- Project plans
- Project activities
- Legislation and standards
- Industry context
Last edited 11 Dec 2020
Understanding the factors affecting flashover of a fire in modern buildings
On 21 April 2017, BRE published; Understanding the factors affecting flashover of a fire in modern buildings (IP 2/17), written by Richard Chitty.
- The development of a fire in an enclosure can be categorised as:
- Ignition and growth.
- Fully developed.
- Decay and burnout.
The term ‘flashover’ refers to the transition of an enclosure or room fire from a localised fire to the ignition of all exposed flammable surfaces, creating conditions where life is no longer tenable. The time to flashover is important in determining the impact on; escaping occupants, firefighting tactics and the building structure.
Theoretical and experimental investigations involving flashover have been undertaken since the 1950s. Initially they involved small enclosures and scale models, used to identify the basic mechanisms of flashover in the context of domestic buildings, cellular offices and similar-sized enclosures. While this work is still relevant today for similar enclosures, different mechanisms may also be involved, or become dominant, in particular in very large or highly-insulated modern spaces.
This 12-page information paper explains the process of flashover and the factors that influence its occurrence and development. It is intended for fire risk assessors, fire safety managers, other safety managers and building managers with some responsibility for safety, as well as community fire safety officers, firefighters and fire investigators. It will also be useful for those who are new to fire safety engineering.
The contents of the information paper are:
- Development of a fire.
- Fires in an enclosure.
- Thermal instability.
- Quantifying the conditions for flashover.
- Example calculations for time to flashover.
- Discussion and conclusions.
- References and further reading.
 Related articles on Designing Buildings Wiki
- Automatic fire detection and alarm systems, an introductory guide to components and systems BR 510.
- Automatic fire sprinkler systems: A good practice guide.
- BRE articles on Designing Buildings Wiki.
- BRE Buzz articles on Designing Buildings Wiki.
- Building Research Establishment BRE.
- External fire spread, Supplementary guidance to BR 187 incorporating probabilistic and time-based approaches.
- External fire spread: building separation and boundary distances (BR 187).
- Fire in buildings.
- Fire performance of external thermal insulation for walls of multistorey buildings, third edition (BR 135).
- Fire spread.
- The causes of false fire alarms in buildings.
- The role of codes, standards and approvals in delivering fire safety.
- Visual alarm devices - their effectiveness in warning of fire.
Featured articles and news
Proper materials and maintenance can help reduce rust.
Is the construction sector responding to calls for ED&I?
Engineers pay tribute by sharing their memories.
The hidden price of infrastructure.
BREEAM incorporates wellbeing into its Building Back Better programme.
Administration signals policy changes on some building-related issues.
From inns and coaching houses to boutiques.
Survey reveals green skills gap.
America's economic collapse produced scores of PWA Moderne projects.
The benefits of glowing aggregates and cement.
Urgent need for open communication to address mental health issues.