Compartment floor
The spread of fire can be restricted by sub-dividing buildings into a number of discrete, contained compartments.
- Prevents the rapid spread of fire which could trap the occupants of a building.
- Reduces the likelihood of fires growing and creating a danger to occupants, fire and rescue services, and people in the vicinity of the building.
- Limits the damage caused to a building and its contents.
A compartment floor is horizontal component that forms part of the enclosure of a fire compartment.
Compartment floors are required to provide a minimum degree of fire resistance as set out in Appendix A of Approved document B2 and Appendix A of Approved document B1 (for dwellinghouses). This fire resistance is generally expressed in terms of the number of minutes of resistance that must be provided. Methods for testing fire resistance are set out in BS 476 Fire tests.
Joints between compartment floors should be fire-stopped to maintain the continuity of resistance; and openings for timber beams, joists, purlins and rafters, and pipes, ducts, conduits or cables that pass through any part of a compartment floor should be kept as few in number as possible, kept as small as practicable; and should be fire-stopped. See Fire stopping for more information.
Additional measures may be needed where an atrium, chute, stair, lift and so on passes through a compartment floor.
[edit] Related articles on Designing Buildings Wiki
Featured articles and news
Apprenticeships and the responsibility we share
Perspectives from the CIOB President as National Apprentice Week comes to a close.
The first line of defence against rain, wind and snow.
Building Safety recap January, 2026
What we missed at the end of last year, and at the start of this...
National Apprenticeship Week 2026, 9-15 Feb
Shining a light on the positive impacts for businesses, their apprentices and the wider economy alike.
Applications and benefits of acoustic flooring
From commercial to retail.
From solid to sprung and ribbed to raised.
Strengthening industry collaboration in Hong Kong
Hong Kong Institute of Construction and The Chartered Institute of Building sign Memorandum of Understanding.
A detailed description from the experts at Cornish Lime.
IHBC planning for growth with corporate plan development
Grow with the Institute by volunteering and CP25 consultation.
Connecting ambition and action for designers and specifiers.
Electrical skills gap deepens as apprenticeship starts fall despite surging demand says ECA.
Built environment bodies deepen joint action on EDI
B.E.Inclusive initiative agree next phase of joint equity, diversity and inclusion (EDI) action plan.
Recognising culture as key to sustainable economic growth
Creative UK Provocation paper: Culture as Growth Infrastructure.
Futurebuild and UK Construction Week London Unite
Creating the UK’s Built Environment Super Event and over 25 other key partnerships.
Welsh and Scottish 2026 elections
Manifestos for the built environment for upcoming same May day elections.
Advancing BIM education with a competency framework
“We don’t need people who can just draw in 3D. We need people who can think in data.”