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Large Buildings study guideLarge and complex buildings

Spatial separation and exposure protection

Limiting distance and unprotected openings, exposing building face construction, wall-to-wall and wall-to-roof exposure, soffits, canopies and walkways.

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Values this chapter turns on

fire response time beyond which limiting distance doubles
10 min
fire response time beyond which limiting distance doubles
limiting distance below which openings need closures
1.2 m
limiting distance below which openings need closures
spacing of openings to one room, low limiting distance
2 m
spacing of openings to one room, low limiting distance
concrete or masonry over exterior foamed plastic
25 mm
concrete or masonry over exterior foamed plastic

Subsection 3.2.3. controls how a fire in one building can spread to another by radiation through windows and walls, and how one part of a building can expose another part. The method is always the same: find the exposing building face and its limiting distance, read the permitted area of unprotected openings from the right table, then use that percentage to set the wall's rating, construction and cladding. After that, check the special exposure rules for exits, angled walls, roofs, soffits and canopies.

The two key terms

An exposing building face is the part of an exterior wall facing one direction, from ground level to the ceiling of the top storey, or the wall of one fire compartment where the building is compartmented (Div. A definitionOBC Div. A 1.4.1.2.(1) Exposing building faceExposing building face means that part of the exterior wall of a building that faces one direction and is located between ground level and the ceiling of its top storey or, where a building is divided into fire compartments, the exterior wall of a fire compartment that faces one direction.). Its area is the whole wall facing that direction, measured from finished ground to the uppermost ceiling (3.2.3.2.OBC Div. B 3.2.3.2. 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 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…). If fire separations rated at least 45 min divide the building into fire compartments, each compartment's face can be assessed on its own. In a sprinklered building with an interconnected floor space, each storey may be treated as its own compartment.

Limiting distance is measured at right angles from the face to the property line, to the centre line of a street, lane or public thoroughfare, or to an imaginary line between two buildings or fire compartments on the same property (Div. A definitionOBC Div. A 1.4.1.2.(1) Limiting distanceLimiting distance means the distance from an exposing building face to a property line, the centre line of a street, lane or public thoroughfare, or to an imaginary line between 2 buildings or fire compartments on the same property, measured at right angles to the exposing building face.). Owners may agree, through a registered agreement with the municipality, to measure it to a point beyond the property line (3.2.3.1.(11)OBC Div. B 3.2.3.1. 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 (a) Table 3.2.3.1.-B or Table 3.2.3.1.-C for an exposing building face conforming to Article…).

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Choosing the right table (3.2.3.1.)

Article 3.2.3.1.OBC Div. B 3.2.3.1. 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 (a) Table 3.2.3.1.-B or Table 3.2.3.1.-C for an exposing building face conforming to Article… points to four tables of permitted unprotected opening percentages:

Building or fire compartment Groups A, C, D, F-3 (Table -D also lists Group B) Groups E, F-1, F-2
Not sprinklered Table 3.2.3.1.-BOBC Div. B Table 3.2.3.1-B. Area of Unprotected Openings for Groups A, C, D, and F, Division 3 Occupancies, %Table 3.2.3.1.-B — Area of Unprotected Openings for Groups A, C, D, and F, Division 3 Occupancies, % Forming Part of Article 3.2.3.1. Exposing Building Face, Maximum Area, m² | Ratio (L/H or H/L)[1] | Limiting Distance, 0 m | Limiting Distance, 1.2 m | Limiting Distance, 1.5 m | Limiting Distance, 2 m | Limiting… Table 3.2.3.1.-COBC Div. B Table 3.2.3.1-C. Area of Unprotected Openings for Groups E and F, Division 1 and 2 Occupancies, %Table 3.2.3.1.-C — Area of Unprotected Openings for Groups E and F, Division 1 and 2 Occupancies, % Forming Part of Article 3.2.3.1. Exposing Building Face, Maximum Area, m² | Ratio (L/H or H/L)[1] | Limiting Distance, 0 m | Limiting Distance, 1.2 m | Limiting Distance, 1.5 m | Limiting Distance, 2 m | Limiting…
Sprinklered compartment in a building sprinklered to Section 3.2. Table 3.2.3.1.-DOBC Div. B Table 3.2.3.1-D. Area of Unprotected Opening for Groups A, B, C, D and F, Division 3 Occupancies, %Table 3.2.3.1.-D — Area of Unprotected Opening for Groups A, B, C, D and F, Division 3 Occupancies, % Forming Part of Sentence 3.1.6.9.(5) and Article 3.2.3.1. Exposing Building Face, Maximum Area, m² | Limiting Distance, 0 m | Limiting Distance, 1.2 m | Limiting Distance, 1.5 m | Limiting Distance, 2 m | Limiting… Table 3.2.3.1.-EOBC Div. B Table 3.2.3.1-E. Area of Unprotected Opening for Groups E and F, Division 1 and 2 Occupancies, %Table 3.2.3.1.-E — Area of Unprotected Opening for Groups E and F, Division 1 and 2 Occupancies, % Forming Part of Sentence 3.1.6.9.(5) and Article 3.2.3.1. Exposing Building Face, Maximum Area, m² | Limiting Distance, 0 m | Limiting Distance, 1.2 m | Limiting Distance, 1.5 m | Limiting Distance, 2 m | Limiting…

How to read the unsprinklered tables:

  1. Work out the face area in m² and find its row. If it falls between rows, using the next larger area row is the conservative reading (for example, 92 m² read on the 100 m² row). Check the table notes in your Compendium before interpolating.
  2. Work out the length-to-height ratio (use whichever of L/H or H/L is greater) and pick "less than 3:1", "3:1 to 10:1" or "over 10:1".
  3. Read across to the limiting distance column. If your distance falls between two columns, the lower column is the conservative choice.
  4. The value is a percentage of the face area. Multiply to get m².

The sprinklered tables (-D and -E) have no ratio column, and the percentages are roughly double. Higher-hazard occupancies (Groups E and F, Divisions 1 and 2) always get smaller percentages for the same face and distance.

Other rules in the Article and its neighbours:

  • If a storey is unsprinklered and the fire department cannot respond within 10 min of the alarm, double the required limiting distance (3.2.3.1.(8)OBC Div. B 3.2.3.1. 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 (a) Table 3.2.3.1.-B or Table 3.2.3.1.-C for an exposing building face conforming to Article…).
  • In unsprinklered buildings with a limiting distance of 2 m or less, each individual opening is also capped, and openings serving one room must be spaced 2 m apart horizontally or vertically.
  • Openings in a wall with a limiting distance under 1.2 m must have closures rated to match the wall, and wired glass or glass block cannot serve as that closure (3.2.3.5.OBC Div. B 3.2.3.5. 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).).
  • An open-air storage garage face may have unlimited openings at 3 m or more. A storey at street level facing a street may have unlimited openings at 9 m or more (3.2.3.10.OBC Div. B 3.2.3.10. 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…).
  • In an unsprinklered building, the permitted opening area may be doubled if the openings are glass block or wired glass assemblies to SB-2 (3.2.3.12.OBC Div. B 3.2.3.12. 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 a building that is not sprinklered is permitted to be doubled if the openings are glazed with (a) glass block conforming to the requirements of Article 3.1.8.16., or (b) wired glass assemblies…).

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Construction of the exposing building face (3.2.3.7.)

Once you know the permitted percentage, Table 3.2.3.7.OBC Div. B Table 3.2.3.7. Minimum Construction Requirements for Exposing Building FacesTable 3.2.3.7 — Minimum Construction Requirements for Exposing Building Faces Forming Part of Sentences 3.1.6.9.(5) and 3.2.3.7.(1) to (4) Occupancy Classification of Building or Fire Compartment | Maximum Area of Unprotected Openings Permitted, % of Exposing Building Face Area | Minimum Required Fire-Resistance… sets the minimum wall rating, construction type and cladding (3.2.3.7.OBC Div. B 3.2.3.7. Construction of Exposing Building Face(1) Except as provided by 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…). The pattern:

Permitted openings Groups A, B, C, D, F-3 rating Groups E, F-1, F-2 rating Construction Cladding
0 to 10% 1 h 2 h noncombustible noncombustible
over 10 to 50% 1 h, then 45 min above 25% 2 h, then 1 h above 25% any noncombustible
over 50% 45 min 1 h any may be combustible

The Table notes add cladding limits for 3.2.2.51., 3.2.2.60. and the mass timber articles. Sentences (3) and (4) let combustible cladding replace the noncombustible requirement in some bands: walls tested to 3.1.5.5. or 3.1.5.6., or, for the over 25 to 50% band, limiting distance over 5 m with sprinklers and specific cladding and backing. Satisfy the construction rules before you take the glass block or wired glass doubling.

Related protection:

  • Foamed plastic insulation in the exterior wall of a building over 3 storeys, where openings over 10% are permitted, must be protected outside by at least 25 mm of concrete or masonry or a tested noncombustible material (3.2.3.8.OBC Div. B 3.2.3.8. 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…).
  • Structural members outside the face and less than 3 m from the property line need exterior fire protection equal to their interior rating, and never less than 1 h (3.2.3.9.OBC Div. B 3.2.3.9. Protection of Structural Members(1) Structural members, including beams, columns and arches, 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…).
  • Combustible projections more than 1 m above ground must stay 1.2 m from a property line and 2.4 m from combustible projections on another building on the same property, except for one or two unit dwellings (3.2.3.6.OBC Div. B 3.2.3.6. Combustible Projections(1) Except for a building containing one or two 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 (a) 1.2 m of a…).

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Exposure within and between buildings

Exits (3.2.3.13.OBC Div. B 3.2.3.13. 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…). Where an exit enclosure wall meets the building wall at less than 135°, openings within 3 m horizontally, and less than 10 m below or 2 m above an exit opening, need protection (glass block, SB-2 wired glass or a rated closure). For an open exterior exit stair the zone is 3 m horizontally, less than 10 m below or less than 5 m above.

Angled walls between fire compartments (3.2.3.14.OBC Div. B 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.(5), 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…). Unprotected openings in two compartments facing each other, or meeting at less than 135°, must be at least D0 apart, where D0 = 2D minus (angle / 90 x D) and D is the greater required limiting distance. Parallel facing walls give 2D, walls at 90° give D, and the result is never under 1 m. The rule does not apply inside a building sprinklered throughout, except across a firewall or from an unsprinklered compartment.

Roofs (3.2.3.15.OBC Div. B 3.2.3.15. Wall Exposed to Adjoining Roof(1) Except as permitted by Sentence 3.2.3.19.(5), 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…). If a wall with windows overlooks the roof of an unsprinklered compartment within 3 storeys vertically and 5 m horizontally, the roof may have no skylights within 5 m of that wall.

Soffits (3.2.3.16.OBC Div. B 3.2.3.16. Protection of Soffits(1) Except as permitted by Sentences (3) and (4), where there is a common attic or roof space above more than two suites of residential occupancy or above more than two patients' or residents' sleeping rooms in a Group B, Division 2 or 3 occupancy, and the common attic or roof space projects beyond the exterior wall…). A common attic over more than two residential suites, or more than two sleeping rooms in Group B, Division 2 or 3, that projects past the wall needs protected soffits within 2,500 mm of a window or door. The protection extends 1,200 mm each side. It can be omitted where the eave is fire-blocked off or where the rooms are fully sprinklered.

Canopies (3.2.3.17.OBC Div. B 3.2.3.17. 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, (a) every opening in the exterior wall of the lower storey that is located vertically below an opening in the storey…). Where a Group E or F, Division 1 or 2 storey is separated from the storey above, windows stacked one above the other need a canopy projecting at least 1 m, rated like the floor but not over 1 h, or a 1 m recess of the upper wall. Sprinklering the building throughout waives both.

Walkways (3.2.3.19.OBC Div. B 3.2.3.19. 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 (4), a walkway connected to a building required to be of…, 3.2.3.20.OBC Div. B 3.2.3.20. Underground Walkway(1) An underground walkway shall not be designed or used for any purpose other than pedestrian travel unless (a) the purpose is permitted, and (b) 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…). Buildings are separated from a walkway by 45 min, or 1 h for an underground walkway. Both are limited to 9 m wide.

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Common traps

  • Using Table -B for a Group E store. Groups E and F, Divisions 1 and 2, use -C (unsprinklered) or -E (sprinklered).
  • Using the sprinklered tables when only one compartment is sprinklered. The whole building must be sprinklered to Section 3.2.
  • Picking the ratio row from the wrong dimension. Use whichever ratio is greater.
  • Forgetting that Table 3.2.3.7. uses the permitted percentage, not the area of windows actually drawn.

Chapter review

Chapter at a glance

One line per section: the idea to carry into the exam. Then the answers that most often catch candidates out.

Usual exam traps

  • Using Table -B for a Group E store. Groups E and F, Divisions 1 and 2, use -C (unsprinklered) or -E (sprinklered).
  • Using the sprinklered tables when only one compartment is sprinklered. The whole building must be sprinklered to Section 3.2.
  • Picking the ratio row from the wrong dimension. Use whichever ratio is greater.
  • Forgetting that Table 3.2.3.7. uses the permitted percentage, not the area of windows actually drawn.

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Questions on Spatial separation and exposure protection (3.2.3), in the exam format, every answer explained and cited to its article. Sign in to start; a free account gets the free questions.

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Code cited in this chapter

Based on the official 2024 Building Code Compendium on ontario.ca.

© King's Printer for Ontario, 2024. Reproduced with permission.

  • OBC Div. A 1.4.1.2.(1) Exposing building face

    Exposing building face means that part of the exterior wall of a building that faces one direction and is located between ground level and the ceiling of its top storey or, where a building is divided into fire compartments, the exterior wall of a fire compartment that faces one direction.

    Open OBC Div. A 1.4.1.2.(1) in the code viewer
  • OBC Div. B 3.2.3.2. 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 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.

    Open OBC Div. B 3.2.3.2. in the code viewer
  • OBC Div. A 1.4.1.2.(1) Limiting distance

    Limiting distance means the distance from an exposing building face to a property line, the centre line of a street, lane or public thoroughfare, or to an imaginary line between 2 buildings or fire compartments on the same property, measured at right angles to the exposing building face.

    Open OBC Div. A 1.4.1.2.(1) in the code viewer
  • OBC Div. B 3.2.3.1. 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

    (a)Table 3.2.3.1.-B or Table 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

    (b)Table 3.2.3.1.-D or Table 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 3.1.18.3.)

    (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,

    (a)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

    (b)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

    (a)the area stated in Table 3.2.3.1.-A, or

    (b)where the limiting distance equal to or greater than 1.2 m, the area calculated by

    Area =

    Area = 0.24[((2 × LD) − 1.2)^2]

    where

    Area = area of the unprotected opening, and

    LD = limiting distance.

    (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

    (a)2 m horizontally of another unprotected opening that is on the same exposing building face and serves the single room or space, or

    (b)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" means a room or space that

    (a)is not divided by a wall,

    (b)is divided by

    (i)a wall that extends less than 1.5 m from the interior face of the exterior wall, or

    (ii)a partial height wall, or

    (c)consists of two or more stacked spaces that are on the same storey.

    (8)If a building has any storey that is not sprinklered and firefighting facilities cannot reach it within 10 min of the alarm being received, the required limiting distance shall be doubled.

    (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:

    A_C = A + (A_E × F_EO)

    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:

    F_EO = ((T_u + 273)^4)/((T_e + 273)^4)

    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

    (a)the actual area of unprotected openings, or

    (b)the corrected area of unprotected openings.

    (11)The required limiting distance for an exposing building face is permitted to be measured to a point beyond the property line that is not the centre line of a street, lane or public thoroughfare if

    (a)the owners of the properties on which the limiting distance is measured and the municipality enter into an agreement in which such owners agree that,

    (i)each owner covenants that, for the benefit of land owned by the other covenantors, the owner will not construct a building on his or her property unless the limiting distance for exposing building faces in respect of the proposed construction is measured in accordance with the agreement,

    (ii)the covenants contained in the agreement are intended to run with the lands, and the agreement shall be binding on the parties and their respective heirs, executors, administrators, successors and assigns,

    (iii)the agreement shall not be amended or deleted from title without the consent of the municipality, and

    (iv)they will comply with such other conditions as the municipality considers necessary, including indemnification of the municipality by the other parties, and

    (b)the agreement referred to in Clause (a) is registered against the title of the properties to which it applies.

    (12)Where an agreement referred to in Sentence (11) is registered against the title of a property, the limiting distance for exposing building faces shall be measured to the point referred to in the agreement.

    Open OBC Div. B 3.2.3.1. in the code viewer
  • OBC Div. B Table 3.2.3.1-B. Area of Unprotected Openings for Groups A, C, D, and F, Division 3 Occupancies, %

    Table 3.2.3.1.-B — Area of Unprotected Openings for Groups A, C, D, and F, Division 3 Occupancies, % Forming Part of Article 3.2.3.1. Exposing Building Face, Maximum Area, m² | Ratio (L/H or H/L)[1] | Limiting Distance, 0 m | Limiting Distance, 1.2 m | Limiting Distance, 1.5 m | Limiting Distance, 2 m | Limiting Distance, 2.5 m | Limiting Distance, 3 m | Limiting Distance, 4 m | Limiting Distance, 5 m | Limiting Distance, 6 m | Limiting Distance, 7 m | Limiting Distance, 8 m | Limiting Distance, 9 m | Limiting Distance, 10 m | Limiting Distance, 11 m | Limiting Distance, 12 m | Limiting Distance, 13 m | Limiting Distance, 14 m | Limiting Distance, 16 m | Limiting Distance, 18 m | Limiting Distance, 20 m | Limiting Distance, 25 m | Limiting Distance, 30 m | Limiting Distance, 35 m | Limiting Distance, 40 m | Limiting Distance, 45 m | Limiting Distance, 50 m 10 | Less than 3:1 | 0 | 8 | 10 | 18 | 29 | 46 | 91 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 10 | 3:1 to 10:1 | 0 | 8 | 12 | 21 | 33 | 50 | 96 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 10 | over 10:1 | 0 | 11 | 18 | 32 | 48 | 68 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 15 | Less than 3:1 | 0 | 7 | 9 | 14 | 22 | 33 | 63 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 15 | 3:1 to 10:1 | 0 | 8 | 10 | 17 | 25 | 37 | 67 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 15 | over 10:1 | 0 | 10 | 15 | 26 | 39 | 53 | 87 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 20 | Less than 3:1 | 0 | 7 | 9 | 12 | 18 | 26 | 49 | 81 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 20 | 3:1 to 10:1 | 0 | 8 | 10 | 15 | 21 | 30 | 53 | 85 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 20 | over 10:1 | 0 | 9 | 14 | 23 | 33 | 45 | 72 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 25 | Less than 3:1 | 0 | 7 | 8 | 11 | 16 | 23 | 41 | 66 | 98 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 25 | 3:1 to 10:1 | 0 | 8 | 9 | 13 | 19 | 26 | 45 | 70 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 25 | over 10:1 | 0 | 9 | 13 | 21 | 30 | 39 | 62 | 90 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 30 | Less than 3:1 | 0 | 7 | 8 | 11 | 15 | 20 | 35 | 56 | 83 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 30 | 3:1 to 10:1 | 0 | 7 | 9 | 12 | 17 | 23 | 39 | 61 | 88 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 30 | over 10:1 | 0 | 8 | 12 | 19 | 27 | 36 | 56 | 79 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 40 | Less than 3:1 | 0 | 7 | 8 | 10 | 13 | 17 | 28 | 44 | 64 | 89 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 40 | 3:1 to 10:1 | 0 | 7 | 8 | 11 | 15 | 20 | 32 | 48 | 69 | 93 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 40 | over 10:1 | 0 | 8 | 11 | 17 | 24 | 31 | 47 | 66 | 88 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 50 | Less than 3:1 | 0 | 7 | 8 | 9 | 12 | 15 | 24 | 37 | 53 | 72 | 96 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 50 | 3:1 to 10:1 | 0 | 7 | 8 | 10 | 14 | 18 | 28 | 41 | 57 | 77 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 50 | over 10:1 | 0 | 8 | 10 | 15 | 21 | 28 | 41 | 57 | 76 | 97 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 60 | Less than 3:1 | 0 | 7 | 8 | 9 | 11 | 14 | 21 | 32 | 45 | 62 | 81 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 60 | 3:1 to 10:1 | 0 | 7 | 8 | 10 | 13 | 16 | 25 | 36 | 49 | 66 | 85 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 60 | over 10:1 | 0 | 8 | 10 | 14 | 20 | 25 | 38 | 51 | 67 | 85 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 80 | Less than 3:1 | 0 | 7 | 7 | 8 | 10 | 12 | 18 | 26 | 36 | 48 | 62 | 79 | 98 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 80 | 3:1 to 10:1 | 0 | 7 | 8 | 9 | 11 | 14 | 21 | 29 | 40 | 52 | 67 | 84 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 80 | over 10:1 | 0 | 8 | 9 | 13 | 17 | 22 | 32 | 44 | 56 | 70 | 86 | 100 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 100 | Less than 3:1 | 0 | 7 | 7 | 8 | 9 | 11 | 16 | 22 | 30 | 40 | 51 | 65 | 80 | 97 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 100 | 3:1 to 10:1 | 0 | 7 | 8 | 9 | 11 | 13 | 18 | 25 | 34 | 44 | 56 | 69 | 84 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 100 | over 10:1 | 0 | 7 | 9 | 12 | 16 | 20 | 29 | 39 | 49 | 61 | 74 | 89 | 100 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 150 | Less than 3:1 | 0 | 7 | 7 | 8 | 9 | 10 | 13 | 17 | 22 | 29 | 37 | 46 | 56 | 67 | 79 | 93 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 150 | 3:1 to 10:1 | 0 | 7 | 7 | 8 | 10 | 11 | 15 | 20 | 26 | 33 | 41 | 50 | 60 | 71 | 84 | 97 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 150 | over 10:1 | 0 | 7 | 8 | 11 | 13 | 17 | 24 | 31 | 39 | 48 | 57 | 68 | 79 | 91 | 100 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 250 | Less than 3:1 | 0 | 7 | 7 | 7 | 8 | 9 | 10 | 13 | 16 | 20 | 25 | 30 | 36 | 43 | 51 | 59 | 68 | 87 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A 250 | 3:1 to 10:1 | 0 | 7 | 7 | 8 | 9 | 10 | 12 | 15 | 19 | 24 | 28 | 34 | 40 | 47 | 55 | 63 | 72 | 92 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A 250 | over 10:1 | 0 | 7 | 8 | 9 | 11 | 14 | 19 | 24 | 30 | 36 | 43 | 50 | 57 | 65 | 73 | 82 | 92 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 350 | Less than 3:1 | 0 | 7 | 7 | 7 | 8 | 8 | 9 | 11 | 14 | 16 | 20 | 24 | 28 | 33 | 38 | 44 | 50 | 64 | 81 | 99 | N/A | N/A | N/A | N/A | N/A | N/A 350 | 3:1 to 10:1 | 0 | 7 | 7 | 8 | 9 | 9 | 11 | 13 | 16 | 19 | 23 | 27 | 32 | 37 | 42 | 48 | 55 | 69 | 85 | 100 | N/A | N/A | N/A | N/A | N/A | N/A 350 | over 10:1 | 0 | 7 | 8 | 9 | 10 | 12 | 16 | 21 | 25 | 30 | 36 | 41 | 47 | 53 | 59 | 66 | 73 | 88 | 100 | 100 | N/A | N/A | N/A | N/A | N/A | N/A 500 | Less than 3:1 | 0 | 7 | 7 | 7 | 7 | 8 | 9 | 10 | 12 | 14 | 16 | 19 | 22 | 25 | 29 | 33 | 37 | 47 | 59 | 71 | 100 | N/A | N/A | N/A | N/A | N/A 500 | 3:1 to 10:1 | 0 | 7 | 7 | 7 | 8 | 8 | 10 | 12 | 14 | 16 | 19 | 22 | 25 | 29 | 33 | 37 | 41 | 52 | 63 | 76 | 100 | N/A | N/A | N/A | N/A | N/A 500 | over 10:1 | 0 | 7 | 7 | 8 | 9 | 11 | 14 | 18 | 22 | 25 | 30 | 34 | 38 | 43 | 48 | 53 | 58 | 70 | 82 | 96 | 100 | N/A | N/A | N/A | N/A | N/A 1,000 | Less than 3:1 | 0 | 7 | 7 | 7 | 7 | 7 | 8 | 9 | 9 | 10 | 12 | 13 | 14 | 16 | 18 | 20 | 22 | 27 | 33 | 39 | 58 | 82 | 100 | N/A | N/A | N/A 1,000 | 3:1 to 10:1 | 0 | 7 | 7 | 7 | 7 | 8 | 9 | 10 | 11 | 12 | 14 | 15 | 17 | 19 | 21 | 23 | 26 | 31 | 37 | 43 | 63 | 86 | 100 | N/A | N/A | N/A 1,000 | over 10:1 | 0 | 7 | 7 | 8 | 8 | 9 | 11 | 13 | 16 | 19 | 21 | 24 | 27 | 30 | 33 | 36 | 39 | 46 | 53 | 60 | 82 | 100 | N/A | N/A | N/A | N/A 2,000 | Less than 3:1 | 0 | 7 | 7 | 7 | 7 | 7 | 7 | 8 | 8 | 9 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 17 | 20 | 23 | 33 | 44 | 58 | 74 | 93 | 100 2,000 | 3:1 to 10:1 | 0 | 7 | 7 | 7 | 7 | 7 | 8 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 20 | 23 | 27 | 37 | 49 | 63 | 79 | 97 | 100 2,000 | over 10:1 | 0 | 7 | 7 | 7 | 8 | 8 | 9 | 11 | 12 | 14 | 16 | 18 | 19 | 21 | 23 | 25 | 27 | 32 | 36 | 40 | 53 | 66 | 82 | 99 | 100 | N/A Notes to Table 3.2.3.1.-B: (1) Apply whichever is greater, L = Length of exposing building face H = Height of exposing building face

    Open OBC Div. B Table 3.2.3.1-B. in the code viewer
  • OBC Div. B Table 3.2.3.1-C. Area of Unprotected Openings for Groups E and F, Division 1 and 2 Occupancies, %

    Table 3.2.3.1.-C — Area of Unprotected Openings for Groups E and F, Division 1 and 2 Occupancies, % Forming Part of Article 3.2.3.1. Exposing Building Face, Maximum Area, m² | Ratio (L/H or H/L)[1] | Limiting Distance, 0 m | Limiting Distance, 1.2 m | Limiting Distance, 1.5 m | Limiting Distance, 2 m | Limiting Distance, 2.5 m | Limiting Distance, 3 m | Limiting Distance, 4 m | Limiting Distance, 5 m | Limiting Distance, 6 m | Limiting Distance, 7 m | Limiting Distance, 8 m | Limiting Distance, 9 m | Limiting Distance, 10 m | Limiting Distance, 11 m | Limiting Distance, 12 m | Limiting Distance, 13 m | Limiting Distance, 14 m | Limiting Distance, 16 m | Limiting Distance, 18 m | Limiting Distance, 20 m | Limiting Distance, 25 m | Limiting Distance, 30 m | Limiting Distance, 35 m | Limiting Distance, 40 m | Limiting Distance, 45 m | Limiting Distance, 50 m | Limiting Distance, 55 m | Limiting Distance, 60 m | Limiting Distance, 65 m | Limiting Distance, 70 m 10 | Less than 3:1 | 0 | 4 | 5 | 9 | 15 | 23 | 46 | 77 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 10 | 3:1 to 10:1 | 0 | 4 | 6 | 10 | 17 | 25 | 48 | 79 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 10 | over 10:1 | 0 | 5 | 9 | 16 | 24 | 34 | 58 | 91 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 15 | Less than 3:1 | 0 | 4 | 5 | 7 | 11 | 16 | 32 | 53 | 79 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 15 | 3:1 to 10:1 | 0 | 4 | 5 | 8 | 13 | 18 | 34 | 55 | 82 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 15 | over 10:1 | 0 | 5 | 8 | 13 | 19 | 26 | 43 | 66 | 93 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 20 | Less than 3:1 | 0 | 4 | 4 | 6 | 9 | 13 | 25 | 40 | 61 | 85 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 20 | 3:1 to 10:1 | 0 | 4 | 5 | 7 | 11 | 15 | 27 | 43 | 63 | 87 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 20 | over 10:1 | 0 | 5 | 7 | 11 | 17 | 22 | 36 | 53 | 74 | 99 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 25 | Less than 3:1 | 0 | 4 | 4 | 6 | 8 | 11 | 20 | 33 | 49 | 69 | 92 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 25 | 3:1 to 10:1 | 0 | 4 | 5 | 7 | 9 | 13 | 22 | 35 | 51 | 71 | 94 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 25 | over 10:1 | 0 | 4 | 6 | 10 | 15 | 20 | 31 | 45 | 62 | 82 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 30 | Less than 3:1 | 0 | 4 | 4 | 5 | 7 | 10 | 18 | 28 | 42 | 58 | 77 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 30 | 3:1 to 10:1 | 0 | 4 | 4 | 6 | 9 | 12 | 20 | 30 | 44 | 60 | 80 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 30 | over 10:1 | 0 | 4 | 6 | 10 | 14 | 18 | 28 | 40 | 54 | 71 | 91 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 40 | Less than 3:1 | 0 | 4 | 4 | 5 | 6 | 8 | 14 | 22 | 32 | 44 | 59 | 76 | 94 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 40 | 3:1 to 10:1 | 0 | 4 | 4 | 6 | 8 | 10 | 16 | 24 | 34 | 47 | 61 | 78 | 97 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 40 | over 10:1 | 0 | 4 | 5 | 8 | 12 | 15 | 23 | 33 | 44 | 57 | 72 | 89 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 50 | Less than 3:1 | 0 | 4 | 4 | 5 | 6 | 7 | 12 | 18 | 26 | 36 | 48 | 61 | 76 | 93 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 50 | 3:1 to 10:1 | 0 | 4 | 4 | 5 | 7 | 9 | 14 | 20 | 29 | 38 | 50 | 63 | 79 | 95 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 50 | over 10:1 | 0 | 4 | 5 | 8 | 11 | 14 | 21 | 29 | 38 | 48 | 61 | 74 | 90 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 60 | Less than 3:1 | 0 | 4 | 4 | 4 | 5 | 7 | 11 | 16 | 23 | 31 | 40 | 52 | 64 | 78 | 94 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 60 | 3:1 to 10:1 | 0 | 4 | 4 | 5 | 6 | 8 | 12 | 18 | 25 | 33 | 43 | 54 | 66 | 81 | 96 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 60 | over 10:1 | 0 | 4 | 5 | 7 | 10 | 13 | 19 | 26 | 34 | 43 | 53 | 64 | 77 | 92 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 80 | Less than 3:1 | 0 | 4 | 4 | 4 | 5 | 6 | 9 | 13 | 18 | 24 | 31 | 40 | 49 | 60 | 71 | 84 | 98 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 80 | 3:1 to 10:1 | 0 | 4 | 4 | 5 | 6 | 7 | 10 | 15 | 20 | 26 | 33 | 42 | 51 | 62 | 74 | 86 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 80 | over 10:1 | 0 | 4 | 5 | 6 | 9 | 11 | 16 | 22 | 28 | 35 | 43 | 52 | 62 | 73 | 85 | 98 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 100 | Less than 3:1 | 0 | 4 | 4 | 4 | 5 | 5 | 8 | 11 | 15 | 20 | 26 | 32 | 40 | 48 | 58 | 68 | 79 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 100 | 3:1 to 10:1 | 0 | 4 | 4 | 4 | 5 | 6 | 9 | 13 | 17 | 22 | 28 | 35 | 42 | 51 | 60 | 70 | 81 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 100 | over 10:1 | 0 | 4 | 4 | 6 | 8 | 10 | 14 | 19 | 25 | 31 | 37 | 44 | 52 | 61 | 71 | 81 | 92 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 150 | Less than 3:1 | 0 | 4 | 4 | 4 | 4 | 5 | 6 | 8 | 11 | 14 | 18 | 23 | 28 | 33 | 40 | 46 | 54 | 70 | 89 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 150 | 3:1 to 10:1 | 0 | 4 | 4 | 4 | 5 | 6 | 8 | 10 | 13 | 16 | 20 | 25 | 30 | 36 | 42 | 49 | 56 | 73 | 92 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 150 | over 10:1 | 0 | 4 | 4 | 5 | 7 | 8 | 12 | 16 | 20 | 24 | 29 | 34 | 39 | 46 | 52 | 59 | 67 | 84 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 250 | Less than 3:1 | 0 | 4 | 4 | 4 | 4 | 4 | 5 | 7 | 8 | 10 | 12 | 15 | 18 | 22 | 25 | 29 | 34 | 44 | 55 | 68 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 250 | 3:1 to 10:1 | 0 | 4 | 4 | 4 | 4 | 5 | 6 | 8 | 10 | 12 | 14 | 17 | 20 | 24 | 27 | 32 | 36 | 46 | 57 | 70 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 250 | over 10:1 | 0 | 4 | 4 | 5 | 6 | 7 | 9 | 12 | 15 | 18 | 21 | 25 | 28 | 32 | 37 | 41 | 46 | 56 | 68 | 81 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 350 | Less than 3:1 | 0 | 4 | 4 | 4 | 4 | 4 | 5 | 6 | 7 | 8 | 10 | 12 | 14 | 16 | 19 | 22 | 25 | 32 | 40 | 49 | 77 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 350 | 3:1 to 10:1 | 0 | 4 | 4 | 4 | 4 | 4 | 5 | 7 | 8 | 10 | 12 | 14 | 16 | 18 | 21 | 24 | 27 | 34 | 43 | 52 | 79 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 350 | over 10:1 | 0 | 4 | 4 | 4 | 5 | 6 | 8 | 10 | 13 | 15 | 18 | 21 | 23 | 26 | 30 | 33 | 36 | 44 | 53 | 62 | 90 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 500 | Less than 3:1 | 0 | 4 | 4 | 4 | 4 | 4 | 4 | 5 | 6 | 7 | 8 | 9 | 11 | 13 | 14 | 16 | 19 | 24 | 29 | 36 | 55 | 78 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A 500 | 3:1 to 10:1 | 0 | 4 | 4 | 4 | 4 | 4 | 5 | 6 | 7 | 8 | 9 | 11 | 13 | 14 | 16 | 18 | 21 | 26 | 31 | 38 | 57 | 80 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A 500 | over 10:1 | 0 | 4 | 4 | 4 | 5 | 5 | 7 | 9 | 11 | 13 | 15 | 17 | 19 | 21 | 24 | 26 | 29 | 35 | 41 | 48 | 68 | 92 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A 1,000 | Less than 3:1 | 0 | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 5 | 5 | 6 | 6 | 7 | 8 | 9 | 10 | 11 | 14 | 16 | 20 | 29 | 41 | 55 | 71 | 89 | 100 | N/A | N/A | N/A | N/A 1,000 | 3:1 to 10:1 | 0 | 4 | 4 | 4 | 4 | 4 | 4 | 5 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 15 | 18 | 22 | 31 | 43 | 57 | 73 | 91 | 100 | N/A | N/A | N/A | N/A 1,000 | over 10:1 | 0 | 4 | 4 | 4 | 4 | 5 | 6 | 7 | 8 | 9 | 11 | 12 | 13 | 15 | 16 | 18 | 20 | 23 | 26 | 30 | 41 | 53 | 68 | 84 | 100 | N/A | N/A | N/A | N/A | N/A 2,000 | Less than 3:1 | 0 | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 5 | 5 | 5 | 6 | 6 | 7 | 7 | 9 | 10 | 12 | 16 | 22 | 29 | 37 | 46 | 56 | 68 | 80 | 94 | 100 2,000 | 3:1 to 10:1 | 0 | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 5 | 5 | 5 | 6 | 6 | 7 | 7 | 8 | 9 | 10 | 12 | 13 | 18 | 24 | 31 | 39 | 49 | 59 | 70 | 83 | 96 | 100 2,000 | over 10:1 | 0 | 4 | 4 | 4 | 4 | 4 | 5 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 16 | 18 | 20 | 26 | 33 | 41 | 50 | 59 | 70 | 81 | 94 | 100 | N/A Notes to Table 3.2.3.1.-C: (1) Apply whichever is greater, L = Length of exposing building face H = Height of exposing building face

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  • OBC Div. B Table 3.2.3.1-D. Area of Unprotected Opening for Groups A, B, C, D and F, Division 3 Occupancies, %

    Table 3.2.3.1.-D — Area of Unprotected Opening for Groups A, B, C, D and F, Division 3 Occupancies, % Forming Part of Sentence 3.1.6.9.(5) and Article 3.2.3.1. Exposing Building Face, Maximum Area, m² | Limiting Distance, 0 m | Limiting Distance, 1.2 m | Limiting Distance, 1.5 m | Limiting Distance, 2 m | Limiting Distance, 2.5 m | Limiting Distance, 3 m | Limiting Distance, 4 m | Limiting Distance, 5 m | Limiting Distance, 6 m | Limiting Distance, 7 m | Limiting Distance, 8 m | Limiting Distance, 9 m 10 | 0 | 16 | 24 | 42 | 66 | 100 | N/A | N/A | N/A | N/A | N/A | N/A 15 | 0 | 16 | 20 | 34 | 50 | 74 | 100 | N/A | N/A | N/A | N/A | N/A 20 | 0 | 16 | 20 | 30 | 42 | 60 | 100 | N/A | N/A | N/A | N/A | N/A 25 | 0 | 16 | 18 | 26 | 38 | 52 | 90 | 100 | N/A | N/A | N/A | N/A 30 | 0 | 14 | 18 | 24 | 34 | 46 | 78 | 100 | N/A | N/A | N/A | N/A 40 | 0 | 14 | 16 | 22 | 30 | 40 | 64 | 96 | 100 | N/A | N/A | N/A 50 | 0 | 14 | 16 | 20 | 28 | 36 | 56 | 82 | 100 | N/A | N/A | N/A 60 | 0 | 14 | 16 | 20 | 26 | 32 | 50 | 72 | 98 | 100 | N/A | N/A 80 | 0 | 14 | 16 | 18 | 22 | 28 | 42 | 58 | 80 | 100 | N/A | N/A 100 | 0 | 14 | 16 | 18 | 22 | 26 | 36 | 50 | 68 | 88 | 100 | N/A 150 or more | 0 | 14 | 14 | 16 | 20 | 22 | 30 | 40 | 52 | 66 | 82 | 100

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  • OBC Div. B Table 3.2.3.1-E. Area of Unprotected Opening for Groups E and F, Division 1 and 2 Occupancies, %

    Table 3.2.3.1.-E — Area of Unprotected Opening for Groups E and F, Division 1 and 2 Occupancies, % Forming Part of Sentence 3.1.6.9.(5) and Article 3.2.3.1. Exposing Building Face, Maximum Area, m² | Limiting Distance, 0 m | Limiting Distance, 1.2 m | Limiting Distance, 1.5 m | Limiting Distance, 2 m | Limiting Distance, 2.5 m | Limiting Distance, 3 m | Limiting Distance, 4 m | Limiting Distance, 5 m | Limiting Distance, 6 m | Limiting Distance, 7 m | Limiting Distance, 8 m | Limiting Distance, 9 m | Limiting Distance, 10 m | Limiting Distance, 11 m | Limiting Distance, 12 m | Limiting Distance, 13 m | Limiting Distance, 14 m | Limiting Distance, 15 m 10 | 0 | 8 | 12 | 20 | 34 | 50 | 96 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 15 | 0 | 8 | 10 | 16 | 26 | 36 | 68 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 20 | 0 | 8 | 10 | 14 | 22 | 30 | 54 | 86 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 25 | 0 | 8 | 10 | 14 | 18 | 26 | 44 | 70 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 30 | 0 | 8 | 8 | 12 | 18 | 24 | 40 | 60 | 88 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A 40 | 0 | 8 | 8 | 12 | 16 | 20 | 32 | 48 | 68 | 94 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A 50 | 0 | 8 | 8 | 10 | 14 | 18 | 28 | 40 | 58 | 76 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A 60 | 0 | 8 | 8 | 10 | 12 | 16 | 24 | 36 | 50 | 66 | 86 | 100 | N/A | N/A | N/A | N/A | N/A | N/A 80 | 0 | 8 | 8 | 10 | 12 | 14 | 20 | 30 | 40 | 52 | 66 | 84 | 100 | N/A | N/A | N/A | N/A | N/A 100 | 0 | 8 | 8 | 8 | 10 | 12 | 18 | 26 | 34 | 44 | 56 | 70 | 84 | 100 | N/A | N/A | N/A | N/A 150 | 0 | 8 | 8 | 8 | 10 | 12 | 16 | 20 | 26 | 32 | 40 | 50 | 60 | 72 | 84 | 98 | 100 | N/A 200 or more | 0 | 8 | 8 | 8 | 8 | 10 | 14 | 18 | 22 | 28 | 34 | 42 | 50 | 60 | 68 | 80 | 92 | 100

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Show all 23 articles
  • OBC Div. B 3.2.3.5. 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).

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  • OBC Div. B 3.2.3.10. 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.

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  • OBC Div. B 3.2.3.12. 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 a building that is not sprinklered is permitted to be doubled if the openings are glazed with

    (a)glass block conforming to the requirements of Article 3.1.8.16., or

    (b)wired glass assemblies conforming to MMAH Supplementary Standard SB-2, "Fire Performance Ratings." (See Note A-3.2.3.12.(1)) (See A-2.3.15. of SB-2)

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  • OBC Div. B Table 3.2.3.7. Minimum Construction Requirements for Exposing Building Faces

    Table 3.2.3.7 — Minimum Construction Requirements for Exposing Building Faces Forming Part of Sentences 3.1.6.9.(5) and 3.2.3.7.(1) to (4) Occupancy Classification of Building or Fire Compartment | Maximum Area of Unprotected Openings Permitted, % of Exposing Building Face Area | Minimum Required Fire-Resistance Rating | Type of Construction Required | Type of Cladding Required Group A, B, C, D, or Group F, Division 3 | 0 to 10 | 1 h | Noncombustible | Noncombustible Group A, B, C, D, or Group F, Division 3 | > 10 to 25 | 1 h | Combustible, Encapsulated Mass Timber Construction, or Noncombustible | Noncombustible Group A, B, C, D, or Group F, Division 3 | > 25 to 50 | 45 min | Combustible, Encapsulated Mass Timber Construction, or Noncombustible | Noncombustible Group A, B, C, D, or Group F, Division 3 | > 50 to < 100 | 45 min | Combustible, Encapsulated Mass Timber Construction, or Noncombustible | Combustible or Noncombustible[1][2] Group E, or Group F, Division 1 or 2 | 0 to 10 | 2 h | Noncombustible | Noncombustible Group E, or Group F, Division 1 or 2 | > 10 to 25 | 2 h | Combustible, Encapsulated Mass Timber Construction, or Noncombustible | Noncombustible Group E, or Group F, Division 1 or 2 | > 25 to 50 | 1 h | Combustible, Encapsulated Mass Timber Construction, or Noncombustible | Noncombustible Group E, or Group F, Division 1 or 2 | > 50 to < 100 | 1 h | Combustible, Encapsulated Mass Timber Construction, or Noncombustible | Combustible or Noncombustible Notes to Table 3.2.3.7.: (1) The cladding on Group C buildings within the scope of Article 3.2.2.51. and on Group D buildings within the scope of Article 3.2.2.60. shall be noncombustible or consist of a wall that satisfies the requirements of Article 3.1.4.8. (2) The cladding on buildings or parts thereof conforming to Article 3.2.2.48., 3.2.2.57. or 3.2.2.93. shall conform to Article 3.1.6.9. or be noncombustible.

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  • OBC Div. B 3.2.3.7. Construction of Exposing Building Face

    (1)Except as provided by 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.

    (3)Except as provided in Articles 3.1.4.8. and 3.1.6.9., 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. or 3.1.5.6.

    (4)Except as provided by Articles 3.1.4.8. and 3.1.6.9., 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

    (a)the limiting distance is greater than 5 m,

    (b)the building or fire compartment and all combustible attic or roof spaces are sprinklered throughout,

    (c)the cladding

    (i)conforms to Subsection 9.27.6., 9.27.7., 9.27.8., 9.27.9. or 9.27.10.,

    (ii)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

    (iii)after conditioning in conformance with ASTM D2898, "Standard Practice for 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),

    (d)the cladding

    (i)conforms to Subsection 9.27.12.,

    (ii)is installed with or without furring members over gypsum sheathing at least 12.7 mm thick or over masonry,

    (iii)has a flame-spread rating not greater than 25 when tested in accordance with Sentence 3.1.12.1.(2), and

    (iv)does not exceed 2 mm in thickness exclusive of fasteners, joints and local reinforcements, or (See Note A-3.2.3.7.(4)(d)(iv))

    (e)the exterior wall assembly complies with Article 3.1.5.5. or 3.1.5.6.

    (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).

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  • OBC Div. B 3.2.3.8. 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

    (a)concrete or masonry not less than 25 mm thick, or

    (b)noncombustible material that complies with the criteria for testing and conditions of acceptance stated in Sentence (2) when tested in conformance with CAN/ULC-S101, "Standard Method of 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

    (a)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,

    (b)the exposed surface shall include typical vertical and horizontal joints,

    (c)the test shall be continued for not less than 15 min and the standard time/temperature curve of the referenced standard shall be followed,

    (d)the noncombustible protective material will remain in place and no through openings should develop that are visible when viewed normal to the face of the material, and

    (e)the noncombustible protective material will 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))

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  • OBC Div. B 3.2.3.9. Protection of Structural Members

    (1)Structural members, including beams, columns and arches, 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 3.2.2.93., 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 an 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.

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  • OBC Div. B 3.2.3.6. Combustible Projections

    (1)Except for a building containing one or two 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

    (a)1.2 m of a property line or the centre line of a public way, or

    (b)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 above the exposing building face shall not project to less than 0.45 m from the property line. (See Note A-3.3.4.6.(2))

    (4)The face of a roof soffit is permitted to project to the property line, where it faces a public way. (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 public way, or from an imaginary line between two buildings or fire compartments on the same property, they shall

    (a)have no openings, and

    (b)be protected by

    (i)not less than 0.38 mm thick sheet steel,

    (ii)unvented aluminum conforming to CAN/CGSB-93.2-M, "Prefinished Aluminum Siding, Soffits and Fascia, for Residential Use,"

    (iii)not less than 12.7 mm thick gypsum soffit board or gypsum ceiling board installed according to CSA A82.31-M, "Gypsum Board Application,"

    (iv)not less than 11 mm thick plywood,

    (v)not less than 12.5 mm thick OSB or waferboard, or

    (vi)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.

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  • OBC Div. B 3.2.3.13. 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

    (a)less than 10 m below an opening in the exterior wall of the exit, or

    (b)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 from an 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

    (a)less than 10 m below the exit stair or ramp, or

    (b)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) to (3) shall consist of

    (a)glass block conforming to the requirements of Article 3.1.8.16.,

    (b)a wired glass assembly conforming to MMAH Supplementary Standard SB-2, "Fire Performance Ratings," or

    (c)a closure conforming to the requirements of Subsection 3.1.8. and Articles 3.2.3.1. and 3.2.3.14.

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  • OBC Div. B 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.(5), 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 D₀ where

    D_o = 2D − ((θ)/90 × D)

    but in no case less than 1 m, 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,

    (a)unprotected openings of fire compartments on opposite sides of a firewall, and

    (b)exposure from unprotected openings of a fire compartment that is not protected by an automatic sprinkler system.

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  • OBC Div. B 3.2.3.15. Wall Exposed to Adjoining Roof

    (1)Except as permitted by Sentence 3.2.3.19.(5), 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.

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  • OBC Div. B 3.2.3.16. Protection of Soffits

    (1)Except as permitted by Sentences (3) and (4), where there is a common attic or roof space above more than two suites of residential occupancy or above more than two patients' or residents' sleeping rooms in a Group B, Division 2 or 3 occupancy, and the common attic or roof space projects beyond the exterior wall of the building, the soffit, and any opening in the soffits or other surface of the projection located within 2,500 mm of a window or door opening, shall be protected by

    (a)noncombustible material

    (i)not less than 0.38 mm thick, and

    (ii)having a melting point not below 650°C,

    (b)plywood not less than 11 mm thick,

    (c)strandboard or waferboard not less than 12.5 mm thick, or

    (d)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

    (a)the fire compartments behind the window and door openings are sprinklered in accordance with Article 3.2.5.12., and

    (b)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.

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  • OBC Div. B 3.2.3.17. 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,

    (a)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

    (b)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.

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  • OBC Div. B 3.2.3.19. 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 (4), a walkway connected to a building required to be of noncombustible construction shall also be of noncombustible construction.

    (3)Except as provided in Sentence (4), a walkway connected to a building or part of a building permitted to be of encapsulated mass timber construction shall be of noncombustible construction or encapsulated mass timber construction.

    (4)A walkway connected to a building required to be of noncombustible construction or to a building or part of a building permitted to be of encapsulated mass timber construction is permitted to be of heavy timber construction provided

    (a)not less than 50% of the area of any enclosing perimeter walls is open to the outdoors, and

    (b)the walkway is at ground level.

    (5)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.

    (6)A walkway between buildings shall be not more than 9 m wide

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  • OBC Div. B 3.2.3.20. Underground Walkway

    (1)An underground walkway shall not be designed or used for any purpose other than pedestrian travel unless

    (a)the purpose is permitted, and

    (b)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

    (a)smoke barrier doors shall be installed at intervals of not more than 100 m, or

    (b)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.

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