This report describes a computer program, EXP0SURE8 OA , written in Symbolics Common Lisp, that leads the user through NFPA 80A: Recommended Practice for Protection of Buildings from Exterior Fire Exposures. EXPOSURE80A is designed for use by fire protection professionals. It tells the user whether two buildings comply with the recommendations of NFPA 80A and if they do not, it suggests changes that will bring the buildings into compliance. EXP0SURE80A is easier to use than the written version of NFPA 80A since an understanding of 80A is not required. The approach used in EXPOSURE80A provides valuable information about the knowledge required of the user and the appropriate interface for the targeted class of users of an expert system, EXPOSURE, which is described in a separate report.