How is a third-party audit different from an AHJ audit?

An AHJ audit is regulatory — the jurisdiction enforces code. A third-party audit is hired by the owner or the certification body (AISC, AWS, ASME) and is contractual. Findings carry different consequences but the documentation standards are similar.

Are third-party auditors stricter than CWIs in-house?

Usually yes. In-house CWIs know the shop's history and habits and may be lenient with familiar deficiencies. Third-party auditors are paid to find issues; their finding count drives perception of audit value. Expect tighter scrutiny.

What's a typical third-party audit fee?

Single-day shop audits: $2,500–$6,000. Multi-day comprehensive audits: $8,000–$25,000. Project-specific audits tied to a contract clause: variable. Costs are often passed through to the contracting party in the bid.

Common WPS deficiencies found in third-party audits

Three-party audits — independent of the shop and the AHJ — find the same WPS deficiencies over and over. Here are the patterns and the preventive fixes.

Third-party welding audits are run by independent firms hired by an owner, EOR, or certification body. They are stricter than in-house reviews because their entire business model is built on finding issues. The deficiencies they find are, with rare exception, the same handful in different combinations. Here are the most common.

1. WPS edition / table-number drift

The single most common finding across audits.

What it looks like: WPS header cites AWS D1.1:2025. WPS body references "Table 6.5 essential variables." But the 2025 edition renumbered that table to 6.6.

Why it happens: WPSs migrated from older editions and only the header was updated.

Fix: Bulk-update table citations during edition migration. A rule engine that knows the table numbering by edition catches this instantly.

2. Single-value parameters instead of ranges

What it looks like: WPS lists "Amperage: 130 A" instead of "Amperage range: 115–145 A."

Why it matters: A single value forces the welder to weld at exactly that amperage. The PQR qualifies a range, not a point. A single value is technically out-of-compliance even though it might be inside the qualified range.

Fix: Every electrical parameter (amperage, voltage, travel speed, wire feed) must be a range.

3. Joint sketch missing or referenced without embedding

What it looks like: WPS says "Joint type: B-U2 per Annex B" with no sketch.

Why it matters: The auditor wants to see the joint geometry without flipping to the code. Standard practice: embed the Annex B sketch directly in the WPS.

Fix: Embed joint sketches. They're available from AWS in DXF format and can be inserted as images.

4. Filler classification incomplete

What it looks like:

"E7018" (missing hydrogen designator)
"E71T-1" (missing C or M suffix to indicate gas)
"ER70S-X" without the X resolved
"E70T" without the dash and number

Why it matters: Each suffix changes essential variables. Missing suffixes prevent the auditor from verifying compliance.

Fix: Use the full AWS A5.X classification. "A5.1 E7018-H8" not "E7018."

5. Preheat below Table 5.8 minimums

What it looks like: WPS lists preheat at 50°F for 1-1/2 in thick A572-50, but Table 5.8 minimum is higher.

Why it matters: Cold cracking risk. Direct safety issue.

Fix: Cross-reference Table 5.8 by material × thickness × hydrogen designator. Rule engines flag this automatically.

6. Supporting PQR can't be produced

What it looks like: WPS cites "PQR-19-007" but the PQR isn't in the file, or is incomplete (missing lab certification).

Why it matters: The qualification path is broken. The auditor can't verify the WPS is supported.

Fix: Audit the PQR archive separately from the WPS library. Every cited PQR must be findable, signed, with lab report and accreditation.

7. Welder's WPQ doesn't cover the actual work

What it looks like: Welder's WPQ qualifies them for 1G groove on 1/4 in plate. The production work is 3G groove on 1/2 in plate.

Why it matters: The welder isn't qualified for this work. Welds are non-compliant.

Fix: Match welders to WPSs by qualified position, thickness, and process. Software that runs this match prevents the assignment mistake.

8. Revision-control breakdown

What it looks like: Current revision in QC is Rev 3. Floor copy is Rev 1. Welder is following Rev 1 parameters that are now superseded.

Why it matters: Production work is being done to an obsolete procedure.

Fix: Single-source library, floor terminal with read-only access, controlled-copy log.

9. Signature without credentials

What it looks like: WPS signed "Joe Smith, QC Manager." No CWI or PE number listed.

Why it matters: The auditor cannot verify Joe's qualifications to sign at the time of signing.

Fix: Signature block lists name, credential type, credential number, and date.

10. CVN scope mismatch

What it looks like: Project drawings call for AISC 341 demand-critical CVN. WPS doesn't invoke Table 6.8 supplementary, supporting PQR has no CVN data.

Why it matters: The WPS doesn't actually qualify the work.

Fix: Identify CVN-required welds at the project planning stage. Stack the WPS library accordingly. Demand-critical WPSs should be tagged distinctly.

The compound finding

Most failed audits aren't single findings — they're a combination of 3–4 of the above on the same WPS. A WPS with old table numbers + single-value amperage + missing hydrogen designator + revision drift fails comprehensively.

A rule engine that runs all ten checks on every WPS revision catches the compound failure mode at the source.