Why are elevators only installed in residential buildings with more than seven floors in China?

Nowadays, most new buildings are equipped with elevators. The presence of elevators is no longer an advantage of a residential community. However, there are still many people who feel unfair about the absence of elevators. The buildings where these people live all share the same feature: they are less than seven floors high.

Then why not design all the buildings to have elevators?

In fact, when Chinese designers do architectural design, unless requested by the client, they generally follow the limits allowed by the standards. The advantage of this is that, under the condition of meeting the specifications, it can reduce the cost of Party A to the greatest extent. The number of floors in a residential building is often set in accordance with the upper limit allowed by the regulations. This can minimize the floor space occupied by the building, and accordingly reduce the area for foundation pit excavation and the number of piles driven. Expand the area of greenery or squares; Increase the distance between buildings; Optimize sunlight conditions, etc.

Related: Detailed Explanation of the Advantages and Disadvantages of Choosing each floor when Buying a house

In the "General Principles for Civil Building Design", residential buildings are classified based on the number of floors: buildings with one to three floors are low-rise buildings, those with four to six floors are multi-story buildings, those with seven to nine floors are mid-high-rise buildings, and those with ten or more floors are high-rise buildings. Almost all the various restrictions imposed by the regulations on the residential building type are formulated based on this classification standard.

There are countless regulations regarding floors, but the ones that truly have a significant impact on indicators such as construction and installation costs and the usable floor area ratio, which concern the interests of all parties, are mainly elevators and stairwells. Therefore, whether to install elevators has become a serious issue

1. Elevator

When the height from the floor of a residential building with seven or more floors or the entrance floor of a household to the outdoor design ground exceeds 16 meters as stipulated in the "Residential Design Code"; For residential buildings with twelve or more floors, each building should be equipped with no less than two elevators, among which one should be capable of accommodating stretchers.

The "Code for Fire Protection Design of Tall Civil Buildings" stipulates that fire elevators should be installed in unit-type residential buildings and cordor-style residential buildings with twelve or more floors. Therefore, if one does not want to install an elevator, it can reach the sixth floor; if one only wants to install one elevator, it can reach the eleventh floor. Elevators increase the cost and affect the usable floor area ratio. Generally, no client uses elevators as a selling point.

Elevator guide shoe

2. Stairwell

The "Code for Fire Protection Design of Tall Civil Buildings" stipulates that for unit-style residential buildings of eleven floors or less, there is no need to have a closed staircase, but the entrance door facing the staircase should be a Class B fire door. Unit-style residential buildings with twelve or eighteen floors should be equipped with enclosed stairwells. Unit-style residential buildings with 19 floors or more should be equipped with smoke-proof stairwells. Corridor-style residences of eleven floors or less should be equipped with enclosed stairwells. Corridor-style residences with more than eleven floors should be equipped with smoke-proof stairwells.

So, if you don't want to set up a closed staircase, you can reach the eleventh floor; if you don't want to set up a smoke-proof staircase, you can reach the eighteenth floor. Smoke-proof stairwells also need to be equipped with smoke-proof anterooms and positive pressure air supply ducts, all of which require the occupation of public area to reduce the usable floor area ratio. In China, the public has no public area at all, which is also part of my home. The improvement of the security level is also a kind of protection concept for me.

According to the "Code for Residential Buildings", residential buildings with a fire resistance rating of Grade 4 are allowed to have a maximum of 3 floors, those with a fire resistance rating of Grade 3 are allowed to have a maximum of 9 floors, and those with a fire resistance rating of Grade 2 are allowed to have a maximum of 18 floors. The fire resistance rating increases step by step, and the requirements for components also rise accordingly. As for the 33rd floor, it is only required that the total height of the building does not exceed 100 meters. A building over 100 meters tall is considered a super high-rise. Not to mention the strict regulations for various specialties, just the requirement of setting up refuge floors is enough to make all stakeholders suffer. Who can stand that shared area?