Pneumatic pressure testing of plant air piping system gone bad (Fatality and Injury)

We have discussed “pressure testing” and the hazards associated with these required tests many times.  This is an example of what can go wrong when doing these tests with a compressed gas vs. hydrostatically!  A mechanical contractor was increasing the pressure into the 4-inch compressed air line from approximately 125psi to the TEST PRESSURE of 175 psi a failure occurred.  One employee died and the other was seriously injured by sections of piping.  (See video of another pneumatic pressure test gone bad)

At approximately 8:30 p.m. on October 21, 2014, Employees #1 and #2 were checking the compressed air system in Maintenance Room #1 of the 7K pellet support building. During the process of increasing the pressure into the 4-inch compressed air line from approximately 125psi to the TEST PRESSURE of 175 psi a failure occurred.

The pressure caused the two (2) sections of the pipe to move or shoot out in opposite direction striking and damaging the interior wall system and puncturing the exterior pre-engineered metal building envelope. The failure broke apart a 90-degree elbow which connected a vertical pipe riser to a horizontal pipe section running overhead and perpendicular to the joists in the open ceiling area above. The failure caused the vertical pipe to disconnect from the upper fitting while the fitting at the bottom of the vertical pipe remained in position.

The top of the vertical pipe riser rotated counterclockwise approximately 165 degrees striking Employee #1 on the left side of his head and Employee #2 was struck on his arm.

Employee #1 was killed.

NOTE: this is NOT the video of the accident in this article – it is another pressure test accident from years ago.