Refuge Area Calculator

Inputs

• Floor plate area in m² (200 to 5,000)
• Occupancy — business or office (about 10 m² per person), mercantile or retail (about 3), assembly (about 1.5) or residential (about 12.5)
• Building height — below 24 m, or 24 m and above

Method

1. Occupant load = floor plate ÷ the occupant load factor for the occupancy, rounded up to a whole person.
2. Refuge area = occupant load × 0.3 m² per person.
3. Where that figure is below 15 m², the 15 m² minimum is applied instead.
4. Flags applicability by height: at 24 m and above refuge area applies under NBC 2016 Part 4; below 24 m it may not be required.

Assumptions

• The occupant load factors are common planning values for each occupancy group; the table in the governing code decides the figure for a specific building.
• 0.3 m² per person and the 15 m² minimum follow the NBC 2016 Part 4 pattern the tool is built on.
• The whole floor plate is treated as occupiable area.

Limitations

• The refuge-floor interval, its position relative to the staircases, fire separation, ventilation and fire-service access are not checked.
• Mixed occupancies on one floor are not modelled.
• The National Building Code 2016 was replaced by the National Building Construction Standards 2026 during 2026 — confirm with the approving authority which applies to the building before relying on the figure.