To protect steel structural components of a building, what may be applied to protect the steel from heat?

To protect steel structural components of a building, what may be applied to protect the steel from heat?

• A. Plywood covering
• B. Polystyrene sheets
• C. Polyurethane foam insulation
• D. Gypsum board

Answer: (D)

To slow heat transfer to steel structural members, you want a barrier that is noncombustible and absorbs heat. Gypsum board does this well because gypsum contains chemically bound water; when exposed to high heat it releases that water as steam, which absorbs a lot of heat and slows the rise in temperature of the steel. This helps maintain the steel’s strength longer during a fire and is a common component of fire-rated assemblies used to protect structural elements. The other materials aren’t as protective: plywood is flammable and can fuel the fire; polystyrene sheets can melt and burn, adding heat and smoke; polyurethane foam insulation is also flammable and degrades with heat, offering little protection to steel.

To slow heat transfer to steel structural members, you want a barrier that is noncombustible and absorbs heat. Gypsum board does this well because gypsum contains chemically bound water; when exposed to high heat it releases that water as steam, which absorbs a lot of heat and slows the rise in temperature of the steel. This helps maintain the steel’s strength longer during a fire and is a common component of fire-rated assemblies used to protect structural elements. The other materials aren’t as protective: plywood is flammable and can fuel the fire; polystyrene sheets can melt and burn, adding heat and smoke; polyurethane foam insulation is also flammable and degrades with heat, offering little protection to steel.