scope:

Description of Driving Event:

A deactivated exhaust gas cooler in a vacuum line collapsed under normal operating conditions of 26 inches of mercury. The cooler was destroyed. There was minor damage to a nearby wall due to negative pressure in the vicinity of the cooler. Skylights in the shop area imploded and a considerable amount of debris was drawn into the piping.

The principal cause of the failure was deterioration of the cooler due to age. Poor welding during assembly and inadequate inspection of the cooler were contributing factors.