Hay can cause barn fires?

There was a friend of one of my co-workers here this morning. They were talking about keeping your outside dog warm. He said to put hay into their doghouse, because hay produces heat. He then said that his uncle's barn burned down twice because of hay spontaneously combusting. Wet hay is even worse, he said. It just produces so much heat that it catches on fire.

This sounds like a load of mularkey to me. Has anyone else heard this?

[Morrigan]

Yes.

http://www.aces.edu/dept/forages/hay/hayfires.html

Morrigan

As far as I know it's true hay mulches like compost and the right mix of dry and wet hay can cause combustion.

edit: Ah spanked by morrigan

Well I'll be...

I figured too much moisture would be bad for fire starting.

You learn something new every day.

[TurquoiseGirl]

Originally Posted by Monza305

Well I'll be...

I figured too much moisture would be bad for fire starting.

You learn something new every day.

If you read the article closely, you will see that it is wet hay that is tightly bundled. This results in anaerobisis in the middle of the hay bale. I suspect that methane (or other combustibles) are produced by bacteria using anaerobic metabolism.

If you spread the hay out on the floor of the dog house (and change it regularly), it shouldn't be a problem.

You will still have to watch out for dog farts though.

[Lainie]

Re: dog bedding, my brother has used cedar bedding, the kind that's used for small animals, in his doghouse. It's warm and soft and it makes the dog smell like cedar.

[Morrigan]

Originally Posted by Lainie

Re: dog bedding, my brother has used cedar bedding, the kind that's used for small animals, in his doghouse. It's warm and soft and it makes the dog smell like cedar.

They're better for dog bedding than straw because the cedar chips repel fleas.

Morrigan

[Griffin2020]

If the hay is properly dried before baling, this is not really an issue. As Troberg said, it is the moisture in the hay that causes the heating (dry hay will not spontaneously combust).

[Brad from Georgia]

Yup, it happens. Granddad also set up a little lumber mill on his farm and raked up a huge pile of sawdust. I remember some of the kids were walking past it one day and my cousin said, "That thing's smoking. This was in the pre-Mask days, and he was being literal--white smoke was curling out of this fifteen-foot high pile of sawdust. It had caught fire at its core, and we had to rake the whole thing down and pour water on it to put out the smolder, a mass of glowing red wood leavings.

[Astra]

One of my instructors used to be a fire investigator and ran across a few incidents of barns catching fire due to hay bales. One time he leaned up against one during what they thought was an arson and realized the heat was coming from inside the bale itself. Turned out not to be an intentionally-set fire after all.

[Troberg]

Yep, it happens. When there's a powerout during the hay harvesting season, the farmers get nervous because the fans that dry the hay stop and if they are not restarted, a fire is likely. I suspect that with the modern fans, a different storage method (compared to pre-industrial) is used that works fine as long as the fans work, but not when they stop.

I can assure you that hay can spontaneously combust under certain conditions. Take it from a farm boy who has been hauling hay all his life. The process that leads to spontaneous combustion is, somewhat counter-intuitively, caused by having hay that's too wet. Hay must be dried thoroughly before it's baled and kept dry until you store it.

Wet hay causes an exothermic reaction that releases significant heat. Since hay is such a great insulator of heat, the temperature builds if it cannot be dissipated, as in the case of a barn full of stacked hay. The temperature CAN rise to combustion levels and will combust if it has enough oxygen.

I've witnessed this effect three or four times in my life. Usually the hay is just smoking and smoldering. But I remember picking up a bale once and having it erupt in flames as soon as it contacted air. Pretty cool, huh!

Yes indeed wet hay in the mow/loft can cause barn fires.
My Dad claims to have found a 'hole' with ashes in the pile of hay, it burned itself out due to running out of oxygen.
When it does burn it (Can) do so Explosively, several years ago our neighbor's barn did just that, We heard the explosion from 2 miles away.