Evacuation Diagram Size: AS 3745 Requirements Explained

What Size Must an AS 3745 Evacuation Diagram Be?

Under AS 3745:2010, the minimum evacuation diagram size depends on what the diagram shows. A diagram carrying only the mandatory elements must be at least A4 (210mm x 297mm); adding any optional elements raises the minimum to A3 (297mm x 420mm). A3 is the practical standard for most buildings because it stays readable from a distance and leaves room for a clear legend. Whatever the size, every diagram should be mounted with the bottom edge at least 1,200mm above the floor or the top edge no more than 1,600mm (clause 3.5.3), and must be oriented so that the top of the diagram matches the direction you walk forward from where you are standing, with the "You Are Here" marker accurate to the installed location.

• A4 (210mm x 297mm): mandatory elements only, floor plan graphic at least 200mm x 150mm (30,000 mm²)
• A3 (297mm x 420mm): any optional elements included, floor plan area at least 300mm x 200mm (60,000 mm²)
• Very large or complex floor plans may need A2 or A1 to keep the plan readable

We design every diagram at A3 because our sheet carries optional elements such as emergency numbers, and we deliver print-ready PDFs to print at 100% scale on A3 paper (enlarging for a bigger sheet is fine; shrinking is not). The Basic package is A$280 for up to 4 diagram locations, and you see a first draft before you pay. See the pricing page for the full comparison.

The Two Size Tiers

AS 3745:2010 defines two minimum size tiers based on what the diagram includes:

Tier 1: Mandatory Elements Only (Minimum A4)

If your diagram shows only the mandatory elements required by AS 3745, the minimum overall size is A4 (210mm x 297mm). The floor plan graphic within the diagram must be at least 200mm x 150mm (30,000 square millimetres).

Mandatory elements are:

• Floor plan with room layout
• "You Are Here" indicator
• Exit routes and emergency exits
• Paths of travel to the exits, shown in green
• Fire extinguisher and hose reel locations
• Manual call point and emergency call point locations
• Fire indicator panel location
• Communications equipment, such as warden intercommunication points (WIP) where installed
• Assembly area
• Building name and address
• Validity date, with the date of issue alongside it
• A legend for every symbol used

Tier 2: With Optional Elements (Minimum A3)

If your diagram includes any optional elements, the minimum size increases to A3 (297mm x 420mm). The floor plan area must be at least 300mm x 200mm (60,000 square millimetres).

Optional elements that trigger the A3 requirement:

• Emergency telephone numbers, including 000
• First aid kit locations
• Defibrillator (AED) locations
• Fire control room
• Disabled refuge areas
• Fire and smoke door locations
• Hydrant locations (beyond extinguishers and hose reels)

Practical Recommendations

While A4 is allowed for a diagram with the mandatory elements only, we draw every diagram at A3, for these reasons:

• A3 is easier to read from a distance, which matters in corridors and large spaces
• Most buildings benefit from including optional elements (emergency numbers, first aid, AED, refuge areas), which requires A3 anyway
• A3 provides space for clear legends, larger floor plans, and readable text
• Most buildings already display A3 diagrams, so an A4 sheet looks small beside them. A4 meets the AS 3745 minimum for a diagram with the mandatory elements only, but it can give the impression of minimal effort.
• The cost difference between A4 and A3 printing is negligible

When A4 Is Appropriate

There are situations where A4 is the better choice, as long as the diagram carries the mandatory elements only (no emergency numbers, first aid or AED locations):

• Hotel guest rooms, where the wall beside the entry door leaves limited space (keep it off the door itself, which is often a fire door)
• Small tenancies (under 50 square metres) where A3 would be disproportionate
• Supplementary diagrams in addition to the main A3 diagrams (for example, a small A4 diagram in a storeroom, drawn as its own A4 sheet with the mandatory elements only, not the A3 sheet printed small)
• Temporary diagrams for events or short-term use

Floor Plan Area Requirements

The size requirements apply to the floor plan graphic, not just the overall diagram. This is an important distinction:

• The floor plan is the map portion of the diagram showing rooms, corridors, and exits
• The overall diagram includes the floor plan plus the legend, title block and border, and on an A3 diagram any optional panels, such as emergency numbers
• On a diagram that carries optional elements (A3 minimum), the floor plan must be at least 300mm x 200mm (60,000 mm²). The remaining space is used for the legend and information panels.
• If your building has a complex floor plan with many rooms, you may need to go larger than A3 to keep the floor plan readable. A2 or A1 diagrams are used in very large buildings.

Site Plans

In addition to floor-level diagrams, large sites may need a site plan showing:

• The overall building footprint or campus layout
• Assembly area location relative to the building
• Emergency vehicle access routes
• Multiple buildings on the same site
• Car parks and pedestrian routes to the assembly area

Site plans are typically displayed in the main lobby and at the assembly area. They are usually A3 or larger.

Get Print-Ready A3 Diagrams

EvacPath delivers diagrams as high-resolution, print-ready PDFs. We design every diagram at A3, and each one includes all mandatory and recommended optional elements for your building type, so print it at 100% scale on A3 paper, or enlarge it for a bigger sheet, never shrink it. Printing an A3 diagram on A4 paper scales it to about 71%, which takes both the sheet and its floor plan below the A3 minimums the standard sets for a diagram with optional elements, so keep any A4 prints of the A3 set as desk or reference copies.

Pricing starts at A$70 per diagram.