California Residential Inspector Practice Exam

What is the maximum flame spread index allowed for insulation materials within wall assemblies?

1. 50

2. 25

3. 35

4. 15

The correct answer is: 25

The maximum flame spread index allowed for insulation materials within wall assemblies is 25. This standard is in place to ensure that materials used in construction have limited combustibility and do not contribute significantly to the spread of fire. A flame spread index of 25 indicates that insulation materials are classified as having a low potential for flame spread, which enhances the overall fire safety of a residential building. This limitation is part of building codes and safety regulations that aim to protect occupants and property from the hazards of fire. Insulation materials with a flame spread index of 25 or lower help to contain fires, allowing occupants more time to evacuate safely and preventing the rapid escalation of a fire. Hence, adhering to these standards is crucial for maintaining safety in residential construction. In the context of the options, a flame spread index of 50, 35, or 15 would not meet the specified requirement. Those values either exceed the maximum limit or suggest a higher potential for flame spread, which would not be suitable for insulation material used within wall assemblies in terms of safety.