Study on Automated Design Method of Process Drawing for Ventilation and Air Conditioning System in Subway Station

The process drawing of ventilation and air conditioning systems in subway stations is an important component of HVAC design deliverables because it describes monitoring requirements, control logic, and operating modes. However, the large number of monitoring parameters and the complex interlocking relationships among equipment make manual drafting repetitive and error-prone. This study proposes a rule-based automatic design method for subway station HVAC process drawings. The method converts 2D CAD system diagrams into structured information on equipment, rooms, loops, and fire/smoke compartments, and then generates control/display lists and operating mode tables through rule-based reasoning and CAD-based table drawing. A Guangzhou metro station project was used as a single-project feasibility validation. In this case, the developed software processed 10 fire protection zones, 9 smoke compartments, 969 equipment items, 347 rooms, and 34 loops, and generated the corresponding process drawings in approximately 50 s on average over multiple runs. The results indicate that the proposed workflow can complete the end-to-end transformation from CAD system diagrams to process drawing outputs under the tested project conditions. Because the validation was limited to one engineering project and no controlled comparison with manual drafting was conducted, the findings should be interpreted as evidence of feasibility rather than as a statistical demonstration of efficiency improvement.