Did you know that fires today develop more than six times faster than in the 1950s?

It’s true! Yet in our comfortable modern lives, our thoughts rarely turn to fire safety. However, the disturbing fact remains that fires in modern buildings develop five to ten times faster than they did just 70 years ago.^[1] And in the case of a fire, this can mean the difference between managing to evacuate safely or being caught in the blaze.

A burning issue

So how can it be possible that fires spread faster today when we have an array of smoke alarms, fire alarms and fire extinguishers in most buildings? One of reasons for this is the increased use of synthetic construction and furnishing materials. These materials are highly combustible and allow a fire to quickly gain hold – leading to what is known as a ‘flashover’.

For a fire to burn and take hold, three elements need to be present. Firstly, there needs to be a source of ignition – such as a spark, secondly there needs to be fuel and thirdly the fire needs oxygen. A fire will continue to burn as a small, localized fire until it is extinguished – or until the combustible materials or oxygen are exhausted. But if the three factors are in place and highly flammable materials are in the area, the flashover point is reached in a matter of minutes. A flashover occurs when the heat is so intense that the fire spreads through the air igniting all combustible materials in the room or building section, transforming from a small fire to one engulfing the entire room. Due to the high quantity of synthetic furnishings and construction materials used in our homes today, it typically takes less than five minutes from a fire starting until the flashover occurs. In the mid-20^th century, this took 29 minutes.

Containing the fire

Using non-combustible construction materials can be key to creating a fire compartment to keeps the fire contained in a room or building section. Once the flashover point has been reached, if the walls, ceilings, floors and doors can withstand being exposed to a fire on one side without transporting heat, flames or toxic gases, they can slow the spread of the fire considerably. This can give the fire crew valuable time to put out the fire.

Some high profile fire events, such as the tragedy at Grenfell Tower in London, have demonstrated just how important it is to use non-combustible construction materials. A subsequent investigation found that using fire-resilient materials in the external cladding could have slowed down the fire, giving residents more time to evacuate safely and the fire crew more time to extinguish the blaze.

The good news is that fire-resistant materials are widely available. For example, when it comes to insulation, stone wool insulation is inherently non-combustible. This means it has zero or minimal contribution to the spread of fire. If a fire does break out, it’s resistant to temperatures exceeding 1,000°C. Or to put it another way, using fire-resistant construction materials, such as stone wall insulation, can mean the difference between having a fire in a building and having a building on fire.

To find out more about boosting the fire resilience of your building, take a look at this fire resilience fact sheet.

^{[1] Underwriters Laboratory, “Analysis of changing residential fire dynamics and its implications on firefighter operational timeframes” (2014), p. 16.}

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