True or False: Concrete is non-combustible and provides thermal protection around a steel-frame construction.

• A. True
• B. False
• C. Not specified
• D. Depends on thickness

Answer: (A)

Concrete does not burn, and it acts as a protective barrier around steel members. When steel is heated, its strength drops quickly, so surrounding it with concrete slows heat transfer and helps keep the steel cooler longer during a fire. This protective effect is due to concrete’s noncombustibility, its high thermal mass, and its insulating properties. In practice, the level of protection depends on how thick the concrete cover is and how well the concrete is cured and maintained, but generally, encasing a steel frame in concrete provides substantial thermal protection. So the statement is true.