The LWF Blog

Fire Safety for Facilities Management Personnel – Understanding Fire Development – Part 281

December 2, 2024 12:07 pm

Lawrence Webster Forrest (LWF) is a specialist fire engineering and fire risk management consultancy whose aim is to give information on best practice in fire safety for facilities management personnel through this blog series. In part 280, LWF looked at human behaviour and fire alarm signals. In part 281, we discuss fire development and peoples’ understanding of it.

The majority of people have little experience of fire. Most people have only been in contact with a fire that they had started and were in control of, such as a garden bonfire or a fire in a grate. A few people may have had to deal with a chip pan fire on the hob, but usually this is contained relatively easily and doesn’t spread beyond the hob.

It can be hugely shocking, therefore, if an uncontrolled fire starts within a building. Uncontrolled fires in buildings behave differently to a bonfire or a grate fire. Grate fires do not spread, they are designed to remain in the grate where the fuel is (coal, logs, etc.), unless the chimney catches fire or a spark from the fire causes something outside the grate to ignite. A fat pan is extinguished by turning off the heat source and/or using a fire blanket or damp tea towel to cover and extinguish.

The closest to an uncontrolled fire that most people might experience is the garden bonfire, but typically, the fire will not spread beyond the fuel source (whatever is being burnt). Equally, people can stand quite close to a garden bonfire and the convective heat, although high, can be quite comfortable.

An indoor fire is entirely different. When the flames climb to the ceiling, they bend over and elongate so that the ceiling becomes a very powerful radiant panel which ignites all the room contents almost simultaneously, resulting in what is known as ‘flashover’.

The perception of people that a fire indoors will act in a similar way to an outdoors bonfire is incorrect and dangerous and may lead to behaviour that may appear irrational or unwise. People have been known to:

• Continue their current activities
• Remain in place to observe the fire develop
• Talk about what to do

In part 282 of this series, LWF will continue to look at how people behave when they do not understand uncontrolled fire development in a building. In the meantime, if you have any queries about your own facilities or wish to discuss this blog series, please contact LWF on freephone 0800 410 1130.

Lawrence Webster Forrest is a fire engineering consultancy based in Surrey with over 35 years’ experience, which provides a wide range of consultancy services to professionals involved in the design, development and construction and operation of buildings.

 

While care has been taken to ensure that information contained in LWF’s publications is true and correct at the time of publication, changes in circumstances after the time of publication may impact on the accuracy of this information.