Mythbusters Exploding Water Heater Revisted

Post by **FlyingPenguin** » Sat Dec 05, 2009 5:18 pm

From various camera angles in case you missed it...

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renovation · Post by **renovation** » Sat Dec 05, 2009 5:50 pm

wow -that water tank had a hell of a punch !

EvilHorace · Post by **EvilHorace** » Sat Dec 05, 2009 8:31 pm

Didn't see that show but what could cause a water heater to do that normally and at the same time its pressure relief valve also fails?

Post by **FlyingPenguin** » Sat Dec 05, 2009 8:36 pm

Well it would be very unlikely. You'd have to bypass the thermostats and the relief valve

normalicy · Post by **normalicy** » Sun Dec 06, 2009 2:33 am

That's the very reason that I built a concrete casing for my water heater... not. Yeah, many things would have to fail at the same time for that to happen.

On the same note though, I recently built an air compressor & it has an 80 gallon tank tank that I converted from some sort of tank a farmer was using. It didn't have a drain valve & I didn't want to have to drill a hole & weld a bung & buy a valve. However, I kept reading about people who let their compressor accumulate condensation & eventually rusting from the inside out & it blowing a hole in various parts of their house/garage. So, I put my compressor project back about 3 days while I found the parts necessary & did the welding (hard to weld air tight by the way, even if the weld looks good).

EvilHorace · Post by **EvilHorace** » Sun Dec 06, 2009 11:23 am

The drain valve on my air compressor has rusted too but like the water heater, it too has a high pressure shut-off valve so it's unlikely that it would stick and keep building up so much pressure that it'd blow up.

normalicy · Post by **normalicy** » Sun Dec 06, 2009 6:25 pm

Yeah, but even if it's only got 125psi in it, if the rust gives way, that's a ton of pressure in a large tank being expelled quickly. Enough to propel it into the sky. That's the difference between a water heater & compressor. A water heater isn't meant to build pressure (or much anyhow).

Post by **FlyingPenguin** » Mon Dec 07, 2009 12:11 am

The water heater in Mythbusters hit something like 400 PSI when it exploded, and it was a steam explosion. The bottom almost always fails so it launches like a rocket. That's a lot of energy. Before they wrecked the fake house they blew one up in the open and it shot up 500 feet.

normalicy · Post by **normalicy** » Mon Dec 07, 2009 3:54 am

Well yeah, if it overheats it'll build some serious pressure, but that's not supposed to happen.

Err · Post by **Err** » Mon Dec 07, 2009 8:54 am

That must have been what it was like for the boilers or trains and in factories to explode.

Another great Mythbusters explosion is where they crush a car with a rocket slead that's going almost 600 mph.

EvilHorace · Post by **EvilHorace** » Mon Dec 07, 2009 9:01 am

A compressor tank with any leak at only 125 psi would be just like an opened air hose. Air will leak out and blow some dirt around but that's it. The unit must weigh about 100lbs too so it's not going anywhere. I see air hoses leak normally in my line of work. Now, a tank at 1000 psi? Yeah.

Post by **FlyingPenguin** » Mon Dec 07, 2009 9:03 am

They topped that. In the same episode as the water heater revisited, they used the rocket sled to revisit cutting a car in half with a snow plow. They mounted a "plow" on top of the rocket sled and cut a car clean in half:

http://www.youtube.com/watch?v=IjZFWY2SLGI

DoPeY5007 · Post by **DoPeY5007** » Mon Dec 07, 2009 5:35 pm

the last view is cool, where it did look like a rocket launch