9.3 Clause 8 — Inspection and Acceptance Criteria

The Inspector's Tasks Under Clause 8

Clause 8 is the working heart of the code for a CWI and the most-referenced clause on Part C. It defines who may inspect, what they must verify, and the accept/reject criteria for visual and nondestructive examination. The code distinguishes the Contractor's Inspector (Fabrication/Erection Inspector) from the Verification Inspector (often the Owner's), but when the term Inspector is used without qualification, the requirement applies to both.

Visual inspection must be performed by an individual qualified as a CWI or SCWI, or by an associate (CAWI) working under their direction, per AWS QC1. In the 2025 edition, NDT personnel must hold ASNT certification (SNT-TC-1A / CP-189 basis) — closing earlier ambiguity. The Inspector's verification duties span the whole job:

The Inspector also verifies that calibration of inspection tools and NDT equipment is current and maintains inspection records.

Table 8.1 — Visual Acceptance Criteria (Verified Values)

Table 8.1 gives different limits for statically loaded nontubular versus cyclically loaded nontubular connections. Cyclic (fatigue) service is always as strict or stricter.

*Undercut exceptions for static loading: on welds ≥12 in [300 mm], up to 1/16 in [2 mm] deep undercut is allowed for an accumulated length up to 2 in [50 mm] in any 12 in; on welds <12 in, accumulated undercut deeper than 1/16 in may not exceed weld length × 0.16.

Porosity Limits (Often Misquoted)

Visual piping porosity acceptance also splits by loading:

• CJP butt groove welds transverse to tensile stress: no visible piping porosity (static and cyclic).
• Fillet/other groove welds (static): sum of pore diameters ≤3/8 in [10 mm] in any linear inch; for welds ≥12 in, ≤3/4 in [20 mm] per 12 in.
• Fillet welds generally: frequency ≤1 pore per 4 in [100 mm], max diameter ≤3/32 in [2.5 mm].

Weld Profiles and Reinforcement

Profiles are governed by Clause 7.23 and Figure 7.4 (renumbered from the older 7.1). Fillet faces may be slightly convex, flat, or slightly concave; maximum convexity is 1/16 in [2 mm] for faces up to 5/16 in [8 mm], and 1/8 in [3 mm] for larger faces. Concavity is allowed only while the effective throat still meets the specified size. Groove (butt) weld face reinforcement is limited (commonly to about 1/8 in [3 mm] for welds under 1 in), and reinforcement must blend smoothly with no overlap.

When NDT Beyond VT Is Required

UT acceptance uses Table 8.2, scoring an indication by its indication rating (dB) versus weld thickness, with a length/severity class. RT rejects all cracks, limits elongated indications (slag, incomplete fusion) by length, and limits rounded indications (porosity) by the porosity charts.

Repair and Re-Inspection

When a weld is rejected, the Inspector documents it; repair follows an approved WPS; gouged areas (e.g., air carbon arc) are ground smooth before rewelding; and the repair is re-examined by the same NDT method(s) used originally.

Static vs. Cyclic: Why the Limits Differ

The split between statically loaded and cyclically loaded acceptance is not arbitrary — it reflects fatigue. A statically loaded member sees essentially constant load; a small surface notch like shallow undercut rarely propagates. A cyclically loaded member (crane runways, bridges, equipment supports) sees thousands to millions of stress reversals, and a notch transverse to the tensile stress becomes a fatigue crack initiation site. 25 mm]** while general static undercut tolerates 1/32 in [1 mm], and why CJP groove welds transverse to tensile stress allow no visible piping porosity in either case.

On Part C, the giveaway words are "cyclically loaded," "fatigue," "transverse to tensile stress," or "primary member" — they pull you to the stricter column.

Surface Discontinuities the Inspector Names

Visual inspection is pattern recognition plus measurement. Know the A3.0 terms and which are categorically rejectable:

Timing of Inspection (A Hidden Trap)

Visual inspection timing matters for quenched-and-tempered steels. Most steels are inspected after cooling to ambient, but ASTM A514, A517, and A709 Grade HPS 100W [HPS 690W] must wait at least 48 hours after weld completion before final inspection, because delayed (hydrogen) cracking can appear hours later. A weld that looked good immediately may crack overnight, so the code mandates the wait.

Documentation and Authority

The Inspector's accept/reject authority is real but bounded: the CWI applies the code and contract criteria and cannot unilaterally waive them — only the Engineer can authorize a deviation. The Inspector documents inspections, marks rejected areas, verifies that repairs follow an approved WPS, and confirms re-examination by the same NDT method. Clean, contemporaneous records are part of the job, not an afterthought.

For the Exam: Table 8.1 is the single most-tested table. Lock in: cracks are never acceptable, the 0.01 in cyclic undercut limit on transverse primary members, and that complete fusion is always required.