Section 400.4620. Interior finish.

(1) The following alphabetical classification of finished materials for flame spread and smoke development, as determined by the tunnel test in accordance with the national fire protection association, standard No. 255, 2006; American society of testing materials E-84-77A, 2014; or Underwriters Laboratories standard No. 723, 2008, shall be used to determine interior finishes:

Class	Flame Spread	Smoke Developed
A	0 - 25	0 - 450
B	26 - 75	51 - 450
C	76 - 200	126 - 450

The  same  alphabetical  classification  is  used  for  combustibility  of  prefabricated acoustical tile units, only under federal specifications test No. SS-5-118a.

(2)   The classification of interior finish materials as to their flame spread and smoke development shall be that of the basic material used, without regard to subsequently applied paint or other coverings, except where such paint or other covering is of such a character or thickness where applied to affect the material classification. Finishes such as lacquer, polyurethane-based materials, or unapproved wall coverings shall not be used.

(3)    In a newly constructed, remodeled, or converted residential group home, an interior finish classification shall be that of the basic material used, without regard to subsequently applied paint or other covering in an attempt to meet the classification.

(4)   Interior finishes and materials shall be at least class C throughout.

History: 1983 AACS; 2015 AACS.