Coffee Break Training: Inspection Techniques: Wall and Ceiling Covering Flame Spread Classifications [open pdf - 155KB]
"Even if a building is constructed of noncombustible materials, human occupants often introduce combustible finishes to soften the environment. Many tragic fires have occurred from easily ignited or fast-burning interior finishes on walls or ceilings. To identify and categorize materials to their relative fire risk, building codes classify interior wall and ceiling materials by flame spread ratings in accordance with requirements of American Society for Testing and Materials (ASTM) E84, Standard Test Method for Surface Burning Characteristics of Building Materials and National Fire Protection Association (NFPA) 255, Standard Method of Test of Surface Burning Characteristics of Building Materials. Materials are classified to indicate their ability to support combustion and flame. Finish materials are compared to the fire spread characteristics of red oak to express their relative risk."
Fire Protection Series No. FP-2012-37
U.S. Fire Administration: http://www.usfa.fema.gov