I Public buildings Basic requirements for layout of evacuation staircase or evacuation staircase
Note:
1. When the enclosed staircase cannot meet the natural smoke exhaust conditions, mechanical smoke prevention facilities shall be set or smoke prevention staircase shall be used.
2. The open staircase can be used for the evacuation staircase directly connected with the open veranda in the multi-storey public building.
3. Outdoor evacuation staircase can be regarded as enclosed staircase or smoke proof staircase.
4. "Building with similar use function" means that the name may be different from the previous name in the article, but the actual use, the density and characteristics of users, and the fire risk of the building are basically the same. For example, hotels, serviced apartments, guest houses and hotels are buildings with similar functions.
2、 What factors are related to the form of evacuation stairs in public buildings?
The form of evacuation staircase in public buildings has no direct relationship with the fire resistance rating of the building, has nothing to do with the building area of the building floor, and has nothing to do with whether several floors of the building can be divided into the same fire compartment, but has nothing to do with its actual use or fire risk, number of floors, personnel density, building height, etc.
For example:
A 2-storey store building with a fire resistance rating of Grade III, with a building area of 500 ㎡ for each floor. Although the total building area of the building is 1000 ㎡, it can be considered as one fire compartment, that is, if an open stairwell is used and the stairwell is regarded as the connecting opening of the upper and lower floors, its building area also meets the specification requirements. However, if the building is a store building, it should use enclosed stairwells. Open stairwells can not be used because of the small area of the store building, and one building can be considered as one fire compartment, unless the building has a direct external emergency exit or an open veranda on the second floor, and the evacuation staircase is directly connected with the veranda.
A 3-storey hotel with a Class II fire resistance rating is equipped with a closed veranda on each floor. The building area of each floor is 800 ㎡. Similarly, although the total building area of the building is less than the allowable building area of one fire compartment (2500 ㎡), the evacuation staircase should still be closed rather than open, which is determined by the function and purpose of the building.
2、 How to define the form of evacuation staircase of podium?
The form of the evacuation staircase of the podium depends on whether the podium is strictly separated from the high-rise main body by the firewall. When the main body and the podium are separated by firewalls and Class A fire doors, the podium and the main body shall consider their respective forms of evacuation staircases. When the podium is separated from the main body by other means, the podium uses a closed staircase.
In addition, when some areas of high-rise buildings are equipped with evacuation stairs that serve the area specifically, the form of the stairwell can be determined according to the number of floors it actually serves or the height of the building, use function or purpose.
3、 Is it necessary to use enclosed staircases in teaching buildings of primary and secondary schools with no more than 5 floors?
The form of evacuation stairwells in teaching buildings of primary and secondary schools with no more than 5 floors can be determined according to the number of floors and the location of evacuation stairwells. The specification does not require that closed stairwells must be used.
4、 Within the projection range of the main body of high-rise public buildings with a building height of more than 32m, is it still necessary to use smoke proof staircases for the evacuation staircases only used for the first to fourth floors (below 24m)?
In a high-rise building, when the evacuation stairwells used in the upper high floor area and the lower low floor area are completely independent and disconnected, the evacuation stairwells in the lower low floor area of the building can be determined according to the number and height of floors they actually serve and their functional uses, The evacuation staircase used in the upper high floor area still needs to be determined according to the total building height it serves.
For example, in a 26 storey public building with a first class fire resistance rating, the first to third floors (with a floor elevation of less than 24m) are stores, and the fourth to twenty sixth floors are offices. The evacuation stairs and emergency exits in the store part are completely independent from those in the office part. The evacuation staircase of the store on the third floor can be a closed staircase, and the office parts on the fourth floor and above should be smoke proof staircases.
