Tom G wrote:
"Jeff Wisnia" wrote in message
...
Metal content: A water heater

This site has a downloadable video of an exploding water heater shooting
out of a hole in a field. Powered by a deliberately caused boiling water
eplosion:

http://www.waterheaterblast.com/

It was only a little 12 gallon job, but the tank landed 400 feet away.

It provides a good graphic demonstration for any fool who wonders why
water heaters have to have T&P valves on them and is tempted to replace a
dripping T&P valve with a pipe plug.

Imagine what the explosion of a six times larger 80 gallon water heater
would have looked like.

Enjoy,

Jeff
I'm trying to imagine. For the sake of argument, would it really be any
greater. The steam is what causes the heater to explode, right? It seems
the heater would explode when a certain pressure was achieved, regardless of
the amount of water heated to begin with. Wouldn't the 80 gallons of water
tend to hold down the remainder of the heater, thus you might get a greater
"flight" from the 12 gallon. I don't believe the entire water contents
would "instantly" become steam and rupture the tank. Now, as I said, I'm
just trying to imagine what would happen...I don't really know and have no
intention of experimenting to find out.

Tom G.


You'd have 80 gallons of water at, say, 290° and 100 psi pressure (I
haven't looked this up in a steam table, I just guessed.) The water is
still liquid because it's held under pressure*. When the tank blows, it
releases the pressure and all that water turns to steam and expands
rapidly. [That should absorb a lot of energy due to the latent heat of
vaporization, but there must be a huge amount of energy stored in the
superheated water.]

*(the critical temperature of water is about 700°F, above this
temperature water is always a gas regardless of the pressure.)

Bob