Views: 0 Author: Site Editor Publish Time: 2025-08-22 Origin: Site
Polyurethane hard bubble insulation composite board (PU hard bubble composite board) is a highly efficient and energy-saving building insulation material. It is composed of polyurethane hard bubble core material and metal or non-metal panels. It has the advantages of low thermal conductivity, strong wind pressure, and adjustable fire resistance. However, its use must strictly follow the specifications, otherwise it may cause insulation failure, safety hazards or shorten service life. The following are the key precautions and detailed instructions:
1. Things to note during the design stage
Fireproof performance matching
Based on the standard: Select the fire protection level according to the 'Fire Protection Code for Building Design' (GB50016).
For residential buildings with a building height of >54m or public buildings with a building height of >50m, the exterior wall insulation material must be Class A (not burnable).
Other buildings can adopt B1 (flammable retardant) or B2 (flammable), but fireproof isolation belts are required.
Non-standard scenarios: If the project requirements are higher than the national standards (such as data centers, chemical plants), PU hard bubble core materials with flame retardant (oxygen index ≥28%) need to be customized, or aluminum foil composite surface layer is used to enhance flame retardancy.
Thermal calculation and verification
Thermal conductivity correction: The thermal conductivity of PU hard bubbles is usually 0.022-0.028W/(m·K), but it needs to be corrected according to the actual use environment:
Low temperature environment (below -10℃): The thermal conductivity increases by 5%-10%, and the plate thickness needs to be increased or the low thermal conductivity model is selected.
Humid environment: Boards with water absorption rate >3% need to be waterproof (such as aluminum foil covering), otherwise the thermal conductivity may double.
Case: A cold storage project in Northeast China has not corrected the low-temperature thermal conductivity, resulting in insufficient insulation thickness and increased energy consumption by 20%.
Structural safety design
Wind load calculation: The wind pressure value is determined according to the 'Building Structure Load Code' (GB50009), and the composite panel must pass the wind pressure resistance performance test (such as GB/T 15227).
High-rise buildings or coastal areas: the density of fixtures needs to be increased (such as from standard 6/㎡ to 8/㎡).
Connection method: Priority is given to mechanical fixing (such as self-tapping screws) or bonding + mechanical fixing composite process to avoid relying solely on adhesives (prone to falling off after long-term aging).
2. Things to note during the construction phase
Grassroots processing requirements
Flatness: The verticality deviation of the base wall is ≤5mm/2m, and the surface concaveness is ≤3mm. Otherwise, cement mortar needs to be leveled.
Cleanliness: Remove oil, dust, loose particles, and moisture content ≤10% (can be detected by the resistivity tester).
Case: A project was not cleaned up, resulting in insufficient bonding strength between the composite panel and the wall, and fell off on a large scale after 3 years.
Environmental Condition Control
Temperature: The construction ambient temperature must be ≥5℃, and the plate temperature must be ≥10℃ (polyurethane foams inadequately at low temperatures and is prone to cracking).
Humidity: Relative humidity is less than 85%. Construction is prohibited in rainy, snowy or strong winds above level 5.
Sun protection and rain protection: Uninstalled boards must be covered with tarp cloth to avoid ultraviolet aging or rainwater soaking (the insulation performance decreases by 30% after absorbing water).
Plate cutting and splicing
Cutting tools: Use a special electric cutting machine or utility knife, the cutout should be flat (default ≤1mm) to avoid burrs piercing the surface layer.
Splicing method:
Qikou splicing: The width of the plate seam is ≤3mm, and it is filled with polyurethane foam glue.
Flat joint: Alkaline-resistant glass fiber mesh cloth + crack-resistant mortar (width ≥200mm) is pasted at the joints to prevent cold bridges.
Taboo: It is strictly forbidden to use fire or electric welding to cut the board (it is easy to cause fire or release toxic gases).
Fixture installation
Spacing: It is determined based on wind load calculation, usually the lateral spacing is ≤600mm and the longitudinal spacing is ≤400mm.
Depth: The self-tapping screw needs to penetrate the panel and enter the base layer ≥25mm (expansion bolts are required for the concrete base layer).
Anti-rust treatment: The fixtures need to be galvanized or dacrocoated (salt spray resistance test ≥500 hours) to avoid rust causing the plate to fall off.
3. Precautions for use and maintenance
Fire Protection Management
Open flame control: During construction and use, electric welding, gas cutting and other operations are strictly prohibited within 10m of the periphery of the board.
Electrical circuits: The pipes through the wall need to be sealed with fireproof mud to avoid short circuits and ignite the board (the ignition point of B2-grade boards is only 270℃).
Case: A shopping mall ignited a B2 insulation board due to aging of electrical lines, and the fire spreads to 3m/s, causing significant losses.
Moisture-proof and seepage-proof
Waterproof layer setting: Concrete flanges (height ≥300mm) are required at the bottom of the exterior wall to prevent rainwater from pouring back.
Drainage system: The roof insulation layer needs to be equipped with exhaust holes (spacing ≤6m) to avoid the accumulation of water vapor and causing the plate to bulge.
Detection cycle: Use infrared thermal imager to detect the moisture content of the board every 2 years, and it needs to be replaced partially in case of abnormalities.
Mechanical protection
Impact protection: Install metal angle guards or PVC angle guards (height ≥2m) on the surface of the board to avoid collision damage to forklifts, scaffolding, etc.
Chemical corrosion: Avoid contact with corrosive substances such as acids, alkalis, and salts (for example, anti-corrosion panels are required for chemical factories).
Regular inspection
Appearance inspection: Check the board for cracks, fall off, or discoloration every year (yellowing may be a precursor to aging).
Performance testing: Thermal conductivity and compressive strength are randomly inspected every 5 years (standard value: thermal conductivity ≤0.030W/(m·K), compressive strength ≥150kPa).
Maintenance plan: If damage is found, it needs to be replaced as a whole (partial repair is likely to form a cold bridge), and the fireproof isolation belt is re-made after replacement.
