Analysis of Key Difficulties in Aluminum Curtain Wall Construction

Different Curtain Wall Joint Treatment Measures

The treatment of different curtain wall joints is also a key focus of this project. The treatment measures for different curtain wall joints are as follows, based on the design drawings: filling the gaps with foam rods and then injecting sealing adhesive. The adhesive surface should be flat and smooth.

The interface between aluminum plates and windows is a special area. Therefore, waterproofing is particularly important in this area due to the contact between aluminum curtain walls and aluminum materials. Therefore, in the contact area between the window and the aluminum curtain wall, foam waterproofing agent is first filled internally to ensure the waterproof performance of the interface. After the foam agent dries, the gap between the aluminum plate and the window is filled with silicone weather-resistant adhesive with excellent performance to ensure long-lasting waterproofness and good waterproof performance of the gap.

Construction Focus of Steel Structure

Corrosion protection of the steel structure is a construction focus. The steel skeleton of the aluminum curtain wall is hot-dip galvanized. Hardware fittings are made of stainless steel. When welding on-site, corrosion protection must be applied to the welded parts, with a galvanized coating thickness of not less than 75um. Steel angle codes, connectors, etc., are treated with hot-dip galvanizing. During the construction of the exterior steel frame coating, construction should not be carried out in rainy or foggy conditions (especially for surface coatings, construction is strictly prohibited). The environment should be clean, the surface must be dry, free of moisture, the temperature should not be lower than +15°C, and the relative humidity should not exceed 60%. Pay attention to changes in weather conditions during construction. Construction is prohibited in case of strong wind, rain, or foggy conditions (especially for surface coatings, construction is strictly prohibited).

Curtain Wall Construction Measurement

The measurement of curtain wall grid lines should be coordinated with the measurement of the main structure. For errors in the main structure, corresponding adjustments should be made promptly to ensure that the processing and production conform to the actual site conditions; measurements should be carried out when the wind force is not greater than level 4, and the position of the curtain wall should be checked regularly every day.

Curtain Wall Waterproofing

Reasonable design of curtain wall profiles is one of the important measures for waterproofing. The profile is designed as a pressure balance system, which is based on the rain screen principle. A guide hole is pre-set on the curtain wall profile to allow external pressure to enter the interior, thereby adjusting the balance of internal and external pressures to prevent external water from entering easily. Meanwhile, drainage holes are opened at the outer edge and bottom of the profile to drain off a small amount of infiltrated water or condensation water indoors. These waterproofing and drainage measures together form a dry sealing system, which not only prevents water from entering the interior of the curtain wall but also automatically drains out any infiltrated water. When setting the preset holes, two holes are set on each horizontal frame, with a hole spacing of about 100mm at the corner, and the horizontal distance between the upper and lower holes is greater than 50mm to prevent air communication.

Construction of Sealant

The construction thickness should be greater than 3.5mm, and the construction width should not be less than twice the construction thickness. Polyethylene foam material should be used to fill the deeper sealant grooves at the bottom; the sealant should form a relative bond inside the joint and should not be bonded on three sides.

Acceptance of Hidden Engineering for Curtain Wall Installation

Coordinate with the owner for the acceptance of hidden engineering, such as the installation of connection nodes between components and the main structure; installation of gap nodes between the curtain wall and the main structure; installation of expansion joints, settlement joints, seismic joints, and wall corner nodes, as well as installation of lightning protection grounding nodes for the curtain wall.

Fire Protection Measures for Curtain Walls

The main fire protection measures are as follows:

1. According to the overall design and requirements of building fire compartments, set up fire isolation belts related to curtain walls with fireproof materials (fireproof rock wool, fireproof panels, fireproof adhesives, etc.). Try to avoid large glass spanning across two fire compartments. If the beams need to be far away from the floor structure due to appearance segmentation, 1.5mm thick fire-resistant galvanized steel plates and fireproof rock wool should be used to connect the beams to form a fire compartment.
2. Interlayer fire protection is located at the upper and lower edges of the building structure, each using 100mm thick fireproof rock wool and 1.5mm thick galvanized iron plate to make continuous laying of fireproof partitions. The fireproof rock wool is installed on the galvanized steel plate, which is fixed on the lateral profile and the edge of the structure. It can effectively prevent the interlayer diffusion of smoke and fire. Non-combustible materials are used as the filling material for fire lines.
3. Adjacent fire compartments on the same floor are separated, and non-combustible materials are used to separate the two compartments.
4. Use materials that meet the requirements of fire protection regulations and control the processing quality. The gap between the plates should be less than 3mm, and the fireproof rock wool should be filled tightly without gaps.
5. All anchoring points supporting the curtain wall are protected by 2-hour fire-resistant materials. Specifically, a 1.5mm thick galvanized steel plate is used to make a 100mm high closed box, which is filled with real fireproof rock wool, firmly attached to the transfer system, and firmly fixed and sealed to the floor structure.
6. The supporting plates should be firmly fixed with suitable fasteners around them according to the different materials of the connected components, with a spacing of 350-450mm between the two fixing points.
7. Ensure that the materials selected meet the national requirements for fire protection and do not use flammable materials or materials that produce toxic gases when exposed to fire, etc.
8. Suggestions for Curtain Wall Fire Protection Technology: (1) Install fire automatic alarm devices on each floor and set up automatic fire extinguishing systems; (2) Set up smoke exhaust measures within a certain height range.

Technical measures for wind resistance and deformation of curtain walls:

Wind pressure deformation has two effects on curtain walls, namely direct effects and indirect additional effects. The direct effect refers to the destruction caused by wind loads directly acting on curtain wall materials (such as glass breakage, failure of rods, etc.), and preventive measures are taken to satisfy the design strength, stiffness, allowable stress, etc., of various curtain wall materials through mechanical calculations. The additional effect refers to the displacement of the building main frame and curtain wall main frame caused by wind pressure, as well as various internal stresses that cause curtain wall damage. This needs to be overcome through specific structural design and conceptual design of curtain walls, such as:

1. All panels are installed in a floating form to facilitate stress release and deformation requirements.
2. A 20mm vertical expansion joint is provided to meet the planar deformation rate requirements.
3. Ensure gaps between panels, and between panels and frames.
4. Flexible connection between the curtain wall and the main structure.
5. Overall, the technical scheme should be a flexible system that can fully adapt to large deformation requirements.

Curtain Wall Waterproofing and Drainage Technology Guarantee Measures

1. Conditions for Curtain Wall Leakage and Remedial Measures:
2. Curtain wall leakage requires the presence of three conditions: water, pressure differential, and leakage pathway.
3. Among them, water cannot be eliminated. Only by eliminating the remaining two factors can water leakage be prevented. The framework system of this project uses external sealing strips and internal sealing strips to form a dual-seal, addressing the issue of water seepage.
4. Measures for External Drainage of Minor Leakage Water:
5. Even in a perfect curtain wall system, it is impossible to completely eliminate minor water seepage caused by human factors during construction. Therefore, necessary external drainage measures must be taken by the curtain wall system: (1) Utilize embedded sealant strips to block a large amount of rainwater on the outer surface of the canopy, preventing water from entering. (2) If a small amount of rainwater or condensation water enters the profile cavity of the curtain wall, use methods such as "collecting troughs, guiding troughs, and external drainage holes" to channel the water to the outside.

Company Details：

Company: Foshan Qi Aluminum Decorative Materials Co.,Ltd

website: www.aluminum-panel.com

Whatsapp: +86 13542961174

Email: [email protected]