oily rags and safety

Paul Downes

Member
Messages
959
Location
Westphalia, Michigan
We probably have all heard of the issue of spontaneous combustion and oily rags. Aside from the best ways to deal with them, mainly burning them as soon as you can after creating them. I have a bit of a problem in that I have a business that generates large quantities of them daily. I use them to clean deep fryers all day long. I also have heat resistant cloth gloves and sleeves that are fairly oil soaked by the end of the week, and then washed and re-used.

So my question is how to deal with the gloves and not burn down my shop or service vans. I think the rags require outside air, namely oxygen in order for the oil to oxidize and generate heat. So I'm thinking that I will keep the gloves in Zip Loc bags to keep the air away from the gloves. Do you folks think this would be a good solution? I don't know enough about the chemistry going on here to be completely at ease that simply denying air will keep stuff from going up in smoke.
 
The combustion problem starts when the oils are of the drying variety, those that oxidize and cure over time (typically linseed oil is the culprit). The oxidation process generates a lot of heat, leading to the fire. Without knowing exactly what oil you are knee deep in, my guess is that it isn't a problem with cooking oils. But if you're still concerned about the gloves, you could always get one of the fire proof cans used for such things. Keep the gloves in there until you're ready to wash them.
 
The one time I've had a burn was when the wife was rubbing some Danish oil on a teak table and putting the used rags in a plastic shopping bag. The confined contents heated up and began to smolder by the time we figured out what was causing the odor. I let my rags 'air out' until dry or throw them in a bucket of water until I can dispose of them.
 
The oil is cooking oil and it will spontaneous combust. I know this from talking to other owners in my business. One had washed gloves burn up his car and garage. I think the issue in his case is that it is very difficult to get all the oil out of cloth and there was enough residual oil left to oxidize and start things going.

My question is: does the cloth/oil combination require outside air to spontaneously combust or is there something going on in a chemical interaction way that might cause heat with little or almost no air. I was thinking about catalytic reactions like with some resins/accelerators that generate heat to set a glue. 2-part epoxy for one. It crossed my mind that if there was a chemical reaction with certain fibers used in clothe(s) and oils, that there might be enough heat to melt a plastic bag and accelerate with the addition of air.

I will take steps to eliminate the issue regardless of what I learn. I do have one fire proof disposal can in one of my 2 service vans. It is just an brain fart on my part to not have one in each van and in the different facilities I use.

I have looked around a bit on the net but most of the articles talk about the fact of spontaneous combustion and not the technical specifics of how it occurs. I guess I should go look for a doctoral dissertation on the subject.
 
The reaction is causing the heat. It's the process of the oil molecules reacting with oxygen as they cure, if they have enough ventilation to disperse the heat, they just dry and turn stiff. If they are piled up the heat builds to a level where it ignites the fabric and oil. Those safety cans work because they are airtight. To reassure yourself, I wouldn't look for a dissertation but rather a local safety expert, like the county EMA or Hazmat administrator.
 
I use a metal rag can AND a solar dryer (clothesline) for my storage. If your not allowed a clothesline, you might be able to hang some on a hanger, around a bird house, for instance.
One other thing that I think should be pointed out (but is more sciencey then I have training it), you mentioned AIR, and someone else, more correctly mentioned OXYGEN. Some detergents break down and release oxygen, so detergent residue, could itself cause a fire.
 
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