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The news article does illustrate how there's a lot of kinetic energy in a compressed air tank.
There is a lot of POTENTIAL energy stored in the compressed air in a tank.
When the tank fails suddenly and launches the tank airborne, then the moving piece(s) have kinetic energy.
Oh, and on that note, inspection plugs are always found on ASME tanks, but are not as often found on smaller tanks. Between that, and the metal plate I see welded on in that picture, I'm thinking this was an ASME tank, which would make it IIRC 60 gallons or larger.
ASME rated/certified pressure vessel can be pretty much any size.
I happen to have two 15 gallon ASME-certified air compressors.
The energy stored in compressed air (or any gas) can be rather large for even a 'moderately' sized tank.
Let's say we have a true 3 hp motor that takes 5 minutes to 'fill' our tank.
That motor running for that time used approximately
3 hp x 550 ft-lb/sec x 5 minutes x 60 sec/min = 495,000 ft-lb of energy
Let's say the the electric motor was only 80% efficient and the compressor pump was also only 80% efficient, that means that approximately
495,000 x 0.8 x 0.8 = 316,800 ft-lb of energy went into the compressed air.
How much potential energy is that?
The same energy as 316,800 lb raised one foot off the ground.
Or 158,400 lb raised two feet off the ground.
Way more than enough energy to launch a 500 or 1000 lb tank through a roof and a pretty far distance, even after using some of that stored energy to rip apart the steel tank itself.
No joke, most folks never think about the LARGE amount of potential energy that is stored in that compressed air.
Which is why I have said multiple times here on GJ (and other places), one does NOT-NOT-NOT 'repair' a pressure vessel (of ANY type or size) unless
you KNOW exactly what you are doing.
Which pretty much means you are an ASME R-certified shop. Full certification, full paper trail, full required inspections.
Because when things go wrong with a pressure vessel, they can go really wrong.
Which is why ASME was first formed back in the late 19th century, when there were over 2000 boiler explosions between 1880 and 1890 in the US alone, and the adoption of boiler and pressure vessel codes in the early 20th century. Notably after the catastrophic boiler explosion in the Grover Shoe Factory in Brockton, MA in 1905
https://en.wikipedia.org/wiki/Grover_Shoe_Factory_disaster
