Fire doors are an important code requirement for most buildings larger than two-family residences. The ratings of the doors and their components are specified according to the amount of time they will hold up in a fire, the classification of wall opening, the use of the wall, and the fire rating of the wall itself. Proper installation can be a matter of life or death when a fire breaks out. Detailed knowledge of code provisions is required. The following is a brief introduction to the subject, excerpted with permission from the booklet Fire Code Summary published by the Architectural Woodwork Institute. It is fairly standard throughout the industry to install fire door assemblies in accordance with NFPA 80: Standard