Analysis of fire resistance of WPC foam board

Basic composition and fire protection mechanism of WPC foam board
WPC foam board is an environmental protection material composed of wood fiber (such as sawdust, bamboo fiber, etc.) and plastic (commonly PVC, PE or PP). During its production process, wood fibers provide strength and rigidity, while plastics endow it with water resistance, weather resistance, and good processability. In order to improve the fire resistance of WPC foam board, many manufacturers will add flame retardants in the materials. These flame retardants can slow down the flame spread when the fire source contacts, or even completely inhibit the fire in some cases.
The principle of flame retardants is mainly achieved through the following ways:
Physical barrier: Some flame retardants can form a carbonized layer at high temperatures, preventing the flame from spreading further.
Chemical inhibition: Flame retardants reduce the oxygen concentration required for combustion through chemical reactions, thereby delaying the spread of flames.
Heat shielding effect: Some special flame retardants can reduce the thermal conductivity of materials and decrease the contact time with fire sources.
Therefore, the fire resistance of WPC foam board not only depends on its own material characteristics, but also is closely related to the type and content of flame retardant added.
2. Fire rating of WPC foam board
The fire performance of WPC foam board is usually measured by professional testing and certification. Common fire rating standards include B1, B2, etc. In building codes in China and other regions, fire rating has strict requirements for the selection of building materials. In general, the fire rating of WPC foam board depends on the type of plastic used and the added flame retardant.
B1 level fireproof material: B1 level materials belong to flame-retardant materials. In the event of a fire, the flame propagation speed is slow, and the harmful gases released during the combustion process are minimal. WPC foam board can reach this fire rating after proper treatment, which is applicable to general building decoration and structural materials.
B2 level fireproof material: B2 level materials belong to combustible materials, but still have certain fire resistance performance, suitable for use in indoor non high fire hazard areas. If the WPC foam board is not fully flame retardant treated, it may meet the B2 standard.
It is worth noting that although the flame retardancy of WPC foam board itself is good, its fire resistance is often closely related to the thickness, density, type of additives and other factors of the board. Therefore, when selecting a suitable WPC foam board, it is necessary to comprehensively consider the use scenario, production process and fire rating requirements.
3. Fire performance test standard of WPC foam board
In order to ensure the safety of materials in actual use, the fire resistance of WPC foam board needs to be strictly tested. Common testing standards include:
GB 8624-2012: This is the fire rating classification standard for building and decorative materials in China, which divides their fire rating based on their combustion characteristics. The fire performance test of WPC foam board usually refers to this standard to test its combustibility, flame propagation speed, toxic gas release and other indicators.
ASTM E84: This is an American standard commonly used to evaluate the surface combustion performance of building materials in the event of a fire. Through this standard, the burning rate, flame spread index (FSI), smoke generation index (SMI) and other indicators of WPC foam plate can be evaluated.
EN 13501-1: This is the fire testing standard for building materials in European countries, which uses different testing methods to evaluate the fire resistance performance of materials. If the WPC foam board is to enter the European market, it must meet the requirements of this standard.
4. How to improve the fire resistance of WPC foam board?
Although WPC foam board has certain fire resistance, the following methods can be adopted to improve its fire resistance in specific applications:
4.1 Selecting appropriate flame retardants
Different types of flame retardants have different fire prevention effects, and common flame retardants include chlorides, phosphates, nitrides, etc. In the production process, selecting appropriate flame retardant according to specific needs can not only improve the fire resistance of WPC foam board, but also reduce the impact of materials on the environment.
4.2 Improving the quality of raw materials
The fire resistance of WPC foam board depends not only on the added flame retardant, but also on the properties of raw materials. For example, choosing higher quality wood fiber and plastic raw materials can improve the fire resistance and flame retardant effect of materials to a certain extent.
4.3 Increasing the thickness and density of the board
The thicker and denser WPC foam board can usually provide better fire protection, because the thicker board can more effectively delay the spread of fire sources. Manufacturers can adjust the thickness and density of the board by optimizing the production process, thereby improving its fire resistance performance.
4.4 Surface Treatment
Special surface treatment of WPC foam board, such as flame retardant coating, can further enhance its fire resistance. Surface coating can form a protective film in the event of a fire, preventing flames from further penetrating into the interior of the material.