[some fire fighting knowledge you may not know]
The entrance doors above the 11th floor are fire doors. Do not replace them casually. In case of fire, if you feel that the door is hot, do not open the door; otherwise, you can open a small gap and select the escape plan according to the external situation. Fold the towel in half and cover your nose three times after the towel is wet. The maximum travel distance of people in the dense smoke is 20-30 meters, and the smoke spreading speed is far greater than the evacuation speed of people. The possibility of escaping after 4 minutes is very small, so the first few minutes should be used as much as possible to escape.
