Fire Strategies for Commercial Office Buildings

Office buildings present a distinctive set of fire safety challenges — primarily the combination of large open-plan floor plates, multiple tenants with varying occupancy densities, complex means of escape, and the trend towards increasingly open-plan working environments that challenge the travel distance assumptions of prescriptive guidance.

The Applicable Standards

Fire strategies for office buildings are typically produced against BS 9999:2017 (Code of practice for fire safety in the design, management and use of buildings) rather than Approved Document B, though both may be relevant depending on the project and the building control body. BS 9999 provides a risk-based approach that is particularly well suited to commercial office buildings, allowing fire safety solutions to be tailored to the specific occupancy characteristics of the office.

Open-Plan Offices and Travel Distances

The trend towards open-plan office working creates a persistent fire strategy challenge: travel distances. Approved Document B limits travel distances in offices with only one direction of travel to 18 metres, and with alternative directions to 45 metres. Large open-plan floor plates — particularly those with central core arrangements — regularly create situations where these distances are exceeded.

Where travel distances exceed the ADB limits, the fire strategy must justify an alternative approach — typically through enhanced automatic detection (providing earlier warning of fire), sprinkler systems, or additional exit points. Fire Safety Services produces fire engineering reports justifying extended travel distances for office buildings across the UK.

Multiple Tenancy Arrangements

Office buildings with multiple tenants present specific compartmentation challenges. Each tenancy typically forms a separate fire compartment, with fire-rated partition walls between tenancies and at the boundary with common areas. Where tenant boundaries change — which is common in flexible commercial office buildings — the compartmentation must be capable of being modified to accommodate new layouts without compromising fire safety.

Refurbishment of Existing Office Buildings

Many fire strategy instructions for office buildings relate to refurbishment — fit-outs, base-build changes, or change of use from offices to residential. In each case, the fire strategy must address the fire safety implications of the proposed changes, taking into account the existing building's compartmentation, means of escape and fire safety systems.