How to navigate three ASME books on the CWI piping Part C

The ASME piping endorsement is the one CWI code exam that asks you to navigate three separate code books in a single open-book sitting, which is exactly why it is the endorsement where book-handling speed decides the result. The exam is a combined 60 questions, split 26 on ASME B31.1 Power Piping, 18 on ASME Boiler and Pressure Vessel Code Section IX, and 16 on ASME B31.3 Process Piping. That split, verified against the AWS Exam References and Editions Guide, is itself a study plan: weight your preparation toward B31.1, then Section IX, then B31.3. This guide maps how each of the three books is organized so you can move between them without losing the clock. It describes structure only and reproduces no code text, which stays your own purchase from ASME. For which editions to buy, see the code book and edition hub; to decide whether this endorsement fits your work, see the ASME piping endorsement guide.

First, know which book a question belongs to

Before you open anything, classify the question by its keywords, because opening the wrong book is where the minutes vanish:

• Procedure or welder qualification, essential variables, a WPS, a PQR, or a welder qualification record: that is Section IX, regardless of which piping code the plant is built to. Both B31 books point to Section IX for how welding is qualified.
• Power plant, boiler external piping, steam, high-temperature service: that is B31.1.
• Refinery, chemical or process plant, and anything that turns on a fluid-service category: that is B31.3.

Get that reflex right and three-quarters of the navigation problem disappears.

ASME Section IX: the qualification book

Section IX is organized into parts, and for welding you live almost entirely in one of them. The parts are QG (General Requirements), QW (Welding), QB (Brazing), and QF (Plastic Fusing). Within Part QW the material is grouped into articles: welding general requirements, welding procedure qualification, welding performance qualification, welding data, and standard welding procedure specifications.

The landmark numbers inside QW are what you tab, because Section IX questions are almost always “is this WPS or this welder qualified for that?”:

• The welding-variables tables (the QW-250 series) list which variables are essential, supplementary essential, or nonessential, organized by welding process. Most procedure- qualification questions resolve here.
• The base-metal groupings (P-Numbers), the filler groupings (F-Numbers), and the weld-metal chemistry groupings (A-Numbers) are the classification tables you use to decide whether a material change requires requalification.
• The performance-qualification tables give the thickness and diameter ranges a welder’s test qualifies, and the position figures define the test positions.
• The standard forms for the WPS, the PQR, and the welder qualification record show what a complete record must contain.

ASME B31.1 Power Piping: the most-weighted book

B31.1 carries the most questions, so it earns the most tabbing. It is organized into Roman- numeral chapters: scope and definitions, design, materials, dimensional requirements, fabrication and assembly and erection, inspection and examination and testing, and operation and maintenance. For a welding inspector the two chapters that matter most are the fabrication chapter and the inspection chapter:

• Welding, preheat, and postweld heat treatment requirements sit in the fabrication, assembly, and erection chapter, in the welding paragraphs.
• Examination extent and the acceptance criteria sit in the inspection, examination, and testing chapter. When a B31.1 question asks how much examination is required or whether an indication is acceptable, that is the chapter you turn to.

ASME B31.3 Process Piping: acceptance turns on fluid service

B31.3 shares the same Roman-numeral chapter skeleton as B31.1, scope and definitions, design, materials, standards for components, fabrication and assembly, inspection and examination and testing, then additional chapters for nonmetallic, Category M, high-pressure, and high-purity piping. The trap that is unique to B31.3 is that the required examination and the acceptance criteria depend on the fluid-service category the piping falls in:

• Welding, preheat, and heat treatment are in the fabrication and assembly chapter.
• Examination and the weld acceptance criteria are in the inspection, examination, and testing chapter, in an acceptance table keyed to fluid service. Normal service, Category D, Category M, severe cyclic, and high-pressure piping do not share the same acceptance limits, so the first thing to read in a B31.3 stem is which fluid-service category applies. Judging a weld against the wrong category is the classic B31.3 mistake.

The mental model for three books at once

The candidates who pass this endorsement do not treat it as three exams. They treat it as one routing problem: every question first gets sorted into Section IX (qualification), B31.1 (power) or B31.3 (process), and only then do they open a book. Because B31.1 carries 26 of the 60 questions, its fabrication and inspection chapters get tabbed most heavily; Section IX’s QW-250 variables and classification tables come next; B31.3’s fluid-service acceptance table comes third. The neutral part-by-part difficulty read for the whole CWI exam is in how hard is the CWI exam, and the full three-part study plan is in the exam guide.

Building navigation speed before exam day

1. Tab all three books to the paragraphs above, and practice reaching for the right book first. Confirm with your test center what book form and tabbing are permitted before you rely on it.
2. Drill the routing decision: read a practice stem and name the book before you open anything. On a three-book exam, wrong-book time is the biggest single leak.
3. For B31.3, always read the fluid-service category first; for B31.1, keep the fabrication and inspection chapters under your thumbs; for Section IX, know the QW-250 variables layout.

Buy the right three editions, then learn to move through them

This endorsement is the one where the wrong-edition mistake is also the most expensive, because it pins three separate books at once. The current pinned editions for Section IX, B31.1, and B31.3, alongside every other endorsement’s code and edition, are in the code book and edition hub, where the three-book cost of this endorsement is laid out plainly against the single-book structural and pipeline endorsements. If you are weighing whether the piping lane is even yours, the endorsement recommender maps your inspections to the code they are actually judged against.

Sources: the AWS Certified Welding Inspector endorsement pages and the AWS Exam References and Editions Guide (last updated August 1 2025), checked 2026-07-24, from which the 60-question split (26 B31.1, 18 Section IX, 16 B31.3) is taken; plus the public table-of-contents structure of ASME BPVC Section IX, ASME B31.1, and ASME B31.3. This page describes the organization of the three code books only and reproduces no code text; the code books themselves are your own purchase from ASME. Part, chapter, article, and paragraph numbering can change when a code edition is reissued, so confirm the arrangement in the specific editions your exam is administered to. This site is independent, is not affiliated with AWS or ASME, and sells no seminar, course, or code book.