Differentiating between verification and validation for a manufacturing process can be confusing, because they are very similar. The difference is in the implementation, desired outcome and the phase of the process. To try to clear things up, let’s look at a simple example of a gear cog that has been manufactured as per the requirements stated by a client:
- The first step is to compare the cog to the design requirements of material, dimensions, tolerance, etc. At this point, you are not actually focusing on whether it will actually work in the machine it is intended for, but rather whether the cog is manufactured within the parameters indicated or not. This is verification, which is the act of testing and confirming that the product meets the specific requirements of the defined instructions.
- The fact that the cog meets the requirements as per the design is not necessarily a guarantee that it will work, because the instructions may be missing some information that is critical to its performance. The next step is to assemble it in the machine it is designed for and test it through the various operations to make sure it works as expected. This is validation, the act of testing and confirming that the product can perform its intended purpose and consistently produce acceptable results.
Now that’s just a simple gear cog, but when it comes to building more complex machinery, the likelihood of unforeseen hurdles increases exponentially. Both verification and validation play critical roles in quality management, reducing errors and making sure the product conforms to the user’s requirements, industry standards and regulatory authority guidelines.
When Do You Need Process Verification?
Verification plays a role in almost every stage, from initial development to production and upscaling. Validation comes into play later in the manufacturing lifecycle once the product is verified and can be tested. Some of the verification processes in each phase of manufacturing are:
- Development: When the initial designs are being drawn up, individual components are modeled and the compatibility of all the parts is verified. The individual parts as well as the product as a whole should be able to demonstrate it would be capable of producing results within the customer’s specified requirements.
- Review: A model or simulation of the entire system is created and checked for adherence to the requirements. Conformity to other limitations, such as size and weight, is verified, and the design is reviewed and altered as needed.
- Production: Throughout the production phase, products should be subjected to regular verification tests to ensure consistent quality. Corrective and preventive actions, installation qualification and operational qualification are forms of verification that are carried out during production.
- Scaleup: When the product is ready to be produced in larger volumes, verification is still an important aspect for ensuring each product that is released in the market will produce acceptable results. This can be done in the form of random inspections for quality and other checks.
When Do You Need Process Validation?
Validation begins during the production phase, can be implemented alongside verification and plays a wide range of roles in creating a satisfactory product.
- Validation can, in some cases, be used in place of verification. This is usually in situations in which the results cannot be measured, or the cost of verifying is too high to justify the need for verification.
- Before scaling up production, properly executed validation in different test conditions ensures acceptable performance when the product is used in real-world environments.
- Even with strict processes in place to ensure product quality and effective prevention tools, unexpected consequences can still occur. Validation can detect and correct these errors before market release.
- Performance qualification requires stringent validation checks to make sure the product can actually perform to the level it is designed for, such as power consumption under heavy load, breakdown point, etc.
Fully Verified or Validated?
Verification can usually be used to control process outputs, but there are some scenarios in which verification may have limited utility, or even be impossible because the output cannot be measured.
As per the FDA’s Quality Systems Regulations, processes that affect the Critical to Quality (CtQ) criteria, can be “validated with a high degree of assurance and approved according to established procedures.” That is to say, to ascertain that defects arising from the unverified processes are unlikely, the process itself can be validated and variations can be controlled by employing suitable techniques like Quality by Design (QbD).
For FDA approval, the process validation will need to be rationalized and accompanied by appropriate documentation. To determine if a process requires validation or verification, many factors need to considered carefully. These include the sufficiency and accuracy of verification, risks related to the process and the feasibility of routine tests.
The likelihood of defects can be reduced significantly by thoroughly understanding the requirements, requesting additional details for variables and verifying at each point in the lifecycle. However, sometimes there are still glitches, and that is why validation can be well worth the investment.
Edward Simpson is a calibration and technical engineer working for RS Calibration Inc.; http://www.rscal.com