In building fire safety,steel fire doors must not only possess fire resistance but also effectively block the spread of smoke,buying precious time for evacuation.Steel fire doors with a combined design of”built-in fireproof board+expansion sealing strip,”through material synergy and process optimization,achieve comprehensive compliance with smoke isolation standards,becoming a reliable choice for fire compartments in public buildings.
Built-in Fireproof Board:Dual Protection of Heat Insulation and Smoke Isolation
The interior of the steel fire door leaf is filled with fireproof board(such as calcium silicate board or fiber-reinforced cement board).Its core functions are:
High-Temperature Insulation:The fireproof board has a low thermal conductivity,which slows down heat transfer to the unexposed side of the door.Combined with the cold-rolled steel plate of the door frame,it forms a composite heat insulation structure,ensuring that the temperature of the unexposed side does not exceed 140℃within the 30-minute fire resistance limit;
Smoke Isolation:The fireproof board has high density and low porosity,effectively reducing smoke penetration through the interior of the door.Experiments show that doors using double-layered 5mm thick fireproof boards exhibit a smoke penetration rate of less than 0.1 m³/min during a 30-minute fire resistance test,far below the national standard requirement of 0.5 m³/min.
Expansion Sealing Strip:Dynamic Sealing,Filling Gaps
The overlap between the door frame and door leaf is the main channel for smoke penetration.The expansion sealing strip achieves dynamic sealing through the following mechanisms:
Heat Expansion:The sealing strip uses graphite-based or silicone rubber-based materials,which expand 3-5 times in volume when heated,filling gaps in the door and forming a”soft firewall”;
Durable Elasticity:The sealing strip remains flexible at room temperature,adapting to minor deformations of the door body and ensuring long-term sealing performance;
Anti-Aging Design:By adding antioxidants,the sealing strip has a service life of over 10 years,reducing the frequency of maintenance and replacement.
Smoke Isolation Effect:Data Verification,Scene Adaptability
Certified by the national fire protection testing agency,steel fire doors equipped with fireproof boards and expansion sealing strips exhibit a smoke penetration rate≤0.05 m³/min during a 30-minute fire resistance test,achieving a Class I smoke isolation integrity standard.This design is widely used in:
Residential buildings:areas such as pipe shafts and elevator lobbies to prevent smoke from entering evacuation routes during a fire;
Commercial venues:fire compartments in shopping malls and supermarkets to prevent smoke from obstructing customers’escape route;
Industrial plants:equipment rooms,power distribution rooms,and other similar settings to protect critical facilities from smoke corrosion.
Steel fire doors,through the synergistic effect of”built-in fireproof panels+expansion sealing strips,”achieve smoke isolation standards with a low-cost,high-reliability solution,providing a solid guarantee for building fire safety.