8.3 In-Service Procedure & Welder Qualification Requirements

8.3 In-Service Procedure & Welder Qualification Requirements

A procedure qualified on a static, air-cooled coupon proves nothing about a weld made onto a flowing, pressurized pipeline. Annex B.2 therefore requires in-service procedures to be qualified under simulated heat-removal conditions, and Annex B.3 does the same for welders.

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1. Simulated Heat-Sink Test Joints (B.2.4)

• Pipeline operating conditions that affect the contents' ability to remove heat from the pipe wall should be simulated while test joints are made.
• The standard's own note: filling the test section with water and allowing it to flow during welding produces thermal conditions equivalent to or more severe than typical in-service applications (Figure B.2 shows an example assembly).
• Procedures qualified under these conservative conditions may then be applied to the less severe field conditions they bound.
• Weld-deposition repairs are qualified on pipe containing simulated wall loss — the ground-down area large enough to yield all test specimens, with remaining wall no greater than the WPS minimum, and the repair built back to full original thickness.

2. Essential Variables (Tables B.1 and B.2)

Table B.1's in-service essential variables include: materials; pipeline operating conditions (pipe contents, flow rate — conditions may be grouped); wall thickness (an essential variable for weld-deposition repairs, where qualification binds the minimum remaining wall); weld deposition sequence; welding process; joint design; filler metal; shielding gas; electrical characteristics; weld heat input; time between passes; direction of welding; and preheat temperature. Table B.2 compares which of these apply to procedure versus welder qualification. Changes not listed require only a WPS revision.

3. Procedure Qualification Testing (Table B.3)

The in-service procedure test assembly is destructively examined with:

• Macro test specimens — cross-sections polished and etched (e.g., with Nital) showing complete fusion at toes and root, no cracks, and acceptable profile;
• Face bend tests (Figure B.6 geometry, approximately 9 in. × 1 in. specimens);
• Vickers hardness surveys — traverses across weld metal and HAZ at the regions of anticipated maximum hardness, with results averaged per five impressions.

4. The Table B.4 Hardness Limits (Non-Sour Service)

Annex B does not print one hardness number. Table B.4 sets maximum weld/HAZ hardness (HV10) by process hydrogen level, effective thickness (Equation B.1), and CE_IIW — with linear interpolation permitted:

Read it as the standard's encouragement toward low-hydrogen practice: the drier the process, the higher the hardness allowance. For sour service, the governing document (e.g., NACE MR0175/ISO 15156) controls instead.

5. Welder Qualification (B.3)

Welders qualify on the same simulated heat-sink assemblies, welding the sleeve, branch, or deposition-repair geometry to be used. The record identifies the pipeline operating conditions (contents, flow rate) for which the welder is qualified; conditions may be grouped. Testing covers visual examination plus the macro, bend, and hardness specimens of the Table B.3/B.5 schedules as applicable — and a Section 6 multiple qualification cannot be assembled by mixing Section 6 and Annex B test welds.

6. Additional Annex B Qualification Structure

• Longitudinal seam welder qualification (Table B.5): welders who will weld the longitudinal groove seams of sleeves qualify with their own specimen schedule — separate from the circumferential fillet work.
• In-service repair procedures (B.6/B.7): repair welding procedures for in-service pipelines carry their own essential-variable table (B.6) and their own specimen schedule for repair procedure qualification (B.7), mirroring how Section 10 handles new-construction repairs.
• Grouping of conditions: both procedure and welder records identify the pipeline operating conditions (contents, flow rate) covered; conditions may be grouped so one qualification covers a documented envelope rather than a single operating point.
• Records: procedure qualification records follow the Section 5.2 discipline (actual values plus complete results, retained while the procedure is in use), and welder qualification records follow Section 6.8.

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7. Welder Qualification Scope and Skill Demonstration (B.3)

Annex B.3 ties the welder’s qualified envelope to the test assembly, and the diameter scope rule mirrors the 12.750 in. (323.9 mm) breakpoint used throughout the standard:

• Diameter scope: a welder qualified on pipe of OD less than 12.750 in. is qualified for all diameters up to and including the test diameter; qualification on OD 12.750 in. or greater qualifies all diameters.
• Position scope for weld-deposition repairs: a test weld made on the bottom of the pipe qualifies all positions; a test weld on the side qualifies the side and top only; a test weld on the top qualifies the top only. Qualifying on the bottom is therefore the efficient choice for repair crews.
• Combined qualification: a welder who already holds a Section 6.3 multiple qualification and adds an Annex B.3 in-service qualification is qualified as an in-service branch or sleeve welder for all positions, all diameters, and all wall thicknesses within the 6.3 essential-variable limits.
• Skill demonstration beyond the coupon (B.3.2): the destructive test joint alone is not the whole check. The company may require the welder to demonstrate the specific skill the WPS depends on — holding heat input within the specified range for heat-input-control procedures, or bead placement within the WPS dimensional tolerances for temper-bead and weld-deposition repair procedures.
• Acceptance: the test weld is evaluated to the same visual (6.4) and destructive (6.5) requirements as any welder qualification weld, with the annex’s own specimen schedules for longitudinal groove seams (Table B.5) and weld-deposition repairs.