What is the rating for an interior finish material with a flame spread index of 100?

What is the rating for an interior finish material with a flame spread index of 100?

A. Class A

B. Class B

C. Class C

D. Class D

View Answer

Answer: B

Explanation:

Interior finish materials are rated based on their flame spread index (FSI), which measures how quickly flames spread across the material’s surface. This classification is outlined in NFPA 101®, Life Safety Code®, Table A.10.2.3.2.

Class A: Flame spread index of 0-25 (lowest flame spread, highest resistance).

Class B: Flame spread index of 26-75 (moderate flame spread).

Class C: Flame spread index of 76-200 (higher flame spread).

Class D: Not defined in NFPA standards (typically exceeds Class C values).

For a flame spread index of 100, the material falls within the Class C range. However, since 100 exceeds the threshold for Class B (75), it is appropriately classified as Class C.

Reference: NFPA 101, Table A.10.2.3.2: Flame spread classifications for interior finishes.