AS 1428.1:2021 Explained: Accessible Signage Specifications You Can't Ignore

AS 1428.1:2021 is the Australian Standard that governs accessible signage in buildings. It's referenced by the National Construction Code, which means compliance isn't optional — it's a condition of occupancy certification for new buildings and significant renovations.

This standard covers everything from letter dimensions to braille placement to the amount of contrast between a sign and the wall it's mounted on. If you're responsible for specifying, manufacturing, or maintaining signage in Australian buildings, these numbers matter.

What is AS 1428.1:2021?

The full title is "Design for Access and Mobility — General Requirements for Access." It's the fourth edition of the standard, published in 2021, replacing the 2009 version.

AS 1428.1 doesn't just cover signage — it covers ramps, doorways, corridors, lifts, and other access provisions. But the signage requirements are among the most frequently referenced sections, particularly by sign manufacturers and building certifiers.

The standard is referenced directly by NCC Specification 15 (Braille and Tactile Signs), which makes these specifications legally enforceable through the building code.

Character specifications

Height

Upper case character height must be between 15 mm and 55 mm. For exit door identification specifically, the minimum increases to 20 mm.

This range exists for a reason. Characters smaller than 15 mm are difficult to perceive by touch. Characters larger than 55 mm require too much tactile exploration to identify quickly.

Tactile relief

Characters must be raised between 1 mm and 1.5 mm above the sign surface. This is enough to be clearly felt by touch but not so raised that it creates a snagging hazard or makes the characters fragile.

Letter spacing

Minimum 2 mm between adjacent characters. This prevents characters from blurring together when read by touch. Too-tight spacing makes individual letters indistinguishable.

Word spacing

Minimum 10 mm between words. This is five times the minimum letter spacing, providing a clear tactile gap that signals a word boundary.

Stroke thickness

Letter strokes must be between 2 mm and 7 mm in thickness, and the thickness must be constant throughout the character.

This is one of the most important — and most frequently violated — specifications. Fonts with varying stroke widths (thick verticals and thin horizontals, for example) do not comply. The standard requires a constant stroke thickness font, which effectively limits you to geometric sans-serif typefaces with uniform strokes.

Common compliant font choices include Helvetica, Arial, Futura, and similar sans-serif families — though the specific stroke width must fall within the 2-7 mm range at the character size being used.

Braille specifications

Grade 1 uncontracted braille

The standard mandates Grade 1 (uncontracted) braille. Every word is spelled out letter by letter.

Grade 2 braille uses contractions — shortened forms of common words and letter combinations — which makes it faster to read for fluent braille users. However, Grade 1 is specified because it's accessible to a wider range of readers, including those who learned braille later in life.

Placement

Braille must be located 8 mm below the bottom line of tactile text. Not beside the text. Not above it. Below, with exactly 8 mm of clearance.

This consistent placement means a braille reader always knows where to find the braille relative to the raised text — they locate the tactile characters first, then move their fingers down 8 mm to find the braille translation.

Form

Braille dots must be raised and domed (not flat-topped or concave). All edges on the sign must be rounded — no sharp edges on characters, borders, or the sign itself.

Luminance contrast requirements

The 30% rule

AS 1428.1 requires a minimum 30% luminance contrast in two relationships:

Between the tactile characters and the sign background
Between the sign background and the mounting surface (wall, door, or panel)

Both relationships must independently meet the 30% threshold. A high-contrast sign mounted on a wall of similar luminance to the sign background will fail the second requirement even if the characters are perfectly legible.

Measuring luminance contrast

Luminance contrast is calculated using the formula:

Contrast = (B1 - B2) / B1 x 100%

Where B1 is the higher luminance value and B2 is the lower. This is measured with a luminance meter, not estimated by eye.

Colour difference alone is not sufficient. A red sign on a green wall may appear high-contrast to someone with normal colour vision, but the luminance values could be similar — failing the 30% threshold. This is particularly important because many people with low vision perceive luminance differences better than colour differences.

Surface finish requirements

All surfaces — characters, symbols, logos, and the sign background — must have a matt or low-sheen finish. The standard specifically prohibits reflective or glossy surfaces.

The reason is glare. A glossy sign surface creates specular reflections that can wash out the visual contrast between characters and background. For people with low vision, glare can make a sign completely unreadable even if the underlying contrast is sufficient.

This applies to the manufacturing finish and to any protective coatings applied to the sign. A clear gloss lacquer over a matt sign would render it non-compliant.

Mounting specifications

Height range

Signs must be mounted so that the sign face is between 1200 mm and 1600 mm above the finished floor level.

For single-line signs, the tactile characters should be positioned between 1250 mm and 1350 mm above the floor. This narrower range centres the sign in the optimal zone for both wheelchair users and standing adults.

Consistency

Signs should be mounted consistently throughout a building. If the first tactile sign a visitor encounters is at 1300 mm, all subsequent signs should ideally be at the same height. Consistency allows wayfinding by touch to become predictable.

Tactile Ground Surface Indicators (TGSIs)

While TGSIs are covered more extensively in AS 1428.4.2:2018, they are part of the accessible wayfinding system that AS 1428.1 establishes.

TGSIs come in two forms:

Warning indicators (truncated domes/cones): Installed at hazard transition points — top and bottom of stairs, platform edges, pedestrian crossings
Directional indicators (elongated bars): Indicate a safe path of travel, oriented in the direction of movement

TGSIs must provide sufficient luminance contrast with the surrounding floor surface and must be correctly positioned relative to the hazard or path they reference.

High contrast and non-reflective: why both matter

It's worth emphasising that AS 1428.1 requires both high contrast and non-reflective surfaces. These are separate requirements that address different vision conditions.

High contrast helps people with low vision, age-related macular degeneration, or other conditions that reduce visual acuity. The 30% luminance contrast threshold ensures characters are distinguishable from the background.

Non-reflective surfaces help people with conditions like photophobia, corneal irregularities, or cataracts where glare causes significant visual interference. Even a high-contrast sign becomes unreadable if surface glare washes out the contrast.

Meeting both requirements simultaneously is the standard's way of ensuring signage works for the widest possible range of vision conditions.

Mandatory signage locations under the NCC

The NCC specifies where AS 1428.1-compliant signage must be installed:

Exit doors: The word "EXIT" with level identification
Level identification in stairwells: Level number at each landing
Lift lobbies: Level identification
Accessible entrances: Directional signage to nearest accessible entry
Accessible sanitary facilities: Directional signage to nearest unisex accessible toilet
Amenities: Identification of all sanitary facilities

Missing signage at any of these locations is a building code non-compliance issue — it can hold up occupancy certification and trigger retrospective compliance orders during change-of-use applications.

The NCC connection

The NCC makes AS 1428.1 compliance a legal building requirement through Specification 15 (Braille and Tactile Signs). This means:

Building certifiers must verify signage compliance before issuing occupancy certificates
Non-compliant buildings cannot be legally occupied
Retrospective compliance may be required during renovations or change-of-use applications
Building owners are ultimately responsible for maintaining compliant signage

This isn't a recommendation or a best-practice guideline. It's the law.

Tracking compliance at scale

For building owners and facility managers responsible for multiple properties, AS 1428.1 compliance requires systematic tracking. Every tactile sign must meet the character height range, stroke thickness, braille placement, mounting height, luminance contrast, and surface finish requirements simultaneously.

Signplanr gives you a way to inventory every accessible sign across your portfolio. Record the specifications, log the installation, schedule periodic inspections, and use photo documentation to verify ongoing compliance. When a sign is damaged or a space is renovated, the replacement specifications are already on record.

Because a single non-compliant sign in a stairwell is all it takes for a DDA complaint — and the defence of "we didn't know" has never been a successful one.