Pressure Vessel Failure during Air Test
Please find below a couple of photos of a Pneumatic Test Incident

Jan 26 2006 Accident occurred in a factory in Brazil, during pneumatic pressure testing with Air from pipe work around a tank.

There were no blind flanges are placed in order to isolate the pipe work to the tank, only the valves were closed. Probably has one or more valves failed, or were not closed, and the tank also has undergone a pressure test.

As a result, there has been a tremendous energy built up in the tank, and the tank "launched" and ended up on top of the installation.