Types and advantages/disadvantages of fire-resistant door core materials
1、Organic-based thermal insulation and fire-resistant door core
This fire-resistant door core material is manufactured using materials such as EPS (expanded polystyrene), XPS (extruded polystyrene), expanded PVC, expanded polyethylene, expanded polyurethane, and sponge-like adhesives.
However, due to the flammability of organic materials and the VOCs released during combustion, this hinders the application of such materials. This has also led to an overemphasis on improving the fire resistance of organic materials and excessively high fire ratings, which not only significantly increases material costs but also, due to the presence of non-environmentally friendly flame retardants, increases the smoke volume and toxicity during combustion, potentially posing a greater fire hazard. Therefore, organic materials are not suitable as core materials for fire doors.
2、Intumescent fire-resistant and insulation materials for fire-resistant doors.
The materials for fire-resistant door cores include mineral wool, cotton wool, fiberglass, silica-aluminum cotton, asbestos, pearlite, expanded perlite, and foam glass, as well as micro-porous calcium silicate.
Inorganic materials offer superior fire resistance and non-toxic, non-smoking properties compared to organic materials. However, each material has certain limitations. Some lack compressive strength and require a supporting carrier, which in turn introduces fire resistance and smoke/toxic gas issues, such as rock wool, mineral wool, fiberglass, aluminosilicate cotton, asbestos, etc. Others are expensive and have high production energy consumption, such as foam glass and micro-porous calcium silicate. Still others have poor fire resistance and high water absorption/humidity, such as pearlite products based on cement or water glass, vermiculite products based on cement or water glass, and foam concrete products. These materials, therefore, limit their use as filling materials for fire doors to varying degrees.
3、Magnesium fire-resistant door core
Magnesium oxide and magnesium chloride-based fire-resistant door core is manufactured using magnesium oxide and magnesium chloride as the binding material, and expanded perlite as the filler. According to GB 50016-2006, the fire resistance limit of rhombus magnesium (chloromagnesium) perlite hollow perforated board wall material is 1.30h, which is a non-combustible material. According to GB/T9978-2008, the fire performance of chloromagnesium wall material is fully compliant with the insulation and integrity requirements within 110min, and the fire resistance limit is 1.83h. Experiments have shown that the foaming agent, when used at normal temperature and pressure, produces a foam magnesium cement with a density (dry) of 32020 kg/m3, thermal conductivity of 0.076~0.09 W/(m?K), compressive strength of 1.5~2.1 MPa, softening coefficient ≥ 0.6, and without any peeling or chipping on the surface. Therefore, magnesium oxide and magnesium chloride-based fire-resistant board has advantages such as fire resistance, insulation, excellent physical and mechanical properties, environmental friendliness, energy-saving and cost-effectiveness, making it a suitable filling material for fire doors.