When the term “requirements” is used in relation to technical products, it refers to a detailed description of the functionalities, performance features, quality characteristics, and other aspects that a product must fulfill in order to meet its users’ needs and expectations. These requirements provide the basis for developing, designing, and manufacturing the product.
In FMEA, “nonfunctional requirements” pose a challenge and shouldn’t really be handled as functions unless they can be reasonably resolved.
More on this in the professional article, "When functions are confused with requirements, trouble looms. A different strategy is needed."