Industrial steel structures, while inherently non-combustible, are susceptible to significant strength loss and deformation when exposed to the high temperatures generated during a fire. This can lead to structural collapse, posing a severe risk to life and property. Therefore, fire resistance is a critical consideration in the design and construction of industrial steel structures.
Fire resistance of industrial steel structures
1. How Fire Affects Steel Structures:
Loss of Strength and Stiffness: Steel’s yield strength and modulus of elasticity significantly decrease as temperature rises. While steel doesn’t melt until around 1300°C, it can lose about half its strength at 650°C, and structural integrity can be compromised as low as 400°C.
Thermal Expansion and Deformation: Steel expands when heated. If restrained, this expansion can induce stresses, leading to buckling, twisting, or warping of members.
Connection Damage: High temperatures can weaken or destroy bolts, welds, and other connections, further compromising the overall stability of the structure.
Microstructural Changes: Prolonged exposure to very high temperatures (above 700-800°C) followed by rapid cooling (e.g., from firefighting water) can lead to permanent changes in the steel’s microstructure, such as the formation of brittle martensite, even if visible deformation is minimal.
2. Fire Resistance Requirements:
Building codes and regulations specify the required fire resistance ratings for different building types and elements, often expressed in minutes (e.g., 30, 60, 90, 120, 180, 240 minutes). This rating indicates the time a structure must withstand a standard fire test without collapsing, allowing for occupant evacuation and firefighting efforts.
Factors influencing the required fire resistance include the building’s purpose, height, area, occupancy, and the type and quantity of combustible materials present.
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More detailed information on the fire resistance of industrial steel structures can be found at: https://www.meichensteel.com/a/news/fire-resistance-of-industrial-steel-structures.html
