Multiple controls for single failure mode

[sulkinsf]

Cross functional review is a design control for all design failure modes. Since it is also a weak control are we required to provide an action even if stronger controls are in place?

For example,

Potential failure mode is poor callout on weld. This is controlled by cross-functional review (weak control), and design rules (strong control).

I am wondering how you guys handle this. I was thinking about consolidating the controls and ranking according to the strongest control.

-Steve.

[Marc]

I often see multiple controls for a single failure mode but have never thought about combining them.

[sulkinsf]

How do you handle the resulting RPN values? Do you assign tasks to the higher RPN knowing that the failure mode is detectable by the other control?

It can be handled in the following manner:
LIst the various controls you have ''
List the ratings for their detection individually say 2,4,7
Take the best i.e 2 in this case (although it will be even better by a combination of all of them together ..I dont want to complicate the issue by combining their probabilities..)

Use the best for prioritising..

HOWEVER, IN THE CASE MENTIONED BY YOU..
"Potential failure mode is poor callout on weld. This is controlled by cross-functional review (weak control), and design rules (strong control). "

I WOULD CONSIDER DESIGN GUIDELINES AS A METHOD WHICH WILL HAVE AN EFFECT ON THE OCCURENCE RATING AND NOT DETECTION RATING.

Thanks

e.s.deo