Section 400.18653. Interior finish.

(1) An interior finish shall be a class A or B finish, except that an interior finish in an individual room may be a class  C  finish   for walls only.

(2)   A combustible finish material shall be applied to, or be furred out not more than 1 inch from, a noncombustible surface behind which the space is firestopped into an area that extends not  more  than   8  feet  in  any direction.

(3)   If a combustible interior finish comprises more than  10%  of   the aggregate wall and ceiling surface of any room or space, and if the finish material is more hazardous than permitted in the provisions of subrule (1) of this rule, then the combustible interior finish may be treated so as to comply with the provisions of subrule (1) of this rule, if the material is secured to the walls or ceilings as specified in subrule (2) of this rule.

(4)  If interior finish is more hazardous than class  A,  and  if   it  is furred more than 1 inch from a noncombustible wall or ceiling surface, it shall be replaced with a noncombustible material or reinstalled to comply with the provisions of subrules (1), (2), and (3) of this rule.

(5)   Existing wood paneling or combustible acoustical interior finish in lobbies, waiting rooms, and office areas in existing buildings may remain if the rooms or areas are separated from  the  rest  of   the  building  by proper walls and fire doors.

(6)   In a completely sprinklered building where  the  basic    material   is class C and is installed to comply with the provisions of  subrules  (1), (2), (3), and (4)  of  this rule,  further  treatment  is not required.

However, where the basic material is more hazardous than class  C  and   is installed to comply with the provisions of subrules (1), (2), (3), and (4) of this rule, it shall be surface treated on its exposed side whether  or not the building is sprinklered.

(7)   Class C interior finish in the form of wainscoting which  extends  not more than 5 feet above the floor and which is installed to comply with the provisions of subrules (1), (2), (3), and (5) of this rule, shall  not  be required to be surface treated.

(8)   Interior finish means the exposed  interior  surfaces   of   buildings including, but not limited to, fixed or moveable walls and  partitions, columns, and ceilings. Doors, trim, the backing of shelving, cabinets, and wardrobes shall be included in the 10% permissible   class   C  finish category.

(9)   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 covering,   except where the paint or other covering is of such character or thickness or so applied as  to  materially  affect  the flame  spread   and  smoke characteristics. Highly combustible material applications, such as lacquer or pyroxylin base materials, or unapproved wall coverings shall not be used.

(10)   Paints or coatings that contain plastics,  polyesters,  or   epoxies may be used on noncombustible surfaces without proof of classification if they are not applied in excess of 8 mils total thickness.

History: 1994 AACS.