On Mon, 28 Mar 2005 23:43:14 -0500, "Morgans"
wrote:
"Roger" wrote
The tank was drained when they struck an arc. It blew out part of the
back end of the trailer. Unfortunately that caused the trailer to
jump forward and there was a guy standing on the rear of the tractor.
Whether it sheared off the 5th wheel or what happened I'm not sure,
but it squashed the guy between the tank and back of the cab like a
bug
Bad news. What is the right way to weld something that large? I know with
something small, like a gas tank, or can, you fill it with inert gas to
displace the oxygen. How about the tanker? Dry ice, to make carbon
dioxide?
I do know that gas fumes are more dangerous in very damp, humid settings,
even when outdoors. I remember a pile of wet leaves jumping off the ground
a couple of feet. I also know a guy that was severely burned, trying to
light a wet brush pile, when the fumes jumped back. It seems they hold to
the ground more, or are more concentrated.
--
There are some other things at work though.
Old, compacted brush piles and even leaves decompose, creating
Methane. After a damp spell with little of no wind the methane can
accumulate in the brush pile, or under the leaves. As Methane has a
rather wide range between the LEL and UEL it can range from startling
to spectacular.
A good many barns have been lost to this. I know of one where the
loose hay was put up without proper drying. He was trying to get the
hay in before it rained. About a month later the barn was gone.
I've "turned" loose hay in a barn and it's ...more than a little work.
The only way to put it is "It's a real bitch!".
Loose is a misnomer, or it is after the hay has been in there for a
while. It packs every bit as tight as any bale. Using "hay forks"
(Interesting and very dangerous piece of machinery) "Hay Forks" come
in various shapes and sizes, but the ones we had were a two legged
affair about 4' tall and about 2 1/2 feet between the legs. The tips
of the legs were sharply pointed had hooks about 4 inches above the
points that pivoted in flush, or stuck out about 3 to 4 inches.
You dropped these suckers into the hay from maybe 20 feet, but more
often than not you ended up, jumping up and down on the cross bar to
drive them into the hay. They don't sound like much, what with loose
hay, but they'd pick up more than an 1 1/2" rope could handle. Easily
one to two tons which meant splicing a rope if you didn't break
something more serious.
After getting down maybe 6 or 8 feet into the hay I've seen the
temperature so high you needed gloves. When you find it that hot you
know you came within a day or two of losing your barn and we had one
very large barn. It was 40' to the peak, over 100' long and I think
about 40' from front to back and not a nail in it except for new
siding.
Speaking of brush piles... We live well out into the rural
subdivisions. There is a lot of construction and rebuilding going on.
We can get permits to burn brush piles by just calling the DNR, but
construction materials are to be properly disposed of. Some how a
lot of scrap lumber manages to make its way into most brush piles.
One neighbor had a very large brush pile that was probably 50% scrap.
Now, he's right out in the open as opposed to our yard which has woods
on two sides.
With all that scrap and fresh brush the pile was rather open. Big, but
open. They apparently used gas instead of kerosene to get it going.
They mush have lit a rag on a stick and threw it as every one still
had their eyebrows, but that was louder than a couple sticks of
dynamite. Shook the whole neighborhood. I'm surprised they didn't
have to put the brush pile back together, but man what a fire when
that thing got going. OTOH the top of the pile was higher than the
peak of our roof.
Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com
Another neighbor had a straw pile next to the barn. He'd have been OK
had the pile been out in the barn yard, but not against the barn.
Moisture collected and down deep inside the pile it got *very* hot.
Jim in NC