Introduction

Travel distance refers to the maximum allowable distance occupants must traverse to reach a safe exit during an emergency. Extended travel distances are carefully regulated to balance building functionality with safety, ensuring evacuation can be completed within a reasonable time.

Single Exit

In buildings with a single exit, the maximum permitted travel distance is typically shorter to mitigate the risk of obstruction. Regulations for single-exit scenarios ensure that occupants can quickly reach the exit in the event of a fire, considering there is no redundancy if the exit becomes inaccessible. These limitations are often stricter in higher-risk settings, such as hospitals or schools.

One of Two or More Alternative Exits

In buildings with multiple exits, the allowable travel distances can be higher than when only a single exit is present. This is because the redundancy of additional exits provides more flexibility for evacuation. However, careful planning ensures that travel distances still align with fire safety principles, preventing delays and congestion during emergencies.

Requirements in the Building Code of Australia (BCA)

In the Building Code of Australia (BCA), Clause D1.4 and D1.5 specifies maximum distances to a single exit/alternative exit and the maximum distance between alternative exits respectively.

As per Clause D1.4 - Exit Travel Distances,

In Class 2 and 3 Buildings -

(i) The entrance doorway of any sole-occupancy unit must not be more than -

(A) 6 m from an exit or from a point from which travel in different directions to 2 exits is available; or

(B) 20 m from a single exit serving the storey at the level of egress to a road or open space; and

(ii) no point on the floor of a room which is not in a sole-occupancy unit must be more than 20 m from an exit or from a point at which travel in different directions to 2 exits available.

In Class 5, 6, 7, 8 or 9 buildings -

(i) no point on a floor must be more than 20 m from an exit, or a point from which travel in different directions to 2 exits is available, in which case the maximum distance to one of those exits must not exceed 40 m; and

(ii) in a Class 5 or 6 building, the distance to a single exit serving a storey at the level of access to a road or open space may be increased to 30 m.

Fire Safety Hazards arising from non-compliance

For issues of extended travel distance to a single exit, the hazard is the potential obstruction of occupants due to an obstacle, smoke or heat due to the increased length of the egress path.

For issues of extended travel distance to an alternative exit, the hazard is the potential for occupants to be subject to untenable conditions due to the increased amount of time required to reach an alternative exit due to the increased length of the egress path.

Performance Requirements to be achieved

The Performance Requirements usually required to be achieved in a non-compliance associated with extended travel distance is -

DP4 - adequate number and location of exits

EP2.2 - evacuation prior to untenable conditions

Typical Fire Safety Systems required

• Smoke Detection and Alarm

• Pre-recorded Voice Alarm

• Emergency Escape Lighting and Exit Signage

• Block Plans

• Management-in-Use to enforce corridors be kept void of storage

In extreme cases, the following fire safety systems can also be used to support a performance solution

• Sprinklers

• Smoke Exhaust

• Automatic heat and smoke vents

• Smoke Baffles