Material Release

Safety Lesson learned: Material Release
Location of Incident: Chocolate Bayou, USA

Brief Account of Incident
During a cycle-ending turn around of 2003, a tie-in was made on the Olefins 1 flare header to enable a hydrogen line to be tied in during the 2005 DCP outage. When this line was placed in service after being tied in, the fitting (4” weld-o-let on 8” header) separated from the flare header, leaving an open hole in the header. Analysis of the failure indicated that fatigue failure was the reason the pipe failed. Investigation determined that the line had not been supported for vibration, only for weight.

Potential Outcome
Because this incident left a hole in the flare header as well as an open-ended hydrogen line, the potential outcome was fire.

What Went Wrong
The hydrogen piping that was tied in to the flare header during the 2005 DCP outage was not braced properly to provide adequate protection from fatigue failure of the weld area.

Immediate Causes
Routine activity without thought – Since the tie-in was routine, the designers did not think to analyze for vibration.

System Causes
- Inadequate technical design
- Inadequate assessment of potential failure
- Inadequate standards or specifications

What Went Well
Operator action and the Emergency Response.

Safety Lesson Learned
1. Add a checklist to the piping portion of the specifications dealing with flow-induced vibration.
2. Review the results of the investigation with the engineering departments.
3. Add the review of this incident to the Lessons Learned document for the DCP outage.
4. Review the Hot Tap procedure in the Process Safety Committee.
5. Survey all tie-ins to the flare at Olefins 1 and Olefins 2 to identify other potential issues.
6. Correct any deficiencies found during the audits.