To protect steel from heat, which material is commonly applied?

• A. Layers of gypsum board
• B. Sprayed polyurethane
• C. Asphalt coating
• D. No protection required

Answer: (A)

Protecting steel from heat relies on adding a fire-resistive barrier that slows heat transfer and preserves strength during a fire. Layers of gypsum board are a common method because gypsum contains water that is released as steam when heated. This energy absorption buys time, keeping the steel cooler longer and helping maintain its structural capacity for the rated period. The thickness and installation determine the fire-resistance rating, so you can achieve a specified duration (like one or two hours) with the right layering. Gypsum board is favored for being relatively inexpensive, easy to install, and predictable in performance within standard fire-rated assemblies. Other options don’t provide the same protective effect: sprayed polyurethane can be combustible and isn’t used as the primary fireproofing for structural steel; asphalt coating isn’t the typical fire-protective method for structural members in most buildings; and assuming no protection would leave steel vulnerable to heat and potential failure during a fire.