GB 51251-2017 第3.1.3条
| **** | For public buildings (including hotels) with a building height of 50 m or less, **natural ventilation** or a mechanically pressurized air supply system may be used for smoke-proof stairwells; when natural ventilation is used, an openable exterior window with an area of not less than 1.0 ㎡ shall be provided at the highest part of the stairwell. |