On what materials is the flame spread rating system based?

The flame spread rating system is primarily based on standardized tests that assess how quickly and potentially how far flames can spread on various building materials. The system assigns numerical ratings to materials, where a lower rating indicates a slower flame spread and therefore a lower risk in terms of fire safety.

The reference materials for these tests typically include red oak wood, which is assigned a flame spread rating of 100, also referred to as a baseline for comparisons. Asbestos cement is often referenced because it is assigned a flame spread rating of zero, indicating it does not contribute to flame spread. This comparison between materials allows fire safety professionals to evaluate the fire performance of different building materials based on a common standard.

In contrast, options that mention combinations of different building materials, such as cement and plastic or brick and fiberboard, do not reflect the standardized method for establishing flame spread ratings, which focuses on the specific properties of materials like red oak and asbestos cement. These options do not provide a basis for comparison within the flame spread rating system as does the selection involving known ratings for red oak and asbestos cement.