On Sat 13 Nov 2004 02:57:13p, "nigel" wrote in
ups.com:
I imagine this is only a problem with plastic tubes/conduits ... metal
would seem to be proof against the whole thing.
What do the experts have to say on this?

Did anybody catch that Mythbusters show where they tried to make the
Static Canon?

The myth is that a construction worker finds a really nice piece of large
diameter, about 8-10 inch, plastic pipe and wants to use it but it's all
dirty so he sandblasts it at the site and builds up such a huge static
charge on it that when he walks around its end, it shoots a lightning
bolt out of it and blows him across the compound.

They tried everything. Couldn't even make the thing spark. They had a
voltmeter on it, and it kept building up a little charge and then
dissipating.

As someone else has said, the stuff is an insulator. Grounding the
outside grounds only the outside. Don't need a resistor, you're only
sending a few volts to the ground. But any charge inside the pipe is
still there.

I've also seen articles on attempts to duplicate a shop explosion. They
found that the dust particles have to be a certain size, and be dispersed
in the air in such a way that each ignited particle ignites the particle
next to it, and in such a manner that it creates an explosion-like
combustion. They found that when they finally got the conditions correct
for a dust explosion, the air was so full of fine-particle dust they
could barely see. And any air currents in the area screwed it up. The
dust particles weren't close enough together. Their conclusion was, if
you have the correct conditions to create a dust explosion, you should be
more worried about breathing than an explosion.

Want me to hunt around for the article? I think it might have been posted
to this very newsgroup.

Dan