At what temperature does steel begin to lose its strength?

Steel begins to lose its strength at elevated temperatures due to changes in its metallurgical structure. Around 1,000 F (538 C), steel can lose approximately 50% of its strength, but significant degradation starts to occur at lower temperatures. Specifically, at around 700 F (371 C), steel starts to experience a measurable loss in strength, which can impair its structural integrity during a fire situation or similar exposure.

At this temperature, the steel is becoming less able to carry loads, and it is crucial for rescue technicians to be aware of these changes when assessing a collapsed structure. This understanding helps them make informed decisions about safety, structural stability, and the feasibility of rescue operations in environments where high temperatures may be present.

Other temperatures listed may indicate points of concern, but they do not reflect the initial significant loss of strength as accurately as 700 F does, making this the most critical temperature to note for assessments in rescue scenarios.