NEBOSH Practice Test

What is a potential consequence of thermal weakening of steelwork during a fire?

1. Equipment upgrade

2. Improved safety regulations

3. Collapse of structures

4. Enhanced work efficiency

The correct answer is: Collapse of structures

Thermal weakening of steelwork during a fire can lead to a significant reduction in the strength and stability of structural elements. Steel has a property where its strength diminishes as temperatures increase. At high temperatures, usually around 400-600 degrees Celsius, steel can lose about 50% of its strength, and at temperatures exceeding 800 degrees Celsius, its strength can decline further. This loss of structural integrity can make the steel unable to support the loads it was designed for, ultimately leading to the collapse of the structure. Understanding this consequence is vital for fire safety engineering and building design since it highlights the importance of incorporating fire protection measures for structural steel. This may include applying fire-resistant coatings, increasing the amount of steel in critical load-bearing elements, or using alternative materials that can withstand higher temperatures without significant weakening. The potential for structural collapse due to thermal weakening underscores the critical nature of fire safety protocols in managing risk in buildings.