The Difference Between Defect and Failure

Some equate product failure with product defect. The failed product that causes property damage or personal injury is called “defective.” Some product liability lawsuits are premised on the mere fact of product failure without consideration of the operational life expectancy of the product. Courts, however, have recognized that products are not expected to last forever, and may fail due to ordinary wear and tear. In order to establish liability, a threshold hurdle is proof of premature failure. By definition, a product that fails after its design operational life expectancy cannot be considered a premature failure.

Life-Cycle Testing

When a manufacturer sets out to create a product, the design specification determines life expectancy. Drawings are created and a prototype product is constructed and tested. At some point, a production sample is made that enables the manufacturer to undergo life-cycle testing. Depending on the product—and the sophistication of the manufacturer—life-cycle testing may be performed. Such testing may actually be needed to obtain a listing or certification required for sale in certain jurisdictions.

Life-cycle testing is used as a proxy for years. For example, a product with a 10-year life expectancy is not going to be tested in the lab for 10 years prior to product introduction. Thus, life-cycle testing is used in an attempt to accelerate the conditions experienced in operating the product a certain number of times each day over the course of a year.