Barrier-free design in NBC 2020 Section 3.8 comes down to a short list of dimensions: a 1 000 mm path, 850 mm doorways, ramps no steeper than 1 in 12 and a 1 700 mm turning circle. Section 2 is open book; Section 1 is not, and three of its objectives name universal accessibility. In our experience, candidates who know these numbers cold answer faster in both. This guide from Examitect, an independent ExAC prep platform unaffiliated with the CACB, gives every number with its article.
| Where it lives | NBC 2020, Division B, Part 3, Section 3.8. Accessibility, from page 3-173 |
|---|---|
| ExAC objectives | 5.2.4 (Section 2); 2.2.4, 6.1.4 and 7.1.4 (Section 1) |
| Structure | 3.8.1 Scope, 3.8.2 Application, 3.8.3 Design |
| Design standard option | CSA B651-18, the clauses in Table 3.8.3.1., in their entirety |
"Memorizing" sounds odd for a code topic, because Section 2 is open book. The 2026 ExAC Preparation Guide (p.12) allows paper copies of the NBC 2020, without provincial adaptations, and the NECB 2020, tabbed and annotated beforehand, in the Section 2 exam only. But Appendix 1 of the Guide names accessibility four times:
| Objective | Wording in the 2026 Preparation Guide | Exam section |
|---|---|---|
| 2.2.4 | Describe impacts of universal accessibility on site design (p.15) | Section 1, closed book |
| 5.2.4 | Interpret the Code requirements concerning barrier-free design (p.17) | Section 2, open book |
| 6.1.4 | Explain the scope of the analysis of the building Code and of universal accessibility at the schematic design phase (p.18) | Section 1, closed book |
| 7.1.4 | Describe the impact of the analysis of the building Code and of universal accessibility at the design development phase (p.18) | Section 1, closed book |
Those three Section 1 objectives are why some numbers belong in memory. A schematic design question might ask what a 1 in 12 ramp does to a sloping site, or whether a washroom core fits a 1 700 mm turning circle, with no code on the desk. Section 3 never names accessibility, though objective 8.6.1 asks you to verify that products, materials and assemblies conform to standards and codes.
In Section 2, the numbers save time. The ExAC Framework Document (p.5) gives Section 2 about 75 multiple-choice questions in a three-hour session. If you know a doorway needs 850 mm clear, you open the book to confirm, not to hunt. Our post on Section 2 pacing explains why those saved minutes matter.
Division A defines barrier-free as meaning "that a building and its facilities can be approached, entered, and used by persons with physical or sensory disabilities." Section 3.8., titled Accessibility, has three Subsections: 3.8.1. Scope, 3.8.2. Application (where) and 3.8.3. Design (how).
Section 3.8 applies to all buildings except:
Sentence 2.1.1.2.(5) of Division A excludes the same three groups from objective OA, Accessibility (OA1 Barrier-Free Path of Travel and OA2 Barrier-Free Facilities), a link that matters for alternative solutions under the NBC.
Part 9 buildings are not off the hook. Article 9.5.2.1. sends every building to Section 3.8, except as provided in Articles 9.5.2.3. and 3.8.2.1. Article 9.5.2.3. lets an apartment building without an elevator limit the path to the entrance level, and drops it where every dwelling unit is more than 600 mm above or below that level. See NBC 2020 Part 3 versus Part 9.
Every pedestrian entrance to a barrier-free storey must be barrier-free, apart from service entrances and some suite entrances (Sentence 3.8.2.2.(1)). From them, the path runs throughout the entrance storey and all other normally occupied floor areas. Sentence 3.8.2.3.(2) lists where a wheelchair path is not required, such as service rooms, janitors' rooms, crawl spaces, attics and high-hazard industrial areas.
Clause (g) is the one examiners like. In buildings no more than 2 storeys high, the floor above or below the entrance level is exempt unless it is served by a passenger elevator, platform lift, escalator or inclined moving walk, is 600 m2 or more in floor area, holds facilities integral to the entrance level's principal function, or contains an assembly occupancy over 100 m2. Note A-3.8.2.3.(2)(g) gives the classic case: a restaurant whose only washrooms are in the basement must have a barrier-free path to them.
Barrier-free buildings are designed to Subsection 3.8.3. or to the CSA B651 provisions listed in Table 3.8.3.1. "in their entirety" (Table 1.3.1.2. of Division B lists CSA B651-18). Note A-3.8.3.1.(1) is blunt: no mixing provisions from the two.
Note A-3.8. opens with four "basic accessibility requirements" that explain most of the rest: an 800 mm by 1 350 mm clear floor space, a 1 000 mm clear width for a 90° turn, a 2 100 mm circle for a 180° turn in one motion, and a 1 700 mm circle for a 180° turn in multiple motions. Every value below is from Division B of the NBC 2020.
| Item | NBC 2020 value | Reference |
|---|---|---|
| Path of travel clear width | Not less than 1 000 mm | 3.8.3.2.(1) |
| Short narrowing | 850 mm for no more than 600 mm of length | 3.8.3.2.(2) |
| Paths over 24 m long | Widen to 1 700 mm for 1 700 mm at intervals of 24 m or less | 3.8.3.2.(5) |
| Turning space after a narrow run | 1 700 mm circle, 1 700 by 1 500 mm, or a 1 700 by 1 500 mm T (for sections under 1 500 mm wide and over 12 m long) | 3.8.3.2.(6) |
| Changes in level | 6 to 13 mm bevelled at 1 in 2; over 13 mm needs a sloped floor or ramp | 3.8.3.2.(3) |
| Exterior walk width | Not less than 1 600 mm | 3.8.3.3.(1) |
| Ramp width and slope | 1 000 mm clear; 1 in 12 maximum | 3.8.3.5.(1) |
| Ramp landings | 1 700 by 1 700 mm at top, bottom and doors; 1 350 mm long every 9 m and at abrupt turns | 3.8.3.5.(1) |
| Ramp handrails and edges | Handrails 865 to 965 mm high; 75 mm curb or rail within 100 mm of the surface | 3.8.3.5.(1) and (5) |
| Doorway clear width | Not less than 850 mm with the door open | 3.8.3.6.(2) |
| Threshold | Not more than 13 mm, bevelled | 3.8.3.6.(5) |
| Door opening force | 38 N exterior swinging; 22 N interior swinging or sliding | 3.8.3.6.(8) |
| Latch-side clearance | 600 mm if the door swings toward you; 300 mm if it swings away | 3.8.3.6.(11) |
| Clear floor space at a swinging door | Pull side 1 700 by 1 500 mm; push side 1 200 by 1 500 mm | 3.8.3.6.(14) and (15) |
| Platform lift | 1 500 by 1 000 mm floor; gates 850 mm (short side) or 1 000 mm (long side) | 3.8.3.7.(1) |
| Accessible stall | 1 500 by 1 500 mm; transfer space 1 500 by 900 mm; 1 700 by 1 700 mm in front | 3.8.3.12.(1) |
| Water closet | Centre line 460 to 480 mm from side wall; seat 430 to 460 mm high | 3.8.3.12.(1)(e) and 3.8.3.14.(1) |
| L-shaped grab bar | Legs 760 mm minimum; horizontal 750 to 850 mm above the floor | 3.8.3.12.(1)(f) |
| Universal washroom turning space | 1 700 mm diameter | 3.8.3.13.(1) |
| Lavatory | Rim 865 mm maximum; knee clearance 735 mm high at the front edge | 3.8.3.16.(1) |
| Service counter | 800 mm long minimum, 865 mm high maximum; knee space 800 by 685 by 485 mm | 3.8.3.20.(1) |
If you memorize one number, make it 1 700 mm: the ramp landing, the pull-side door space, the space in front of the accessible stall, the universal washroom turning circle and the widening on long corridors.
Every ExAC cycle, the post-exam debriefs our team runs with candidates turn up the same mix-ups here.
A direct exterior path must link a barrier-free entrance to the barrier-free parking area and passenger-loading zone, where provided, and to a public thoroughfare. Exterior walks on it are 1 600 mm wide, and a loading zone needs a 1 500 by 6 000 mm access aisle (Article 3.8.3.4.). This is objective 2.2.4 territory, so expect it in Section 1 too.
Parking is a trap. The NBC does not mandate a number of accessible spaces. Note A-3.8.2.5. offers guidance where bylaws are silent, and an option calling it "required by the NBC" is wrong.
The table has the widths, slope and landings. Run the arithmetic once: a 750 mm rise at 1 in 12 already takes about 9 m of ramp, the most allowed between landings. Note A-3.8.3.5.(1)(b) calls 1 in 20 "safer and less strenuous" and suggests limiting 1 in 12 ramps to 3 m where space is tight. Ramps steeper than 1 in 15 need hard or resilient surfaces.
Clause 3.8.3.5.(1)(e) borrows the handrails of Article 3.4.6.5. but sets their height at 865 to 965 mm. And Article 3.8.3.5. is ramps; Article 3.8.3.3. is exterior walks.
The 850 mm doorway is measured with the door open, from the face of the door to the stop on the frame (Note A-3.8.3.6.(2)), so a nominal 850 mm frame does not pass. Closers on interior doors take at least 3 s to move from 70° open to 75 mm from closed (Sentence 3.8.3.6.(10)).
Power door operators are a scoping question. Article 3.8.2.7. requires them on self-closing doors at barrier-free entrances (vestibule doors included), along the path to suites and rooms off public corridors, and at washrooms with a barrier-free water closet. Their controls sit within 1 500 mm of the door swing, operable at 150 to 300 mm and 900 to 1 100 mm above the floor (Sentence 3.8.3.6.(6)).
At each location where washrooms are provided on a storey that needs a barrier-free path, at least one universal washroom is required. A washroom with more than two water closets, or more than one water closet and one urinal, needs one barrier-free stall. Washrooms inside residential or care suites are exempt from both. Larger Group A, Group B, Division 2 and Group E buildings (occupant load over 500) also need an accessible change space with an adult-sized change table (Sentence 3.8.2.8.(15)).
The accessible stall in Article 3.8.3.12. has an 850 mm door that swings out unless the stall has extra room. The universal washroom in Article 3.8.3.13. is a room with one water closet and one lavatory, a door lockable from inside and releasable from outside, and a 1 700 mm turning space. The grab bars themselves are covered in Subsection 3.7.2., Plumbing Facilities, not Section 3.8: Article 3.7.2.7. sets 30 to 40 mm diameter, 35 to 45 mm clearance from the wall and resistance to a 1.3 kN load.
Section 3.8 does not size elevator cabs. Article 3.5.2.1. sends elevators to provincial or territorial regulations, municipal bylaws or ASME A17.1/CSA B44, and Sentence 3.5.2.1.(3) requires passenger elevators to conform to its Appendix E. Section 3.8 covers platform-equipped devices: Article 3.8.3.7. requires CSA B355 and the sizes in the table. For floors above or below the first storey that are not sprinklered and have a barrier-free path, Article 3.3.1.7. adds a fire-safety layer: a protected elevator, two zones divided by fire separations normally rated at least 1 h, balconies in residential occupancies, an exterior exit at ground level, or a ramp to ground level.
Signs must mark barrier-free entrances, washrooms, showers, elevators, parking spaces and assistive listening systems (Sentence 3.8.2.10.(1)), with the International Symbol of Access or its hearing-loss version (Sentence 3.8.3.9.(3)). Tactile door signs are centred 1 500 mm above the floor (Sentence 3.8.3.9.(2)). In assembly buildings, classrooms, auditoria, meeting rooms and theatres over 100 m2 need an assistive listening system covering the entire seating area (Sentences 3.8.2.9.(1) and 3.8.3.19.(1)). Table 3.8.2.3. sets wheelchair spaces in fixed seating: 2 spaces for 2 to 99 seats, then 3 plus 1 for each 70 seats over 100, up to 499.
Section 1 drawings and Section 2 scenarios reward the same habit: trace the path the way a wheelchair user would, from the street to the facility.
Rule out the Article 3.8.2.1. exceptions, and for a Part 9 building check Articles 9.5.2.1. and 9.5.2.3.
Link each barrier-free entrance to parking, the loading zone and the public thoroughfare, with 1 600 mm exterior walks.
Apply Sentence 3.8.2.3.(1) and test each exemption in Sentence 3.8.2.3.(2), especially Clause (g).
Check 1 000 mm clear width, the 850 mm narrowing rule, 1 700 mm widening every 24 m and turning spaces after narrow runs.
Over 13 mm needs a ramp or sloped floor; check ramp slope, landings and handrails, or a platform lift.
Look for 850 mm clear width, latch-side clearance, clear floor space, vestibule depth and power operators.
Confirm washroom counts, stall and universal washroom sizes, counters, signs and listening systems.
In the Section 2 room, three tabs carry this route: Section 3.8 itself (page 3-173), the start of Subsection 3.8.3. with Table 3.8.3.1. (page 3-177), and Note A-3.8. (page 3-266). Check those pages against your own printing. The free NBC tabs sample shows a labelled set. Learn the 1 700 mm family, the 850 mm door and the 1 in 12 ramp, and barrier-free design becomes one of the steadier sets of marks on the exam.
The minimum clear width of a barrier-free path of travel is 1 000 mm under Sentence 3.8.3.2.(1) of Division B. Exterior walks on the path must be at least 1 600 mm wide under Clause 3.8.3.3.(1)(b).
A ramp in a barrier-free path of travel can be no steeper than 1 in 12 under Clause 3.8.3.5.(1)(b) of the NBC 2020. It needs a clear width of 1 000 mm, 1 700 mm by 1 700 mm level areas at the top and bottom, and 1 350 mm long landings at intervals of no more than 9 m.
A doorway in a barrier-free path of travel needs a clear width of at least 850 mm with the door open, under Sentence 3.8.3.6.(2) of the NBC 2020. Note A-3.8.3.6.(2) says the width is measured from the face of the open door to the stop on the frame, not across the frame opening.
Article 3.8.2.1. exempts detached and semi-detached houses, houses with a secondary suite, duplexes, triplexes, townhouses, row houses and boarding houses, Group F, Division 1 buildings, and buildings not occupied on a daily or full-time basis. Part 9 buildings are covered through Article 9.5.2.1.
Note A-3.8. of the NBC 2020 gives a 1 700 mm diameter for a 180° turn in multiple motions and 2 100 mm for one motion. The code requires 1 700 mm in universal washrooms (Clause 3.8.3.13.(1)(j)) and, with a 1 700 by 1 500 mm or T-shaped option, after long narrow corridor sections (Sentence 3.8.3.2.(6)).
Yes, Article 3.8.3.1. of the NBC 2020 lets you design to the CSA B651 provisions listed in Table 3.8.3.1. instead of Subsection 3.8.3., but only in their entirety. Note A-3.8.3.1.(1) says you cannot mix provisions from the NBC and the standard. The referenced edition is CSA B651-18.
You do not need the whole Section, but the core numbers are worth knowing cold. Section 2 is the only open-book section, and Section 1 objectives 2.2.4, 6.1.4 and 7.1.4 in the 2026 ExAC Preparation Guide test universal accessibility at the site, schematic and design development stages with no code book on the desk.
The NBC 2020 requires a barrier-free path from a designated barrier-free parking area, where one is provided, under Article 3.8.2.5. It does not mandate the number of spaces. Note A-3.8.2.5. offers guidance, one space per 100 once more than 50 are provided, only where local bylaws are silent.