-Facility managers usually need to make decisions under different types of MEP system breakdowns. They usually fight to find the information required to restore the system. However, the BIM model developed usually lacks information to satisfy the what-if analysis under various maintenance scenarios. This study first takes the air-conditioning system as the example to analyze the causes and the solutions of the common system breakdowns. Then an ontology is developed to determine the rules of developing BIM model to satisfy the information requirements for conducting simulation for different maintenance scenarios. In addition, a series of Dynamo modules are developed as the implementation to quickly develop the simulationready BIM model. Result shows, with this proposed approach, the BIM model can be used to help facility managers make decisions efficiently and effectively.