GB 7588-2003 第8.4.1条
| | Car ventilation: Ventilation openings shall be provided at the top and bottom of the car, with effective areas not less than 1% of the car's effective area (top) and 1% (bottom) respectively, and the ventilation openings shall be capable of preventing foreign objects from entering (e.g., mesh size not greater than 10 mm × 10 mm). |