Editor’s note: Welcome to the sixth post in our series on Absorbent Training. We hope you find the series to be helpful in explaining the basics of absorbents. Links to the previous and next post in the series, if applicable, are at the bottom of the posts.
Spoiler alert: This post is not about a person who suddenly burst into flames for no apparent reason. Come on – do you really think I’d get the bandwidth to write about that?
But spontaneous combustion is serious stuff, so listen up.
If your facility uses, stores or processes vegetable or drying oils, biodiesel or other self-heating liquids, recognizing the hazards and establishing safety and housekeeping plans can help you prevent fires.
When it comes to spontaneous combustion, you need to understand these three things:
- Certain types of oil — like vegetable or drying oil and biodiesel — undergo a chemical process known as oxidation that releases energy in the form of heat when exposed to air. It’s oxidation that creates the potential for spontaneous combustion. Petroleum products like motor oil and gasoline, while flammable, do not undergo oxidation. Also, the tendency of oil to spontaneously combust is related to its iodine number — if it’s 130 or greater, the potential is there.
- Absorbent materials, like rags, wipers and mats, do not change the properties of the liquids they absorb. Absorbents soaked with flammable liquids remain flammable. Absorbents soaked with corrosives remain corrosive. Absorbents soaked with vegetable oil will oxidize.
- No absorbent eliminates the potential for spontaneous combustion and it can exist with any type or brand of absorbent media: mats, wipers, rags, corncob, sawdust, clay, wood chips or peat. Remember: it’s the property of the liquid being absorbed — not the absorbent itself — that creates the potential for a reaction.
Like any fire, three elements are needed for spontaneous combustion: heat, fuel and oxygen. External heat sources like a match or a spark are not needed because heat is created through the oil’s natural oxidization process. The oil and absorbents become the fuel while oxygen is present in the air.
To reduce the risk of spontaneous combustion, remove one of the three elements using one of the following techniques:
- Place saturated absorbents in sealed containers for disposal or recycling (make sure the container is nearly full)
- Place saturated absorbents in sealed bags to limit oxygen exposure
- Dry saturated absorbents in a single layer before disposal or recycling (consider the potential for emissions and whether this is permissible in your jurisdiction)
- Keep containers or bags of spent absorbents out of direct sunlight, away from heat sources and out of high-temperature areas or store containers of spent materials in climate-controlled areas or away from structures until they can be shipped for recycling or disposal
You tell us: Leave a comment below to tell us what types of liquids you’re absorbing. We’d love to get a feel for how many of our customers and readers need to worry about these types of liquids!