On the Purpose of Performing the Operational Qualification (OQ) for an Equipment


A company I worked for believes that the purpose of performing an operational qualification of an equipment is to demonstrate that the equipment functions at the settings expected to be used in production. As such, it does not feel it is necessary to validate the manufacturer’s claims about its product’s greater functional range. I wholly disagree with this limited perception.

Consider a simple hypothetical example wherein I intend to make bread. The recipe calls for the bread to be baked in an oven at 400 F for 25 minutes. Applying this company’s point of view, the operational qualification of my oven would require only demonstrating that it functions at 400 F for 25 minutes. There is no need to validate that the oven is capable of functioning to its manufacturer’s claim of 170 F to 550 F. I believe this model for conducting an equipment operational qualification to be shortsighted at best and a total misunderstanding of what an operational qualification is at worst.

While such an approach fulfills the immediate need to demonstrate that my oven is capable of generating 400 F, such a limited test does not take into account my future potential needs. Perhaps better bread might be made by baking it at 350 F for 35 minutes. Or, I might want to make pizza – that requires my oven to operate at 550 F, the hottest it gets. Or, I might want to keep food warm in the oven at 170 F. An operational qualification of this type precludes me from using my oven at temperatures that haven’t been tested. I would have to repeat the operational qualification at other temperatures before use.

But, I believe that this approach to performing an operational qualification is actually more than just shortsighted. It is wrong. It is an incorrect interpretation of what a proper operational qualification is intended to demonstrate: that the equipment is capable of performing to its manufacturer’s claims. A proper operational qualification should be done such that the functionality of the equipment is evaluated at a minimum at the high & low settings of all its critical input controls. The design of experiments provides a statistically robust and cost efficient method to do this.

In an abstract sense an operational qualification is part of the receiving inspection process, albeit a complex one. And just as in the typical receiving inspection process, it is better to find defects or deficiencies in the equipment at this stage (even those that don’t directly impact our immediate application) than to discover them during production. Defects, like cracks, tend to migrate into the production operating zone over time.

At its most basic level an operational qualification has very little, if anything, to do with using the equipment for any given application. Operational qualification of my oven has very little to do with me using the oven to bake bread, make pizza or keep food warm. Validating that the equipment will perform as expected for a given application is done as part of a performance qualification (PQ) of the equipment. So, when my former employer performed an operational qualification of a tool at an application specific setting, it was actually performing a performance qualification; bypassing operational qualification.

When a proper operational qualification has been performed for a piece of equipment, it does not need to be repeated until the equipment undergoes some sort of preventive or breakdown maintenance when consumable or broken parts are replaced. As such, a company that intends to extend the use of a piece of equipment to multiple applications needs to only perform a performance qualification of the equipment for a given application’s settings before releasing the tool to run that new application.

It is disturbing when quality managers do not take the time to understand the purpose of a particular assurance activity. As you can imagine, this leads to wrong tests being run, wrong data being collected and wrong conclusions being drawn. The problem is compounded by their willingness to take shortcuts. Is getting to the wrong place faster better? It doesn’t make any sense to me why a company would not perform a check of the manufacturer’s claims when the effort required isn’t any greater and the long term benefits are significant.

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