NDIS SDA vs Commercial Evacuation Diagrams: Key Differences

NDIS Specialist Disability Accommodation (SDA) builds are a rapidly growing category of housing in Australia. They serve participants with extreme functional impairment or very high support needs under the National Disability Insurance Scheme. Like any occupied building, an SDA dwelling needs evacuation diagrams that meet AS 3745. What changes is what the diagrams emphasise, how they are oriented, and how many you actually need per build.

This guide walks through the practical differences between an SDA evacuation diagram and a standard commercial diagram, drawing on AS 3745 requirements and the realities of SDA design certification.

The Mobility Impaired Persons panel replaces RACE

Standard AS 3745 evacuation diagrams typically include a procedure summary block based on the RACE mnemonic: Rescue, Alert, Confine, Evacuate. RACE works for office buildings, retail tenancies, warehouses, and other commercial settings where most occupants can self-evacuate.

In an SDA dwelling, the RACE wording is replaced or supplemented by a Mobility Impaired Persons procedure panel. The panel speaks to the actual workflow during an emergency:

• Alert all support staff present in the dwelling
• Call 000 and provide the dwelling address and access details
• Evacuate residents using the marked path if it is safe to do so
• If evacuation is not possible, remain in a safe area near a window where emergency services can locate occupants

The exact wording is tailored to the support model in place at each dwelling. A 24/7 onsite support model is different from a drop-in support model, and the panel reflects that. AS 3745 calls for a Mobility Impaired Persons panel whenever the building has occupants who cannot self-evacuate, and SDA dwellings make this the default rather than the exception.

Heads-up orientation per clause 3.6

AS 3745 clause 3.6 is one of the most-misunderstood requirements in evacuation diagram production. The clause requires diagrams to be oriented heads-up so that the direction the viewer is facing while reading the diagram matches the top of the page.

In a commercial fitout this typically means producing one base diagram and rotating it for each mounting location. In an SDA unit with three diagram-mount points (primary bedroom, respite or visitor bedroom, kitchen or living area), the same dwelling produces three differently-rotated diagrams. The floor plan is the same; the orientation is not.

This matters for SDA more than for most building types because residents may rely on the diagram to mentally rehearse the path ahead. A diagram that contradicts the resident actual facing direction increases cognitive load at the worst possible moment.

A useful design pattern is to keep the site plan inset in fixed orientation across all diagrams in a build. The site plan inset shows the dwelling within the property, the route to the assembly area, and street access for emergency services. Keeping this inset stable across diagrams gives the viewer one consistent external reference even as the floor plan rotates.

How many diagrams a typical 4-unit SDA build needs

A common question is how many diagrams a typical SDA build needs. The answer depends on the unit count and the layout, but a rule of thumb that works for most 4-unit single-storey SDA builds is around 13 to 14 diagrams:

• 3 diagrams per unit (primary bedroom, respite or visitor bedroom, kitchen or living area), accounting for 12 unit diagrams across 4 units
• 1 diagram for the laundry, garage, or storage utility building if standalone
• 1 diagram for the support staff office or meeting room if separate from the resident space

Compare this to a similarly-sized 4-tenancy retail strip mall, which might need 4 to 8 diagrams total (one per tenancy plus shared back-of-house). The SDA count is higher per square metre because each unit is treated as its own dwelling with its own evacuation routes, and each mounting location needs its own oriented diagram.

Symbol conventions for SDA diagrams

AS 3745 includes a symbols schedule that defines acceptable graphic representations for fire and emergency equipment. The standard allows some flexibility in colour and presentation, and SDA diagrams typically use the following conventions:

• Smoke alarms marked with a red filled circle. Smoke alarms are not always legally required to appear on evacuation diagrams, but SDA design certifiers usually expect them.
• Sprinkler heads marked with a blue filled circle, where installed. Some SDA dwellings use residential sprinkler systems; others rely on smoke alarms and early evacuation. The diagram should reflect what is actually installed.
• Exit paths drawn in green with a clear directional arrow. Primary paths use a solid line; alternative paths use a dashed line.
• Assembly area marked with a star or distinct symbol on the site plan inset, with a label such as "Assembly Area" and any specific features (for example, "Beneath flagpole at front fence").
• Fire extinguishers marked with a red square and the appropriate class label.

Symbol consistency across all diagrams in the build is more important than which exact symbol set you choose. SDA design certifiers will check for consistency between diagrams, and inconsistent symbols are a common reason for re-issue.

Site plan and assembly area

The site plan inset is where SDA diagrams diverge most from commercial diagrams. In a multi-tenancy office building, the site plan often shows the building and the immediately adjacent street. In an SDA build, the site plan shows the dwelling within its property, the boundary fence, the driveway, and the assembly area location.

The assembly area for an SDA dwelling needs to be accessible to residents who may use mobility aids. Common assembly area choices include:

• A flat paved area near the front fence
• A driveway turning circle clear of vehicles
• A neighbour nature strip if pre-arranged

The assembly area should be clear of fire-fighting access for emergency services. In practice this means at least 6 metres from the dwelling, ideally with a clear path that does not cross the driveway used by fire trucks.

Display location and printing

AS 3745 clause 3.4 sets minimum size requirements: A4 if the diagram includes only mandatory elements, A3 if the diagram includes optional elements. SDA dwellings almost always need A3 because the Mobility Impaired Persons panel and the site plan inset add detail beyond the mandatory minimum.

Mounting follows AS 3745 clause 3.5. The centre of the diagram should be 1,200 to 1,600 mm from floor level, in clear view, and not behind opening doors or under storage. In SDA dwellings the typical mount points are:

• Bedroom wall opposite the door (or beside the door if the wall is full of cabinetry)
• Kitchen or living area wall near the main exit path
• Utility building wall near the entry door
• Support staff office wall above the desk

Always confirm the wall is mountable before finalising the You Are Here marker. Kitchen walls in particular are often full of cabinetry that leaves no clear mounting space, in which case the diagram moves to an adjacent wall or to a beside-the-door location.

Get AS 3745-aligned SDA diagrams

EvacPath produces AS 3745-aligned evacuation diagrams for NDIS SDA accommodation builds across Australia. We work from your design plans (floor plans plus a marked-up sketch noting wall finishes and intended mounting points) and deliver print-ready A3 PDFs in 3 to 5 business days. No site visit required. Pricing starts at A$70 per diagram, with volume pricing for multi-unit builds.

Send your floor plans through our /get-started page or visit the SDA accommodation page to start.