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 must be mounted between 1,200mm and 1,600mm above the floor and 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

EvacPath designs to A3 as standard and delivers print-ready PDF diagrams you can print at any size, with A4 versions for hotel rooms and small tenancies. 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
• Fire extinguisher and hose reel locations
• Manual call point locations
• Assembly area
• Emergency contact numbers (000)
• Building name and address
• Date of issue

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:

• First aid kit locations
• Defibrillator (AED) locations
• Fire control room
• Disabled refuge areas
• Warden intercommunication points (WIP)
• Fire and smoke door locations
• Hydrant locations (beyond extinguishers and hose reels)

Practical Recommendations

While A4 is technically allowed for basic diagrams, we recommend A3 as the standard for most installations:

• A3 is easier to read from a distance, which matters in corridors and large spaces
• Most buildings benefit from including optional elements (first aid, AED, refuge areas), which requires A3 anyway
• A3 provides space for clear legends, larger floor plans, and readable text
• Fire authorities and inspectors generally expect A3. While A4 is compliant, 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:

• Inside hotel room doors where space is limited
• 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)
• 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, emergency numbers, and border
• On an A3 diagram, the floor plan must be at least 300mm x 200mm. 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 the Right Size Diagrams

EvacPath delivers diagrams as high-resolution PDFs that can be printed at any size. We design to A3 as standard, with A4 versions available for hotel rooms and small spaces. Each diagram includes all mandatory and recommended optional elements for your building type.

Pricing starts at A$70 per diagram regardless of size.