Spontaneous combustion might sound like an unusual way for a fire to start. But while it’s not one of the most common causes of ignition, you might be surprised to hear there have actually been many incidents over the past few years where spontaneous combustion was identified as the cause. Very sadly, some of the fires that were suspected to have ignited due to spontaneous combustion even resulted in fatalities.
What causes spontaneous combustion?
Spontaneous combustion is effectively a fire breaking out when there’s no application of heat from an external source; a process of self-heating takes place instead.
It can happen when a combustible object, often fabric, has some kind of flammable substance on it such as oil or solvent. The danger occurs if the combustible object is heated to its ignition temperature by an oxidation process. Usually oxidation is so slow that heat releases into surrounding areas as quickly as it’s formed. So in most instances there’s no increase in temperature of the material. But some oils generate heat faster than they can be dissipated. That raises the temperature in the material. Spontaneous combustion becomes a risk if there’s not enough draft to carry the heat away as quickly as it’s being generated but there’s still enough oxygen available for the reaction to occur. As the inside temperature of the material rises, it can reach the point at which a fire starts.
Because it depends on a specific combination of conditions, it’s impossible to predict when a material will heat spontaneously. There are all kinds of scenarios where this type of combustion could potentially be an issue. A stack of laundry that’s been put away. Many of us will have done DIY or refurbishment jobs at work or at home; you might have left oil or solvent soaked rags in a pile for a period of time. Even essential oils present a risk if they stain fabric which is then washed and stored somewhere warm. There are other factors that can accelerate the process too – for example the warmer the weather, the quicker the ignition temperature can be reached.
The fire and rescue service has highlighted a number of businesses and premises that may be particularly vulnerable. They include residential care premises, guest houses and hotels, restaurants and cafes, launderettes and dry cleaners and schools. But as long as there is the combination of flammable objects alongside combustible material the risk exists pretty much anywhere.
How can you reduce the fire risk?
- Know the common offenders. Make sure you identify any potentially flammable materials; oils or oil-based products, wood stains and fuels are amongst the potential culprits. Always follow the safety precautions identified on their containers and store them safely away from any heat generating equipment.
- Never bundle up, pile, stack or fold any combustible fabric material that’s been in contact with a solvent-based material.
- Use washing temperatures and detergents that are suitable for the optimum removal of oil-based substances.
- Complete cooling cycles in tumble dryers before taking laundry out.
- Give laundry a shake to ventilate it before it’s folded or hang it up instead. Never leave warm, damp laundry in polythene bags, plastic containers or baskets or in poorly ventilated areas.
- Keep tumble dryers well maintained. Clean out filters and remove any bits of fluff, lint and debris.