scope:

Description of Driving Event:

A section of a piping system was removed from a test facility for outside pressure testing. The pipe section had an expansion bellows mounted on the end that was not restrained and under nitrogen gas pressure the bellows ruptured injuring several employees. Although the pressure in the system was under the design maximum, it was determined that the primary cause of the accident was failure of the bellows. While properly designed for its application, it was not tested under conditions for which it was designed.