Safe evacuation distanceSafe evacuation distance includes two meanings:Evacuation distance from the farthest point in the room to the door, and the distance from the door to the evacuation stairwell or external exit.For crowded places such as gymnasiums, theaters, etc., the distance from the farthest point indoors to the evacuation exit is controlled by limiting the number of seats between aisles.For places with non-fixed seats, it is controlled by specifying the farthest straight-line distance from the farthest point in the room to the door.In crowded public places such as theaters, cinemas, auditoriums and gymnasiums, when arranging evacuation walkways, the number of seats between horizontal walkways should not exceed 20 rows. The number of seats between the longitudinal walkways should not exceed 22 in each row of theaters, cinemas, auditoriums, etc., and should not exceed 26 in each row of gymnasiums. However, when the row spacing between the front and rear rows of seats is not less than 90 cm, it can be increased to 50, and the seats will be halved when only one side has a longitudinal walkway.Evacuation distance of multi-storey civil buildingsThe distance from the room door directly leading to the public walkway to the nearest external exit or closed stairwell shall meet the requirements in Table 5.3.8.Note: ① The longest distance from the room door of the open veranda building to the external exit or stairwell can be increased by 5.00m according to this table. (The outer corridor is open, and ventilation, smoke exhaust, lighting and cooling are generally more conducive to safe evacuation than the inner corridor building.)② For buildings with automatic sprinkler system, the safe evacuation distance can be increased by 25% as specified in this table. (Give the design some flexibility)The distance from the door of the room to the nearest unsealed stairwell, if the room is located between two stairwells, shall be reduced by 5.00m according to Table 5.3.8. If the room is located in the bag-shaped walkway or at the end, it should be reduced by 2.00m according to Table 5.3.8.The first floor of the stairwell should be provided with a direct external exit. When the number of floors does not exceed four, the external exit can be set at a place not more than 15m away from the stairwell.No matter what form of stairwell is adopted, the distance from the farthest point in the room to the door shall not exceed the farthest distance from the door to the external exit or stairwell of the room on both sides or at the end of the bag-shaped walkway specified in Table 5.3.8.The door with the longest distance to the external exit or closed stairwell refers to the door that leads directly to the public walkway or the door that opens directly to the stairwell, not to the compartment door in the suite or the bedroom door in the door.The straight-line distance from any indoor point to the nearest evacuation exit in the audience hall, exhibition hall, multi-function hall, dining room, business hall and reading room in high-rise buildings should not exceed 30m. The linear distance from the farthest point in other rooms to the door should not exceed 15m.The safe evacuation distance of the veranda residence should be calculated from the door, and a distance of small stairs should be calculated according to its 1.50 times horizontal projection.According to the square hall, the distance from the center to the four exits can reach 30m, and the area of this hall is 60m× 60m = 3600m2. It is consistent with the relaxed fire zone area of commercial business halls and exhibition halls.The safe evacuation distance of the factory building is determined according to the fire risk, the allowable evacuation time and the fire resistance rating of the factory building.