Glossary — Fire Safety Law
Means of Escape
A means of escape is the continuous route from any point in a building to a place of ultimate safety. It is a legal requirement, not a design preference. Every element — corridor width, door hardware, emergency lighting, signage — is specified. A blocked or unlit route is a criminal failure.
Definition
Means of escape — a structural way out of a building to a place of ultimate safety outside. It must be provided, maintained, and kept clear in all non-domestic premises under the Regulatory Reform (Fire Safety) Order 2005. In homes, the Building Regulations (Approved Document B) define requirements for new construction. A means of escape must be usable under fire conditions without a key, tool, or special knowledge.
Key elements of an adequate means of escape
| Element | Requirement |
|---|---|
| Travel distance | Maximum travel distance to a fire exit — varies by building use (typically 18 m in one direction, 45 m where two routes are available in offices) |
| Width of escape routes | Minimum 750 mm for low-occupancy routes; 800–1200 mm+ for higher-occupancy buildings; wider for disabled access |
| Protected staircase | In buildings over two storeys, the staircase forming the means of escape must be enclosed in fire-resisting construction |
| Emergency lighting | Escape routes must have emergency lighting that activates on mains failure; battery-backed, minimum 3-hour duration |
| Exit signage | Illuminated running man signs at every junction and above every exit; ISO 7010 standard pictograms |
| Clear route maintenance | Escape routes must be kept clear of obstructions at all times — storing items in corridors or stairwells is illegal |
| Final exit | A door that opens directly to the outside or to a place of safety; must open in the direction of travel; must not require a key |
Protected escape routes
An escape route must be protected from the effects of fire for long enough for all occupants to evacuate safely. In a multi-storey building, this means the staircase is enclosed in fire-resisting construction (typically 30 or 60 minutes depending on building height), with fire doors at every opening. This "protected staircase" should be largely smoke-free during evacuation.
The design principle is that occupants should be able to move from any floor to the outside without encountering fire or untenable smoke conditions. This relies on compartmentation limiting fire spread, and on fire doors keeping smoke out of the escape route.
Travel distance and the "two-direction" rule
Travel distance is the actual walking distance from any point in a building to the nearest fire exit. Building Regulations and fire safety guidance set maximum travel distances — which are shorter when there is only one route available (since that route could be blocked by fire) and longer when two independent routes are available. Typical limits for offices: 18 m in a single direction; 45 m where two directions are available.
This two-direction principle is central to domestic escape planning too: see our two-ways-out escape planning guide for how to apply it in a home.
Common means of escape failures
- Escape routes stored with boxes, furniture, or equipment — the most frequent enforcement notice category
- Fire exit doors locked with a key (only acceptable if a maintained break-glass release box is provided)
- Emergency lighting not tested or batteries exhausted
- Exit signs missing, obscured, or non-illuminated
- Fire doors held open on wedges, defeating their smoke-sealing function
- No alternative route where primary route could be cut off by a single fire
These are also the most commonly cited failures in fire risk assessments. See our workplace fire safety guide for a practical inspection checklist.
Frequently asked questions
FAQ