Which flame spread rating is applicable to insulation?

The flame spread rating applicable to insulation is a crucial safety standard that indicates how quickly and easily flames can spread over the surface of a material. This rating is determined through testing and is important in assessing the fire safety of building materials.

In this case, a flame spread rating that does not exceed 25 indicates that the insulation material performs within the acceptable limits for safety and efficacy in construction. A rating of 25 or lower generally qualifies materials for use in specific applications, particularly in residential and commercial settings where fire risk is a concern. Insulation with this rating allows for a balance between thermal efficiency and fire safety, making it suitable for a wide range of building types.

Choosing a flame spread rating of no more than 25 ensures compliance with building codes and safety regulations, helping to mitigate fire risks in structures where insulation is installed. This is why option C is the correct choice for the flame spread rating applicable to insulation.