4 meters. The width of the fire escape requires the standard of the width of the fire escape. The clear width and clearance height of the lane should not be less than 4.0m, and the turning radius should meet the requirements of the fire truck turning. There should be no obstacles such as trees and overhead pipelines between the fire escape and the building, and the edge of the fire escape near the external wall of the building should not be less than 5m away from the external wall of the building. Therefore, Longhua Sub-district Office in Shenzhen requires that the fire exits in online rental houses should be 4m wide.