Typical Performance Solution 1: Extended Travel Distances
Extended travel distances are one of the most common fire safety non-compliances encountered in building design. They arise when occupants must travel further than the limits prescribed by the National Construction Code (NCC) to reach a safe exit.
This article explains what extended travel distances are, why they matter, the NCC requirements, and how a fire engineering performance solution can be used to achieve compliance without compromising design intent.
What Are Travel Distances?
Travel distance refers to the maximum distance occupants must travel to reach a safe exit during an emergency. These limits are carefully set to ensure occupants can evacuate before conditions become untenable due to smoke, heat, or fire spread.
Travel distance requirements vary depending on:
- Building classification
- Number of available exits
- Occupant risk profile
When these limits cannot be met, a performance-based fire engineering solution may be required. Learn more about this approach on our Performance-Based Design page.
Single Exit vs Multiple Exits
Single Exit Scenarios
In buildings with a single exit, travel distances are typically shorter. This reduces the risk to occupants should that exit become blocked by smoke or fire.
Single-exit travel distances are especially restricted in higher-risk occupancies such as:
- Residential buildings
- Healthcare facilities
- Schools and educational buildings
Two or More Alternative Exits
Where two or more alternative exits are provided, the NCC allows longer travel distances. Exit redundancy improves evacuation resilience, provided that exit locations are appropriately distributed.
Fire engineers assess these layouts to ensure congestion, wayfinding, and evacuation times remain within safe limits.
NCC Requirements for Travel Distances
Under the NCC (formerly the BCA), Clauses D1.4 and D1.5 specify maximum travel distances to exits and the maximum distance between alternative exits.
Examples include:
- Class 2 & 3 buildings: limits of 6 m to a choice of exits, 20 m to a single exit, and 40 m to one of two alternative exits
- Class 5–9 buildings: generally 20 m to a single exit or 40 m where alternative exits are provided
When these distances are exceeded, a fire engineering assessment is required to demonstrate compliance with NCC performance requirements.
Fire Safety Hazards of Extended Travel Distances
Excessive travel distances increase the likelihood that occupants may be exposed to:
- Smoke accumulation
- Heat and toxic gases
- Congestion or delayed evacuation
For single exits, the key hazard is exit obstruction. For alternative exits, the hazard is untenable conditions before occupants reach safety.
These risks are assessed through a detailed Fire Risk Assessment.
Performance Requirements to Be Achieved
Performance solutions addressing extended travel distances typically aim to satisfy NCC requirements such as:
- DP4 – Adequate number, location, and accessibility of exits
- EP2.2 – Evacuation prior to the development of untenable conditions
A Fire Engineering Report (FER) documents how these objectives are met using engineering analysis and compensatory measures.
Typical Fire Safety Measures Used
To support extended travel distances, fire engineers may recommend a combination of systems, including:
- Smoke detection and occupant warning systems
- Emergency lighting and exit signage
- Pre-recorded or voice alarm systems
- Management-in-use procedures to keep egress paths clear
In more complex or higher-risk cases, additional systems may be required, such as:
- Automatic fire sprinkler systems
- Smoke exhaust or mechanical ventilation
- Automatic heat and smoke vents
- Smoke baffles
These strategies are often supported by advanced modelling, including Complex Numerical Modelling.
Final Thoughts
Extended travel distances are a common and manageable fire safety challenge. With early engagement of a fire engineer, performance solutions can often deliver compliant outcomes while preserving architectural flexibility.
If your project involves extended travel distances or other NCC non-compliances, explore our full range of Fire Engineering Services or Contact Us to discuss your project with our Brisbane-based fire engineers.
