The inner steel fire door is filled with pearlite synthesized door core. The melting temperature of hardware fittings, including fire-lock, hinge, door-closer, latch, sequencer, is above 950℃. The assemblies have all passed tests of national fire departments.The inner notch of door frame is lined with fire-resistant expanding seals, which will rapidly expand in high temperature. All the timbers have been specially processed of fire prevention and flame-retarding, so this doorsets have good performances of fire-proof, sound&heat insulation and environment-friendly.Fire-resistant & heat-insulation steel doorsets is widely used in plants, hotels, restaurants, residential areas and other industrial and civil buildings. Meanwhile, within the certificated product scope, customers can choose satisfied products and styles based on the door hole dimensions.