Click here to make tpub.com your Home Page

Page Title: Appendix C - Causal Factor Analysis Examples
Back | Up | Next

Click here for thousands of PDF manuals

Google


Web
www.tpub.com

Home

   
Information Categories
.... Administration
Advancement
Aerographer
Automotive
Aviation
Construction
Diving
Draftsman
Engineering
Electronics
Food and Cooking
Logistics
Math
Medical
Music
Nuclear Fundamentals
Photography
Religion
   
   

 



Corrective actions included repair of the broken connection, inspection of the other connections, and
installation of shrink tubing for structural support. In addition, a checklist, including vibration, was
developed to avoid oversight in design considerations.
EXAMPLE 3
An experiment high-temperature alarm occurred during reactor startup. (Change analysis, Mini-MORT,
or Cause and Effects are all adequate for this investigation.) It was revealed that:
The cooling gas lead was hooked to the wrong cylinder
The operator had followed the startup procedure to verify correct hook up
The procedure was not sufficiently detailed to ensure adequate verification (the procedure
did not state that the operator was to verify the correct hookup, only to verify the correct
gas mixture in the cylinder)
The cylinders had been moved by maintenance personnel to facilitate other noncylinder
work in the area and had been returned to the wrong position in the rack (management
did not want the cylinders moved by maintenance, but had not implemented any controls)
The cylinders were not color coded.
This was classified as an off-normal occurrence related to nuclear safety. The problem was inadequate
cooling and the resulting high temperature in the experiment loop. The direct cause was not verifying
correct hookup because of inadequate startup procedures (Cause Code 2A, Procedure Problem, Defective
or Inadequate Procedure). Contributing causes were maintenance personnel returning the cylinder to the
wrong position (Cause Code 3B, Personnel, Inadequate Attention to Detail), and identical leads and colors
of cylinders with different contents (Cause Code 4A, Design, Inadequate Man-Machine Interface). The
root cause was determined to be the prevailing attitudes and culture that contributed to the maintenance
errors and poor design (Cause Code 6E, Management, Policy Not Adequately Defined, Disseminated, or
Enforced). In this case, personnel error is not a valid cause because the operator had not been trained to
this requirement and could not reasonably have been expected to take the extra precautions.
Note that in this case, as a minimum, corrective action should include review (and revision as appropriate)
of other procedures and training operators to the new procedures. Further corrective action would include
installation of fittings that make it impossible to hook up the wrong cylinder, a review of other hookups
within the facility to correct similar problems, and the use of human factors (ergonomics) in configuration
design and control.
EXAMPLE 4
A large 2400-volt fan system blew a fuse. The electrician obtained a fuse from the store room, tagged out
the switch and replaced the fuse. The system would not work, so the electrician bypassed a safety interlock
and used a meter to check the fuse. A large fireball erupted causing burns that required hospitalization
and 50 lost workdays.
This was classified as an off-normal, personnel safety occurrence (in-patient hospitalization). However,
because this was a near fatality and because there existed a potential for significant programmatic impact,
the investigation used formal Cause and Effects Analysis with charting to identify all of the contributing
conditions and any weaknesses in programmatic or operational control. A condensed version of the
working chart is given in Figure C-1. The significant findings are given below. The worksheets following
the chart illustrate transferring the findings to the ORPS cause subcategories on the worksheets.
C-2


Privacy Statement - Press Release - Copyright Information. - Contact Us

Integrated Publishing, Inc. - A (SDVOSB) Service Disabled Veteran Owned Small Business