Door Width Requirements for Accessible Buildings

What This Requirement Covers

Door width requirements for accessible buildings set the minimum clear opening and related doorway dimensions to ensure people with disability - including wheelchair users, people using mobility aids, and those with limited vision - can enter, exit and move through buildings safely and independently. These requirements exist to provide equitable access to buildings and services, to meet the functional needs of an ageing population, and to satisfy legal accessibility obligations in the National Construction Code (NCC) and referenced Australian Standards.

The rules apply to buildings and parts of buildings that the NCC requires to be accessible. That includes many public, commercial, institutional and some multi-residential buildings (Classes 2 to 9 and parts of Class 1 buildings that are required to be accessible), as well as routes from accessible car parking and the principal pedestrian entrance. The NCC references Australian Standard AS 1428.1 for detailed doorway and threshold requirements; those Standards, together with specific NCC clauses and state schedules, give the measurable door width and threshold provisions designers and builders must follow.

Key Requirements

1. Clear opening width: 850 mm - Where a doorway on an accessway has multiple leaves (except an automatic opening door), at least one leaf must provide a clear opening width of not less than 850 mm in accordance with AS 1428.1, as specified in NCC Volume One, D4D3(5).
2. Accessible pedestrian entrances coverage - In buildings required to be accessible, an accessway must be provided through the principal pedestrian entrance and through at least 50% of pedestrian entrances; where multiple doorways serve a pedestrian entrance, the NCC treats the doorway as the clear unobstructed opening (see NCC Volume One, D4D3(2)-(4)).
3. Thresholds and level transitions - Thresholds must not incorporate a step or ramp closer to the doorway than the width of the door leaf except in specified cases; for doorways in buildings required to be accessible, threshold ramps or step ramps must comply with AS 1428.1, as set out in SA D3D16 and clauses addressing thresholds in NCC Volume One (see SA D3D16(1)
4. (c) and related provisions).
5. Automatic and powered doors - Where required (for example in certain healthcare and some public amenity contexts) the NCC and companion provisions specify automated entrance doors with appropriate clear opening widths (see provisions such as S27C9 for special facilities and references to AS 1428.1 for automated door controls and operation).
6. Special-use provisions - Doors and doorways in special-use buildings (for example public transport facilities, Class 9b, and parts of Class 9a) must comply with clauses in AS 1428.2 as referenced in NCC Volume One (see I2D5, I2D3 and related clauses).
7. Referenced Standards
8. AS 1428.1 (Design for access and mobility - General requirements for access - New building work) - primary technical standard for clear opening widths, thresholds, manoeuvring space, door hardware and contrast requirements.
9. AS 1428.2 (Design for access and mobility - Enhanced and additional requirements) - where the NCC references enhanced access requirements for ramps, doors and related elements in special buildings.
10. Where relevant, other Australian Standards may be referenced for associated works (for example AS 1735.12 for lifts, and building material standards referenced elsewhere in the NCC).
11. Exact clause references (examples)
12. NCC Volume One, D4D3 - Accessway door and pedestrian entrance coverage and doorway definition, and D4D3(5) requiring an 850 mm clear leaf where multiple leaves exist on an accessway doorway.
13. SA D3D16 (Thresholds) - restrictions on steps or ramps in the immediate threshold zone and requirement that doorways in buildings required to be accessible use threshold ramps in accordance with AS 1428.1.
14. NCC Volume One, I2D5 - Doorways and doors in special-use buildings must comply with clause 11 (except clause 11.5.2) of AS 1428.2.

Note: AS 1428.1 contains detailed diagrams and measurement methods for determining the required clear opening (for example how to measure clear opening width with door leaves and hardware in place) and should be consulted for design details and tolerances.

Residential vs Commercial

1. Residential (Class 1 and Class 10):
2. Typical single dwelling houses (Class 1a) are generally not required to be fully accessible by the NCC unless specific provisions or local requirements apply (for example if alterations trigger access provisions or if the dwelling contains a publicly accessible part). Where accessible design is incorporated voluntarily or mandated by other instruments (e.g. Housing for older persons, state housing provisions), designers adopt AS 1428.1 clear-opening guidance. The NCC’s Part D4 access obligations are primarily directed at buildings required to be accessible rather than ordinary detached dwellings.
3. Class 1 dwellings containing sole-occupancy units may be subject to different provisions when they form part of multi-residential developments (see NCC Volume One schedules and Class 2 references). Where dwellings are required to provide accessible entrances (for example in multi-unit developments subject to accessible housing provisions), designers should adopt the 850 mm clear opening where an accessible accessway is involved and follow AS 1428.1 for thresholds and manoeuvring clearances.
4. Commercial / Public (Class 2 to 9):
5. Most commercial, institutional and public buildings that the NCC requires to be accessible must meet the explicit accessway and doorway provisions in Part D4 and referenced Standards. For such buildings the 850 mm clear opening requirement on an accessway doorway leaf applies, thresholds must meet AS 1428.1, and entry coverage (percentage of entrances that must be accessible) applies as set out in NCC Volume One, D4D3(2)-(4).
6. Special building classes (for example Class 9a health-care, Class 9b public transport) have additional or altered requirements in the NCC and associated parts (see SA D3D16 for some threshold exceptions and I2D5/I2D3 for special-use door requirements).

Exceptions and Exemptions

1. Threshold and sill exceptions: SA D3D16 allows limited exceptions for thresholds in certain clinical or resident care areas where the door sill may differ in height (for example patient care areas in Class 9a where door sill may be up to 25 mm) and where a ramp with specified gradient is provided in resident use areas of Class 9c.
2. Exempted entrances and areas: The NCC allows exemptions for certain pedestrian entrances or areas (see D4D5 and related clauses). For example, small ancillary entrances that serve exempted areas need not be accessible; the NCC also limits the coverage requirement when a building has only a small number of doorways.
3. Alternative solutions: The NCC permits performance-based or alternative solutions where compliance with the Deemed-to-Satisfy provisions is not feasible. An alternative solution must demonstrate equivalent or better access outcomes, with verification through evidence such as expert engineering, accessibility testing, or building certifier acceptance. Where an alternative solution is used, designers must clearly document how the alternative provides equivalent functionality to the specified clear opening and threshold requirements and cite the relevant NCC performance provisions.

State and Territory Variations

1. State schedules in NCC Volume One: Each state and territory may publish schedules that modify or add to national provisions. The NCC instructs users to check the relevant state schedule (Schedules 4-12) for jurisdictional changes. Examples include:
2. South Australia and other jurisdictions include SA D3D16-style provisions addressing thresholds and sill heights; check the state schedule for the specific textual form and any local numerical differences.
3. Queensland, New South Wales, Victoria, Western Australia, Tasmania, the Northern Territory and the Australian Capital Territory may have specific local amendments or administrative requirements affecting how access provisions are applied (for instance, different triggers for accessible housing provisions, or expanded requirements for public transport facilities).
4. Practical step: Always verify the applicable state schedule in NCC Volume One and any state building authority guidance (for example disability access guides and local planning requirements) because the national clauses reference but do not replace state-level amendments.

Practical Compliance Tips

1. Check whether the building is “required to be accessible” under Part D4 before applying the door-width rules - this determines whether the 850 mm clear-leaf requirement and entrance coverage rules apply.
2. Use AS 1428.1 as the technical reference for measuring clear opening width and thresholds - measure the clear opening with door hardware and seals in place, and follow the Standard’s method for clearances and manoeuvring space.
3. Provide at least one leaf with a minimum 850 mm clear opening on any accessway doorway with multiple leaves; where single-leaf doors are used, ensure the clear opening after swing and hardware is sufficient for intended users.
4. Design thresholds to comply with AS 1428.1 - avoid steps or abrupt lips at the threshold; where small sill heights are unavoidable, supply compliant threshold ramps and record the justification in the documentation.
5. Consider future-proofing by designing to wider clear openings (for example 900 mm to 1000 mm) where possible - this improves usability for larger mobility aids, parent/child combinations and furniture movement, and reduces the risk of noncompliance during later fitout changes.
6. Coordinate door hardware, closers and architraves early in design - heavy closers, large architraves or inward-opening leaves that reduce clear opening can unintentionally reduce the usable clear width below required minimums.
7. Verify state schedule differences and council/certifier expectations early - provide clear references to the NCC clause (for example NCC Volume One, D4D3(5)) and AS 1428.1 clause numbers in documentation submitted for approval.

Citations

1. NCC 2022 Volume One - Building Code of Australia, Part D4 (Access and Egress), D4D3 (doorway and pedestrian entrance coverage) and D4D3(5) (850 mm clear leaf requirement).
2. SA D3D16 - Thresholds (state amendment example addressing thresholds and exception cases).
3. NCC 2022 Volume One, I2D5 and I2D3 - Doorways, ramps and doors in special-use buildings referencing AS 1428.2.
4. AS 1428.1 - Design for access and mobility: General requirements for access - New building work (for clear opening measurement, manoeuvring space, threshold ramps and door hardware requirements).

Note: This article summarises the NCC and Standards requirements relevant to doorway widths for accessible buildings. For project-specific applications, always consult the full NCC text, the applicable state schedule in NCC Volume One, and AS 1428.1 (and AS 1428.2 where applicable). If the documentation available does not clearly address a complex or unusual scenario, confirm with a registered building certifier or accessibility specialist.