The Government has issued several acts such as "Building Public Safety Inspection Code" for fire protection of buildings. Since building fire protection codes are complex and are usually interrelated in various decrees, the inspectors have difficult time to properly apply them to various situations. This research aims to establish a fire inspection and protection expert system (FIRES) using object-oriented programming and knowledge-based expert system techniques. The decrees in each related code are represented in objects. Regulations in the decrees are represented by constraints and thresholds in the objects, while corresponding actions are represented by methods in the objects. Together with the objects, IF-THEN rules are also employed to form the knowledge base. Thus, the system is able to computerize the complex fire protection codes for fast queries to facilitate fire protection inspectors when performing their inspection tasks. The system can also serve as a reference tool for general publics to perform self-inspections.