Reliability, Maintainability and Risk, 9th Edition

Appendix 10

Scoring Criteria for BETAPLUS Common Cause Model

A10.1. Checklist and Scoring for Equipment Containing Programable Electronics

Score between 0 and 100% of the indicated maximum values.

1. Separation/segregation	A Max. Score	B Max. Score
Are all signal cables separated at all positions?	15	52
Are the programable channels on separate printed circuit boards?	85	55
OR are the programable channels in separate racks?	90	60
OR in separate rooms or buildings?	95	65
MAXIMUM SCORE	110	117

2. Diversity	A Max. Score	B Max. Score
Do the channels employ diverse technologies; 1 electronic + 1 mechanical/pneumatic?	100	25
OR 1 electronic or CPU + 1 relay based?	90	25
OR 1 CPU + 1 electronic hardwired?	70	25
OR do identical ...