Safety Analysis of Commonly Used Exterior Wall Insulation Materials:
In China, the most commonly used organic thermal insulation materials in buildings are polystyrene and polyurethane rigid foam. These materials are favored for their lightweight and excellent thermal insulation properties. However, they have a major drawback—poor fire resistance.
1. Polystyrene Board
Polystyrene foam is divided into Expanded Polystyrene (EPS) and Extruded Polystyrene (XPS). EPS is widely used due to its low cost. Despite being treated with flame retardants, it still falls under B2 flammable category. This means that when exposed to fire, it can melt, drip, and spread rapidly, creating serious safety risks. The dangers include:
(1) When heated, polystyrene boards melt and drip, forming a melting zone along the wall base. If exposed to an open flame, the fire can quickly spread through this area, intensifying the blaze.
(2) In case of a fire, these organic materials release large amounts of toxic gases and thick smoke. Smoke and toxic fumes are often referred to as the "number one killer" in fires. In past Chinese fires, nearly 80% of casualties were caused by gases released from burning building materials.
(3) Heat from the polystyrene board can cause shrinkage and deformation, leading to the detachment of tiles. This not only poses a risk to people but also hinders rescue operations, making internal search and rescue difficult.
(4) If the insulation material cracks or falls off, it can ignite quickly, allowing the fire to spread over a wide area.
(5) Once the exterior wall catches fire, standard firefighting equipment may not be able to reach the affected area, especially in high-rise buildings where the situation becomes even more dangerous.
2. Polyurethane Rigid Foam (PU)
Polyurethane is considered one of the best thermal insulation materials globally, with a thermal conductivity of just 0.018–0.023 W/m·K. However, it is an organic polymer and thus inherently flammable. While some companies ignore the fire risks, others use substandard materials due to an unregulated market and incomplete safety standards. The dangers associated with PU include:
(1) Rigid polyurethane foam is porous and has very low thermal conductivity, which can lead to heat accumulation. Once ignited, it burns rapidly, increasing the danger significantly.
(2) When burned, polyurethane foam does not fully combust, producing thick black smoke and releasing large amounts of toxic gases, including carbon monoxide, hydrogen cyanide, and benzene cyanide. These substances are highly dangerous to human health.
(3) The massive smoke generated during combustion severely limits visibility for firefighters, making it difficult to locate the fire source and conduct effective rescue operations.
Automotive Springs,Car Springs,Auto Suspension Springs,Engine Valve Springs,Seat Springs
Dongguan Jiufukai Hardware Products Co., Ltd , https://www.jfkspring.com