Precautions for glass curtain wall fire partition

[China Glass Net] The glass curtain wall is a building exterior wall enclosing structure composed of metal members and glass plates, with three types: distinct frame, half-frame and hidden frame glass curtain wall. The materials that make up the glass curtain wall are: steel, aluminum alloy, glass, stainless steel and adhesive sealant. In the actual curtain wall design, attention should be paid to the design of the fire compartment. Fire protection zone refers to the division of the floor and space of a building into a number of zones with firewalls, fire doors and windows, fire shutters and certain fire resistance limits. The fire zone includes two parts: the horizontal partition and the vertical partition of the floor. The measures of dividing the fire zone in the building can effectively control the fire within a certain range in the event of a fire in the building, prevent the fire from spreading and expanding, reduce the fire damage, and at the same time, evacuate the personnel and fire the fire. Provide favorable conditions. The importance of fire zones has been proven in countless fire lessons.

First, the concept and classification of fire zones

Fire protection zones can be divided into two categories according to the function of preventing fire from spreading beyond the fire zone: one is the vertical fire zone to prevent vertical fire spread between the layers of the multi-storey or high-rise buildings. Vertical fire zone refers to the fire separation of each floor in the vertical direction of the building with refractory slabs and window walls (including under-walls).

The second is a horizontal fire zone to prevent the fire from spreading in the horizontal direction. Horizontal fire zone refers to a fire zone that separates each floor horizontally with a fire barrier such as a firewall or fire door or fire shutter. It prevents fire from spreading in the horizontal direction of the floor. The firewall partition is separated by a firewall. If it is difficult, use a fire curtain with a cooling water curtain or a closed water spray system, or separate it with a fireproof partition.

From the perspective of fire prevention, the smaller the fire compartment is divided, the better it is to ensure the fire safety of the building. The size of the fire zone shall be determined by considering the nature of the building, its importance, the fire hazard, the height of the building, the ability of the firefighting and the speed of the fire.

Second, the vertical direction of fire blocking design

The vertical fireproof sealing design is the top priority of the curtain wall fire protection design. According to the different building structures, the following situations are classified:

1. When there is a solid window sill wall inside the curtain wall (the specification requirements include the structural beam plate and the upper flood height ≥800mm, according to the bonfire radius, the height should be 1200mm). For this node, the design should pay attention to the following points:

1.1 Correctly dividing the panel curtain wall The designer should correctly understand the concept of fire compartment. The floor beam and the physical window wall are the partitions of the upper and lower fire zones. Therefore, it is unreasonable to divide the fire partition of the window wall by the horizontal line of the floor. The division is determined by the outer lines of the floor, the floor beam and the physical window wall. The glass plate does not cross the two fire zones, and it does not contradict the relevant requirements in the specification. Even if the glass block of the floor is damaged in the fire, the fire blockage can still be effective because the fire blockage of the upper road is not damaged. Barrier effect. It is recommended not to adopt the division mode. If it is necessary to adopt this division mode for construction reasons, it is recommended that the glass at the floor be fireproof glass, and the expansion joint of the column should be set slightly downward to offset the corner position of the beam. Or add a fireproof plug on the top of the front of the floor to ensure that even if the plate at the floor is damaged, the fire protection can be effectively protected due to the unprotected fire blockage. However, this structure is seen from the inside because the height of the window sill is too high, which obviously affects the visual effect.

1.2 The fireproof layer should be placed at the lower edge of the beam as close as possible to the ceiling (or flush with the bottom of the beam) and placed under the beam of the curtain wall. The purpose is also to protect the embedded parts and steel corners from fire. The bearing capacity of the steel will decrease at 300 ° C -400 ° C, the bearing capacity will be lost at 600 ° C, and the refractory temperature of the aluminum profile will be lower). If the bearing capacity and the steel corner code are seriously affected after the fire is seriously affected, the bearing capacity is reduced or even lost. At this time, when the entire curtain wall skeleton falls off, the consequences are extremely serious.

1.3 It is advisable to add a smoke-proof sealing at the intersection of the wall and the curtain wall. Usually, the curtain wall glass with such a window wall does not use fire-proof glass. Once the glass is broken, the physical wall (including beams and plates) is protected. Usually, the open flame is difficult to directly hit the previous floor, but a large amount of toxic fumes generated in the fire will enter the upper floor as the glass breaks. If a smoke blocking is added to the intersection of the upper part of the window sill and the curtain wall, this problem can be basically solved.

1.4 When using this structure, the fire-retardant layer usually supports the inner fire-proof mineral wool with 1.5mm thick steel plate. When designing, it should be noted that the steel plate cannot directly contact the curtain wall glass to avoid the steel plate being thermally expanded and smashed in the fire. However, the steel plate can not be too far from the curtain wall glass to avoid the negative pressure (in the case of fire, the indoor pressure is higher than the outdoor temperature, and the curtain wall is subjected to the negative pressure), and the steel plate and the curtain wall glass are pulled off. The formation of open seams causes the smoke to rise and the fire barrier does not have the proper fire protection effect.

2. When there is no window sill on the floor (or the height of the slab is less than 800mm), it is not ideal from the perspective of safety. Due to structural reasons, the upper and lower fire zones are usually connected by a slab, which is often supported by the beam in the next fire zone. on. When a fire breaks out in the next fire zone, the glass plate is easily destroyed (tempered glass usually breaks 5-8 minutes after fire). Once the glass breaks, due to the lack of physical wall protection, smoke or even an open flame can easily reach the previous fire zone. Therefore, the key to the fire protection design of this structure is the treatment of this piece of glass. That is, the fireproof glass for the glass plate connecting the upper and lower fireproof zones (the height of the piece of glass should be larger than the radius of the fire, if the height of the glass is too large, it is better to set two fireproof glass up and down). If the curtain wall glass is uncoated glass, the double-tempered fire-resistant glass is used instead of the steel plate and mineral wool or the single-piece fire-proof potassium-fired glass is used for sealing. If the curtain wall glass is coated glass, it is horizontally blocked. In addition, when the structure is adopted, the cross-beam corner code at the floor surface is also fixed. The rest is the same as the vertical blockage with a window sill.

Third, the horizontal direction of fire blocking design

The horizontal fire protection closure design is substantially identical to the vertical fire protection closure design described above, but is easily overlooked during design. According to the different building structures, there are two cases:

1. When there is a window partition between the two fire zones, the curtain wall is usually flush with the window wall (the curtain wall is rarely outside the window wall), and the fire is mainly realized by the window wall. According to the requirements of 5.2.2 in the “Fire Protection Code for High-rise Civil Buildings (GB50045-95, 2001 Edition)”, the width of the window wall should be greater than 2m. If the width of the window is less than 2m, fireproof glass is also required at the two fire zones.

2. When there is no window wall between the two fire zones in the horizontal direction, the fireproof blocking node can refer to the fireproof blocking design in the vertical direction when there is no window wall at the floor position. However, the column should be set up from the partition of the two fire zones. The column shall be provided with fireproof sealing at both fireproof sections, and appropriate sealing materials shall be selected according to the interior decoration requirements. It should be noted that the two curtain wall glass of the fire partition partition should be made of fireproof glass, and the sum of the widths of the two fireproof glass should not be less than 2m.

3. In order to ensure safety, it is recommended that regardless of whether there is a window partition or not, in the case of fireproof sealing, the columns adjacent to the two fireproof sections should be sealed with fireproof mineral wool in the fireproof layer (two when there are window walls) The column is installed to ensure that the structure in the other fire zone is not greatly affected during the fire. At the same time, the clearance between the fireproof panel and the curtain wall glass used as the fireproof plugging requirement is the same as the vertical gap between the fireproof panel and the glass.

4. Fireproof glass shall be used for the following parts of the curtain wall:

Transparent layer interval smoke blocking;

Vertical transparent fire belt on the left and right sides of the firewall;

a transparent horizontal fireproof belt on the lower side of the floor when there is insufficient height of the solid wall or solid wall under the window;

a transparent firewall that divides the fire partition;

Other transparent fireproof partitions, transparent floor slabs.

V. Other points of fire protection design reference points

1. Pipeline wells and cable wells of low-rise buildings shall be sealed at intervals of 2-3 floors with non-combustion bodies with a fire resistance of not less than 0.5 h at the floor. The well walls shall be incombustible with a fire resistance of not less than 1 h. . Class A fire doors shall be used for inspection doors on the shaft wall.

2. The elevator shaft should be set independently. It is strictly forbidden to lay flammable gas and liquid pipes of Class A, B and C in the well. Cables and wires that are not related to the elevator should not be laid. In addition to the opening of the elevator door and the vent hole, the elevator shaft wall should not open other openings. Elevator doors should not be fenced.

3. Vertical pipeline wells such as cable wells, pipeline wells, exhaust ducts, exhaust ducts, and garbage lanes of high-rise buildings shall be independently installed; the well wall shall be a non-combustion body with a fire resistance rating of not less than 1 h; Class A fire doors shall be used for the inspection doors above.

4. For high-rise buildings with a building height not exceeding 100 meters, the cable wells and pipeline wells shall be separated from each other by a non-combustible body equivalent to the fire resistance limit of the floor at every 2__3 floor.

to sum up

In summary, in the actual design process, we should fully do the fire protection design of the vertical and horizontal fire zones. Clarify your responsibilities, follow the construction procedures, and design and construct in strict accordance with the specifications. Reduce the risk of glass curtain wall fires and fully serve the entire design of the building.

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