Excluding 7.5.2 - Validation of Processes for Production and Service Provision

[hiroyuki6]

Hey guys,

Thank you for your explaination. Our work certainly involved welding.

Probably our consultant is trying to find an easy way out by excluding this.

 

[somashekar]

Hey guys,

Thank you for your explaination. Our work certainly involved welding.

Probably our consultant is trying to find an easy way out by excluding this.

Welding is a technical and skilled process that can be very well validated, and operator qualification is a very important element in this. A good weld could be more stronger than the base material when correctly performed.
Perhaps the easiest way is by validating it.

 

[QSMLauren]

The Global Harmonization Task Force published Process Validation Guidance in 2004. (I believe I first learned of it /got the link in this forum!) They have a list of processes that should be validated: Clean Room, Aseptic filling, sterile packaging, plating processes, but not welding. Where is everyone getting that welding is a special process from? Doesn't it depend on whether you can verify the results of the process prior to shipping to the customer and the risk involved? We weld, test our welds with water pressure and again test and inspect 100% of our product in final inspection to make sure it meets requirements. We do have exclusion to 7.5.2. I must also add that if our weld is compromised, there is very little risk to user/patient injury.

 

[Big Jim]

The Global Harmonization Task Force published Process Validation Guidance in 2004. (I believe I first learned of it /got the link in this forum!) They have a list of processes that should be validated: Clean Room, Aseptic filling, sterile packaging, plating processes, but not welding. Where is everyone getting that welding is a special process from? Doesn't it depend on whether you can verify the results of the process prior to shipping to the customer and the risk involved? We weld, test our welds with water pressure and again test and inspect 100% of our product in final inspection to make sure it meets requirements. We do have exclusion to 7.5.2. I must also add that if our weld is compromised, there is very little risk to user/patient injury.

Having some welding experience, I'm not buying that claim. I've seen a lot of sloppy welds, even made a few myself while becoming competent. Believe me, you don't want someone that hasn't been properly vetted welding steel framing on high rise buildings, ship hulls, or boiler tanks.

Even as carefully as the welding was vetted on the Alaska pipeline, weld failures continue to haunt that project.

 

[pldey42]

I'm not in the medical device industry but, being a software engineer, always struggle to understand special processes, so I try to learn by contributing ...

"The Global Harmonization Task Force published Process Validation Guidance in 2004."

Just to be clear, this report says in its introduction:

This process validation guidance is intended to assist manufacturers in understanding quality management system requirements concerning process validation and has general applicability to manufacturing (including servicing and installation) processes for medical devices.

The list in the report is a list of examples, not exhaustive. It does not say there is no need to validate welding processes.

FDA guidance

http://www.fda.gov/MedicalDevices/D...dicalDeviceQualitySystemsManual/ucm122439.htm

says

"For example, visual inspections usually are not capable of detecting defects in structural welds. Such defects may be detectable only by using destructive testing, expensive test equipment, or very slow test methods."

I've never understood why, if a weld has to be of a certain strength, testing that it is indeed strong enough isn't enough. Does the test itself weaken the weld so that, even if it was initially strong enough, it's now more likely to fail in the field?

Is it the case that while pipelines and buildings have to withstand huge forces that can break weak welds, medical devices generally don't get subjected to mechanical forces anything near the breaking point of even a substandard weld? This might explain why the FDA guidance mentions welds yet the GHTF list does not.

Just my 2c, ignore if completely off-base
Pat

 

[QSMLauren]

Having some welding experience, I'm not buying that claim. I've seen a lot of sloppy welds, even made a few myself while becoming competent. Believe me, you don't want someone that hasn't been properly vetted welding steel framing on high rise buildings, ship hulls, or boiler tanks.

Even as carefully as the welding was vetted on the Alaska pipeline, weld failures continue to haunt that project.

I agree that the products specifed above should have their processes validated. However, many welded products do not have the same risk as those and can be verified prior to shipping to the cusotmer. If there is any guidance anywhere to support that welding special process for ISO 7.5.2 please advise.

According to training we purchased through ASQ, 7.5.2 guidance says to validate the process only if you cannot check the product. For example you have to open each sterilized package to check if it is sterilized. My opinion is that it is not a general statement "welding processes" should be validated. Welding is a process. It becomes a "special process" only if the resulting product cannot be fully verified by inspection and testing to customer or product specifications including safety.

Regards,

 

[pldey42]

In support of QSMLauren's question:

Most answers to the question "Why is welding a special process?" seem to be either "Because auditors always say it is," or "Because you can't tell if a weld is good just by inspecting it." Few people seem able to explain why.

Here's an answer that's not so dogmatic, from Sidney Vianna:
http://elsmar.com/Forums/showpost.php?p=274596&postcount=18

QSMLauren said that the GHTF does not identify welding as a special process. It's talking about medical devices. Big Jim's examples were to do with high rise buildings, ship's hulls and pipelines.

I think we're talking chalk and cheese.

As QSMLauren said, medical devices can be pressure-tested for strength of welds. Buildings, ship's hulls and pipelines can't be tested for strength and therefore their welds have to be a special process. The medical devices can be tested and therefore don't have to be a special process. (They might benefit from being a special process if that reduces reject rates, but that's not the question.)

The only way that welding in medical devices, too, would have to be a special process would be if the testing itself weakens the weld, but since the GHTF does not call welding out automatically as a special process, one assumes that is not the case.

Hopefully helpfully,
Pat

 

[Big Jim]

I agree that the products specifed above should have their processes validated. However, many welded products do not have the same risk as those and can be verified prior to shipping to the cusotmer. If there is any guidance anywhere to support that welding special process for ISO 7.5.2 please advise.

According to training we purchased through ASQ, 7.5.2 guidance says to validate the process only if you cannot check the product. For example you have to open each sterilized package to check if it is sterilized. My opinion is that it is not a general statement "welding processes" should be validated. Welding is a process. It becomes a "special process" only if the resulting product cannot be fully verified by inspection and testing to customer or product specifications including safety.

Regards,

I would agree that welding as a special process is one of those "it depends" situations.

To be on the safe side, I would suggest that an organization should assume welding is a special process unless or until they can justify that it is not.

When I say to be on the safe side, I particularly mean safety of users, but to a lesser extent safe from over zealious auditors.

In any event, the organization should be able to explain fully why it is not, not just assume it is not because it would be inconvenient to explain it.