By what measurement is the flame-spread index of wall and ceiling finishes restricted?

The flame-spread index is a critical measurement used to assess the fire resistance of wall and ceiling finishes, indicating how quickly flames can spread across a given material surface. The restriction of the flame-spread index to a measurement of 200 is significant because it aligns with safety standards set by building codes. This limit is aimed at minimizing the potential for fire to quickly engulf an area, which is essential in protecting building occupants and property.

Materials with a flame-spread index higher than 200 are generally deemed hazardous as they can enable flames to spread rapidly, increasing the risk of fire damage and jeopardizing life safety. By ensuring that finishes maintain a flame-spread index of 200 or lower, building codes help enforce the use of safer materials designed to resist combustion and limit fire spread, thereby enhancing overall fire protection within buildings.