Fire resistance of steel structure workshop
Steel structure warehouse are mainly supported by steel columns and steel beams, so the fire resistance limit of steel structures determines the fire resistance of the workshop. The steel structure workshop mainly uses carbon structural steel and low-alloy high-strength structural steel as the main materials.
Generally, the critical temperature for losing static equilibrium stability under full load is about 540°C. The overall mechanical properties vary with temperature. Again in general, when the structural temperature reaches 350°C, 500°C, and 600°C, the intensity decreased by 1/3, 1/2, and 2/3 respectively. In a fire, the temperature of the fire field usually reaches 800~1200℃. In such an environment, the steel structure with high thermal conductivity will generally be plastically deformed in about 15 minutes, causing partial damage, and complete loss of bearing capacity. The whole thing collapsed. Among them, different wall materials and temperature characteristics will have a certain impact on the internal temperature rise of the steel structure and the deformation under high temperatures.
In existing steel structure workshops, sandwich panels are usually used as partition walls and exterior walls, and polystyrene, polyurethane, and rock wool with high thermal insulation properties are used as filling materials inside. The first two materials have poor fire resistance and are susceptible to heat and combustion, which will increase the building’s fire load, accelerate the temperature rise of the steel structure, and reduce the fire resistance. The rock wool itself is an inorganic silicate fiber, which is non-flammable, and its combustion performance depends on the type and quantity of the binder. Under normal circumstances, the fire resistance limit of the metal sandwich panel is about 10 minutes before it loses its load-bearing function and collapses.
