ICC Exam Structure: B1, B2, E1, P1 & M1 — Questions & Time

The Five Certifications at a Glance

All ICC inspector exams share the same DNA: open book, multiple choice, 75% to pass. Here is the full comparison:

Note: verify the exact numbers in the current official ICC exam bulletin for your certification and code edition — ICC occasionally updates formats.

B1 — Residential Building Inspector (IRC)

The entry-point certification covering one- and two-family dwellings and townhouses up to three stories. Content follows the IRC: administration, building planning, foundations, floors, walls, wall covering, roof-ceiling construction, roofing, chimneys, and energy efficiency. 60 questions in 2 hours — about 2 minutes per question.

B2 — Commercial Building Inspector (IBC)

The commercial counterpart, based on the International Building Code. B2 is the longest exam in the family: 80 questions in 3.5 hours. Content covers occupancy classification, types of construction, fire protection, means of egress, accessibility, and structural provisions.

E1 — Residential Electrical Inspector (NEC + IRC)

The E1 exam tests the National Electrical Code along with the IRC electrical chapters (Ch. 34–43). Expect questions on services, feeders, branch circuits, wiring methods, grounding and bonding, overcurrent protection, and residential electrical inspection procedures.

P1 — Residential Plumbing Inspector (IPC + IRC)

The P1 exam covers the International Plumbing Code plus the IRC plumbing chapters (Ch. 25–33): fixtures, water supply, drainage and venting, traps, and inspection of plumbing systems in residential construction.

M1 — Residential Mechanical Inspector (IMC + IRC)

The M1 exam covers the International Mechanical Code plus the IRC mechanical chapters (Ch. 12–24): heating and cooling equipment, duct systems, combustion air, venting, and fuel-gas systems in residential buildings.

How the Open-Book Format Changes Your Strategy

Every one of these exams is open book, so your preparation should be navigation-heavy: learn the chapter map of your code, drill index-first lookups, and practice with questions that cite exact sections. Read our IRC navigation guide and open-book study techniques to build that skill.

Ready to practice? Try free ICC practice questions in the real exam format. For the full picture of what each credential is for, read the complete ICC certification guide and the NHIE national home inspector exam guide.

Frequently Asked Questions

How many questions are on each ICC exam?

Most ICC inspector certification exams have 60 multiple-choice questions. The B1, E1, P1 and M1 exams each have 60 questions; the B2 Commercial Building Inspector exam has 80.

How long is each ICC exam?

The B1, E1, P1 and M1 exams each have a 2-hour time limit. The B2 Commercial Building Inspector exam is longer, at 3.5 hours. Time limits are listed with each exam in the official ICC exam catalog.

What is the passing score for ICC exams?

Most ICC inspector certification exams use a passing scale score of 75. Always confirm the current passing score, question count and time limit for your exam in the official ICC exam catalog for your code edition.

Are ICC exams open book?

Yes. Every core ICC inspector certification exam is open book, multiple choice. You bring the applicable code — the IRC for B1, the IBC for B2, the NEC plus IRC for E1, the IPC plus IRC for P1, and the IMC plus IRC for M1 — and you are tested on finding and applying its requirements.

Which ICC certification should I start with?

Most candidates start with B1 (Residential Building Inspector) because the IRC scope is the narrowest and the exam is the shortest. Once you are comfortable with code navigation, you can add B2, E1, P1 or M1 using the same skills. See our ICC certification guide for the full path.