintained in file |
| How do you handle a welder who fails a facility weld test? | Clear replacement policy; tracks defect and fail-rate data across placements |
| What is your welder defect rate on recent placements? | Should be able to provide data; refusal is a red flag |
| Do you carry workers' compensation and general liability? | Must carry both; request certificates of insurance naming your facility |
| What is your mobilization timeline for certified pipe welders? | 24–72 hours for pre-vetted roster; longer suggests no bench depth |
For a deeper framework on evaluating staffing agencies for your trade workforce, see what procurement wants from trade staffing agencies. For shutdown-specific welder mobilization, see the shutdown staffing checklist.