So your statement, without weasel-words built in as you have done, is
"Sawdust from a woodworking shop cannot spontaneously combust", yes or no?
And yet, there are people who don't understand it, and will expand one
situation to an unlrelated situation.
That's kind of amusing to read, since I'm the one in the back of the
ambulance, working on the patient.
Draw a venn diagram of your sawdust/manure/fire theory, and you can show
yourself where the flaw in your logic is.
Yeah, me too, WHAT? WTF are you responding to, George? You don't
even see with this blatant example, why your insistance on top-posting
I have no contempt for precise knowledge. Why don't you try exhibiting
some and we'll see if you can.
I notice you ignored this. Do you have _any_ point to make here,
George, or are you just making noise to listen to yourself?
Venn diagrams are meaningless in cause-effect relationships.
"Communication" with the unreasoning is impossible.
I would expect someone else with a medic's card to have some scientific
background, and respect for learning. In your case, I'm wrong.
Good lord. You must be being _intentionally_ dense.
Of the set of all objects which are causes for spontaneous combustion,
some of them apply to manure. Some of them apply to hay. Some of
them apply to oily rags, and so on. Oily rags are not cow manure.
Sawdust is not oily rags. Wet hay is neither.
I've noticed that.
I have plenty of respect for science, communication, and learning. You
continue not to exhibit any of those.
Third time: (I bet you'll evade it again)
Are you saying that spontaneous combustion of sawdust is impossible?
That's quite a brash statement (that they outgas the same). But I like
the way you make brash (or ambiguous) statements and then mock everyone
who disagrees. It makes the internet worth while.
Anyway, to the matter at hand...a cursory search of the internet, which
as we know never provides false information, shows many examples of
spontaneously combusting sawdust, albeit usually at the bottom of a 20'
mound. I did, however, find an example of a fire caused by a "pile of
sawdust under a sawbench." How big a pile? I dunno'. See:
Likely, the dust was from green wood.
Now, because of the nature of the danger, this problem has actually been
studied (believe it or not, we need not concern ourselves with hay
fires!). The following absolute truth was also found on the internet:
From <http://www.ciwm.co.uk/mediastore/FILES/10867.pdf :
"As with compost and rubber tyres, wood chips and sawdust material can
undergo self-heating reactions, leading to spontaneous combustion, under
certain storage conditions. Factors that will play a part in whether
self-heating leading to combustion will occur are the size of the wood
chips, the moisture content, the presence of other flammable waste
materials within the stockpile that are easily ignitable, and the
natural oil content of the wood. Sawdust has been tested extensively
over any years and it has been found that the greater the proportion of
oil present in the wood, the lower the critical ignition temperature
(the temperature at which a runaway reaction occurs)."
1. Bowes, P C. Self-heating: evaluating and controlling the hazards.
Building Research Establishment. Department of the Environment. 1984. HMSO.
It seems this Bowes fella' made a career out of this stuff. Even though
he died in 2001, he was nice enough to write it all down in a book.
Sadly, now that I'm no longer a student, I can't get my hands on it
easily. But maybe if one of you could find it, it could settle the
matter of whether or not s.c. is possible in this case. It might also
answer the more immediate question of who can piss farther.
In the above, I note the following:
1) Oil content is critical. How much oil is in sawdust from green wood
vs. dust from air dried vs. kilned, I don't know. Anyone?
2) Note that several other factors, including other oil sources are
important. This certainly has bearing on the original poster's question.
Does, for example, it make a difference if he cuts plywood or any
other source of organics? What if he hacks up an old project that was
treated with linseed oil?
I suspect that if one read the book, you'd be hard pressed to make a
case for s.c. at this small a scale (especially since the water content
must be just right); nevertheless, I bet you _could_ come up with a
scenario, albeit unlikely. Would I worry about it? No. But I'm not silly
enough to put water in my DC system...
As for hay, I found this incontrovertible evidence (of course, because
it's on the internet):
"Hay fires usually occur within six weeks of baling, but they may occur
in hay several years old. Fire can occur in loose hay, small bales,
large bales or in stacks. The fires can occur in hay stored inside as
well as in hay stored outside. Regardless of when or where the fires
occur, the most common cause is excessive moisture."
Note that "old" hay is also subject to s.c., the point being that once
dried, s.c. is rare because, well, it's dry. But if re-wetted, I see no
reason why bacterial growth can't restart. Of course the C:N ratio of
wood is so high that it's hard to get a lot of bacterial growth and heat
production, but that obviously happened in the s.c. examples above. I
have certainly felt warmth in sawdust piles, but they were outside where
heat/organics couldn't build up enough for s.c.
Anyway, the point is that if you want to claim that hay and sawdust
outgas the same, then if old hay can s.c., then surely you agree that
old sawdust can, too. Yes?
Well, of course there is. But if we don't understand _all_ of the
factors involved, then changing the input (cause) may lead to an
unexpected result (effect). That is why scientists have jobs -- because
not everything is understood.
There's also how much oil in one species vs another, say Southern Longleaf
Yellow Pine heartwood vs some comparatively oilless species, and the
composition of the oil--Lapacho for example is about as combustible as
concrete, despite being oily enough that you can polish it with its own
Reply to jclarke at ae tee tee global dot net
I'd rather not find out the hard way. Spontaneous combustion _can_ occur
with _dry_ wood but it takes a big pile. Get a little rot going and who
knows--that's pretty much the mechanism by which haystacks catch fire after
a rain. While spontaneous combustion is the topic of a certain amount of
research I don't think it can be described as a perfectly understood
Reply to jclarke at ae tee tee global dot net
J. is not a scientist, but a believer.
You are correct in assuming that it is the oxidation of volatile
organics -exothermic reaction - in confinement which causes ignition. They
are not normally found in seasoned wood.
Flashed on a friend who loved cats and loved his wife, who was allergic to
cat dander. Solution--remove the dander. So once a week he bathed six
cats. Surprisingly, the cats got to where they liked their bath, would
line up to be bathed, and became petulant if he didn't bathe them on time.
Reply to jclarke at ae tee tee global dot net
When I was growing up, our cat felt the need to supervise people baths.
Sitting right on the edge of the tub. With his tail dangling _into_ the
I don't recall ever finding out his opinion of a -cat- bath. But he did
like to be _vacuumed_. Directly by the hose of a regular canister vacuum.
We also had a big Chesapeake Retriever who would 'shake' _on_command_ --
no, not 'shake hands', though he did that too, but after a bath. We would
tell him 'stand still', tent a big towel over him, and say 'Okay, _now_
shake', whereupon he would. Was also _real_ handy when bringing him in from
outside when it was raining or snowing.
What can I say. The cat was practically bigger than the vacuum was. <grin>
Anyway, he'd just lay down on his side, and when one side was done, he'd
I don't remember how he got _introduced_ to it, but this was an _old_
green Eureka canister. It was extremely quiet, despite having a lot of
pulling power. Did a _great_ job of pulling out the old winter under-coat,
come spring time.
I gotta tell ya, vacuuming the livestock is a whole *lot* more efficient
than having to vacuum all the furniture, rugs, etc. to pick up shed hairs.
Chesapeake's are *smart* -- _ANNOYINGLY_ smart. However, in this case, he
knew the difference between 'sit' / 'shake', and 'stand still' / 'now shake'.
Heck, for 'shake' (hands), if you put out your left hand, he'd use his left
paw, and if you put out your right hand, he'd use his right paw. And if you
then said 'the other one' he'd drop whichever paw he had up, and offer 'the
The 'stand still... OK, now shake' DID impress the hell out of any visitors
who happened to see it -- almost invariably the reaction was "I wouldn't
have believed it, if I hadn't seen it with my own eyes!"
i shower my 4 cats pretty regularly. with 2 of them, i have to bang them
pretty good with the vacuum to get them to move. they're not afraid of it at
all and must think i'm pretty annoying when i want them to move.
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