What is the maximum travel distance in an office?

Under Approved Document B, the maximum travel distance in an office is 18m in one direction (dead end) or 45m where travel is possible in two or more directions. With a sprinkler system, these distances can be increased by 50% to 27m and 67.5m respectively.

How is travel distance measured?

Travel distance is measured along the actual path of travel from any point in the room to the nearest exit, following the route a person would walk. It is not a straight-line measurement. Furniture and obstructions must be considered. The distance includes travel within the room and along corridors.

What is a dead-end condition?

A dead end occurs when escape is possible in only one direction from a point in the building. This is the most restrictive condition with shorter maximum travel distances because occupants have no alternative route if their escape path is blocked by fire.

Do sprinklers allow longer travel distances?

Yes, Approved Document B allows travel distances to be increased by up to 50% where a building is fitted with a sprinkler system designed to BS 9251 (residential) or BS EN 12845 (commercial). This can be very cost-effective in avoiding the need for additional exits.

What is an inner room?

An inner room is one from which escape is possible only by passing through another room (the access room). Inner rooms have restricted travel distances (typically 12m for non-domestic, 9m for dwellings). The access room must not be a place of special fire risk and must have a suitable fire detection system.

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Fire Escape Distance Calculator

Check travel distances to fire exits against Approved Document B maximum limits. Calculate compliance for one-direction and two-direction escape routes.

Building Type

Determines maximum travel distance

Escape Directions

One direction = dead end (more restrictive)

Actual Travel Distance

Measured along path of travel

Sprinkler System

BS 9251 or BS EN 12845 system

How We Calculate This

This calculator checks actual travel distances against the maximum limits in Approved Document B, Table 3.

Maximum distances

Max distance depends on building use, escape directions and sprinklers

One direction: 9-25m depending on building type
Two directions: 18-45m depending on building type
Sprinklers: +50% on above distances
Inner rooms: max 12m (9m for dwellings)

Frequently Asked Questions

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Last updated: March 2026

All calculations are estimates. Verify with your supplier.