What term describes equipment or materials that have been tested and listed by a nationally recognized testing agency?

The term that best describes equipment or materials that have been tested and listed by a nationally recognized testing agency is "listed." When equipment or materials are labeled as listed, it indicates that they have undergone rigorous testing and evaluation to meet specific safety and performance standards as defined by that agency. This designation is critical in ensuring compliance with building codes and safety regulations, as it assures designers, installers, and consumers that the products have been thoroughly vetted.

The other terms do not capture this specific connotation. For example, "validated" generally refers to a process whereby something is confirmed to meet certain requirements but does not necessarily imply official testing or approval by a recognized authority. Similarly, "verified" can denote checks confirming the accuracy or truth of something, yet does not imply formal evaluation by a testing agency. "Documented" refers to the existence of records or proofs of something and does not convey the formal testing and recognition process that "listed" does. Thus, "listed" is the most precise term for this context.