What is InterNACHI's estimation for the life expectancy of standard steel beams?

InterNACHI estimates that the life expectancy of standard steel beams exceeds 200 years. This long lifespan is primarily due to the durability and strength of steel as a construction material. Steel is resistant to many forms of deterioration, such as rot and insect damage that can affect materials like wood. Although steel can corrode in the presence of moisture and certain environmental conditions, proper maintenance and protective coatings can significantly extend its lifespan, allowing it to perform effectively over a century and beyond.

The figure of 200+ years reflects not only the material's inherent characteristics but also advances in steel treatment and protection methods. This understanding is crucial for home inspectors, as it helps them provide accurate assessments in the context of building longevity and safety. The other options suggest shorter life spans that do not align with the extensive durability associated with modern structural steel applications.