scope:

Description of Driving Event:

Recently a "Close Call" involving the unintentional over-pressurization of a low pressure system designed to operate at less than 150 p.s.i.g. The system was opened to a pressure of 2300 p.s.i.g. for a fraction of a second until a shop air hose, rated for 300 p.s.i.g., ruptured into two sections. It was fortunate that no one was hurt as the potential for serious injury was very real. The sequence of events was started with a work-around that was initiated to replace the shop air (which was out of specification) in the LubeLok spray booth with compressed air from a supplied Manifold K-bottle Rack. The engineer in charge misread the Rack's pressure gauge and "assumed" the output pressure was 160 p.s.i.g. when what he had read off the gauge (see picture) was 160 BAR, approximately the equivalent of 2300 p.s.i.g.

Root Causes:

1. Failure to pay attention to details because no one involved took the time to correctly observe the high pressure indicated on the gauge. (see picture)

2. Lack of training and failure to take time to understand the Manifold Rack's design which would have revealed that there was no pressure regulator built into the Rack system.

3. Failure to develop detailed work authorization documents to perform work on a Safety Reviewed system that processes Flight Hardware and which requires "material specifications".

4. No gauge or pressure indication visible from control valve.