Which of these air temperatures exceeds the maximum permissible for certain air ducts?

The maximum permissible air temperature for certain air ducts is critical for ensuring safety and system performance. Exceeding this temperature can lead to issues such as material degradation, fire hazards, and system inefficiency.

In this context, the option indicating 260 degrees Fahrenheit is significant because many standards set limits around this temperature for specific duct types, particularly those made of non-metallic materials. Non-metallic ducts typically have lower temperature thresholds compared to their metallic counterparts, due to the potential for melting or degradation of the material.

The reasoning behind establishing a strict maximum temperature is based on the materials used and their ability to withstand heat without compromising structural integrity or safety. Air temperatures above this limit can lead to smoke generation and fire risks, making it imperative to adhere to the specified maximum temperatures in duct installation and design.

Understanding these limits helps professionals in the HVAC field ensure they choose the appropriate materials for their applications and maintain the longevity and safety of their systems.