zxcvbob wrote:
George E. Cawthon wrote:
Jeff Wisnia wrote:
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

Isn't it wonderful that I live in a place where they don't put all
sorts of safety stuff in the lines. If my water heater overheats, the
pressure just equalizes with the incoming cold water line since there
are no restriction between the water tank to the street water supply.

First the water tank would boil and the pressure would push the water
back in the cold water line. When the boiling water level dropped to
the upper electrode, the electrode would burn out, possibly turning
the power off, but if not, the water would continue to boil until the
lower electrode was uncovered which at that time the electrode would
burn out and coldwater would fill the tank.

Of course if I had a gas heater (which I do now), it would just boil
dry and then the bottom would burn out and cold water would poor in.

I wouldn't notice anything until the water flooded.

I'll bet way more people are killed by lightening each year than by an
exploding water tank. Probably about 10,000 to 1 more by lightening.



I've wondered the same thing. You'd have to have a closed valve (or a
check valve) before the water heater tank and all the hot water faucets
closed to get in trouble. But if it ever did BLEVE, there's a *lot* of
energy released.

Bob


I would bet that in most cases a hot water line
would fail before the tank, especially in the
supply line to faucets which are rubber hose,
skinny metal, or plastic.