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!
2 Comments
Tom Winkelsays:
02/13/2015 at 1:25 pmIs it necessary to have a steel closed lid container just for a few grease and oil rags around a typical work shop? And aren’t they supposed to be disposed of daily anyway according to OSHA?
Jensays:
02/13/2015 at 4:14 pmTom, you are correct that for certain operations, OSHA requires disposal happen at the end of each shift. Dipping and coating may or may not pertain to your operation directly, but here is one example:
OSHA 29 CFR 1910.125(e)(4)(ii&iii):
Rags and other material contaminated with liquids from dipping or coating operations are placed in approved waste cans immediately after use; and waste can contents are properly disposed of at the end of each shift
It is definitely possible that even for a small amount of oily and greasy rags, that a closed container might be a requirement. Here are a couple more OSHA examples:
OSHA 29 CFR 1926.252(e):
(e) All solvent waste, oily rags, and flammable liquids shall be kept in fire resistant covered containers until removed from worksite.
OSHA 29 CFR 1910.106(e)(9)(iii):
Waste and residue.
Combustible waste material and residues in a building or unit operating area shall be kept
to a minimum, stored in covered metal receptacles and disposed of daily.
With more specifics on your situation we can give you better guidance. This would include calling in the help of our partners at Aarcher Environmental if needed. We offer this service to our customers at no charge because so many situations require some one-on-one consultation to get the right solutions and process in place. You can always email us more details at hothogs@newpig.com. If you just want to be on the safe side, we of course offer an entire line of latching container lids to help comply with closed container regs.
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