At approximately what temperature does steel fail?

• A. 800 degrees
• B. 1000 degrees
• C. 1200 degrees
• D. 1800 degrees

Answer: (B)

Steel loses strength as it heats, so under fire conditions its ability to carry load drops the hotter it gets. Around 1000 degrees Fahrenheit, steel has typically shed about half of its strength, making it prone to failure under load in a fire. That makes 1000 degrees the best approximate point where failure becomes likely. At lower temperatures like 800°F, it still retains much of its capacity; at higher temperatures such as 1200°F or 1800°F, the weakening is more severe, but the threshold where significant loss leads to failure is about 1000°F.