The use of gypsum boards to form air shafts should be limited to systems where temperatures do not exceed what?

The correct answer reflects the recommended maximum temperature limit for using gypsum boards in air shafts. Gypsum board is commonly used in building construction due to its fire-resistant properties, but its structural integrity can be compromised at higher temperatures.

When temperatures exceed 125 degrees Fahrenheit, gypsum boards may start to lose their strength and fire resistance, leading to potential structural failures and safety hazards. This limit is set to ensure that the material performs adequately in maintaining air quality and safety standards within mechanical systems.

Using gypsum boards beyond this temperature can lead to issues such as warping, reducing air tightness, or even causing the material to disintegrate. Therefore, understanding this limitation is crucial for designing and maintainingHVAC systems and ensuring they operate safely and efficiently.