(a) General. Except for foam plastic materials and as provided in this section, exposed and concealed thermal insulating materials, including any facings, must be tested in accordance with NFPA 255-96, Standard Method of Test of Surface Burning Characteristics of Building Materials (incorporated by reference, see § 3280.4) and must have a flame spread index of 25 or less and a smoke developed index of 450 or less. The flame spread and smoke developed limitations do not apply to:

1. (1) Coverings and facings of insulation batts or blankets installed in concealed spaces when the facings are in substantial contact with the unexposed surface of wall, floor, or ceiling finish; or
2. (2) Cellulose loose-fill insulation that complies with paragraph (b) of this section.

(b) Loose-fill insulation.

1. (1) Cellulose loose-fill insulation that is not spray-applied or self-supporting must comply with, and each package must be labeled in accordance with the Consumer Product Safety Commission requirements in 16 CFR parts 1209 and 1404.
2. (2) Other loose-fill insulation that cannot be mounted in the NFPA 255-96, test apparatus without a screen or other artificial support must be tested in accordance with CAN/ULC S102.2-M88, Standard Method of Test for Surface Burning Characteristics of Floor Coverings and Miscellaneous Materials and Assemblies (incorporated by reference, see § 3280.4), and must have a flame spread index of 25 or less and a smoke developed index of 450 or less.