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Wilkinson Coutts & Matthews Integrity Training

Who are we?

WILKINSON COUTTS / MATTHEWS INTEGRITY HUB: an up-to-the-minute information mix designed to help you with your lifework and career development in the asset integrity, inspection and NDE industries.

Matthew Petroleum Notes


Q1. Fillet-welded patches

According to API codes, which of these items are allowed to have fillet-welded ‘lap’ patches added as a permanent repair for wall-thinning corrosion?

a) Pipework
b) Unfired pressure vessels
c) Atmospheric oil storage tanks
d) None of the above

Ans c .API 653 allows fillet welded patches to be permanent on storage tanks. API 510 and 570 define them as temporary on vessels and pipework.

Qu 2: Scope of Post Construction Codes (PCCs)

When doing site weld repairs to pressure envelope components using PCCs, one criterion of the construction code which is commonly overridden is:

a) PWHT requirements
b) Welding consumable P-No
c) Welder qualifications
d) WPS essential variables

Ans (a). PCC-2 and API codes both give alternatives for replacing construction-code PWHT. They would not override the others as this would be more likely to affect weld integrity.

Qu3. Pipework welded repairs

Which of these is only allowed as a temporary repair on process pipework?

a) Flush ‘insert’ patches
b) Grinding out a through-wall defect and rewelding
c) Full encirclement welded split sleeve
d) Weld overlay

Answer c, from API 570 .The others are allowed as permanent repairs on pipework as they fully restore the original strength .

Qu4. Fillet welded patch restrictions

Which of these features is prohibited on fillet-welded patches to API 570?

a) A patch on material of 20,000psi tensile strength
b) 3in long patch on a 12in line
c) A patch on material of 35,000psi tensile strength
d) 8in long patch on a 12in line

Ans (d). The length of a fillet welded patch is limited to 50% of pipe diameter. Any material lower than 40,000 psi can be patched

Qu 5: Weld overlay repair on flange faces

When can weld overlay be used to build up a heavily corroded area on a flange face?

a) Never; it is not allowed by construction code or PCC
b) If the flange is not yet corroded to minimum code thickness
c) If Carbon Equivalent is less than 0.3%
d) In all cases, as long as the materials are compatible

Ans (d). ASME PCC-2 covers flange repair and place no limitations. PWHT may be needed if the material is above a certain thickness and/or Carbon Equivalent value.


How did you do? If you didn’t get them all correct, have a look through our 5-minute coaching points below


Welded repairs to pressure equipment

ASME and API PCCs are comprehensive documents covering a very practical subject. Once you gain familiarity with them they will enable you actually specify and design repairs, as well as just inspecting repairs done by others. The issue of which repairs can be classed as temporary or permanent depends on which code is used, and the type of component.

See our short slide presentation covering this topic

In-Service Repair

 Matthews Masterclass