Verification vs Validation iigsystems（验证和确认iigsystems）.pdf

Verification vs Validation The design requirements (section 7.3) for ISO 9001:2000 require that designs be verified and validated. This requirement has been in the ISO 9000 series requirements from their inception. It has also been a source of confusion. To discuss the subject we will nee some definitions. Verification is the conformation that a product meets identified specifications. Validation is conformation that a product appropriately meets its design function or the intended use. So far the distinction is just words and not helpful determining what to do. The following example may be helpful. One of our clients makes an epoxy material that is used to form the head gasket of an engine. There are a variety of specifications including formulation, specific gravity, flow characteristics, and temperature resistance that apply to the epoxy. Testing that assures conformance to these specifications is verification. When the epoxy is applied to an engine properly it must withstand the working pressures of an engine and perform as a head gasket. If the epoxy leaked when the engine was pressurized it would fail validation. It may have met all the material specifications (verification) but it did not work as a head gasket (validation). Obviously, almost all properly designed products will pass validation testing if they pass verification testing. But, some products are difficult or impossible to verify by the manufacturer. For example, the engine mounts on a car. Their design function is to physically support the engine and decouple engine vibration from the chassis. The only way to validate the engine mount is to assemble it in a car and determine if it isolates engine vibration. None of the specification testing (verification) can absolutely assure that the mount will provide sufficient vibration decoupling (validation). The engine mount manufacturer cannot perform validation testing