7.1 Repair Procedure Qualification & Limitations

7.1 Repair Procedure Qualification & Limitations

Weld repairs concentrate heat into a small, fully restrained volume of pipe — the highest-risk welding on a pipeline. Section 10 of API 1104:2021 therefore wraps repairs in authorization gates, dedicated procedure qualification, and strict retest limits.

---

1. When Authorization and a Qualified Repair Procedure Are Required

Company authorization (10.2.1) is required for:

• crack repair;
• back weld repair;
• double repair; and
• repair of a weld in pipe with specified OD less than 2.375 in. (60.3 mm).

Repairs that add no heat or weld metal (grinding, filing) need no authorization. A qualified repair procedure is required whenever welding is used and any of these holds: a welding procedure different from the original is used; the repair is in a previously repaired area (double repair); a crack is repaired; a back weld repair is made where no back weld was in the original procedure; or the company requires one. A procedure qualified for a double repair covers a single repair, and a crack-repair procedure covers other defect types.

---

2. Crack Rules — Read Them Twice

• A weld containing a crack defect shall be repaired or cut out.
• Mandatory cut-out: the length of a single crack, or the aggregate length of more than one crack, exceeds 8% of the weld length (length = longest dimension, any orientation).
• A double repair of a crack is not permitted — additional cracking after repair forces cut-out.
• Crater/star cracks found completely within internal or external weld reinforcement may be removed by grinding without a qualified repair procedure; if grinding goes beyond the reinforcement, the reinforcement is replaced using a qualified welding procedure.

3. Grinding-Only Repairs

Repairs made only by grinding are allowed without a qualified repair procedure when the pipe surface contour and minimum design wall/weld thickness are not violated (when the minimum design value is unknown, defect removal is restricted to the reinforcement height of the root and cover passes). Grinding repair lengths and counts are unlimited.

---

4. Repair Types and the Table 10 Substitution Matrix

The five repair types of 10.3.2: full-thickness, internal partial-thickness, external partial-thickness, cover pass, and back weld repairs. Qualification is on a full-circumference butt weld, and butt-joint repair qualifications extend to branch and fillet joint designs. Table 10 controls substitution: e.g., a full-thickness qualification covers external partial-thickness, cover pass, and back weld repairs (Category II restricts some options).

Repair area length (10.2.6): each repair area must measure at least 2 in. (50 mm) at the deepest part of the excavation; the maximum individual or accumulated repair length in a weld is a percentage of weld length set by the company.

5. Essential Variables (Table 9)

Repair-procedure essential variables include: welding process or application method; a change from one repair type to another (except as Table 10 allows); a change from multiple-bead to single-bead repair; a change of excavation location (weld centerline ↔ fusion line) for partial-thickness and cover-pass repairs; and a bevel geometry change greater than ±25%. Table 1 variables apply as well, to the repair weld only, and Table 9 supersedes Table 1 on conflict. Category II applies when hardness/toughness limits are specified.

6. Testing the Repair Procedure (Table 11 + Hardness + Charpy)

Destructive testing is by repair type and wall thickness — from 3 specimens for a full-thickness repair down to 1 for a cover-pass or back-weld repair (tensile, root/face/side bends per Table 11). Additional requirements:

• Macrosection + hardness (10.3.6.4) when the original procedure required hardness testing: Vickers HV10 traverses at the Figure 22-27 locations, against Table 12 maximum values — low-hydrogen process: weld metal 275, HAZ 350; any process: weld metal 275, HAZ 325 root/mid (300 when base metal is 0.375 in. / 9.5 mm and above) and 275 at the cap.
• Charpy impact testing (10.3.6.3) when the production weld had toughness requirements: weld metal and HAZ, three valid specimens each, tested at or below minimum design temperature, meeting the production weld's specified values.
• The repair welder and repair procedure may be qualified simultaneously, with the added specimens of Table 14.

7. Conduct of the Repair Itself (10.1-10.2)

• The full length of the defect in a repair area must be removed and repaired — intentional partial repair of a defect is prohibited. If part of the original defect remains but the repair weld meets Section 9 acceptance, the repair weld is acceptable, as are new indications introduced by the repair that meet the criteria.
• Defects rejected by Annex A are repaired along the full length of the identified defect.
• A repair welder qualification covers the repair type tested per the Table 16 matrix; a single welder deposits the entire repair thickness of a qualification test — qualification may not be split between welders (10.4).
• Qualification test repairs are made in a fully completed circumferential butt weld, with each repair weld at least about 8 in. (203 mm) long so the required specimens can be removed.