Electrical Power Plant Supply failure in PFMEAs

[Cephissus]

Hello all,

Say we have a plant in Mexico, and once in a while there is power outage.

Must that be taken into consideration in PFMEAs? Or is it enough to cover it in contingency plans?

Thanks a lot!

Manuel

 

[Jim Wynne]

Hello all,

Say we have a plant in Mexico, and once in a while there is power outage.

Must that be taken into consideration in PFMEAs? Or is it enough to cover it in contingency plans?

Thanks a lot!

Manuel

In general, the PFMEA should address potential failures that are intrinsic to the process in question. If we include things like power failures that affect the entire facility, we might as well include asteroid strikes. The contingency plan, if properly executed, should address what must happen in production in the event of whatever extrinsic phenomena might occur. It should be assumed that if power outages are recurring phenomena there are plans in place to deal with the potential results.

 

[Bev D]

I have a slightly different take on this.
If the process is dependent on electrical power for important process functions, then power plant failures enter the FMEA as a cause of the process failure.

we have several critical processes where a power disruption (from whatever source) has catastrophic results on the product. we therefore put mitigations in place to reduce the occurrence of disruptions, robust against them, etc.

 

[Jim Wynne]

I have a slightly different take on this.
If the process is dependent on electrical power for important process functions, then power plant failures enter the FMEA as a cause of the process failure.

we have several critical processes where a power disruption (from whatever source) has catastrophic results on the product. we therefore put mitigations in place to reduce the occurrence of disruptions, robust against them, etc.

I don't think there's anything to be gained by including in the PFMEA potential causes that we have absolutely no control over. There are not very many manufacturing processes that don't depend on a consistent supply of electricity. That's why things like power outages and acts of nature that have a global effect are best dealt with in contingency plans. That's what contingency plans are for.

 

[Bev D]

Jim - of course you can do and advise whatever you want, but my experience is quite different. I don't think about what I have direct control over but what can I mitigate or robust against or plan for. That mind set shift has resulted in substantial improvements in quality problems and other waste.

These actions never supplant "business contingency plans" but for some processes a power disruption - regardless of the source - is catastrophic.

Part of our product portfolio involves the manufacture of large batches of material that must maintain temperature and vacuum for extended periods of time and a disruption results in huge scrap costs, schedule effects and backorder. It can also cause stability concerns with our end product that can't be caught by release QC testing.

Some products must be kept at cold temperature during the manufacturing process as well as shipping and any disruption to that also causes scrap, stability concerns and potential notification to governing bodies. So instead of relying on the whims of mother nature and the god of electricity we take measures to maintain temperature in the face of an outage through other means than externally sourced electrical powered refrigeration. if we didn't we wouldn't survive as a business.

 

[Golfman25]

I think the difference is what the effect of power issues is on the product. For us, if the power goes out (used to happen quite often) everything stops. We clean up or get to all those things that have been "sitting there." When the power comes back up, we start up again. There is no affect on the parts we make. No different than stopping for lunch break or the night. Other processes may be more power affected.

 

[Miner]

I have a slightly different take on this.
If the process is dependent on electrical power for important process functions, then power plant failures enter the FMEA as a cause of the process failure.

we have several critical processes where a power disruption (from whatever source) has catastrophic results on the product. we therefore put mitigations in place to reduce the occurrence of disruptions, robust against them, etc.

I agree with Bev on this. The way it was posed by the OP was that this was a common event, not a rare event. Having worked at several companies that have facilities in Mexico, this is a familiar event to me also.

An analogous utility situation for me was air powered torque drivers. Periodically the plant air pressure would drop, which would cause the applied torque to drop also. While not proactively done, we added pressure regulators set below the level of the pressure drop, reset the torque drivers to work properly and added the issue and actions to our PFMEA for the future.

My current company makes a product line that protects against voltage sags, which account for about 70% of power disruptions. The point is that there are often ways to mitigate, if not eliminate, the risks.

 

[outdoorsNW]

How often is one and a while? If it is once a week, I think it should be included. Once a month, probably.
I think severity matters too. If a power failure (regardless of how often one occurs) may cause an event that would cause injury or worse, (severity of 9 or 10 in the AIAG scale), I think it needs to be included in the PFMEA.

 

[Cephissus]

I agree with Bev on this. The way it was posed by the OP was that this was a common event, not a rare event. Having worked at several companies that have facilities in Mexico, this is a familiar event to me also.

An analogous utility situation for me was air powered torque drivers. Periodically the plant air pressure would drop, which would cause the applied torque to drop also. While not proactively done, we added pressure regulators set below the level of the pressure drop, reset the torque drivers to work properly and added the issue and actions to our PFMEA for the future.

My current company makes a product line that protects against voltage sags, which account for about 70% of power disruptions. The point is that there are often ways to mitigate, if not eliminate, the risks.

Thank you everybody for your contribution and comments

If the frequency of the event can help determine inclusion or not, and settle the discussion between Jim and Bev, I might add that it happens normally only twice a year for only a couple of hours.

When asked, both the plant and the HQ Process Engineers are against including in the PFMEA. Our HQ Quality Assurance Supervisor is in favor of. I was looking for some FMEA guideline-inspired rule of thumb to help decide...

So far it seems it's still up for user's interpretation?

 

[Cephissus]

How often is one and a while? If it is once a week, I think it should be included. Once a month, probably.
I think severity matters too. If a power failure (regardless of how often one occurs) may cause an event that would cause injury or worse, (severity of 9 or 10 in the AIAG scale), I think it needs to be included in the PFMEA.

Also to take into account outdoorsNW comment: our product is not critical at all and as such no Severity exceeds 6 or 7 so far...