Page 34 - Root Cause Failure Analysis

Root Cause Failure Analysis Methodology 25

Group interviews cannot be used in a hostile environment. If the problem or event is
controversial or political, this type of interview process is not beneficial. The personal
agendas of the participants generally preclude positive results.

Collecting Physical Evidence
The first priority when investigating an event involving equipment damage or failure
is to preserve physical evidence. Figure 3-5 is a flow diagram illustrating the steps
involved in an equipment-failure investigation. This effort should include all tasks and
activities required to fully evaluate the failure mode and determine the specific bound-
ary conditions present when the failure occurred.

If possible, the failed machine and its installed system should be isolated from service
until a full investigation can be conducted. On removal from service, the failed
machine and all its components should be stored in a secure area until they can be
fully inspected and appropriate tests conducted.

If this approach is not practical, the scene of the failure should be fully documented
before the machine is removed from its installation. Photographs, sketches, and the
instrumentation and control settings should be fully documented to ensure that all
data are preserved for the investigating team. All automatic reports, such as those gen-
erated by the Level I computer-monitoring system, should be obtained and preserved.

The legwork required to collect information and physical evidence for the investiga-
tion can be quite extensive. The following is a partial list of the information that
should be gathered:

Currently approved standard operating (SOP) and maintenance (SMP) pro-
cedures for the machine or area where the event occurred.
Company policies that govern activities performed during the event.
Operating and process data (e.g., strip charts, computer output. and data-
recorder information).
Appropriate maintenance records for the machinery or area involved in the
event.
Copies of log books, work packages, work orders, work permits, and main-
tenance records; equipment-test results, quality-control reports; oil and
lubrication analysis results; vibration signatures; and other records.
Diagrams, schematics, drawings, vendor manuals, and technical specitica-
tions, including pertinent design data for the system or area involved in the
incident.
Training records, copies of training courses, and other information that
shows skill levels of personnel involved in the event.
Photographs, videotape, or diagrams of the incident scene.
Broken hardware (e.g., ruptured gaskets, burned leads. blown fuses, failed
bearings).