The Ontario Building Code | Combustible Sign Faces
188.8.131.52. Combustible Sign Faces
(1) Plastic materials used in the construction of sign faces shall,
(a) have an average burning rate not greater than 65 mm/min in sheets 1.5 mm thick when tested in accordance with ASTM D635, "Rate of Burning and/or Extent and Time of Burning of Plastics in a Horizontal Position",
(b) have an average burning rate not greater than 140 mm/min when tested in accordance with ASTM D568, "Rate of Burning and/or Extent and Time of Burning of Flexible Plastics in a Vertical Position", and
(c) have a measurement of material thickness in accordance with Method B-Machinists’ Micrometer Without Ratchet of ASTM D374, "Thickness of Solid Electrical insulationhttp://thehandyforce.com/insulation/" title ="Toronto home insulation">insulation".
(2) Except as provided in Sentence (3), where the exterior cladding of a wall is required to be noncombustible, a plastic sign face or a group of contiguous plastic sign faces may be placed over such cladding provided each such sign face or group of contiguous sign faces,
(b) does not exceed 15 m2in area or 1 200 mm in height at each storey, and
(c) when located above the first storey, is vertically separated from other plastic sign faces by 1 200 mm of noncombustible constructionunless separated by a horizontal noncombustibleprojection such as a canopy, extending the full width of, and projecting at least 900 mm beyond the exterior sign face.
(3) Where a plastic exterior sign is mounted as a face on a metal sign box that is at least 200 mm in depth, the requirements of Sentence (2) need not apply provided the sign box is mounted on a noncombustibleexterior wall.
(4) Notwithstanding the requirements of Sentence (5), the plastic portion of an interior sign placed over or forming part of an interior wall surface in corridors, covered or enclosed walkwaysat or above grade in buildingsshall,
(b) be supported by a device that will not detrimentally affect the fire-resistance ratingof the interior wall to which it is attached or of which it may form a part, and encase the edges of the plastic sign face in metal,
(c) not be positioned or sized in such a manner that it is less than 600 mm from the vertical line separating two adjacent premises,
(e) be permitted to have an increase of 100% in area required in Clause (a) and a decrease of 50% of the separation distances required in Clauses (c) and (d) if the area is sprinklered, and
(f) have a flame-spreading rating not more than 250.
(5) Signs in exits and underground walkways shall have a flame-spread rating not more than 25.
3.15.5. Location Restrictions