Travel Distance vs Straight-Line Distance: Measuring Egress the Right Way
· 4 min read · By Verify AI
Travel distance is one of the most common fire-code checks and one of the most commonly measured wrongly. The requirement is simple to state: from the most remote point in an occupied space, a person must be able to reach an exit within a maximum distance. The trouble is in the word distance.
What travel distance actually measures
Travel distance is the length of the path a person would really walk from the farthest point of a space to the nearest exit or to the door of a protected staircase. It follows corridors, goes around partitions and fixed furniture, and passes through doorways.
It is not the straight line between two points. A radial measurement ignores every wall in between, so it always comes out shorter than the true walking path. A plan can look compliant on a radial check and still exceed the limit once the path is measured properly.
An illustrative example
Imagine an open office with a service core in the middle and the only exit on the far side of the floor. The numbers below are illustrative only, to show how the two methods diverge. They are not code limits.
| Method | What it measures | Result |
|---|---|---|
| Straight line | Point to exit, through the core | 24 m |
| Walking path | Around the core, along the corridor, through the door | 33 m |
If the permitted limit for the occupancy were 30 m, the straight-line check would pass while the real path fails. The actual limits depend on occupancy, on whether the building is sprinklered, and on the edition of the code and any local amendments, so always confirm the figure that applies to your project.
How to measure it correctly
- Start at the most remote point in each occupied space, not at the room centre.
- Follow the natural walking route along circulation, around fixed obstructions such as walls, columns, counters and built-in furniture.
- Go through the door opening, not through the door leaf's swing arc.
- End at the correct destination. Depending on the code and the layout, that is a final exit, an exit staircase door or a protected lobby. Be clear about which one you are measuring to.
- Check every floor. Upper floors have different core positions and often different partitions.
Related checks that are easy to confuse
Three egress limits are often mixed up, and they are checked separately:
- Travel distance is the total distance to an exit.
- Common path of travel is the part of the route shared before occupants have a choice of exits.
- Dead-end corridor length is how far a corridor continues past the last exit access point.
A floor can pass one and fail another, so a review should cover all three. See the fire NOC pre-submission checklist for where these sit in a wider review.
How automated shortest-path checking works
Software can do the measurement consistently across every space on every floor. The general approach is:
- Read the model's spaces, walls and door openings to build a map of where people can and cannot walk.
- Treat the walkable area as a network, with nodes at doorways and corridor junctions.
- Run a shortest-path search from the most remote points in each space to the nearest valid exit.
- Compare each result to the applicable limit and report the ones that exceed it, along with the route that was measured.
The quality of the answer depends on the quality of the input. Missing spaces, doors modelled as generic objects, or walls that do not close the rooms will all distort the path. That is why a good check reports the route it used, so a person can confirm it matches reality. Our guide to checking an IFC model for code compliance covers the model-quality side.
Where Verify AI fits
Verify AI calculates real walking distance from your model, flags the spaces that exceed the limit and shows the path on the floor plan, so the conversation with the reviewer is about a specific corridor rather than a general concern. Explore the features, or talk to us about running it on a live project.