The installation of obstacle marker lights for obstacles should indicate the highest point and edge (i.e. visual height and width) of the obstacle, and aviation obstacle lights should be installed. The spacing between the middle floors must not be greater than 45 meters. In urban buildings with a height of over 100 meters, it is particularly important to consider adding aviation obstacle lights in the middle floor. The vertical and horizontal distance of aviation obstruction lights should not be greater than 45 meters (that is, if the top of the object is higher than its ground by more than 45 meters, obstruction signs must be added in the middle)