Most API 653 candidates lose welding marks on paperwork, not on technique. The exam asks whether the records in front of you prove the weld was allowed.
What does the welding domain of API 653 cover?
It is domain II, titled Welding on Atmospheric Aboveground Storage Tanks. The body of knowledge says the inspector should have the knowledge and skills to review a Welding Procedure Specification (WPS), a Procedure Qualification Record (PQR) and a Welder Performance Qualification (WPQ).
Three jobs sit inside that sentence. First, the procedure and qualification records must comply with the ASME code and any extra API 653 requirements. Next comes the question of whether the essential and non-essential variables were properly addressed. Last, you judge whether the welder is qualified to make the production weld the WPS describes.
A fourth sits beside them. The PQR lists mechanical tests, and you judge whether they are the right tests and whether the results are acceptable.
API 653 — Myth: API 653 is only for crude oil storage. Watch on YouTube · CertCrafter The channel’s short on the myth that API 653 is only for crude oil storage is a quick reminder that this inspector’s job covers many stored products.
How do the WPS, PQR and WPQ fit together?
Think of a chain. The PQR is the test record: a coupon was welded, tested, and the results written down. The WPS is the instruction the welder follows in production, and it must reference the PQR that supports it. The WPQ shows that a welder passed a test coupon welded to a qualified WPS.
The body of knowledge adds a small rule that is easy to forget: the PQR must be signed and dated.
What is in scope and what is excluded?
The scope is narrow on purpose. That is good news, because Section IX is a large code and you only need a slice of it.
| Limit | What the body of knowledge says |
|---|---|
| Processes | SMAW or GMAW only |
| Per document | One process on a single WPS, PQR or WPQ |
| Support | The WPS is supported by a single PQR |
| Filler metals | One per process |
| Base metals | P-No. 1 |
| Coupon | The WPQ test coupon is welded to a qualified WPS |
Several things are specifically excluded: dissimilar base metal joints, powdered filler metals and consumable inserts, special processes such as overlay and hard-facing, Charpy impact requirements and supplementary essential variables. Any PQR and WPS on the exam will not include heat treatment requirements.
Skip those topics. The hours you save belong to the calculations and the open-book lookups.
What do inspectors actually check on a repair job?
On site, the welding paperwork arrives before the welder strikes an arc. A contractor sends a package for a shell repair, and the inspector reads it against the job.
The useful habit is to start from the production weld and work backward. What process will be used? The procedure that covers it comes next, then the record that supports that procedure. Last, who will run it, and does that welder’s qualification cover this joint?
Field mistakes usually sit in the links, not in the words. A WPS that names a PQR which does not exist in the package. A welder qualified on a different procedure. A record that was never signed. Each one is a stop, however good the weld might look.
Worked example: reviewing a record package
These documents are invented for practice. A contractor proposes SMAW for a shell repair and submits one WPS, one PQR and one WPQ.
- Count the processes. The WPS, PQR and WPQ each show SMAW only, so the one-process rule holds.
- Check the link. The WPS names the PQR it relies on, and that PQR is the one in the package.
- Check the PQR itself. It is signed and dated, and it states the values actually used on the coupon.
- Compare the variables. Each essential variable on the WPS must be supported by the PQR, and the non-essential variables must be addressed too.
- Read the mechanical tests. Are they the right tests for the coupon, and are the results acceptable?
- Match the welder. The WPQ coupon was welded to a qualified WPS. Does it cover the position and the joint the production weld needs?
One failed step stops the package. The exam question will usually hide the failure in one line of a long scenario.
The API 653 Complete Exam Kit puts more of these records in front of you under timed conditions, with every answer explained.
Which general welding rules do you need?
Two documents carry them. In API 650 Section 9 the body of knowledge lists typical joints and definitions, weld sizes, restrictions on joints, maximum allowable reinforcement and inspection requirements. In API 653 Section 11 you need the general rules for welding on tanks already in service.
The March 2027 effectivity sheet lists API 650 in its 14th Edition of August 2025, API 653 with Addenda 1 through 4, and ASME Section IX in the 2025 Edition, welding only.
Where do candidates lose marks on welding questions?
Scope creep comes first. Candidates read a Section IX chapter on special processes and spend a weekend on material the exam excludes.
Second, mixing up what each record holds. A PQR states the values used on the test coupon. Ranges belong on the WPS. A question that offers a PQR with ranges is telling you something.
Third, missing the open-book split. Some welding items are open-book and some are closed-book, and a closed-book item will not let you look anything up. Know the basic rules cold.
Fourth, reading the welder qualification too generously. Passing a test on one procedure does not make a welder qualified for every weld.
Two free questions in the kit’s sample set show the framing: one is about electrodes left exposed on a tank repair, the other about a PQR on A283 plate. Try the free quiz first and note how each scenario hides its answer in one detail.
What should you study first?
Read the domain II text of the body of knowledge twice, then list the exclusions so you stop worrying about them. Practice the six-step review on any set of records you can find, and say out loud which link failed. After that, drill the API 650 Section 9 and API 653 Section 11 topics named above.
The API 653 product page holds the exam facts, the full bundle has the welding items marked closed-book or open-book, and the guides hub lists the rest. To see how mistakes cluster across domains, read API 653 common mistakes.
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