N.Y.C. Admin. Code § 27-507: § 27-507 Use of combustible materials.

(a) General. In all signs required to be constructed of noncombustible materials under the provisions of this code, wood or other materials of combustible characteristics similar to wood may be used for moldings, cappings, trim, nailing blocks, letters, latticing, and other purely ornamental features.

(b) Slow-burning plastics. Slow-burning plastics may be used in sign construction subject to the following conditions and requirements.

(1) If all parts of the sign other than the letters and decorations are made from noncombustible materials, the display surface or sign facing may be made of slow-burning plastic, or may be occupied or covered by letters and decorations made from, or faced with, slow-burning plastics not exceeding a total area calculated from the values given in tables 7-2 and 7-3.

TABLE 7-2 Ground Signs and Wall Signs (Noncombustible Materials)

Area of Facing or Display Surface

Area Occupied or Covered by Plastics

150 sq. ft. or less

100 per cent of display surface area

Over 150 sq. ft., but not over 2,000 sq. ft.

150 sq. ft. plus 50 per cent of the difference between 150 sq. ft. and the area of the display surface

Over 2,000 sq. ft.

Not over 1,050 sq. ft. without permission of the commissioner

TABLE 7-3 Roof Signs, Projecting Signs, and Marquee Signs (Noncombustible Materials)

Area of Facing or Display Surface

Area Occupied or Covered by Plastics

150 sq. ft. or less

100 per cent of display surface area

Over 150 sq. ft. but not over 2,000 sq. ft.

150 sq. ft. plus 25 per cent of the difference between 150 sq. ft. and the area of the display surface.

Over 2,000 sq. ft.

Not more than 575 sq. ft. without permission of the commissioner

(2) If combustible materials are permitted in the framework, moldings, cappings, trim, nailing blocks, latticing or other parts of the sign, the display surface or sign facing may be occupied or covered by letters and decorations made from or faced with slow-burning plastics not exceeding a total area calculated from the values given in tables 7-4 and 7-5.

TABLE 7-4 Ground Signs and Wall Signs (Combustible Materials)

Area of Facing or Display Surface

Area Occupied or Covered by Plastics

300 sq. ft. or less

50 per cent of display surface area

Over 300 sq. ft. but not over 2,000 sq. ft.

150 sq. ft. plus 25 per cent of the difference between 150 sq. ft. and the total area of the display surface

Over 2,000 sq. ft.

Not over 575 sq. ft. without permission of the commissioner

TABLE 7-5 Roof Signs (Combustible Materials)

Area of Facing or Display Surface

Area Occupied or Covered by Plastics

1,000 sq. ft. or less

25 per cent of display surface area

Over 1,000 sq. ft. but not over 2,000 sq. ft.

250 sq. ft. plus 10 per cent of the difference between 1,000 sq. ft. and the total area of the display surface

Over 2,000 sq. ft.

Not more than 350 sq. ft. without special permission of the commissioner