Limiting Distance and Area of Unprotected Openings

1. Except as permitted by Articles 3.2.3.10. to 3.2.3.12., the area of unprotected openings in an exposing building face for the applicable limiting distance shall be not more than the value determined in accordance with
   1. a) Table 3.2.3.1.-B or 3.2.3.1.-C for an exposing building face conforming to Article 3.2.3.2. of a building or fire compartment which is not sprinklered, or
   2. b) Table 3.2.3.1.-D or 3.2.3.1.-E for an exposing building face conforming to Article 3.2.3.2. of a sprinklered fire compartment that is part of a building which is sprinklered in conformance with Section 3.2. (See Note A-3.) (See also Article 3.1.6.3.)
2. The area of the unprotected openings in an exposing building face shall be the aggregate area of unprotected openings expressed as a percentage of the area of the exposing building face in Table 3.2.3.1.-B, 3.2.3.1.-C, 3.2.3.1.-D or 3.2.3.1.-E. (See Sentence 3.2.3.2.(1).)
3. For the purpose of determining the type of construction and cladding and the fire-resistance rating of an exterior wall,
   1. the exposing building face shall be taken as the projection of the exterior wall onto a vertical plane located so that no portion of the exterior wall of the building or of a fire compartment, if the fire compartment complies with the requirements of Article 3.2.3.2., is between the vertical plane and the line to which the limiting distance is measured, and
   2. the area of unprotected openings shall be determined from Table 3.2.3.1.-B, 3.2.3.1.-C, 3.2.3.1.-D or 3.2.3.1.-E.
4. For the purpose of determining the actual percentage of unprotected openings permitted in an exterior wall, the location of the exposing building face is permitted to be taken at a vertical plane located so that there are no unprotected openings between the vertical plane and the line to which the limiting distance is measured. (See Note A-3.2.3.1.(4).)
5. Except for buildings that are sprinklered, where the limiting distance is 2 m or less, individual unprotected openings in an exposing building face shall be no greater than
   1. the area stated in Table 3.2.3.1.-A, or
   2. where the limiting distance is equal to or greater than 1.2 m, the area calculated by
      
      where
      Area = area of the unprotected opening, and
      LD = limiting distance.
      
      

      Table 3.2.3.1.-A
      Maximum Concentrated Area of Unprotected Openings
      Forming Part of Sentence 3.2.3.1.(5)

      
      
6. The spacing between individual unprotected openings described in Sentence (5) that serve a single room or space described in Sentence (7) shall not be less than
   1. 2 m horizontally of another unprotected opening that is on the same exposing building face and serves the single room or space, or
   2. 2 m vertically of another unprotected opening that serves the single room or space, or another room or space on the same storey.
7. For the purpose of Sentence (6), "single room or space" shall mean
   1. two or more adjacent spaces having a full-height separating wall extending less than 1.5 m from the interior face of the exterior wall, or
   2. two or more stacked spaces that are on the same storey.
8. A limiting distance equal to half the actual limiting distance shall be used as input to Tables 3.2.3.1.-B and 3.2.3.1.-C, where
   1. the time from receipt of notification of a fire by the fire department until the arrival of the first fire department vehicle at the building exceeds 10 min in 10% or more of all fire department calls to the building, and
   2. b) any storey in the building is not sprinklered.
      (See Notes A-3.2.3.1.(8) and A-3.2.3.)
9. If the surface temperature on the unexposed surface of a wall assembly exceeds the temperature limit of a standard fire test as permitted by Article 3.1.7.2., an allowance shall be made for the radiation from the hot unexposed wall surface by adding an equivalent area of unprotected opening to the area of actual openings as follows:
   
   where
   A_C = corrected area of unprotected openings including actual and equivalent openings
   A = actual area of unprotected openings,
   A_F = area of exterior surface of the exposing building face, exclusive of openings, on which the temperature limit of the standard test is exceeded, and
   F_EO = an equivalent opening factor derived from the following expression:
   
   T_u = average temperature in degrees Celsius of the unexposed wall surface at the time the required fire-resistance rating is reached under test conditions,
   T_e = 892°C for a fire-resistance rating not less than 45 min, 927°C for a fire-resistance rating not less than 1 h, and 1 010°C for a fire-resistance rating not less than 2 h.
10. Unless a closure used to protect an opening in an exposing building face has a protective performance equivalent to that required for the wall assembly in which it is located, an equivalent area of unprotected opening, determined in accordance with the procedures of Sentence (9) shall be added to the greater of
    
    1. the actual area of unprotected openings, or
    2. the corrected area of unprotected openings.

Notes to Table 3.2.3.1.-B:
(1) Apply whichever ratio is greater.
L = Length of exposing building face
H = Height of exposing building face

Table 3.2.3.1.-C
Unprotected Opening Limits for a Building or Fire Compartment that is not Sprinklered Throughout
Forming Part of Article 3.2.3.1.

Notes to Table 3.2.3.1.-C:
(1) Apply whichever ratio is greater.
L = Length of exposing building face
H = Height of exposing building face

Table 3.2.3.1.-D
Unprotected Opening Limits for a Building or Fire Compartment that is Sprinklered Throughout
Forming Part of Article 3.2.3.1.

Table 3.2.3.1.-E
Unprotected Opening Limits for a Building or Fire Compartment that is Sprinklered Throughout
Forming Part of Article 3.2.3.1.

Area of Exposing Building Face

1. Except as permitted by Sentences (2) and (3), the area of an exposing building face shall be calculated as the total area of an exterior wall facing in one direction on any side of a building measured from the finished ground level to the uppermost ceiling.
2. If a building is divided by fire separations into fire compartments, the area of exposing building face is permitted to be calculated for each fire compartment provided the fire separations have a fire-resistance rating not less than 45 min.
3. In a building that is sprinklered throughout and contains an interconnected floor space, the area of the exposing building face for the interconnected floor space is permitted to be determined by considering each storey as a separate fire compartment notwithstanding openings through the floor assemblies.

Wall Enclosing Attic or Roof Space

1. An exterior wall enclosing an attic or roof space and located above an exposing building face, shall be constructed in conformance with the requirements for the exposing building face.

Party Wall

1. A party wall shall be constructed as a firewall. (See Note A-3.2.3.4.(1).)

Wall with Limiting Distance Less Than 1.2 m

1. Openings in a wall that has a limiting distance less than 1.2 m shall be protected by closures whose fire-protection rating is in conformance with the fire-resistance rating required for the wall.
2. Wired glass or glass block shall not be used for a closure referred to in Sentence (1).

Combustible Projections

1. Except for a building containing one or 2 dwelling units only, combustible projections on the exterior of a wall that could expose an adjacent building to fire spread and are more than 1 m above ground level, including balconies, platforms, canopies and stairs, shall not be permitted within
   1. 1.2 m of a property line or the centre line of a public way, or
   2. 2.4 m of a combustible projection on another building on the same property.
2. Except as provided in Sentence (4), where the exposing building face has a limiting distance of not more than 0.45 m, projecting roof soffits shall not be constructed above the exposing building face. (See Note A-3.2.3.6.(2).)
3. Except as provided in Sentence (4), where the exposing building face has a limiting distance of more than 0.45 m, the face of roof soffits shall not project to less than 0.45 m from the property line. (See Note A-3.2.3.6.(2).)
4. The face of a roof soffit is permitted to project to the property line, where it faces a street, lane or public thoroughfare. (See Note A-9.10.14.5.(11) and 9.10.15.5.(10).)
5. Where roof soffits project to less than 1.2 m from the centre line of a lane or public thoroughfare, or from an imaginary line between two buildings or fire compartments on the same property, they shall
   1. have no openings, and
   2. be protected by
      1. not less than 0.38 mm thick sheet steel,
      2. unvented aluminum conforming to CAN/CGSB-93.2-M, "Prefinished Aluminum Siding, Soffits, and Fascia, for Residential Use,"
      3. not less than 12.7 mm thick gypsum soffit board or gypsum ceiling board installed according to CSA A82.31-M, "Gypsum Board Application,"
      4. not less than 11 mm thick plywood,
      5. not less than 12.5 mm thick OSB or waferboard, or
      6. not less than 11 mm thick lumber.
6. For buildings of combustible construction, materials installed to provide the required protection of soffits may be covered with a combustible or noncombustible finish material.

Construction of Exposing Building Face

1. Except as provided in Sentences (3) and (4), and Articles 3.2.3.10. and 3.2.3.11., the fire-resistance rating, construction and cladding for exposing building faces of buildings or fire compartments of Group A, B, C, D or Group F, Division 3 occupancy classification shall comply with Table 3.2.3.7.
2. Except as provided in Sentences (3) and (4) and Article 3.2.3.10., the fire-resistance rating, construction and cladding for exposing building faces of buildings or fire compartments of Group E or Group F, Division 1 or 2 occupancy classification shall comply with Table 3.2.3.7.
   

   Table 3.2.3.7.
   Minimum Construction Requirements for Exposing Building Faces
   Forming Part of Sentences 3.2.3.7.(1) and (2)

   
   Notes to Table 3.2.3.7.:
   (1) The cladding on Group C buildings conforming to Article 3.2.2.50. and on Group D buildings conforming to Article 3.2.2.58. shall be noncombustible.
3. Except as provided in Article 3.1.4.8., the requirement in Table 3.2.3.7. for noncombustible cladding for buildings or fire compartments where the maximum permitted area of unprotected openings is more than 10% of the exposing building face is permitted to be waived for exterior wall assemblies that comply with Article 3.1.5.5.
4. Except as provided in Article 3.1.4.8., the requirement in Table 3.2.3.7. for noncombustible cladding for buildings or fire compartments where the maximum permitted area of unprotected openings is more than 25% but not more than 50% of the exposing building face is permitted to be waived where
   1. the limiting distance is greater than 5 m,
   2. the building or fire compartment and all combustible attic and roof spaces are sprinklered throughout,
   3. the cladding
      1. conforms to Subsections 9.27.6. , 9.27.7. , 9.27.8. , 9.27.9. or 9.27.10.,
      2. is installed without furring members, or on furring not more than 25 mm thick, over gypsum sheathing at least 12.7 mm thick or over masonry, and
      3. after conditioning in conformance with ASTM D 2898, "Accelerated Weathering of Fire-Retardant-Treated Wood for Fire Testing," has a flame-spread rating not greater than 25 on the exterior face when tested in accordance with Sentence 3.1.12.1.(1),
   4. the cladding
      1. conforms to Subsection 9.27.12.,
      2. is installed with or without furring members over gypsum sheathing at least 12.7 mm thick or over masonry,
      3. has a flame-spread rating not greater than 25 when tested in accordance with Sentence 3.1.12.1.(2), and
      4. does not exceed 2 mm in thickness exclusive of fasteners, joints and local reinforcements, or
   5. the exterior wall assembly complies with Article 3.1.5.5.
5. The construction requirements for the exposing building face stated in Sentences (1) and (2) shall be satisfied before increasing the unprotected opening area as permitted by Sentence 3.2.3.12.(1).

Protection of Exterior Building Face

1. Except as permitted by Sentence (3) and in addition to the requirements of Sentences 3.2.3.7.(1) and (2) and where the maximum permitted area of unprotected openings is greater than 10% of the exposing building face, foamed plastic insulation used in an exterior wall of a building more than 3 storeys in building height shall be protected on its exterior surface by
   1. concrete or masonry not less than 25 mm thick, or
   2. noncombustible material that complies with the criteria for testing and the conditions of acceptance stated in Sentence (2) when tested in conformance with CAN/ULC-S101, "Fire Endurance Tests of Building Construction and Materials."
2. The criteria for testing and the conditions of acceptance for a wall assembly to satisfy the requirements of Clause (1)(b) are that
   1. the fire exposed area of the wall assembly shall be not less than 9.3 m2 and have no dimension less than 2.75 m,
   2. the exposed surface shall include typical vertical and horizontal joints,
   3. the test shall be continued for not less than 15 min and the standard time/temperature curve of the referenced standard shall be followed,
   4. the noncombustible protective material must remain in place and no through openings should develop that are visible when viewed normal to the face of the material, and
   5. the noncombustible protective material should not disintegrate in a manner that would permit fire to propagate along the surface of the test assembly.
3. The requirements of Sentence (1) are waived for wall assemblies that comply with the requirements of Article 3.1.5.5. (See Note A-3.1.4.1.(1).)

Protection of Structural Members

1. Structural members, including beams, columns and arches, that are placed wholly or partly outside the exterior face of a building and are less than 3 m from the property line or the centre line of a public thoroughfare shall be protected from exterior fire exposure by fire protection having a fire-resistance rating not less than that required for their protection from interior fire exposure, as stated in Articles 3.2.2.20. to 3.2.2.90., but not less than 1 h.
2. Structural members of heavy timber construction, including beams, columns and arches, that are placed wholly or partly outside the exterior face of a building and are 3 m or more from the property line or the centre line of a public thoroughfare need not be covered with noncombustible cladding.

Unlimited Unprotected Openings

1. An exposing building face in a storage garage with all storeys constructed as open-air storeys is permitted to have unlimited unprotected openings provided it has a limiting distance not less than 3 m.
2. The exposing building face of a storey that faces a street and is at the same level as the street is permitted to have unlimited unprotected openings if the limiting distance is not less than 9 m.

Low Fire Load, One Storey Building

1. An exposing building face of a building of low-hazard industrial occupancy conforming to Article 3.2.2.89. is permitted to be of noncombustible construction without a fire-resistance rating provided
   1. it is not a loadbearing wall, and
   2. the limiting distance is not less than 3 m.

Area Increase for Unprotected Openings

1. Except as required by Sentence 3.2.3.7.(5), the maximum area of unprotected openings in any exposing building face of an unsprinklered building is permitted to be doubled if the openings are glazed with
   1. glass block conforming to the requirements of Article 3.1.8.16., or
   2. wired glass assemblies conforming to D-2.3.15. in Appendix D.

Protection of Exit Facilities

1. Except as required by Sentence (3) and as permitted by Sentence 3.4.4.3.(1), if the plane of an exterior wall of an exit enclosure forms an angle less than 135° with the plane of an exterior wall of the building it serves, and an opening in the exterior wall of the exit enclosure could be exposed to fire from an opening in the exterior wall of the building, the opening in either the exterior wall of the exit or the exterior wall of the building shall be protected in conformance with the requirements of Sentence (4) where the opening in the exterior wall of the building is within 3 m horizontally and
   1. less than 10 m below an opening in the exterior wall of the exit, or
   2. less than 2 m above an opening in the exterior wall of the exit. (See Note A-3.2.3.14.(1).)
2. If an unenclosed exterior exit stair or ramp could be exposed to fire froman opening in the exterior wall of the building it serves, the opening in the exterior wall of the building shall be protected in conformance with the requirements of Sentence (4) where the opening in the exterior wall of the building is within 3 m horizontally and
   1. less than 10 m below the exit stair or ramp, or
   2. less than 5 m above the exit stair or ramp.
3. Except as permitted by Sentence 3.4.4.3.(1), if an exterior exit door in one fire compartment is within 3 m horizontally of an opening in another fire compartment and the exterior walls of these fire compartments intersect at an exterior angle of less than 135°, the opening shall be protected in conformance with the requirements of Sentence (4).
4. The opening protection referred to in Sentences (1), (2) and (3) shall consist of
   1. glass block conforming to the requirements of Article 3.1.8.16.,
   2. a wired glass assembly conforming to D-2.3.15. in Appendix D, or
   3. a closure conforming to the requirements of Subsection 3.1.8. and Articles 3.2.3.1. and 3.2.3.14.

Wall Exposed to Another Wall

1. Except as required by Sentences (3) and 3.2.3.13.(1) or as permitted by Sentence 3.2.3.19.(4), if an unprotected opening in an exterior wall of a fire compartment is exposed to an unprotected opening in the exterior wall of another fire compartment, and the planes of the 2 walls are parallel or at an angle less than 135°, measured from the exterior of the building, the unprotected openings in the 2 fire compartments shall be separated by a distance not less than D_o where
   
   but in no case less than 1m, and
   D = the greater required limiting distance for the exposing building faces of the 2 fire compartments, and
   θ = the angle made by the intersecting planes of the exposing building faces of the 2 fire compartments (in the case where the exterior walls are parallel and face each other, θ = 0°).
   (See Note A-3.2.3.14.(1).)
2. The exterior wall of each fire compartment referred to in Sentence (1) within the distance, D_o, shall have a fire-resistance rating not less than that required for the interior vertical fire separation between the fire compartment and the remainder of the building.
3. Sentence (1) does not apply to unprotected openings of fire compartments within a building that is sprinklered throughout, but shall apply to
   1. unprotected openings of fire compartments on opposite sides of a firewall, and
   2. exposure from unprotected openings of a fire compartment that is not protected by an automatic sprinkler system.

Wall Exposed to Adjoining Roof

1. Except as permitted by Sentence 3.2.3.19.(4), if a wall in a building is exposed to a fire hazard from an adjoining roof of a separate fire compartment that is not sprinklered in the same building, and the exposed wall contains windows within 3 storeys vertically and 5 m horizontally of the roof, the roof shall contain no skylights within 5 m of the exposed wall.

Protection of Soffits

1. Except as permitted by Sentences (3) and (4), where there is a common attic or roof space above more than 2 suites of residential occupancy or above more than 2 patients' sleeping rooms, and the common attic or roof space projects beyond the exterior wall of the building, the soffit, and any opening in the soffit or other surface of the projection located within 2 500 mm of a window or door opening, shall be protected by
   1. noncombustible material
      1. not less than 0.38 mm thick, and
      2. having a melting point not below 650°C,
   2. plywood not less than 11 mm thick,
   3. strandboard or waferboard not less than 12.5 mm thick, or
   4. lumber not less than 11 mm thick.
2. The soffit protection required by Sentence (1) shall extend the full width of the opening and to not less than 1 200 mm on either side of it, and shall apply to all openings through the soffit within this limit.
3. If an eave overhang is completely separated from the remainder of the attic or roof space by the use of fire blocks, the requirements of Sentence (1) do not apply.
4. The protection required by Sentence (1) for projections is permitted to be omitted if
   1. the fire compartments behind the window and door openings are sprinklered in accordance with Article 3.2.5.12., and
   2. all rooms, including closets and bathrooms, having openings in the wall beneath the soffit are sprinklered, notwithstanding exceptions permitted in the standards referenced in Article 3.2.5.12. for the installation of automatic sprinkler systems.

Canopy Protection for Vertically Separated Openings

1. Except as permitted by Sentences (2) and (3), if a storey classified as a Group E or Group F, Division 1 or 2 major occupancy is required to be separated from the storey above by a fire separation,
   1. every opening in the exterior wall of the lower storey that is located vertically below an opening in the storey above shall be separated from the storey above by a canopy projecting not less than 1 m from the face of the building at the intervening floor level, and
   2. the canopy required by Clause (a) shall have a fire-resistance rating not less than that required for the floor assembly but need not be more than 1 h, except as required elsewhere in this Subsection.
2. Except as permitted by Sentence (3), the canopy required by Sentence (1) is permitted to be omitted if the exterior wall of the upper storey is recessed not less than 1 m behind the exterior wall containing the opening in the lower storey.
3. The requirements of Sentences (1) and (2) are permitted to be waived if the building is sprinklered throughout.

Covered Vehicular Passageway

1. A covered vehicular passageway designed as a receiving or shipping area shall be separated from every building or part of a building adjoining it by a fire separation having a fire-resistance rating not less than 1.5 h.
2. A covered vehicular passageway constructed below grade shall be of noncombustible construction.

Walkway between Buildings

1. Except as required by Sentence 3.2.3.20.(2), if buildings are connected by a walkway, each building shall be separated from the walkway by a fire separation with a fire-resistance rating not less than 45 min .
2. Except as permitted by Sentence (3), a walkway connected to a building required to be of noncombustible construction shall also be of noncombustible construction.
3. A walkway connected to a building required to be of noncombustible construction is permitted to be of heavy timber construction provided
   1. not less than 50% of the area of any enclosing perimeter walls is open to the outdoors, and
   2. the walkway is at ground level.
4. A walkway of noncombustible construction used only as a pedestrian thoroughfare need not conform to the requirements of Articles 3.2.3.14. and 3.2.3.15.
5. A walkway between buildings shall be not more than 9 m wide.

Underground Walkway

1. An underground walkway shall not be designed or used for any purpose other than pedestrian travel unless
   1. the purpose is acceptable to the authority having jurisdiction, and
   2. sprinklers are installed in any space in the walkway containing an occupancy.
2. Buildings connected by an underground walkway shall be separated from the walkway by a fire separation with a fire-resistance rating not less than 1 h.
3. An underground walkway shall be of noncombustible construction suitable for an underground location.
4. In an underground walkway
   1. smoke barrier doors shall be installed at intervals of not more than 100 m, or
   2. the travel distance from the door of an adjacent room or space to the nearest exit shall be not more than one and a half times the least allowable travel distance to an exit for any of the adjacent occupancies as permitted by Sentence 3.4.2.5.(1).
5. An underground walkway between buildings shall be not more than 9 m wide.

Storage and Process Equipment Located Outdoors

1. Location of outdoor storage and outdoor process equipment in relation to buildings shall conform to Parts 3 and 4 of Division B of the NFC.

Installation of Service Lines Under Buildings

1. When a building is erected over existing buried flammable gas mains, such service lines shall be encased in gas-tight conduits in conformance with CAN/CSA-Z662, "Oil and Gas Pipeline Systems."