The explanatory Notes in the NBC 2020 are some of the most useful pages you can open in ExAC Section 2, and some of the easiest to misread. Each Note carries an "A-" number that matches the requirement it explains, sits at the end of its Part, and is printed as explanatory only, not part of the requirements. In our experience, candidates who tab the right Notes settle classification and definition questions faster. This guide from Examitect, an independent ExAC prep platform unaffiliated with the CACB, covers what the Notes are, where they sit in both volumes, which ones matter most and how to use one on exam day.
| Exam section | Section 2, about 75 multiple-choice questions, open book |
|---|---|
| Objective | 5.1.2, plus the Notes behind many 5.2, 5.3 and 5.4 questions |
| Status | Explanatory only, not part of the requirements |
| Volume 1 | End of each Part in Divisions A, B and C (no Notes to Part 7) |
| Volume 2 | Notes to Part 9, pp. 9-511 to 9-662 |
| Room rule | Tabs and annotations made beforehand; no added pages |
The National Building Code of Canada 2020 attaches explanatory material to many of its requirements. Each piece is a Note, numbered with the prefix "A-" followed by the number of the provision it explains. The Notes for each Part are printed together at the end of that Part under the heading "Notes to Part 3", "Notes to Part 9" and so on. Candidates and older study guides still call them "Appendix A" or "the appendix notes", a name carried over from earlier editions, and the A- prefix is what remains of it.
Appendix 1 of the 2026 ExAC Preparation Guide (p. 17) sets specific objective 5.1.2: "Explain the Division B appendices and notes in Volume 1 and 2 of the Code." In the NBC 2020 that phrase covers three kinds of material:
| Material | What it contains | Where it is |
|---|---|---|
| Notes to Part (A- Notes) | Explanations, examples, figures and background for specific provisions | End of each Part of Division B, Volumes 1 and 2 (Part 7 has none) |
| Appendix C, Climatic and Seismic Information | Climatic design values in Table C-2 for over 600 locations, plus seismic hazard information | Volume 1, after Part 8, pp. C-1 to C-48 |
| Appendix D, Fire-Performance Ratings | Assigned fire-resistance ratings, flame-spread ratings and smoke developed classifications for common assemblies and materials | Volume 1, after Appendix C, pp. D-1 to D-44 |
Divisions A and C carry Notes too, on compliance, defined terms and the administrative provisions. This guide stays with the Notes; Appendix C and D questions are lookups in their own tables.
The NBC answers this in its own words. At the foot of the opening page of each Notes section, the Code prints: "These Notes are included for explanatory purposes only and do not form part of the requirements." The next sentence says that the number introducing each Note corresponds to the applicable requirement in that Part. You can see both on p. 3-225 of Division B, where the Notes to Part 3 begin.
The Preface (p. viii of Volume 1) makes the same point from another angle. It describes the NRC's separate intent statements as serving explanatory purposes only and calls them "similar in function to the explanatory Notes at the end of each Part." That sets three working rules for the exam:
Keep one distinction clear. Many tables carry their own numbered notes, printed directly under the table as "Notes to Table 3.1.3.1.:" and called up by superscript numbers in the table cells. Those notes belong to the table and are printed with it. The explanatory-purposes statement appears in the Notes to Part sections, not under tables, so a question about "the notes to Table 3.2.3.1.-B" is pointing at the table itself.
The Preface sets out one numbering system for the whole Code: Part, Section, Subsection, Article, Sentence, Clause. A Note can attach at any of those levels. A-3 explains Part 3 as a whole, A-3.8. explains Section 3.8., A-3.2.3. explains Subsection 3.2.3., A-3.8.2.2. explains Article 3.8.2.2., A-3.1.2.1.(1) explains a Sentence and A-1.2.1.1.(1)(b) in Division A explains a Clause. Tables get Notes too, such as A-Table 4.1.2.1. on importance categories.
The link from a requirement to its Note is a parenthetical marker. Sentence 3.1.2.1.(1), on p. 3-1 of Division B, ends "(See Note A-3.1.2.1.(1).)". Section and Subsection Notes are flagged beside the heading instead: Section 3.8. Accessibility carries "(See Note A-3.8.)" on p. 3-173, and Subsection 3.2.3., Spatial Separation and Exposure Protection, carries "(See Note A-3.2.3.)" on p. 3-78. Definitions in Division A work the same way; the definition of flight ends "(See Note A-1.4.1.2.(1).)".
Markers can cross Parts. Sentence 9.10.14.2.(2) in Volume 2 (p. 9-64), on locating the exposing building face of an irregular wall, ends "(See Note A-3.2.3.1.(4).)", a Part 3 Note printed in Volume 1 on p. 3-236. Note (1) to Table 9.10.2.1. (p. 9-46) sends Part 9 occupancy classification to Note A-3.1.2.1.(1). Keep both volumes within reach.
The Notes come last in each Part, after the requirements and the attribution table (and, in Part 9, after the span tables). The page numbers below are from the NBC 2020 as published by the NRC (second printing, March 2025 revisions); check them against your own copy.
| Volume and Division | Notes to Part | Pages |
|---|---|---|
| Volume 1, Division A | Part 1 Compliance; Part 2 Objectives; Part 3 Functional Statements | 1-17 to 1-26; 2-7 to 2-8; 3-5 to 3-6 |
| Volume 1, Division B | Part 1 General; Part 2 Farm Buildings | 1-35 to 1-36; 2-23 to 2-28 |
| Volume 1, Division B | Part 3 Fire Protection, Occupant Safety and Accessibility | 3-225 to 3-288 |
| Volume 1, Division B | Part 4 Structural Design; Part 5 Environmental Separation; Part 6 HVAC; Part 8 Construction Sites | 4-103 to 4-128; 5-23 to 5-38; 6-21 to 6-26; 8-7 to 8-8 |
| Volume 1, Division C | Part 2 Administrative Provisions | 2-7 to 2-10 |
| Volume 2, Division B | Part 9 Housing and Small Buildings | 9-511 to 9-662 |
Most Notes are background you will never need under time pressure. The short list below is ours, built from the Section 2 objectives rather than from any official ranking.
| Note | Where | What it gives you | Objective |
|---|---|---|---|
| A-1.4.1.2.(1) Defined Terms | Division A, pp. 1-20 to 1-25 | Plain-language notes on terms such as exit, fire separation, flight, grade, public corridor and suite | 5.1, 5.2 |
| A-1.2.1.1.(1)(b) | Division A, p. 1-18 | The "as well as" test for alternative solutions | 5.4 |
| A-3 Application of Part 3 | Division B, pp. 3-225 to 3-226 | Discretion for unusual buildings and the firefighting assumptions behind Part 3 | 5.2 |
| A-3.1.2.1.(1) | Division B, pp. 3-226 to 3-229 | Examples of buildings in every major occupancy Group and Division | 5.2.1 |
| A-3.2.3. and A-3.2.3.1.(4) | Division B, p. 3-236 | Limiting distance versus separation between buildings, and how Sentences (3) and (4) work together | 5.2.2 |
| A-3.8. | Division B, p. 3-266 | Barrier-free design principles and four basic space dimensions | 5.2.4 |
| A-9.25.1.1.(2) | Volume 2, p. 9-584 | The difference between a vapour barrier and an air barrier | 5.3.4 |
| A-2.3.1. | Division C, p. 2-8 | Why alternative-solution documentation is kept | 5.4.4 |
Table 3.1.2.1. (p. 3-2) describes each Group and Division in a single line; the Note lists real building types under each one. Watch the pairs that make good distractors: television studios admitting a viewing audience are Group A, Division 1, while those that do not admit one are Group F, Division 2. Police stations with detention quarters are Group B, Division 1, and those without are Group D. Dental and medical offices are Group D. Laboratories appear under both Group F, Division 2 and Group F, Division 3, so the hazard decides.
The defined-terms Note explains the words examiners like to test. On p. 1-22 it says a fire separation is not always required to have a fire-resistance rating but should still act as a barrier to the spread of smoke and fire; where sprinklers allow the rating to be waived, the separation must stay in place as a smoke barrier until the sprinklers actuate. The exit Note confirms that exits include doors or doorways leading directly into an exit stair or directly outside.
Note A-3 explains that 10 to 30 minutes usually pass between the outbreak of fire in an unsprinklered building and high radiation levels, which is the window spatial separation is designed around. Note A-3.2.3. explains why limiting distance is measured to the property line rather than to the neighbouring building. Note A-3.2.3.1.(4) says Sentence (3) is applied first, to set the wall's rating, construction and cladding, before Sentence (4) refines the opening percentage. Our spatial separation worked example runs the full calculation.
Note A-3.8. lists four basic accessibility dimensions: a clear floor space of at least 800 mm by 1 350 mm, a 1 000 mm clear width for a 90° turn, a 2 100 mm diameter for a 180° turn in one motion and a 1 700 mm diameter for a 180° turn in multiple motions. Our post on barrier-free design in NBC Section 3.8 covers the numbers in the requirements themselves.
A vapour barrier restricts water vapour moving because of vapour pressure differences, while an air barrier restricts air moving because of air pressure differences. A vapour barrier does not have to be continuous or sealed to do its job, but an air barrier must be continuous and fully sealed.
Section 2 is the only open-book section of the ExAC. The 2026 Preparation Guide (p. 12) permits paper copies of the NBC 2020, without the provincial adaptations, and the NECB 2020. Your copies may be annotated, highlighted and tabbed, but you may not add pages, such as an index or a table, or make any mark once in the room. The ExAC Framework Document (p. 9) adds that digital versions of the code books are not permitted.
Our guide on how to tab the NBC 2020 covers the full tab set. For the Notes, these habits save the most time:
The free NBC tabs sample shows a labelled set you can copy.
Take this practice item, our own example rather than a real exam question: Under the NBC 2020, a police station without detention quarters is classified as which major occupancy? A) Group A, Division 2. B) Group B, Division 1. C) Group D. D) Group F, Division 2. Work it in this order:
Classification is Sentence 3.1.2.1.(1) in Division B, on p. 3-1.
It requires classification by Table 3.1.2.1. and ends with "(See Note A-3.1.2.1.(1).)".
Table 3.1.2.1. on p. 3-2 describes Group D as business and personal services occupancies and Group B, Division 1 as detention occupancies.
Open the Notes to Part 3 (from p. 3-225) and find A-3.1.2.1.(1) on p. 3-226.
Police stations without detention quarters are listed under Group D on p. 3-228; those with detention quarters are under Group B, Division 1 on p. 3-227.
The Note illustrates the table and overrides nothing, and both agree: the answer is C, Group D.
The same route works for definitions through A-1.4.1.2.(1), for spatial separation through A-3.2.3. and for alternative solutions through A-1.2.1.1.(1)(b), which our post on NBC alternative solutions unpacks. If a Note does not settle the question within a minute, answer from the requirement and move on; our post on Section 2 pacing explains why. Practise the marker-to-Note jump until it is automatic, and the Notes become a quiet advantage of the open book.
The appendix notes are the explanatory Notes of the NBC 2020. Each is numbered with an "A-" prefix and the number of the provision it explains, and the Notes for each Part are printed together at the end of that Part under the heading "Notes to Part". Candidates still call them Appendix A after the name used in earlier editions.
No, the NBC explanatory Notes are not mandatory. The Code states that they are included for explanatory purposes only and do not form part of the requirements. The Sentence a Note explains is the requirement, and the Note shows how it is meant to be read.
Look for the "(See Note ...)" marker at the end of the Sentence or beside the heading. The Note number matches the provision, so open the Notes to Part section of the same Part, which starts on p. 3-225 for Part 3 and on p. 9-511 for Part 9, and find that number.
The Part 9 Notes are in Volume 2, at the end of Part 9, on pp. 9-511 to 9-662. Some Part 9 requirements point to Part 3 Notes in Volume 1, such as Sentence 9.10.14.2.(2), which refers to Note A-3.2.3.1.(4) on p. 3-236.
Yes, you can write in your NBC before the ExAC. The 2026 Preparation Guide (p. 12) allows handwritten annotations, highlighting, circling, underlining and tabs. You may not add pages, and you may not make any mark once you are in the examination room.
ExAC objective 5.1.2 asks candidates to explain the Division B appendices and notes in Volume 1 and 2 of the Code (2026 Preparation Guide, p. 17). In the NBC 2020 that means the Notes to Part, Appendix C on climatic and seismic information and Appendix D on fire-performance ratings.
A table note is printed directly under its table and is called up by a superscript number in a table cell, so it is read as part of that table. An NBC Note carries an A- number, sits in the Notes to Part section at the end of the Part, and is explanatory only.
In our experience the most useful NBC Notes for Section 2 are A-3.1.2.1.(1) on occupancy examples, A-1.4.1.2.(1) on defined terms, A-3.2.3. on spatial separation, A-3.8. on barrier-free design, A-9.25.1.1.(2) on air and vapour barriers and A-1.2.1.1.(1)(b) on alternative solutions.