Excerpts from the Canadian National Building Code
You must cover all polyurethane foam products with exceptions as shown below in the fire protection
excerpt from the National Building Code.
Fire Protection
3.1.4 Combustible Construction
3.1.4.2. Protection of Foamed Plastics
1) Foamed plastics which form part of a wall or ceiling assembly in combustible construction shall be
protected from adjacent spaces in the building, other than adjacent concealed spaces within attic or roof
spaces, crawl spaces, and wall assemblies
a) by one of the interior finishes described in Subsections 9.29.4 to 9.29.9
b) provided the building does not contain a Group B or Group C major occupancy, by sheet metal
i) mechanically fastened to the supporting assembly independent of the insulation,
ii) not less than 0.38mm thick, and
iii) with a melting point not below 650°C, or
c) any thermal barrier that meets the requirements of Sentence 3.1.5.11. (2) (See Appendix A.)
3.1.5. Noncombustible Construction
3.1.5.11. Combustible Insulation and Its Protection
1) Combustible insulation, other than foamed plastics, is permitted in a building, required to be of noncombustible construction provided that it has a flame-spread rating not more than 25 on any exposed
surface, or any surface that would be exposed by cutting through the material in any direction, where
the insulation is not protected as described in Sentences (3) and (4).
2) Foamed plastic insulation having a flame-spread rating not more than 25 on any exposed surface, or
any surface that would be exposed by cutting through the material in any direction, is permitted in
a building required to be of noncombustible construction provided the insulation is protected from
adjacent space in the building, other than adjacent concealed spaces within wall assemblies, by a
thermal barrier consisting of
a) not less than 12.7 mm thick gypsum board mechanically fastened to a supporting assembly
independent of the insulation,
b) lath and plaster, mechanically fastened to a supporting assembly independent of the insulation,
c) masonry,
d) concrete, or
e) any thermal barrier that meets the requirements of classification B when tested in conformance with
CAN4-S124-M, Standard Method of Test for the Evaluation of Protective Coverings for Foamed Plastic
(See Appendix A).
3) Combustible insulation having a flame-spread rating more than 25 but not more than 500 on an
exposed surface, or any surface that would be exposed by cutting through the material in any direction,
is permitted in the exterior walls of a building required to be of noncombustible construction, provided
the insulation is protected from adjacent space in the building, other than adjacent concealed spaces
within wall assemblies, by a thermal barrier as described in Sentence (2), except that in a building that is
not sprinklered throughout and is more than 18 m high, measured between the grade and the floor level
of the top storey, the insulation shall be protected by a thermal barrier consisting of
a) gypsum board not less than 12.7 mm thick, mechanically fasted to a supporting assembly independent
of the insulation and with all joints either backed or taped and filled,
b) lath and plaster, mechanically fastened to a supporting assembly independent of the insulation,
c) masonry or concrete not less than 25 mm thick, or
d) any thermal barrier that, when tested in conformance with CAN/ULC-S101-M, Standard Methods of
Fire Endurance Tests of Building Construction and Materials,' will not develop an average temperature
rise more than 140°C or a maximum temperature rise more than 180°C at any point on its unexposed
face within 10 min. (See also Article 3.2.3.7.)
4) Combustible insulation having a flame-spread rating more than 25 but not more than 500 on any
exposed surface, or any surface that would be exposed by cutting through the material in any direction,
is permitted in the interior walls, within ceilings and within roof assemblies of a building required to be
of noncombustible construction, provided the insulation is protected from adjacent space in
the building other than adjacent concealed spaces within wall assemblies, by thermal barrier as
described in Sentence (2), except that in a building that is not sprinklered throughout and is more than
18m high, measured between grade and the floor level of the top storey , the insulation shall be
protected by a thermal barrier consisting of
a) Type X gypsum board not less than 15.9 mm thick, mechanically fastened to a supporting assembly
independent of the insulation and with all joints either backed or taped and filled, conforming to
i) CAN/CSA-A82.27-M, Gypsum Board,
ii) ASTM C 36, Gypsum Wallboard,
iii) ASTM C 442, Gypsum Backing Board and Coreboard,
iv) ASTM C 588, Gypsum Base for Veneer Plaster,
v) ASTM C 630, Water Resistant Gypsum backing Board,
vi) ASTM C 931, Exterior Gypsum Soffit Board, or
vii) ASTM C 960, Predecorated Gypsum Board.
b) non- loadbearing masonry or concrete not less than 50 mm thick,
c) loadbearing masonry or concrete not less than 75 mm thick, or
d) any thermal barrier that, when tested in conformance with CAN/ULC-S101-M, Standard Methods of
Fire Endurance Tests of Building Construction and Materials,
i) will not develop an average temperature rise more than 140°C or a maximum temperature rise than
180°C at any point on its unexposed face within 20 min, and
ii) will remain in place for not less than 40 min.
5)Combustible insulation, including foamed plastics, installed above roof decks, outside
of foundation walls below ground level and beneath concrete slabs-on-ground is permitted to be used in
a building required to be of non-combustible construction.
6) Thermosetting foamed plastic insulation having a flame-spread rating of not more than 500 which
forms part of a factory-assembled exterior wall panel that does not incorporate an air space is permitted
to be used in a building required to be of noncombustible construction provided
a) the foamed plastic is protected on both sides by sheet steel not less than 0.38mm thick which will
remain in place for not less than 10 min when the wall panel is tested in conformance with CAN/ULC-
S101-M, Standard Methods of Fire Endurance Tests of Building Construction and Materials,
b) the flame-spread rating of the wall panel, determined by subjecting a sample including an assembled
joint to the appropriate test described in Subsection 3.1.12., is not more than the flame-spread
ratingpermitted for the room or space which I bounds,
c) The building does not contain a Group B or Group C major occupancy, and
d) The building is not more than 18m high, measured between grade and the floor level at the top storey.
3.1.11. Fire Stops in Concealed Spaces
3.1.11.2. Fire Stopping in Wall Assemblies
1) Except as permitted by Sentence (2), fire stops conforming to Article 3.1.11.7 shall be provided to
block off concealed spaces within a wall assembly
a) at every floor level,
b) at every ceiling level where the ceiling forms part of an assembly required to have a fire-resistance
rating, and
c) so that the maximum horizontal dimension is not more than 20 m and the maximum vertical
dimension is not more than 3 m.
2) Fire stops conforming to Sentence (1) are not required provided
a) the wall space is filled with insulation,
b) the exposed construction materials and any insulation within the wall space are noncombustible,
c) the exposed construction material and any insulation within the wall space have a flame-spread rating
not more than 25 on any exposed surface, or on any surface that would be exposed by cutting through
the material in any direction, and fire stops are installed so that the vertical distance between them is
not more than 10 m, or
d) the insulated wall assembly contains not more than one concealed air space, and the horizontal
thickness of that air space is not more than 25 mm.
3.2.2. Building Size and Construction Relative to Occupancy
3.2.2.9. Crawl Spaces
1) For the purpose of Articles 3.2.1.4. and 3.2.1.5., a crawl space shall be considered as a basement if it
is
a) more than 1.8m high between the lowest part of the floor assembly and the ground or other surface
below,
b) used for any occupancy
c) used for the passage of flue pipes, or
d) used as a plenum in combustible construction.
9.10.8.8. Crawl Spaces
1) Where a crawl space exceeds 1.8 m in heights or is used for any occupancy or as
a plenum in combustible construction or for the passage of flue pipes, it shall be considered as
a basement in applying the requirements of Article 9.10.8.1.
9.10.15.1. Required Fire Stops in Concealed Spaces
1) Vertical concealed spaces in interior walls and exterior walls shall be separated by fire stops
a) one from the other, and
b) from horizontal concealed spaces.
2) Horizontal concealed spaces in attics, roof spaces, ceilings, floors, and crawl spaces shall be
sepeartated by fire stops
a) one from the other, and
b) from vertical concealed spaces
3) Fire stops shall be provided at all inter-connections between concealed vertical and horizontal spaces
in interior cover ceilings, drop ceilings and soffits where the exposed construction materials within the
concealed spaces have a surface flame-spread rating greater than 25.
9.10.16.10. Protection of Foamed Plastics
1) Except as provided in Sentence (2), foamed plastics which form part of a wall or ceiling assembly
incombustible construction shall be protected from adjacent spaces in the building, other than adjacent
concealed spaces within attic or roof spaces, crawl spaces, and wall assemblies, by
a) one of the interior finishes described in Subsections 9.29.4. to 9.29.9,
b) sheet metal mechanically fastened to the supporting assembly independent of the insulation and
having a thickness of not less than 0.38mm and a melting point not below 650°C, provided
the buildingdoes not contain a Group C major occupancy, or
c) any thermal barrier that meets the requirements of Clause 3.1.5.11.(2)(e).
9.29.4. Plastering
9.29.5. Gypsum Board Finish (Taped Joints)
9.29.5.1. Application
1) The requirements for application of gypsum board in this Subsect5ion apply to the single layer
application of gypsum board to wood furring or framing using nails or screws.
2) Gypsum board applications not described in this Subsection shall conform to CSA A82.31-M, Gypsum
Board Application.
9.29.6. Plywood Finish
9.29.6.1. Thickness
1) Except as provided in Sentences (2) and (3), the minimum thickness of plywood interior finish shall
conform to Table 9.29.6.1.
Table 9.29.6.1.
Thickness of Plywood Interior Finish
Forming Part of Articles 9.29.6.1. and 9.29.6.2.
Maximum
Spacing of
Supports,
mm(o.c.)
Minimum Thickness
On Supports with On Supports with
no Horizontal
Blocking
Blocking at
Vertical Intervals
not Exceeding 1.2
m
400
4.7
4.0
600
8.0
4.7
3) No minimum thickness is required where plywood is applied over continuous backing.
9.29.7. Hardboard Finish
9.29.7.1. Material Standard
1) Hardboard shall conform to CAN/CGSB11.3-M, Hardboard.
9.29.7.2. Thickness
1) Hardboard shall be not less than
a) 3 mm thick when applied over continuous back-up,
b) 6 mm thick when applied over supports spaced not more than 400 mm o.c., and
c) 9 mm thick when applied over supports spaced not more than 600 mm o.c.
9.29.8. Insulating Fibreboard Finish
9.29.8.1. Material Standard
1) Insulating fibreboard shall conform to CAN/CSA-A247-M, Insulating Fibreboard.
9.29.8.2 Thickness
1) Insulating fibreboard tile shall be not less than 12.7 mm thick on supports spaced not more than 400
mm o.c.
9.29.9. Particleboard, OSB or Waferboard Finish
9.29.9.1. Material Standard
1) Particleboard finish shall conform to CAN3-O188.1-M, Interior Mat-Formed Wood Particleboard.
2) OSB or waferboard finish shall conform to CSA O437.0 OSB and Wafterboard.
9.29.9.2. Minimum Thickness
1) Except as provided in Sentences (2) and (3), the minimum thickness of O-2 grade OSB used as an
interior finish shall conform to that shown for plywood in Table 9.29.6.1.
2) Thickness listed in Table 9.29.6.1. shall permit a manufacturing tolerance of -0.4mm.
3) No minimum thickness is required where O-2 grade OSB is applied over continuous backing.
4) OSB conforming to O-1 grade, waferboard conforming to R-1 grade and particleboard shall be
a) not less than 6.35 mm thick on supports not more than 400 mm o.c.,
b) not less than 9.5 mm thick on supports not more than 600 mm o.c., and
c) not less than 6.35 mm thick on supports notmore than 600 mm o.c. in walls where blocking is provided
at midwall heights.