Spontaneous combustion

June 11th, 2020

Decorators, and DIYers alike, should be aware of the possibility of spontaneous combustion when using products such as linseed oil, especially in the warmer weather.  Although the risk has lessened since the introduction of VOC regulation, good practices should still be observed.

Solvent based oils, paints and other coatings that are applied by cloth can, given the right environment, be potentially hazardous due to the excess product remaining on the material.  Products and coatings that carry this risk will indicate so on the packaging, therefore it is always advised to read this thoroughly before starting the job.

Where does it occur?

When decorating, the main risks arise when rags or cloths, used to apply coatings, are left in a pile.  The chemicals in the coating react with the oxygen in the air (oxidation) creating heat that cannot escape from the pile and therefore the risk of combustion is increased.

As you would expect, the summer months when the air is warmer and drier presents a greater possibility of spontaneous combustion plus the use of the riskier types of products is more popular at that time of year.

Mineral oils such as white spirit, mineral turpentine or lubricating oil are not so prone to self heating.  Drying oils however, such as linseed, rapeseed, cottonseed, peanut, corn and fish oil pose a possible risk.

Reducing the risk

It is simple to prevent spontaneous combustion since oxygen is required for it to occur. 

Cloths that have been used to apply hazardous coatings can be immersed in water or spread out in a safe place to dry to reduce the risk.  

When transporting product soaked cloths between jobs or sites they should be sealed in metal containers as this will prevent the oxidation reaching a critical point.

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