Removing Detection from DFMEA - Medical Device company using ISO 13485

[pbell0000]

I work for a medical device company using ISO 13485. We were recently sited by our Notified Body for using a detection scale in our design FMEAs. This came as a shock to us for sure!

Since then, I've been researching, and it seems detection is generally being removed as an RPN factor and incorporated into the Probability scale. So, an RPN, is simply severity times probability. Our old detection scale was the likelihood that our internal controls (inspection, validation, etc.) were effective at catching a failure mode before shipment. Probability was the chance the failure mode would occur (with no regard to detection).

I'm having some issue figuring out the new scales for probability. Anybody out there have a scale and definition of probability that includes detection (that you can share)?

Also, the idea of regenerating all of our old DFMEAs is pretty daunting with this new method. Has anyone been through this and have suggestions for handling old risk assessments using the "old school" severity x probability x detection scale?

Thanks!

-pbell

 

[rob73]

pbell
Take a look at this recent thread it may (or may not) help
http://elsmar.com/Forums/showthread.php?t=52880
Rob

 

[John Broomfield]

I work for a medical device company using ISO 13485. We were recently sited by our Notified Body for using a detection scale in our design FMEAs. This came as a shock to us for sure!

Since then, I've been researching, and it seems detection is generally being removed as an RPN factor and incorporated into the Probability scale. So, an RPN, is simply severity times probability. Our old detection scale was the likelihood that our internal controls (inspection, validation, etc.) were effective at catching a failure mode before shipment. Probability was the chance the failure mode would occur (with no regard to detection).

I'm having some issue figuring out the new scales for probability. Anybody out there have a scale and definition of probability that includes detection (that you can share)?

Also, the idea of regenerating all of our old DFMEAs is pretty daunting with this new method. Has anyone been through this and have suggestions for handling old risk assessments using the "old school" severity x probability x detection scale?

Thanks!

-pbell

pbell,

Detectability in product design is not about the manufacturer being able to detect a nonconformity by inspection before shipping.

It is about the product's failure or impending failure quickly becoming obvious to its user so they can avoid loss or damage.

Is the product designed so when it about to fail it warns the user? Rather like the battery low warning on your cell phone.

It appears that you have confused your product design FMEA with your process design FMEA.

John

 

[pbell0000]

Still confused. Let's try an example:

If you perform a production test that verifies that device functions properly (on every product built), can't you at least take some credit for that in a design FMEA? The design is tested to ensure its function is proper.