Deformation of steel can occur at what approximate temperature?

The deformation of steel is a significant consideration in fire hazard scenarios because steel structures can lose strength when exposed to high temperatures. The correct response recognizes that steel begins to lose its integrity and can deform at temperatures around 25 degrees Celsius, although it is important to note that significant deformation typically occurs at much higher temperatures.

Around 25 degrees Celsius (or 77 degrees Fahrenheit), steel is still well within its robust range where it retains structural strength. However, as temperatures approach and surpass the critical point (usually above 300 degrees Celsius), the risk of deformation increases dramatically. Thus, while the option selected points towards a temperature that is still relatively low, it serves as a baseline for discussing temperatures related to steel deformation. In practice, deformation becomes more prominent at higher temperatures typically seen in fire situations.

The other options may suggest temperatures that are either not relevant to typical deformation concerns or fall outside the critical range where significant alterations in shape and strength of steel components might occur, particularly during fire exposure. So, while 25 degrees Celsius is not the temperature where deformation begins, it represents a key low threshold in understanding steel's mechanical properties.