NBC 2020 Part 9 Illustrated

Placeholder page for the supporting reference NBC 2020 Part 9 Illustrated, part of the Examitect reading list for the ExAC.

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NBC Part 9 Illustrated at a glance

Here is the quick-reference summary for Intern Architects opening this resource for the first time.

Full titleNational Building Code of Canada 2020: Part 9, Housing and Small Buildings (Illustrated) (commonly cited as "NBC Part 9 Illustrated" or "Part 9 Illustrated")
PublisherNational Research Council of Canada (NRC). Check nrc-cnrc.gc.ca for current access terms.
EditionAligned with NBC 2020. Earlier editions aligned with NBC 2015 and NBC 2010.
LanguagesEnglish and French
Primary audienceIntern architects, practising architects, and building officials working on housing and small building projects
ScopePart 9 of the NBC, covering Housing and Small Buildings: residential buildings up to three storeys and 600 m² per storey
ExAC relevanceSupporting reference on Examitect's ExAC study plan for Section 2 (Codes). Most useful for Part 9 code questions on housing projects.
Where to accessThrough the NRC. Check with your provincial regulator, as some provide access to members.

Why it matters for the ExAC

ExAC Section 2 tests your ability to apply the NBC 2020 and the National Energy Code of Canada for Buildings (NECB) to real project scenarios. Housing and small buildings appear regularly in Section 2 questions because they are the building type most intern architects encounter early in the Internship in Architecture Program (IAP).

Part 9 questions on the ExAC tend to test specific numbers: the minimum width of a public corridor serving dwelling units, the fire-resistance rating (FRR) required between a garage and a living space, the minimum sound transmission class (STC) between separate suites, and the airtightness requirements for operable windows. These are not conceptual questions. You either know the number or you don't. Part 9 Illustrated helps you internalize these thresholds by presenting them in context, which makes recall faster under exam pressure.

On Examitect's ExAC study plan, NBC Part 9 Illustrated is listed as a supporting reference for Section 2. The primary code reference is the full NBC 2020; this illustrated companion reinforces the visual application of its Part 9 requirements.

ExAC sections

See the ExAC sections table below for study-plan coverage.

What NBC Part 9 Illustrated is

Part 9 of the National Building Code of Canada covers Housing and Small Buildings. It is the section of the NBC that applies to detached and semi-detached houses, townhouses, secondary suites, and other small residential buildings up to three storeys in building height with a building area no greater than 600 m² per storey. Buildings beyond those thresholds move into Part 3 territory, with stricter requirements for structure, fire protection, and egress.

The illustrated companion to Part 9 presents the technical requirements in the same structure as the code but adds drawings and section details that show how the requirements translate to actual construction. If you have ever read a code clause about air barrier lapping, travel distance limits, or fire blocking spacing and found it hard to visualize, the illustrated format closes that gap. The drawings show the dimension in context, which is exactly the kind of understanding ExAC scenario questions test.

Inside Part 9 Illustrated: the key sections

NBC Part 9 is organized into numbered sections covering the full scope of housing construction. The sections most frequently tested on the ExAC are listed below with notes on their exam relevance.

Part 9 section Subject ExAC relevance
9.7 Windows, Doors and Skylights Airtightness ratings, forced-entry resistance, installation clearances, security requirements for windows within 2 m of grade
9.9 Means of Egress Corridor widths, door clear-opening widths, travel distances, landing requirements, emergency egress window dimensions, opening forces
9.10 Fire Protection, Occupant Safety and Accessibility Fire-resistance ratings for separations, STC requirements, smoke alarms, flame-spread ratings, spatial separation, fire blocking, firefighting access
9.25 Heat Transfer, Air Leakage and Condensation Control Air barrier system requirements, vapour barrier permeance (60 ng/(Pa·s·m²) maximum), insulation installation, floors-on-ground details
9.26 Roofing Fastener requirements for asphalt shingles, flashing to masonry, eave protection, valley flashing widths, cedar shake exposure limits

Part 9 also covers foundations, framing, cladding, masonry, mechanical, and electrical requirements. The five sections above are the most exam-focused based on Examitect's ExAC study plan for Section 2.

Key Part 9 terms every ExAC candidate should know

Term Definition
Airtightness rating Classification for windows, doors, and skylights based on measured air leakage. An A2 rating means maximum 1.5 L/(s·m²) for operable units; fixed units must not exceed 0.2 L/(s·m²).
Means of egress The continuous path from any point in a building to a public thoroughfare, including access to exits, exits, and exit discharges.
Travel distance The floor distance from the most remote point to the nearest exit. Limit is 40 m for business/personal services, 30 m for other occupancies, and 45 m in sprinklered buildings.
Fire-resistance rating (FRR) Time in hours or minutes that an assembly resists fire under test conditions. Ranges from 45 minutes (public corridors and exits) to 2 hours (repair garages, incinerator rooms).
Sound Transmission Class (STC) Single-number rating of airborne sound reduction. Part 9 requires STC 50 between separate dwelling units and STC 43 between a secondary suite and the primary dwelling.
Air barrier system Continuous layer controlling air movement through the envelope. Polyethylene must conform to CAN/CGSB-51.34-M and be lapped at least 100 mm at all joints.
Vapour barrier Material with water vapour permeance at or below 60 ng/(Pa·s·m²) (1 perm), installed on the warm side of insulation to prevent condensation within the assembly.
Spatial separation The horizontal distance from a building face to the property line or centre line of a street. Determines allowable percentage of unprotected openings. No unprotected openings permitted less than 1.2 m from the property line.
Flame-spread rating (FSR) Numerical rating of how quickly flame travels across a surface. Exits and public corridors are limited to FSR 25 on 90% of the surface area.
Fire blocking Material placed in concealed cavities to stop fire and smoke spread. Required in concealed spaces deeper than 25 mm: every 3 m vertically and every 20 m horizontally.
Emergency egress window A bedroom window sized to allow escape. Minimum opening area 0.35 m², no dimension less than 380 mm, sill no more than 1 m above floor, no more than 7 m above grade.
Smoke alarm A detection device required in every dwelling unit, each bedroom, and every storey including the basement. Must be interconnected within a unit, with battery backup for at least 7 days and sound pressure of 75 to 110 dBA within the suite.

How Part 9 Illustrated compares to other ExAC references

Knowing where each reference fits helps you reach for the right book during study without second-guessing yourself.

Reference What it covers How it differs from Part 9 Illustrated
NBC 2020 Full National Building Code (Parts 1 through 12) The primary code reference; Part 9 Illustrated focuses on Part 9 specifically with added visual content.
NECB National Energy Code of Canada for Buildings NECB covers energy performance; Part 9 Illustrated covers all Part 9 building requirements, not just energy.
CHING Building construction illustrated, international scope CHING is a general construction reference without Canadian code specifics; Part 9 Illustrated is code-binding in Canadian jurisdictions.
CHOP Canadian Handbook of Practice: professional practice CHOP covers project delivery, contracts, and practice management; Part 9 Illustrated covers technical code compliance for housing.
RSMeans Construction cost data RSMeans is a cost reference; Part 9 Illustrated is a code compliance reference.
Yardsticks Canadian construction cost data Yardsticks covers cost benchmarks; Part 9 Illustrated covers regulatory requirements.

How to study NBC Part 9 Illustrated for the ExAC

  • Start with 9.9 and 9.10. These two sections contain the most frequently tested specific numbers: travel distances, door widths, fire-resistance ratings, smoke alarm requirements, and flame-spread limits. Study them first and revisit them last as a final check.
  • Build a critical-numbers cheat sheet. As you work through each section, pull every threshold into a one-page table: minimum corridor widths, maximum travel distances, fire ratings by assembly type, STC minimums, and air barrier lapping requirements. The act of writing them down is part of the memorization.
  • Sketch the details by hand. Redraw the key diagrams yourself, without looking at the reference: a means-of-egress plan, an air barrier joint detail, a fire separation wall section. Drawing fixes dimensions in memory more reliably than re-reading.
  • Cross-reference the main NBC 2020 text. Use Part 9 Illustrated to understand visual application, then find the corresponding clause number in the main NBC 2020 code. ExAC answers sometimes require you to cite the code, not just the concept.
  • Apply Part 9 to a notional housing project. Work through a two-storey house with a secondary suite and check each section you have studied for compliance. Scenario application converts passive reading into the active recall the ExAC tests.
  • Know what sprinklering changes. Several Part 9 limits relax in sprinklered buildings: travel distance increases from 40 m to 45 m, emergency egress windows may not be required in sprinklered bedrooms, and maximum opening sizes in fire separations double. Sprinklering trade-offs appear regularly in Section 2 questions.

ExAC sections NBC Part 9 Illustrated supports

ExAC Section How Part 9 Illustrated shows up
Section 1 (Design and Analysis) Limited. Housing schematic design and programming may reference Part 9 scope limits (three storeys, 600 m²), but CHOP and CHING are the primary references for this section.
Section 2 (Codes) Primary use. NBC Part 9 Illustrated is a supporting reference on Examitect's ExAC study plan for Section 2. Most Part 9 code questions appear here, covering housing egress, fire protection, envelope performance, and fenestration.
Section 3 (Sustainability and Final Project) Moderate. Section 9.25 on air barriers and vapour barriers connects directly to building envelope and building science topics in Section 3. Study 9.25 alongside your envelope performance notes.
Section 4 (Construction and Practice) Limited. CHOP and CCDC documents are the primary references for practice management and construction administration. Part 9 Illustrated is not a practice reference.

Tips for Intern Architects reading Part 9

Tip 1, Start with egress and fire, not fenestration. Sections 9.9 and 9.10 are where the exam goes most often. Get comfortable with corridor widths (1.1 m minimum for public corridors), door clear widths (810 mm minimum for a single door), travel distances, and fire-resistance ratings before you spend time on window airtightness ratings. The highest-yield numbers are in those two sections.

Tip 2, Memorize the fire-resistance rating matrix. Part 9 has specific FRR requirements depending on the assembly type: 45 minutes for public corridors and exits, 45 minutes for individual residential suites up to one storey, 1 hour for suites two or more storeys, 1 hour for storage garages up to five cars, and 2 hours for repair garages. Know each one cold.

Tip 3, Treat the air barrier and vapour barrier as two separate systems. Candidates often conflate the two. The air barrier controls air movement (poly conforming to CAN/CGSB-51.34-M, lapped 100 mm minimum). The vapour barrier controls moisture diffusion (permeance at or below 60 ng/(Pa·s·m²), installed on the warm side). An exam question may ask about one, the other, or the relationship between them.

Tip 4, Know the sprinklering trade-offs. In a sprinklered Part 9 building: travel distance increases to 45 m, bedroom emergency egress windows may not be required, and maximum opening areas in fire separations double. These trade-offs make sprinklering a common exam theme, especially in scenario questions about residential design decisions.

Tip 5, Learn the STC requirements for suites. The STC values are specific and testable: STC 50 between separate dwelling units, STC 43 between a secondary suite and the primary dwelling. Knowing which applies in which situation is exactly the kind of detail Part 9 questions probe.

Tip 6, Connect roofing details to your specifications knowledge. Part 9.26 specifies fastener types, head diameters, shank diameters, lapping requirements, and flashing dimensions for common roofing systems. If you are also studying specifications and construction documents for Section 3, the roofing material specs in Part 9 reinforce what goes into Division 07 of a spec.

Common ExAC scenarios where Part 9 is the answer

  • You are reviewing permit drawings for a two-storey house with an attached garage (capacity five cars). What fire-resistance rating is required for the separation between the garage and the living space?
  • A client asks whether the bedroom in an unsprinklered new house requires an emergency egress window. What are the minimum dimensions for the opening, and what is the maximum sill height?
  • A public corridor in a low-rise residential building serves two dwelling units. The contractor has framed it at 1.0 m clear. Does it comply with Part 9?
  • An inspector raises a concern about smoke alarm interconnection in a new single-family dwelling. What does Part 9 require for the location, interconnection, and backup power of smoke alarms?
  • The drawings show a travel distance of 43 m from the most remote bedroom to the nearest exit in a non-sprinklered residential building classified as a business and personal services occupancy on the ground floor. Is this compliant?
  • A contractor proposes using loose-fill mineral fibre insulation in a sloped unconfined roof space. What is the maximum slope permitted for this installation under Part 9?
  • You are specifying the separation wall between a primary dwelling and a secondary suite in the same building. What is the minimum STC rating required, and what is the minimum gypsum board thickness for a smoke-tight barrier?

How Examitect reinforces NBC Part 9

Examitect's ExAC practice questions for Section 2 include scenario-based questions tied directly to Part 9 housing and small buildings requirements. Each question links its answer explanation to the specific NBC clause, so you can trace the reasoning back to the code rather than just memorizing a number in isolation.

When a question tests a Part 9 threshold, the explanation walks through why the number exists, what changes if the building is sprinklered, and which assembly type or occupancy classification triggers a different requirement. That context is what turns a correct answer on one question into reliable recall across related questions.

If you are working through Examitect's ExAC study plan for Section 2, NBC Part 9 Illustrated is the recommended companion for the housing code questions. Start your reading there, then test your retention with a free practice question before committing to a full plan.

NBC Part 9 Illustrated FAQ

Part 9 of the National Building Code of Canada (NBC) 2020 covers Housing and Small Buildings. It applies to residential buildings and other small buildings up to three storeys in building height, with requirements for structure, enclosure, fire protection, means of egress, and building services for those building types. Buildings exceeding three storeys or 600 m² per storey fall under Part 3 instead.

The NBC 2020 code presents requirements as text-based clauses, tables, and footnotes. Part 9 Illustrated adds drawings and section details showing how those requirements apply in real construction. For ExAC candidates who learn visually, the illustrated format makes it easier to internalize how specific dimensions and ratings translate to building details before exam day.

Yes. NBC 2020 Part 9 Illustrated is listed as a supporting reference on Examitect's ExAC study plan for Section 2 (Codes). The primary reference for Section 2 is the full NBC 2020, but the illustrated companion is recommended for candidates who want a more visual approach to Part 9 housing code requirements.

Based on Examitect's ExAC study plan, the most exam-relevant Part 9 sections are 9.9 (Means of Egress), 9.10 (Fire Protection, Occupant Safety and Accessibility), and 9.25 (Heat Transfer, Air Leakage and Condensation Control). These sections contain specific numbers that ExAC questions test directly: travel distances, fire-resistance ratings, STC values, and air barrier requirements.

Part 9 requires a Sound Transmission Class (STC) rating of 50 minimum for walls between separate dwelling units. For the wall between a secondary suite and the primary dwelling within the same building, the minimum STC is 43. Knowing which threshold applies in which situation is a common exam distinction.

Under Part 9, the maximum travel distance is 40 m (131 ft.) for business and personal services occupancies and 30 m (98 ft.) for other occupancies. In sprinklered buildings, both limits increase to 45 m (148 ft.). Dead-end corridors are limited to 6 m (20 ft.) regardless of sprinklering.

Part 9 applies to residential buildings up to three storeys in building height with a building area of 600 m² or less per storey. Buildings that exceed those limits fall under Part 3 of the NBC, which has more stringent requirements. Many apartment buildings fall under Part 3, not Part 9, so always confirm the applicable Part before applying specific requirements.

Use Part 9 Illustrated to understand the visual application and intent of the requirements, then cross-reference the specific clause number in the NBC 2020 text when you need precise regulatory language. Examitect's Section 2 practice questions link each answer to a specific NBC clause, so you can trace reasoning from the scenario back to the code and back to the illustrated detail.

Other ExAC reference books

The five primary ExAC references each get their own guide on Examitect.

CHING

Building Construction Illustrated: the visual reference for building systems and construction methods, used across Sections 1 and 3.

CHOP

Canadian Handbook of Practice: the RAIC's guide to architectural practice, contracts, and construction administration. Covers Sections 1, 3, and 4.

NBC 2020

National Building Code of Canada: the primary code reference for ExAC Section 2, covering all Parts from structural loads to Part 9 housing.

NECB

National Energy Code of Canada for Buildings: the energy performance standard tested alongside the NBC in ExAC Section 2.

RSMeans

RSMeans Cost Data: the construction cost reference used for cost management and estimating questions in ExAC Section 1.

Supporting References

See the full list of extended references on Examitect's ExAC study plan, including CCDC contracts, RAIC documents, and specialty guides.