Appendix D — Division B

Fire-Performance Ratingschange end

Section D-1. General

The content of this Appendix was prepared on the recommendations of the Standing Committee on Fire Safety and Occupancy, which was established by the Canadian Commission on Building and Fire Codes (CCBFC) for this purpose.

D-1.1. Introduction

D-1.1.1. Scope
1) This fire-performance information is presented in a form closely linked to the performance requirements and the minimum materials specifications of the British Columbia Building Code.
2) The ratings have been assigned only after careful consideration of all available literature on assemblies of common building materials, where they are adequately identified by description. The assigned values based on this information will, in most instances, be conservative when compared to the ratings determined on the basis of actual tests on individual assemblies.
3) The fire-performance information set out in this Appendix applies to materials and assemblies of materials which comply in all essential details with the minimum structural design standards described in Part 4 of the British Columbia Building Code. Additional requirements, where appropriate, are described in other Sections of this Appendix.
4) Section D-2 of this Appendix assigns fire-resistance ratings for walls, floors, roofs, columns and beams related to CAN/ULC-S101, “Fire Endurance Tests of Building Construction and Materials,” and describes methods for determining these ratings.
5) Section D-3 assigns flame-spread ratings and smoke developed classifications for surface materials related to CAN/ULC-S102, “Test for Surface Burning Characteristics of Building Materials and Assemblies,” and CAN/ULC-S102.2, “Test for Surface Burning Characteristics of Flooring, Floor Coverings, and Miscellaneous Materials and Assemblies.”
6) Section D-4 describes noncombustibility in building materials when tested in accordance with CAN/ULC-S114, “Test for Determination of Non-Combustibility in Building Materials.”
7) Section D-5 contains requirements for the installation of fire doors and fire dampers in fire-rated stud wall assemblies and the installation of fire stop flaps in fire-rated membrane ceilings.
8) Section D-6 contains background information regarding fire test reports, obsolete materials and assemblies, assessment of archaic assemblies and the development of the component additive method.

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D-1.1.2. Referenced Documents
1) Where documents are referenced in this Appendix, they shall be the editions designated in Table D-1.1.2.
Table D-1.1.2.
Documents Referenced in Appendix D Fire-Performance Ratings
Forming part of Sentence (1)
Issuing Agency Document Number(1) Title of Document(2) Reference
ANSI A208.1-2009 Particleboard Table D-3.1.1.A.
change beginASTM C 330/C 330M-09 Lightweight Aggregates for Structural Concrete D-1.4.3.(2)change end
change beginASTM C 1396/C 1396M-11 Gypsum Board D-1.5.1.
Table D-3.1.1.A.change end
CCBFC NRCC 30629 Supplement to the National Building Code of Canada 1990 D-6.2.
D-6.3.
D-6.4.
CGSB 4-GP-36M-1978 Carpet Underlay, Fiber Type Table D-3.1.1.B.
CGSB CAN/CGSB-4.129-97 Carpets for Commercial Use Table D-3.1.1.B.
CGSB CAN/CGSB-11.3-M87 Hardboard Table D-3.1.1.A.
CGSB CAN/CGSB-92.2-M90 Trowel or Spray Applied Acoustical Material D-2.3.4.(5)
CSA A23.1-09/A23.2-09 Concrete Materials and Methods of Concrete Construction/Test Methods and Standard Practices for Concrete D-1.4.3.(1)
CSA CAN/CSA-A23.3-04 Design of Concrete Structures D-2.1.5.(2)
D-2.6.6.(1)
Table D-2.6.6.B.
D-2.8.2.(1)
Table D-2.8.2.
CSA A82.5-M1978 Structural Clay Non-Load-Bearing Tile Table D-2.6.1.A.
CSA A82.22-M1977 Gypsum Plasters Table D-3.1.1.A.
CSA CAN/CSA-A82.27-M91 Gypsum Board D-1.5.1.
Table D-3.1.1.A.
CSA A82.30-M1980 Interior Furring, Lathing and Gypsum Plastering D-1.7.2.(1)
D-2.3.9.(1)
Table D-2.5.1.
CSA A82.31-M1980 Gypsum Board Application D-2.3.9.(1)
D-2.3.9.(6)
CSA CAN/CSA-A165.1-04 Concrete Block Masonry Units Table D-2.1.1.
CSA O86-09 Engineering Design in Wood D-2.11.2.(1)
D-2.11.2.(2)
CSA O121-08 Douglas Fir Plywood Table D-3.1.1.A.
CSA O141-05 Softwood Lumber D-2.3.6.(2)
Table D-2.4.1.
CSA O151-09 Canadian Softwood Plywood Table D-3.1.1.A.
CSA O153-M1980 Poplar Plywood Table D-3.1.1.A.
CSA CAN/CSA-O325-07 Construction Sheathing D-3.1.1.A.
CSA O437.0-93 OSB and Waferboard Table D-3.1.1.A.
CSA S16-09 Design of Steel Structures D-2.6.6.(1)
D-2.6.6.(3)
Table D-2.6.6.B.
change beginNFPA 80-2010 Fire Doors and Other Opening Protectives D-5.2.1.(1)
D-5.2.1.(2)change end
ULC CAN/ULC-S101-07 Fire Endurance Tests of Building Construction and Materials D-1.1.1.(4)
D-1.12.1.
D-2.3.2.
change beginULC CAN/ULC-S102-10 Test for Surface Burning Characteristics of Building Materials and Assemblies D-1.1.1.(5)change end
change beginULC CAN/ULC-S102.2-10 Test for Surface Burning Characteristics of Flooring, Floor Coverings, and Miscellaneous Materials and Assemblies D-1.1.1.(5)
Table D-3.1.1.B.change end
ULC CAN/ULC-S114-05 Test for Determination of Non-Combustibility in Building Materials D-1.1.1.(6)
D-4.1.1.(1)
D-4.2.1.
ULC ULC-S505-1974 Fusible Links for Fire Protection Service D-5.3.2.
ULC CAN/ULC-S702-09 Mineral Fibre Thermal Insulation for Buildings Table D-2.3.4.A.
Table D-2.3.4.D.
D-2.3.5.(2)
D-2.3.5.(4)
Table D-2.6.1.E.
D-6.4.
change beginULC CAN/ULC-S703-09 Cellulose Fibre Insulation (CFI) for Buildings D-2.3.4.(5)change end
change beginULC CAN/ULC-S706-09 Standard for Wood Fibre Insulating Boards for Buildings Table D-3.1.1.A.change end
Notes to Table D-1.1.2.:
(1) Some documents may have been reaffirmed or reapproved. Check with the applicable issuing agency for up-to-date information.
(2) Some titles have been abridged to omit superfluous wording.

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D-1.1.3. Applicability of Ratings
The ratings shown in this document apply if more specific test values are not available. The construction of an assembly that is the subject of an individual test report must be followed in all essential details if the fire-resistance rating reported is to be applied for use with this Code.
D-1.1.4. Higher Ratings
The authority having jurisdiction may allow higher fire-resistance ratings than those derived from this Appendix, where supporting evidence justifies a higher rating. Additional information is provided in summaries of published test information and the reports of fire tests carried out by the Institute for Research in Construction, National Research Council of Canada, included in Section D-6, Background Information.
D-1.1.5. Additional Information on Fire Rated Assemblies
Assemblies containing materials for which there is no nationally recognized standard are not included in this Appendix. Many such assemblies have been rated by Underwriters Laboratories (UL), Underwriters' Laboratories of Canada (ULC), or Intertek Testing Services NA Ltd. (ITS).

D-1.2. Interpretation of Test Results

D-1.2.1. Limitations
1) The fire-performance ratings set out in this Appendix are based on those that would be obtained from the standard methods of test described in the Code. The test methods are essentially a means of comparing the performance of one building component or assembly with another in relation to its performance in fire.
2) Since it is not practicable to measure the fire resistance of constructions in situ, they must be evaluated under some agreed test conditions. A specified fire-resistance rating is not necessarily the actual time that the assembly would endure in situ in a building fire, but is that which the particular construction must meet under the specified methods of test.
3) Considerations arising from departures in use from the conditions established in the standard test methods may, in some circumstances, have to be taken into account by the designer and the authority having jurisdiction. Some of these conditions are covered at present by the provisions of the British Columbia Building Code.
4) For walls and partitions, the stud spacings previously specified as 16 or 24 inch have been converted to 400 and 600 mm, respectively, for consistency with other metric values; however, the use of equivalent imperial dimensions for stud spacing is permitted.

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D-1.3. Concrete

D-1.3.1. Aggregates in Concrete
Low density aggregate concretes generally exhibit better fire performance than natural stone aggregate concretes. A series of tests on concrete masonry walls, combined with mathematical analysis of the test results, has allowed further distinctions between certain low density aggregates to be made.

D-1.4. Types of Concrete

D-1.4.1. Description
1) For purposes of this Appendix, concretes are described as Types S, N, L, L 1, L2, L40S, L120S or L220S as described in Sentences (2) to (8).
2) Type S concrete is the type in which the coarse aggregate is granite, quartzite, siliceous gravel or other dense materials containing at least 30% quartz, chert or flint.
3) Type N concrete is the type in which the coarse aggregate is cinders, broken brick, blast furnace slag, limestone, calcareous gravel, trap rock, sandstone or similar dense material containing not more than 30% of quartz, chert or flint.
4) Type L concrete is the type in which all the aggregate is expanded slag, expanded clay, expanded shale or pumice.
5) Type L1 concrete is the type in which all the aggregate is expanded shale.
6) Type L2 concrete is the type in which all the aggregate is expanded slag, expanded clay or pumice.
7) Type L40S concrete is the type in which the fine portion of the aggregate is sand and low density aggregate in which the sand does not exceed 40% of the total volume of all aggregates in the concrete.
8) Type L120S and Type L220S concretes are the types in which the fine portion of the aggregate is sand and low density aggregate in which the sand does not exceed 20% of the total volume of all aggregates in the concrete.
D-1.4.2. Determination of Ratings
Where concretes are described as being of Type S, N, L, L1 or L2, the rating applies to the concrete containing the aggregate in the group that provides the least fire resistance. If the nature of an aggregate cannot be determined accurately enough to place it in one of the groups, the aggregate shall be considered as being in the group that requires a greater thickness of concrete for the required fire resistance.
D-1.4.3. Description of Aggregates
1) The descriptions of the aggregates in Type S and Type N concretes apply to the coarse aggregates only. Coarse aggregate for this purpose means that retained on a 5 mm sieve using the method of grading aggregates described in CSA A23.1/A23.2, “Concrete Materials and Methods of Concrete Construction/Test Methods and Standard Practices for Concrete.”
2) Increasing the proportion of sand as fine aggregate in low density concretes requires increased thicknesses of material to produce equivalent fire-resistance ratings. Low density aggregates for Type L and Types L-S concretes used in loadbearing components shall conform to change beginASTM C 330/C 330M, “Lightweight Aggregates for Structural Concrete.”change end
3) Non-loadbearing low density components of vermiculite and perlite concrete, in the absence of other test evidence, shall be rated on the basis of the values shown for Type L concrete.

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D-1.5. Gypsum Wallboard

D-1.5.1. Types of Wallboard
1) Where the term gypsum wallboard is used in this Appendix, it is intended to include, in addition to gypsum wallboard, gypsum backing board and gypsum base for veneer plaster as described in
  1. CAN/CSA-A82.27-M, “Gypsum Board,” or
  2. ASTM C 1396/C 1396M, “Gypsum Board.”
2) Where the term Type X gypsum wallboard is used in this Appendix, it applies to special fire-resistant board as described in
  1. CAN/CSA-A82.27-M, “Gypsum Board,” or
  2. ASTM C 1396/C 1396M, “Gypsum Board.”

D-1.6. Equivalent Thickness

D-1.6.1. Method of Calculating
1) The thickness of solid-unit masonry and concrete described in this Appendix shall be the thickness of solid material in the unit or component thickness. For units that contain cores or voids, the Tables refer to the equivalent thickness determined in conformance with Sentences (2) to (10).
2) Where a plaster finish is used, the equivalent thickness of a wall, floor, column or beam protection shall be equal to the sum of the equivalent thicknesses of the concrete or masonry units and the plaster finish measured at the point that will give the least value of equivalent thickness.
3) Except as provided in Sentence (5), the equivalent thickness of a hollow masonry unit shall be calculated as equal to the actual overall thickness of a unit in millimetres multiplied by a factor equal to the net volume of the unit and divided by its gross volume.
4) Net volume shall be determined using a volume displacement method that is not influenced by the porous nature of the units.
5) Gross volume of a masonry unit shall be equal to the actual length of the unit multiplied by the actual height of the unit multiplied by the actual thickness of the unit.
6) Where all the core spaces in a wall of hollow concrete masonry or hollow-core precast concrete units are filled with grout, mortar, or loose fill materials such as expanded slag, burned clay or shale (rotary kiln process), vermiculite or perlite, the equivalent thickness rating of the wall shall be considered to be the same as that of a wall of solid units, or a solid wall of the same concrete type and the same overall thickness.
7) The equivalent thickness of hollow-core concrete slabs and panels having a uniform thickness and cores of constant cross section throughout their length shall be obtained by dividing the net cross-sectional area of the slab or panel by its width.
8) The equivalent thickness of concrete panels with tapered cross sections shall be the cross section determined at a distance of 2 t or 150 mm, whichever is less, from the point of minimum thickness, where t is the minimum thickness.
9) Except as permitted in Sentence (10), the equivalent thickness of concrete panels with ribbed or undulating surfaces shall be
  1. ta for s less than or equal to 2 t,
  2. t + (4 t/s - 1)(ta - t) for s less than 4 t and greater than 2 t, and
  3. t for s greater than or equal to 4 t
where
t= minimum thickness of panel,
ta= average thickness of panel (unit cross-sectional area divided by unit width), and
s= centre to centre spacing of ribs or undulations.
10) Where the total thickness of a panel described in Sentence (9), exceeds 2 t, only that portion of the panel which is less than 2 t from the non-ribbed surface shall be considered for the purpose of the calculations in Sentence (9).

D-1.7. Contribution of Plaster or Gypsum Wallboard Finish to Fire Resistance of Masonry or Concrete

D-1.7.1. Determination of Contribution
1) Except as provided in Sentences (2), (3), (4) and (5), the contribution of a plaster or gypsum wallboard finish to the fire resistance of a masonry or concrete wall, floor or roof assembly shall be determined by multiplying the actual thickness of the finish by the factor shown in Table D-1.7.1., depending on the type of masonry or concrete to which it is applied. This corrected thickness shall then be included in the equivalent thickness as described in Subsection D-1.6.
Table D-1.7.1.
Multiplying Factors for Masonry or Concrete Construction
Forming part of Sentence (1)
Type of Surface Protection Type of Masonry or Concrete
Solid Clay Brick, Unit Masonry and Monolithic Concrete, Type N or S

Cored Clay Brick, Clay Tile, Monolithic Concrete, Type L40S and Unit Masonry, Type L120S

Concrete Unit Masonry, Type L1 or L220S and Monolithic Concrete, Type L

Concrete Unit Masonry, Type L2

Portland cement-sand plaster or lime sand plaster 1 0.75 0.75 0.50
Gypsum-sand plaster, wood fibred gypsum plaster or gypsum wallboard 1.25 1 1 1
Vermiculite or perlite aggregate plaster 1.75 1.5 1.25 1.25
2) Where a plaster or gypsum wallboard finish is applied to a concrete or masonry wall, the calculated fire-resistance rating of the assembly shall not exceed twice the fire-resistance rating provided by the masonry or concrete because structural collapse may occur before the limiting temperature is reached on the surface of the non-fire-exposed side of the assembly.
3) Where a plaster or gypsum wallboard finish is applied only on the non-fire-exposed side of a hollow clay tile wall, no increase in fire resistance is permitted because structural collapse may occur before the limiting temperature is reached on the surface of the non-fire-exposed side of the assembly.
4) The contribution to fire resistance of a plaster or gypsum wallboard finish applied to the non-fire-exposed side of a monolithic concrete or unit masonry wall shall be determined in conformance with Sentence (1), but shall not exceed 0.5 times the contribution of the concrete or masonry wall.
5) When applied to the fire-exposed side, the contribution of a gypsum lath and plaster or gypsum wallboard finish to the fire resistance of masonry or concrete wall, floor or roof assemblies shall be determined from Table D-2.3.4.A. or D-2.3.4.B.
D-1.7.2. Plaster
1) Gypsum plastering shall conform to CSA A82.30-M, “Interior Furring, Lathing and Gypsum Plastering.”
2) Portland cement-sand plaster shall be applied in 2 coats: the first coat containing 1 part Portland cement to 2 parts sand by volume, and the second coat containing 1 part Portland cement to 3 parts sand by volume.
3) Plaster finish shall be securely bonded to the wall or ceiling.
4) The thickness of plaster finish applied directly to monolithic concrete without metal lath shall not exceed 10 mm on ceilings and 16 mm on walls.
5) Where the thickness of plaster finish on masonry or concrete exceeds 38 mm, wire mesh with 1.57 mm diam wire and openings not exceeding 50 mm by 50 mm shall be embedded midway in the plaster.
D-1.7.3. Attachment of Wallboard and Lath
Gypsum wallboard and gypsum lath finishes applied to masonry or concrete walls shall be secured to wood or steel furring members in conformance with Article D-2.3.9.
D-1.7.4. Sample Calculations
The following examples are included as a guide to the method of calculating the fire resistance of concrete or hollow masonry walls with plaster or gypsum wallboard protection:
Example (1)
A 3 h fire-resistance rating is required for a monolithic concrete wall of Type S aggregate with a 20 mm gypsum-sand plaster finish on metal lath on each face.
  1. The minimum equivalent thickness of Type S monolithic concrete needed to give a 3 h fire-resistance rating = 158 mm (Table D-2.1.1.).
  2. Since the gypsum-sand plaster finish is applied on metal lath, D-1.7.1.(5) does not apply. Therefore, the contribution to the equivalent thickness of the wall of 20 mm gypsum-sand plaster on each face of the concrete is 20 × 1.25 = 25 mm (see D-1.7.1.(1) to (4)).
  3. The total contribution of the plaster finishes is 2 × 25 = 50 mm.
  4. The minimum equivalent thickness of concrete required is 158 mm - 50 mm = 108 mm.
  5. From Table D-2.1.1., the 108 mm equivalent thickness of monolithic concrete gives a contribution of less than 1.5 h. This is less than half the rating of the assembly so that the conditions in D-1.7.1.(2) are not met. Thus the equivalent thickness of monolithic concrete must be increased to 112 mm to give 1.5 h contribution.
  6. The total equivalent thickness of the plaster finishes can then be reduced to 158 mm - 112 mm = 46 mm.
  7. The total actual thickness of the plaster finishes required is therefore 46 mm ÷ 1.25 = 37 mm (D-1.7.1.(1) to (4)) or 18.5 mm on each face.
  8. Since the thickness of the plaster finish on each face exceeds 16 mm, metal lath is still required (D-1.7.2.(4)).
  9. Since this wall is symmetrical with plaster on both faces, the contribution to fire resistance of the plaster finish on either face is limited to one-quarter of the wall rating by virtue of D-1.7.1.(2). Under these circumstances, the conditions in D-1.7.1.(4) are automatically met.
Example (2)
A 2 h fire-resistance rating is required for a hollow masonry wall of Type N concrete with a 12.7 mm Type X gypsum wallboard finish on each face.
  1. Since gypsum wallboard is used, D-1.7.1.(5) applies. The 12.7 mm gypsum wallboard finish on the fire-exposed side is, therefore, assigned 25 min by using Table D-2.3.4.A.
  2. The fire resistance required of the balance of the assembly is 120 min - 25 min = 95 min.
  3. Interpolating between 1.5 h and 2 h in Table D-2.1.1. for 95 min fire resistance, the equivalent thickness for hollow masonry units required is 95 mm + (18 mm × 5/30) = 95 mm + 3 mm = 98 mm.
  4. The contribution to the equivalent thickness of the wall of the 12.7 mm gypsum wallboard finish on the non-fire-exposed side using Table D-1.7.1. = 12.7 × 1.25 = 16 mm.
  5. Equivalent thickness required of concrete masonry unit = 98 - 16 = 82 mm.
  6. The fire-resistance rating of a concrete masonry wall having an equivalent thickness of 82 mm = 1 h for 73 mm + (9 mm × 30/22) = 1 h 12 min.
As this is more than 1 h, the conditions of D-1.7.1.(2) are met and the rating of 2 h is justified.
Example (3)
A 2 h fire-resistance rating is required for a hollow masonry exterior wall of Type L220S concrete with a 15.9 mm Type X gypsum wallboard finish on the non-fire-exposed side only.
  1. According to Table D-2.1.1., the minimum equivalent thickness for Type L220S concrete masonry units needed to achieve a 2 h rating is 94 mm.
  2. Since gypsum wallboard is not used on the fire-exposed side, D-1.7.1.(5) does not apply. The contribution to the equivalent thickness of the wall by the 15.9 mm Type X gypsum wallboard finish applied on the non-fire-exposed side is 15.9 × 1 ≈ 16 mm (see D-1.7.1.(1) and Table D-1.7.1.).
  3. Therefore, the equivalent thickness required of the concrete masonry unit is 94 - 16 = 78 mm.
  4. The contribution to fire resistance of a 78 mm L 220S concrete hollow masonry unit is 85 min. The contribution of the Type X gypsum wallboard finish is 120 - 85 = 35 min, which does not exceed half the 85 min contribution of the masonry unit or 42.5 min, so that the conditions in D-1.7.1.(4) are met.
  5. The rating of the wall (120 min) is less than twice the contribution of the masonry unit (170 min) so that the conditions in D-1.7.1.(2) are also met.

D-1.8. Tests on Floors and Roofs

D-1.8.1. Exposure to Fire
All tests relate to the performance of a floor assembly or floor-ceiling or roof-ceiling assembly above a fire. It has been assumed on the basis of experience that fire on top will take a longer time to penetrate the floor than one below, and that the fire resistance in such a situation will be at least equal to that obtained from below in the standard test.

D-1.9. Moisture Content

D-1.9.1. Effect of Moisture
1) The moisture content of building materials at the time of fire test may have a significant influence on the measured fire resistance. In general, an increase in the moisture content should result in an increase in the fire resistance, though in some materials the presence of moisture may produce disruptive effects and early collapse of the assembly.
2) Moisture content is now controlled in standard fire test methods and is generally recorded in the test reports. In earlier tests, moisture content was not always properly determined.

D-1.10. Permanence and Durability

D-1.10.1. Test Conditions
The ratings in this Appendix relate to tested assemblies and do not take into account possible changes or deterioration in use of the materials. The standard fire test measures the fire resistance of a sample building assembly erected for the test. No judgment as to the permanence or durability of the assembly is made in the test.

D-1.11. Steel Structural Members

D-1.11.1. Thermal Protection
Since the ability of a steel structural member to sustain the loading for which it was designed may be impaired because of elevated temperatures, measures shall be taken to provide thermal protection. The fire-resistance ratings, as established by the provisions of this Appendix, indicate the time periods during which the effects of heat on protected steel structural members are considered to be within acceptable limits.

D-1.12. Restraint Effects

D-1.12.1. Effect on Fire-Resistance Ratings
In fire tests of floors, roofs and beams, it is necessary to state whether the rating applies to a thermally restrained or thermally unrestrained assembly. Edge restraint of a floor or roof, structural continuity, or end restraint of a beam can significantly extend the time before collapse in a standard test. A restrained condition is one in which expansion or rotation at the supports of a load-carrying element resulting from the effects of fire is resisted by forces or moments external to the element. An unrestrained condition is one in which the load-carrying element is free to thermally expand and rotate at its supports.
Whether an assembly or structural member can be considered thermally restrained or thermally unrestrained depends on the type of construction and location in a building. Guidance on this subject can be found in Appendix A1 of CAN/ULC-S101, “Fire Endurance Tests of Building Construction and Materials.” Different acceptance criteria also apply to thermally unrestrained and thermally restrained assemblies. These are described in CAN/ULC-S101.
The ratings for floors, roofs, and beams in this Appendix meet the conditions of CAN/ULC-S101, “Fire Endurance Tests of Building Construction and Materials,” for thermally unrestrained specimens. In a thermally restrained condition, the structural element or assembly would probably have greater fire resistance, but the extent of this increase can be determined only by reference to behavior in a standard test.
 

Section D-2. Fire-Resistance Ratings

D-2.1. Masonry and Concrete Walls

D-2.1.1. Minimum Equivalent Thickness for Fire-Resistance Rating
The minimum thicknesses of unit masonry and monolithic concrete walls are shown in Table D-2.1.1. Hollow masonry units and hollow-core concrete panels shall be rated on the basis of equivalent thickness as described in Subsection D-1.6.
Table D-2.1.1.
Minimum Equivalent Thicknesses(1) of Unit Masonry and Monolithic Concrete Walls Loadbearing and Non-Loadbearing, mm
Forming part of Article D-2.1.1.
Type of Wall Fire-Resistance Rating
30 min 45 min 1 h 1.5 h 2 h 3 h 4 h
Solid brick units (80% solid and over), actual overall thickness 63 76 90 108 128 152 178
Cored brick units and hollow tile units (less than 80% solid), equivalent thickness 50 60 72 86 102 122 142
Solid and hollow concrete masonry units, equivalent thickness              
Type S or N concrete(2) 44 59 73 95 113 142 167
Type L120S concrete 42 54 66 87 102 129 152
Type L1 concrete 42 54 64 82 97 122 143
Type L220S concrete 42 54 64 81 94 116 134
Type L2 concrete 42 54 63 79 91 111 127
Monolithic concrete and concrete panels, equivalent thickness              
Type S concrete 60 77 90 112 130 158 180
Type N concrete 59 74 87 108 124 150 171
Type L40S or Type L concrete 49 62 72 89 103 124 140
Notes to Table D-2.1.1.:
(1) See definition of equivalent thickness in Subsection D-1.6.
(2) Hollow concrete masonry units made with Type S or N concrete shall have a minimum compressive strength of 15 MPa based on net area, as defined in CAN/CSA-A165.1, “Concrete Block Masonry Units.”
D-2.1.2. Applicability of Ratings
1) Ratings obtained as described in Article D-2.1.1. apply to either loadbearing or non-loadbearing walls, except for walls described in Sentences (2) to (6).
2) Ratings for walls with a thickness less than the minimum thickness prescribed for loadbearing walls in this Code apply to non-loadbearing walls only.
3) Masonry cavity walls (consisting of 2 wythes of masonry with an air space between) that are loaded to a maximum allowable compressive stress of 380 kPa have a fire resistance at least as great as that of a solid wall of a thickness equal to the sum of the equivalent thicknesses of the 2 wythes.
4) Masonry cavity walls that are loaded to a compressive stress exceeding 380 kPa are not considered to be within the scope of this Appendix.
5) A masonry wall consisting of 2 types of masonry units, either bonded together or in the form of a cavity wall, shall be considered to have a fire-resistance rating equal to that which would apply if the whole of the wall were of the material that gives the lesser rating.
6) A non-loadbearing cavity wall made up of 2 precast concrete panels with an air space or insulation in the cavity between them shall be considered to have a fire-resistance rating as great as that of a solid wall of a thickness equal to the sum of the thicknesses of the 2 panels.
D-2.1.3. Framed Beams and Joists
Beams and joists that are framed into a masonry or concrete fire separation shall not reduce the thickness of the fire separation to less than the equivalent thickness required for the fire separation.
D-2.1.4. Credit for Plaster Thickness
On monolithic walls and walls of unit masonry, the full plaster finish on one or both faces multiplied by the factor shown in Table D-1.7.1. shall be included in the wall thickness shown in Table D-2.1.1., under the conditions and using the methods described in Subsection D-1.7.
D-2.1.5. Walls Exposed to Fire on Both Sides
1) Except as permitted in Sentence (2), portions of loadbearing reinforced concrete walls, which do not form a complete fire separation and thus may be exposed to fire on both sides simultaneously, shall have minimum dimensions and minimum cover to steel reinforcement in conformance with Articles D-2.8.2. to D-2.8.5.
2) A concrete wall exposed to fire from both sides as described in Sentence (1) has a fire-resistance rating of 2 h if the following conditions are met:
  1. its equivalent thickness is not less than 200 mm,
  2. its aspect ratio (width/thickness) is not less than 4.0,
  3. the minimum thickness of concrete cover over the steel reinforcement specified in Clause (d) is not less than 50 mm,
  4. each face of the wall is reinforced with both vertical and horizontal steel reinforcement in conformance with either Clause 10 or Clause 14 of CAN/CSA-A23.3, “Design of Concrete Structures,”
  5. the structural design of the wall is governed by the minimum eccentricity (15 + 0.03h) specified in Clause 10.15.3.1 of CAN/CSA-A23.3, “Design of Concrete Structures,” and
  6. the effective length of the wall, klu, is not more than 3.7 m
    where
    k= effective length factor obtained from CAN/CSA-A23.3, “Design of Concrete Structures,”
    lu= unsupported length of the wall in metres.

D-2.2. Reinforced and Prestressed Concrete Floor and Roof Slabs

D-2.2.1. Assignment of Rating
1) Floors and roofs in a fire test are assigned a fire-resistance rating which relates to the time that an average temperature rise of 140°C or a maximum temperature rise of 180 °C at any location is recorded on the unexposed side, or the time required for collapse to occur, whichever is the lesser. The thickness of concrete shown in Table D-2.2.1.A. shall be required to resist the transfer of heat during the fire resistance period shown.
Table D-2.2.1.A.
Minimum Thickness of Reinforced and Prestressed Concrete Floor or Roof Slabs, mm
Forming part of Sentence (1)
Type of Concrete Fire-Resistance Rating
30 min 45 min 1 h 1.5 h 2 h 3 h 4 h
Type S concrete 60 77 90 112 130 158 180
Type N concrete 59 74 87 108 124 150 171
Type L40S or Type L concrete 49 62 72 89 103 124 140
2) The concrete cover over the reinforcement and steel tendons shown in Table D-2.2.1.B. shall be required to maintain the integrity of the structure and prevent collapse during the same period.
Table D-2.2.1.B.
Minimum Concrete Cover over Reinforcement in Concrete Slabs, mm
Forming part of Sentence (2)
Type of Concrete Fire-Resistance Rating
30 min 45 min 1 h 1.5 h 2 h 3 h 4 h
Type S, N, L40S or L concrete 20 20 20 20 25 32 39
Prestressed concrete slabs Type S, N, L40S or L concrete 20 25 25 32 39 50 64
D-2.2.2. Floors with Hollow Units
The fire resistance of floors containing hollow units may be determined on the basis of equivalent thickness as described in Subsection D-1.6.
D-2.2.3. Composite Slabs
1) For composite concrete floor and roof slabs consisting of one layer of Type S or N concrete and another layer of Type L40S or L concrete in which the minimum thickness of both the top and bottom layers is not less than 25 mm, the combined fire-resistance rating may be determined using the following expressions:
  1. when the base layer consists of Type S or N concrete,
  2. when the base layer consists of Type L40S or L concrete,
    where
    R= fire resistance of slab, h,
    t= total thickness of slab, mm, and
    d= thickness of base layer, mm.
2) If the base course described in Sentence (1) is covered by a top layer of material other than Type S, N, L40S or L concrete, the top course thickness may be converted to an equivalent concrete thickness by multiplying the actual thickness by the appropriate factor listed in Table D-2.2.3.A. This equivalent concrete thickness may be added to the thickness of the base course and the fire-resistance rating calculated using Table D-2.2.1.A.
3) The minimum concrete cover under the main reinforcement for composite concrete floor and roof slabs with base slabs less than 100 mm thick shall conform to Table D-2.2.3.B. For base slabs 100 mm or more thick, the minimum cover thickness requirements of Table D-2.2.1.B. shall apply.
4) Where the top layer of a 2-layer slab is less than 25 mm thick, the fire-resistance rating for the slab shall be calculated as though the entire slab were made up of the type of concrete with the lesser fire resistance.
Table D-2.2.3.A.
Multiplying Factors for Equivalent Thickness
Forming part of Sentence (2)
Top Course Material Base Slab Normal Density Concrete
(Type S or N)		 Base Slab Low Density Concrete
(Type L40S or L)
Gypsum wallboard 3 2.25

Cellular concrete (mass density 400 – 560 kg/m3 )

2 1.50
Vermiculite and perlite concrete (mass density 560 kg/m3 or less) 1.75 1.50
Portland cement with sand aggregate 1 0.75
Terrazzo 1 0.75
Table D-2.2.3.B.
Minimum Concrete Cover under Bottom Reinforcement in Composite Concrete Slabs, mm
Forming part of Sentence (3)
Base Slab Concrete Type Fire-Resistance Rating
30 min 45 min 1 h 1.5 h 2 h 3 h 4 h
Reinforced concrete              
Type S, N, L40S or L 15 15 20 25 30 40 55
Prestressed concrete              
Type S 20 25 30 40 50 65 75
Type N 20 20 25 35 45 60 70
Type L40S or L 20 20 25 30 40 50 60
D-2.2.4. Contribution of Plaster Finish
1) The contribution of plaster finish securely fastened to the underside of concrete may be taken into account in floor or roof slabs under the conditions and using the methods described in Subsection D-1.7.
2) Plaster finish on the underside of concrete floors or roofs may be used in lieu of concrete cover referred to in D-2.2.1.(2) under the conditions and using the methods described in Subsection D-1.7.
D-2.2.5. Concrete Cover
1) In prestressed concrete slab construction, the concrete cover over an individual tendon shall be the minimum thickness of concrete between the surface of the tendon and the fire-exposed surface of the slab, except that for ungrouted ducts the assumed cover thickness shall be the minimum thickness of concrete between the surface of the duct and the bottom of the slab. For slabs in which several tendons are used, the cover is assumed to be the average of those of individual tendons, except that the cover for any individual tendon shall be not less than half of the value given in Table D-2.2.1.B. nor less than 20 mm.
2) Except as provided in Sentence (3), in post-tensioned prestressed concrete slabs, the concrete cover to the tendon at the anchor shall be not less than 15 mm greater than the minimum cover required by Sentence (1). The minimum concrete cover to the anchorage bearing plate and to the end of the tendon, if it projects beyond the bearing plate, shall be 20 mm.
3) The requirements of Sentence (2) do not apply to those portions of slabs not likely to be exposed to fire, such as the ends and tops.
D-2.2.6. Minimum Dimensions for Cover
Minimum dimensions and cover to steel tendons of prestressed concrete beams shall conform to Subsection D-2.10.

D-2.3. Wood and Steel Framed Walls, Floors and Roofs

D-2.3.1. Maximum Fire-Resistance Rating
The fire-resistance rating of walls constructed of wood studs or light gauge steel studs, floors constructed of wood joists or open web steel joists, and roofs constructed of wood joists, pre-manufactured wood trusses or open web steel joists, can be determined for ratings up to 90 min from the information in Subsection D-2.3.
D-2.3.2. Loadbearing Conditions
1) The ratings derived from the information in Subsection D-2.3. apply to both loadbearing and non-loadbearing wood framed walls, to non-loadbearing steel framed walls and to loadbearing floors and roofs.
2) Loadbearing conditions shall be as defined in CAN/ULC-S101, “Fire Endurance Tests of Building Construction and Materials.”
D-2.3.3. Limitations of Component Additive Method
(See D-6., Background Information.)
1) The fire-resistance rating of a framed assembly depends primarily on the time during which the membrane on the fire-exposed side remains in place.
2) The assigned times in D-2.3.4.(2), (3) and (4) are not intended to be construed as the fire-resistance ratings of the individual components of an assembly. These assigned times are the individual contributions to the overall fire-resistance rating of the complete assembly.
3) Wallboard membranes are permitted to be installed in multiple layers only as listed in Table D-2.3.4.A. (double 12.7 mm Type X gypsum wallboard).
D-2.3.4. Method of Calculation
1) The fire-resistance rating of a framed assembly may be calculated by adding the time assigned in Sentence (2) for the membrane on the fire-exposed side plus the time assigned in Sentence (3) for the framing members plus the time assigned in Sentence (4) for additional protective measures such as the inclusion of insulation or the reinforcement of a membrane.
2) The times which have been assigned to membranes on the fire-exposed side of the assembly, based on their ability to remain in place during fire tests, are listed in Tables D-2.3.4.A. and D-2.3.4.B. (This is not to be confused with the fire-resistance rating of the membrane, which also takes into account the rise in temperature on the unexposed side of the membrane. [See D-2.3.3.(2).])
Table D-2.3.4.A.
Time Assigned to Wallboard Membranes on Fire-Exposed Side
Forming part of Article D-2.3.4.
Description of Finish Time, min
11.0 mm Douglas Fir plywood phenolic bonded

10(1)
14.0 mm Douglas Fir plywood phenolic bonded

15(1)
12.7 mm Type X gypsum wallboard 25
15.9 mm Type X gypsum wallboard 40
Double 12.7 mm Type X gypsum wallboard

80(2)
Notes to Table D-2.3.4.A.:
(1) Non-loadbearing walls only, stud cavities filled with mineral wool conforming to CAN/ULC-S702, “Mineral Fibre Thermal Insulation for Buildings,” and having a mass of not less than 2 kg/m2, with no additional credit for insulation according to Table D-2.3.4.D.
(2) Applies to non-loadbearing steel framed walls only.
Table D-2.3.4.B.
Time Assigned for Contribution of Lath and Plaster Protection on Fire-Exposed Side, min(1)
Forming part of Article D-2.3.4.
Type of Lath Plaster Thickness, mm Type of Plaster Finish

Portland Cement and Sand(2) or Lime and Sand

Gypsum and Sand or Gypsum Wood Fibred Gypsum and Perlite or Gypsum and Vermiculite
9.5 mm gypsum 13 — 35 55
16 — 40 65
19 — 50

80(1)
Metal 19 20 50

80(1)
23 25 65

80(1)
26 30 80

80(1)
Notes to Table D-2.3.4.B.:
(1) Values shown for these membranes have been limited to 80 min because the fire-resistance ratings of framed assemblies derived from these Tables shall not exceed 1.5 h.
(2) For mixture of Portland cement-sand plaster, see D-1.7.2.(2).
3) When the membrane on the fire-exposed side of a framed assembly falls off, there is a brief period before structural failure occurs during which the studs or joists are exposed directly to flame. Table D-2.3.4.C. lists the times which have been assigned to the framing members based on the time involved between failure of the membrane and collapse of the assembly.
Table D-2.3.4.C.
Time Assigned for Contribution of Wood or Light Steel Frame
Forming part of Article D-2.3.4.
Description of Frame Time Assigned to Frame, min

Wood studs 400 mm o.c. maximum

20

Wood studs 600 mm o.c. maximum

15

Steel studs 400 mm o.c. maximum

10

Wood floor and wood roof joists 400 mm o.c. maximum

 10

Open web steel joist floors and roofs with ceiling supports 400 mm o.c. maximum

10

Wood roof and wood floor truss assemblies 600 mm o.c. maximum

5
4) Preformed insulation of glass, rock or slag fibre provides additional protection to wood studs by shielding the studs from exposure to the fire and thus delaying the time of collapse. The use of reinforcement in the membrane exposed to fire also adds to the fire resistance by extending the time to failure. Table D-2.3.4.D. shows the time increments that may be added to the fire resistance if these features are incorporated in the assembly.
Table D-2.3.4.D.
Time Assigned for Additional Protection
Forming part of Article D-2.3.4.
Description of Additional Protection Time Assigned, min

Add to the fire-resistance rating of wood stud walls, sheathed with gypsum wallboard or lath and plaster, if the spaces between the studs are filled with preformed insulation of rock or slag fibres conforming to CAN/ULC-S702, “Mineral Fibre Thermal Insulation for Buildings,” and with a mass of not less than 1.22 kg/m2 of wall surface(1)

 15

Add to the fire-resistance rating of non-loadbearing wood stud walls, sheathed with gypsum wallboard or lath and plaster, if the spaces between the studs are filled with preformed insulation of glass fibres conforming to CAN/ULC-S702, “Mineral Fibre Thermal Insulation for Buildings,” and having a mass of not less than 0.6 kg/m2 of wall surface

5

Add to the fire-resistance rating of plaster on gypsum lath ceilings if 0.76 mm diam wire mesh with 25 mm by 25 mm openings or 1.57 mm diam diagonal wire reinforcing at 250 mm o.c. is placed between lath and plaster

30

Add to the fire-resistance rating of plaster on gypsum lath ceilings if 76 mm wide metal lath strips are placed over joints between lath and plaster

 10

Add to the fire-resistance rating of plaster on 9.5 mm thick gypsum lath ceilings (Table D-2.3.4.B.) if supports for lath are 300 mm o.c.

10
Notes to Table D-2.3.4.D.:
(1) There are no test data to justify the 15 min additional protection for preformed glass fibre insulation.
5) Cellulose fibre insulation conforming to CAN/ULC-S703, “Cellulose Fibre Insulation (CFI) for Buildings,” applied in conformance with CAN/CGSB-92.2-M, “Trowel or Spray Applied Acoustical Material,” does not affect the fire-resistance rating of a steel stud wall assembly, provided that it is sprayed to either face of the wall cavity.
D-2.3.5. Considerations for Various Types of Assemblies
1) Interior vertical fire separations shall be rated for exposure to fire on each side, and a membrane shall be provided on both sides of the assembly. In the calculation of the fire-resistance rating of such an assembly, however, no contribution to fire resistance can be assigned for a membrane on the non-fire-exposed side, since this membrane may fail when the structural members fail.
2) When an exterior wall assembly is required to be rated from the interior side only, such wall assemblies shall have an outer membrane consisting of sheathing and exterior cladding with spaces between the studs filled with insulation conforming to CAN/ULC-S702, “Mineral Fibre Thermal Insulation for Buildings,” and having a mass of not less than 1.22 kg/m2 of wall surface.
3) In the case of a floor or roof, the standard test provides only for testing for fire exposure from below. Floor or roof assemblies of wood, light-gauge steel members or open-web steel joist framing shall have an upper membrane consisting of a subfloor and finish floor conforming to Table D-2.3.5. or any other membrane that has a contribution to fire resistance of not less than 15 min in Table D-2.3.4.A. For the purposes of this requirement, it is not necessary to comply with note (1) to Table D-2.3.4.A.
Table D-2.3.5.
Flooring or Roofing Membranes for Wood, Cold Formed Steel Members or Open-Web Steel Joists
Forming part of Article D-2.3.5.
Type of Assembly Structural Members Subfloor or Roof Deck Finish Flooring or Roofing
Floor Wood or steel joists and wood trusses

12.5 mm plywood or
17 mm T & G softwood

Hardwood or softwood flooring on building paper
Resilient flooring, parquet floor, felted synthetic fibre floor coverings, carpeting, or ceramic tile on 8 mm thick panel-type underlay
Ceramic tile on 30 mm mortar bed
Steel joists

50 mm reinforced concrete or
50 mm concrete on metal lath or
formed steel sheet, or
40 mm reinforced gypsum-fibre concrete on 12.7 mm gypsum wallboard

Finish flooring
Roof Wood or steel joists and wood trusses

12.5 mm plywood or
17 mm T & G softwood

Finish roofing material with or without insulation
Steel joists

50 mm reinforced concrete or 50 mm concrete on metal lath or formed steel sheet, or 40 mm reinforced gypsum-fibre concrete on 12.7 mm gypsum wallboard

Finish roofing material with or without insulation
4) Insulation used in the cavities of a wood floor assembly will not reduce the assigned fire-resistance rating of the assembly provided:
  1. the insulation is preformed of rock, slag or glass fibre conforming to CAN/ULC-S702, “Mineral Fibre Thermal Insulation for Buildings,” and having a mass of not more than 1.1 kg/m2 and is installed adjacent to the bottom edge of the framing member, directly above steel furring channels,
  2. the gypsum wallboard ceiling membrane is attached to
    1. wood trusses in conformance with D-2.3.9.(2) by way of steel drywall furring channels spaced not more than 400 mm o.c., and the channels are secured to each bottom truss member with a double strand of 1.2 mm galvanized steel wire, or
    2. wood joists by way of drywall or resilient steel furring channels spaced not more than 400 mm o.c. in conformance with D-2.3.9.(2) and (3), and
  3. a steel furring channel is installed midway between each furring channel mentioned in Clause (b) to provide additional support for the insulation.
D-2.3.6. Framing Members
1) The values shown in Tables D-2.3.4.A., D-2.3.4.B. and D-2.3.12. apply to membranes supported on framing members installed in their conventional orientation and spaced in conformance with Table D-2.3.4.C.
2) Wood studs and wood roof and floor framing members are assumed to be not less than 38 mm by 89 mm. Wood trusses are assumed to consist of wood chord and web framing members and connector plates fabricated from not less than 1 mm thick galvanized steel with projecting teeth not less than 8 mm long. Dimensions for dressed lumber are given in CSA O141, “Softwood Lumber.”
3) The allowable spans for wood joists listed in Part 9 of Division B of this Code are provided for floors supporting specific occupancies.
4) Except as otherwise required in this Appendix, metal studs shall be of galvanized steel not less than 0.5 mm thick, not less than 63 mm wide and with a flange width of not less than 31 mm.
5) Metal studs in walls required to have a fire-resistance rating shall be installed with not less than 12 mm clearance between the top of the stud and the top of the runner to allow for expansion in the event of fire. Where attachment of the studs is necessary for alignment purposes during erection, such attachment shall be made to the bottom runners only.
6) Except as required in D-2.3.5.(4), resilient or drywall furring channels may be used to attach a gypsum wallboard ceiling membrane to a floor or roof assembly. The channels must be of galvanized steel not less than 0.5 mm thick, placed at a spacing of not more than 600 mm o.c. perpendicular to the framing members, with an overlap of not less than 100 mm at splices and a minimum end clearance between the channels and walls of 15 mm.
D-2.3.7. Plaster Finish
The thickness of plaster finish shall be measured from the face of gypsum or metal lath.
D-2.3.8. Edge Support for Wallboard
Gypsum wallboard installed over framing or furring shall be installed so that all edges are supported, except that 15.9 mm Type X gypsum wallboard may be installed horizontally with the horizontal joints unsupported when framing members are at 400 mm o.c. maximum.
D-2.3.9. Membrane Fastening
1) Except as provided in Sentences (2) to (6), the application of lath and plaster finish shall conform to CSA A82.30-M, “Interior Furring, Lathing and Gypsum Plastering,” and gypsum wallboard finish shall conform to CSA A82.31-M, “Gypsum Board Application.”
2) Where a membrane referred to in Tables D-2.3.4.A., D-2.3.4.B. and D-2.3.12. is applied to steel framing or furring, fasteners shall penetrate not less than 10 mm through the metal.
3) Except as provided in Sentences (4) and (5) where a membrane referred to in Tables D-2.3.4.A., D-2.3.4.B. and D-2.3.12. is applied to wood framing or furring, minimum fastener penetrations into wood members shall conform to Table D-2.3.9. for the time assigned to the membrane.
Table D-2.3.9.
Minimum Fastener Penetrations for Membrane Protection on Wood Frame, mm
Forming part of Article D-2.3.9.
Type of Membrane

Assigned Contribution of Membrane to Fire Resistance(1), min

5 – 25 30 – 35 40 50 55 – 70 80
Single layer 20 29 32 — — —
Double layer 20 20 20 29 35 44
Gypsum lath 20 20 23 23 29 29
Notes to Table D-2.3.9.:
(1) Assigned contributions of membranes to fire resistance are determined in Tables D-2.3.4.A., D-2.3.4.B. and D-2.3.12.
4) Where a membrane is applied in 2 layers, the fastener penetrations described in Table D-2.3.9. shall apply to the base layer. Fasteners for the face layer shall penetrate not less than 20 mm into wood supports.
5) Where adhesives are used to attach the face layer of gypsum wallboard in a double layer application for walls, the top and bottom of the face layer shall be secured to the supports by mechanical fasteners having lengths as required in Sentences (2) and (4) and spaced not more than 150 mm o.c. for wood supports and not more than 200 mm o.c. for steel supports.
6) In a double layer application of gypsum wallboard on wood supports, fastener spacing shall conform to CSA A82.31-M, “Gypsum Board Application.”
D-2.3.10. Ceiling Membrane Openings – Combustible Construction
1) Except as permitted in Article D-2.3.12., where a floor or roof assembly of combustible construction is assigned a fire-resistance rating on the basis of Subsection D-2.3. and incorporates a ceiling membrane described in Table D-2.3.4.A. or D-2.3.4.B., the ceiling membrane may be penetrated by openings leading to ducts within concealed spaces above the membrane provided:
  1. the assembly is not required to have a fire-resistance rating in excess of 1 h,
  2. the area of any openings does not exceed 930 cm2 (see Sentence (2)),
  3. the aggregate area of openings does not exceed 1% of the ceiling area of the fire compartment,
  4. the depth of the concealed space above the ceiling is not less than 230 mm,
  5. no dimension of any opening exceeds 310 mm,
  6. supports are provided for openings with any dimension exceeding 150 mm where framing members are spaced greater than 400 mm o.c.,
  7. individual openings are spaced not less than 2 m apart,
  8. the ducts above the membrane are sheet steel and are supported by steel strapping firmly attached to the framing members, and
  9. the clearance between the top surface of the membrane and the bottom surface of the ducts is not less than 100 mm.
2) Where an individual opening permitted in Sentence (1) exceeds 130 cm2 in area, it shall be protected by
  1. a fire stop flap conforming to Subsection D-5.3., or
  2. thermal protection above the duct consisting of the same materials as used for the ceiling membrane, mechanically fastened to the ductwork and extending 200 mm beyond the opening on all sides (see Article D-2.3.10.A-A).
Figure D-2.3.10.A-A
Thermal protection above a duct
D-2.3.11. Ceiling Membrane Openings – Noncombustible Construction
1) Except as permitted in Article D-2.3.12., where a floor or roof assembly of noncombustible construction is assigned a fire-resistance rating on the basis of Subsection D-2.3. and incorporates a ceiling membrane described in Table D-2.3.4.A. or D-2.3.4.B., the ceiling membrane may be penetrated by openings leading to ducts located within concealed spaces provided:
  1. the area of any opening does not exceed 930 cm2 (see Sentence (2)),
  2. the aggregate area of openings does not exceed 2% of the ceiling area of the fire compartment,
  3. no dimension of any opening exceeds 400 mm,
  4. individual openings are spaced not less than 2 m apart,
  5. openings are located not less than 200 mm from major structural members such as beams, columns or joists,
  6. the ducts above the membrane are sheet steel and are supported by steel strapping firmly attached to the framing members, and
  7. the clearance between the top surface of the membrane and the bottom surface of the duct is not less than 100 mm.
2) Where an individual opening permitted in Sentence (1) exceeds 130 cm2 in area, it shall be protected by
  1. a fire stop flap conforming to Subsection D-5.3., or
  2. thermal protection above the duct consisting of the same materials as used for the ceiling membrane, mechanically fastened to the ductwork and extending 200 mm beyond the opening on all sides (see Article D-2.3.10.A-A).
D-2.3.12. Ceiling Membrane Rating
Where the fire-resistance rating of a ceiling assembly is to be determined on the basis of the membrane only and not of the complete assembly, the ratings may be determined from Table D-2.3.12., provided no openings are located within the ceiling membrane.
Table D-2.3.12.
Fire-Resistance Rating for Ceiling Membranes
Forming part of Article D-2.3.12.
Description of Membrane Fire-Resistance Rating, min
15.9 mm Type X gypsum wallboard with ≥ 75 mm mineral wool batt insulation above wallboard 30

19 mm gypsum-sand plaster on metal lath

30
Double 14.0 mm Douglas Fir plywood phenolic bonded 30

Double 12.7 mm Type X gypsum wallboard

 45

25 mm gypsum-sand plaster on metal lath

45

Double 15.9 mm Type X gypsum wallboard

 60

32 mm gypsum-sand plaster on metal lath

60
D-2.3.13. Beams
1) Where a beam is included with an open-web steel joist or similar construction and is protected by the same continuous ceiling, the beam is assumed to have a fire-resistance rating equal to that assigned to the rest of the assembly.
2) The ratings in this Appendix assume that the construction to which the beam is related is a normal one and does not carry unusual loads from the floor or slab above.
D-2.3.14. Wired Glass Assembly Support
1) Openings in a vertical fire separation having a fire-resistance rating of not more than 1 h are allowed to be protected by wired glass assemblies, provided the wired glass is
  1. not less than 6 mm thick;
  2. reinforced by a steel wire mesh in the form of diamonds, squares or hexagons having dimensions of
    1. approximately 25 mm across the flats, using wire of not less than 0.45 mm diam, or
    2. approximately 13 mm across the flats, using wire of not less than 0.40 mm diam, the wire to be centrally embedded during manufacture and welded or intertwined at each intersection;
  3. set in fixed steel frames with metal not less than 1.35 mm thick and providing a glazing stop of not less than 20 mm on each side of the glass; and
  4. limited in area so that
    1. individual panes are not more than 0.84 m2, with neither height nor width more than 1.4 m, and
    2. the area not structurally supported by mullions is not more than 7.5 m2.
2) It is intended that the structural mullions referred to in Subclause (1)(d)(ii) will not distort or be displaced to the extent that there would be a failure of the wired glass closure during the period for which a closure in the fire separation would be expected to function. Hollow structural steel tubing not less than 100 mm square filled with a Portland cement-based grout will satisfy the intent of the Subclause.

D-2.4. Solid Wood Walls, Floors and Roofs

D-2.4.1. Minimum Thickness
The minimum thickness of solid wood walls, floors and roofs for fire-resistance ratings from 30 min to 1.5 h is shown in Table D-2.4.1.
Table D-2.4.1.
Minimum Thickness of Solid Wood Walls, Roofs and Floors, mm(1)(2)
Forming part of Article D-2.4.1.
Type of Construction Fire-Resistance Rating
30 min 45 min 1 h 1.5 h

Solid wood floor with building paper and finish flooring on top(3)

 89 114 165 235
Solid wood, splined or tongued and grooved floor with building paper and finish flooring on top(4) 64 76 — —

Solid wood walls of loadbearing vertical plank(3)

 89 114 140 184

Solid wood walls of non-loadbearing horizontal plank(3)

 89 89 89 140
Notes to Table D-2.4.1.:
(1) See CSA O141, “Softwood Lumber,” for sizes.
(2) The fire-resistance ratings and minimum dimensions for floors also apply to solid wood roof decks of comparable thickness with finish roofing material.
(3) The assembly shall consist of 38 mm thick members on edge fastened together with 101 mm common wire nails spaced not more than 400 mm o.c. and staggered in the direction of the grain.
(4) The floor shall consist of 64 mm by 184 mm wide planks either tongued and grooved or with 19 mm by 38 mm splines set in grooves and fastened together with 88 mm common nails spaced not more than 400 mm o.c.
D-2.4.2. Increased Fire-Resistance Rating
1) The fire-resistance rating of the assemblies described in Table D-2.4.1. may be increased by 15 min if one of the following finishes is applied on the fire-exposed side:
  1. 12.7 mm thick gypsum wallboard,
  2. 20 mm thick gypsum-sand plaster on metal lath, or
  3. 13 mm thick gypsum-sand plaster on 9.5 mm gypsum lath.
2) Fastening of the plaster to the wood structure shall conform to Subsection D-2.3.
D-2.4.3. Supplementary Ratings
Supplementary ratings based on tests are included in Table D-2.4.3. The ratings given shall apply to constructions that conform in all details with the descriptions given.
Table D-2.4.3.
Fire-Resistance Rating of Non-Loadbearing Built-up Solid Wood Partitions(1)
Forming part of Article D-2.4.3.
Construction Details Actual Overall Thickness, mm Fire-Resistance Rating
Solid panels of wood boards 64 mm to 140 mm wide grooved and joined with wood splines, nailed together, boards placed vertically with staggered joints, 3 boards thick 58 30 min
Solid panels with 4 mm plywood facings(2) glued to 46 mm solid wood core of glued, tongued and grooved construction for both sides and ends of core pieces with tongued and grooved rails in the core about 760 mm apart 54 1 h
Notes to Table D-2.4.3.:
(1) The ratings and notes are taken from “Fire Resistance Classifications of Building Constructions,” Building Materials and Structures Report BMS 92, National Bureau of Standards, Washington, 1942.
(2) Ratings for plywood faced panel are based on phenolic resin glue being used for gluing facings to wood frames. If other types of glue are used for this purpose, the ratings apply if the facings are nailed to the frames in addition to being glued.

D-2.5. Solid Plaster Partitions

D-2.5.1. Minimum Thickness
The minimum thickness of solid plaster partitions for fire-resistance ratings from 30 min to 4 h is shown in Table D-2.5.1.
Table D-2.5.1.
Minimum Thickness of Non-Loadbearing Solid Plaster Partitions, mm
Forming part of Article D-2.5.1.

Type of Plaster on Metal Lath(1)

 Fire-Resistance Rating
30 min 45 min 1 h 1.5 h 2 h 3 h 4 h
Portland cement-sand(2) or Portland cement-lime-sand

50(3)

 — — — — — —
Gypsum-sand

50(3)

50(3)

 64 — — — —
Gypsum-vermiculite, gypsum-perlite, Portland cement-vermiculite or Portland cement-perlite

50(3)

50(3)

50(3)

 58 64 83 102
Notes to Table D-2.5.1.:
(1) Metal lath shall be expanded metal lath or welded woven wire fabric supported on 19 mm vertical light steel studs spaced not more than 600 mm o.c. Plaster shall be applied to both sides of the lath.
(2) For mixture of Portland cement-sand plaster, see D-1.7.2.(2).
(3) CSA A82.30-M, “Interior Furring, Lathing and Gypsum Plastering,” does not permit solid plaster partitions less than 50 mm thick.

D-2.6. Protected Steel Columns

D-2.6.1. Minimum Thickness of Protective Covering
The minimum thickness of protective covering to steel columns is shown in Tables D-2.6.1.A. to D-2.6.1.F. for fire-resistance ratings from 30 min to 4 h.
Table D-2.6.1.A.
Minimum Thickness of Concrete or Masonry Protection to Steel Columns, mm
Forming part of Article D-2.6.1.
Description of Cover Fire-Resistance Rating
30 min 45 min 1 h 1.5 h 2 h 3 h 4 h
Monolithic concrete              
Type S concrete(1) (column spaces filled)(2) 25 25 25 25 39 64 89
Type N or L concrete(1) (column spaces filled)(2) 25 25 25 25 32 50 77

Concrete masonry units(3) or precast reinforced concrete units

             
Type S concrete (column spaces not filled) 50 50 50 50 64 89 115
Type N or L concrete (column spaces not filled) 50 50 50 50 50 77 102

Clay or shale brick(4) (column spaces filled)(2)

 50 50 50 50 50 64 77

Clay or shale brick(4) (column spaces not filled)

50 50 50 50 50 77 102

Hollow clay tile(5) (column spaces filled)(2)

50(6)

50(6)

50(6)

50(6)

(7)

(7)

(7)

Hollow clay tile(5) (column spaces not filled)

50(6)

50(6)

50(6)

 — — — —
Notes to Table D-2.6.1.A.:
(1) Applies to cast-in-place concrete reinforced with 5.21 mm diam wire wrapped around column spirally 200 mm o.c., or 1.57 mm diam wire mesh with 100 mm by 100 mm openings.
(2) The space between the protective covering and the web or flange of the column shall be filled with concrete, cement mortar or a mixture of cement mortar and broken bricks.
(3) Concrete masonry shall be reinforced with 5.21 mm diam wire or wire mesh with 1.19 mm diam wire and 10 mm by 10 mm openings, laid in every second course.
(4) Brick cover 77 mm thick or less shall be reinforced with 2.34 mm diam wire or 1.19 mm diam wire mesh with 10 mm by 10 mm openings, laid in every second course.
(5) Hollow clay tiles and masonry mortar shall be reinforced with 1.19 mm diam wire mesh with 10 mm by 10 mm openings, laid in every horizontal joint and lapped at corners.
(6) Hollow clay tiles shall conform to CSA A82.5-M, “Structural Clay Non-Load-Bearing Tile.”
(7) 50 mm nominal hollow clay tile, reinforced with 1.19 mm diam wire mesh with 10 mm by 10 mm openings laid in every horizontal joint and covered with 19 mm gypsum-sand plaster and with limestone concrete fill in column spaces, has a 4 h fire-resistance rating.
Table D-2.6.1.B.
Minimum Thickness of Plaster Protection to Steel Columns, mm
Forming part of Article D-2.6.1.
Description

Fire-Resistance Rating(1)(2)
30 min 45 min 1 h 1.5 h 2 h 3 h 4 h
Gypsum-sand plaster on 9.5 mm gypsum lath(3) 13 13 13 20 — — —
Gypsum-perlite or vermiculite plaster on 9.5 mm gypsum lath(3) 13 13 13 20 25 — —
Gypsum perlite or vermiculite plaster on 12.7 mm gypsum lath(3) 13 13 13 20 25 32 50
Gypsum perlite or vermiculite plaster on double 12.7 mm gypsum lath(3) 13 13 13 20 25 25 32
Portland cement-sand plaster on metal lath(4)(5) 25 25 25 — — — —
Notes to Table D-2.6.1.B.:
(1) Fire-resistance ratings of 30 min and 45 min apply to columns whose M/D ratio is 30 or greater. Fire-resistance ratings greater than 45 min apply to columns whose M/D ratio is greater than 60. Where the M/D ratio is between 30 and 60 and the required fire-resistance rating is greater than 45 min, the total thickness of protection specified in the Table shall be increased by 50%. (To determine M/D, refer to Article D-2.6.4.)
(2) Where the thickness of plaster over gypsum lath is 25 mm or more, wire mesh with 1.57 mm diam wire and openings not exceeding 50 mm by 50 mm shall be placed midway in the plaster.
(3) Lath held in place by 1.19 mm diam wire wrapped around lath 450 mm o.c.
(4) Expanded metal lath 1.36 kg/m 2 fastened to 9.5 mm by 19 mm steel channels held in vertical position around column by 1.19 mm diam wire ties.
(5) For mixture of Portland cement-sand plaster, see D-1.7.2.(2).
Table D-2.6.1.C.
Minimum Thickness of Gypsum-Sand Plaster on Metal Lath Protection to Steel Columns, mm
Forming part of Article D-2.6.1.

M/D(1)

 Fire-Resistance Rating
30 min 45 min 1 h 1.5 h 2 h 3 h
30 to 60 16 16 32 — — —
over 60 to 90 16 16 16 32 — —
over 90 to 120 16 16 16 25 39 —
over 120 to 180 16 16 16 16 25 —
over 180 16 16 16 16 25 39
Notes to Table D-2.6.1.C.:
(1) To determine the M/D ratio, refer to Article D-2.6.4.
Table D-2.6.1.D.
Minimum Thickness of Gypsum-Perlite or Gypsum-Vermiculite Plaster on Metal Lath Protection to Steel Columns, mm
Forming part of Article D-2.6.1.

M/D(1)

 Fire-Resistance Rating
30 min 45 min 1 h 1.5 h 2 h 3 h 4 h
30 to 60 16 16 20 32 35 — —
over 60 to 90 16 16 16 20 26 35 45
over 90 to 120 16 16 16 16 26 35 45
over 120 to 180 16 16 16 16 20 32 35
over 180 16 16 16 16 16 26 35
Notes to Table D-2.6.1.D.:
(1) To determine the M/D ratio, refer to Article D-2.6.4.
Table D-2.6.1.E.
Steel Columns with Sheet-Steel Membrane and Insulation as Shown in Figures D-2.6.1-A. and D-2.6.1-B.
Forming part of Article D-2.6.1.
Type of Protection

Steel Thickness,(1) mm

Fastening(2)

 Insulation Fire-Resistance Rating
See Figure D-2.6.1.-A 0.51

No. 8 sheet-metal screws 9.5 mm long, 200 mm o.c.

50 mm mineral wool batts(3)

 45 min
See Figure D-2.6.1.-B 0.64

Self-threading screws or No. 8 sheet-metal screws, 600 mm o.c.

2 layers 12.7 mm gypsum wallboard 1.5 h
See Figure D-2.6.1.-A 0.64

No. 8 sheet-metal screws, 9.5 mm long 200 mm o.c.

75 mm mineral wool batts,(3) 12.7 mm gypsum wallboard

2 h
See Figure D-2.6.1.-B 0.76

Crimped joint or No. 8 sheet-metal screws, 300 mm o.c.

2 layers 15.9 mm gypsum wallboard

2 h
Notes to Table D-2.6.1.E.:
(1) Minimum thickness, galvanized or wiped-zinc-coated sheet-steel.
(2) Sheet-steel shall be securely fastened to the floor and superstructure, or where sheet-steel cover does not extend floor to floor, fire stopping shall be provided at the level where sheet-steel protection ends. In the latter case, an alternate type of fire protection shall be applied between the fire stopping and the superstructure.
(3) Conforming to CAN/ULC-S702, “Mineral Fibre Thermal Insulation for Buildings,” Type 1A, minimum density 30 kg/m3: column section and batts wrapped with 25 mm mesh chicken wire.
Table D-2.6.1.F.
Minimum M/D Ratio for Steel Columns Covered with Type X Gypsum Wallboard Protection(1)
Forming part of Article D-2.6.1.

Minimum Thickness of Type X Gypsum Wallboard Protection,(2) mm

Fire-Resistance Rating
1 h 1.5 h 2 h 3 h
12.7 75 — — —
15.9 55 — — —
25.4 35 60 — —
28.6 35 50 — —
31.8 35 40 75 —
38.1 35 35 55 —
41.3 35 35 45 —
44.5 35 35 35 —
47.6 35 35 35 —
50.8 35 35 35 75
63.5 35 35 35 45
Notes to Table D-2.6.1.F.:
(1) To determine the M/D ratio, refer to Article D-2.6.4.
(2) See Article D-2.6.5.
Figure D-2.6.1.-A
Column protected by sheet-steel membrane and mineral-wool insulation
Figure D-2.6.1.-B
Column protected by sheet-steel membrane and gypsum wallboard
D-2.6.2. Hollow Unit Masonry Columns
For hollow-unit masonry column protection, the thickness shown in Tables D-2.6.1.A. to D-2.6.1.D. is the equivalent thickness as described in Subsection D-1.6.
D-2.6.3. Effect of Plaster
The effect on fire-resistance ratings of the addition of plaster to masonry and monolithic concrete column protection is described in Subsection D-1.7.
D-2.6.4. Determination of M/D Ratio
1) The ratio M/D to which reference is made in Tables D-2.6.1.B., D-2.6.1.C., D-2.6.1.D. and D-2.6.1.F. shall be found by dividing “M,” the mass of the column in kilograms per metre by “D,” the heated perimeter of the steel column section in metres.
2) The heated perimeter “D” of steel columns, shown as the dashed line in Figure D-2.6.4.-A, shall be equal to 2 (B+H) in Examples (1) and (2), and 3.14B in Example (3). In Figure D-2.6.4.-B, the heated perimeter “D” shall be equal to 2 (B+H).
Figure D-2.6.4.-A
Example (1), standard or wide-flange beam; Example (2), hollow structural section (rectangular or square); Example (3), hollow structural section (round)
Figure D-2.6.4.-B
Columns protected by Type X gypsum wallboard without sheet-steel membrane
D-2.6.5. Attachment of Gypsum Wallboard
1) Where Type X gypsum wallboard is used to protect a steel column without an outside sheet-steel membrane, the method of wallboard attachment to the column shall be as shown in Figure D-2.6.4.-B and shall meet the construction details described in Sentences (2) to (7).
2) The Type X gypsum wallboard shall be applied vertically without horizontal joints.
3) The first layer of wallboard shall be attached to steel studs with screws spaced not more than 600 mm o.c. and other layers of wallboard shall be attached to steel studs and steel corner beads with screws spaced at a maximum of 300 mm o.c. Where a single layer of wallboard is used, attachment screws shall be spaced not more than 300 mm o.c.
4) Steel tie wires spaced at a maximum of 600 mm o.c. shall be used to secure the second last layer of wallboard in 3- and 4-layer systems.
5) Studs shall be fabricated of galvanized steel not less than 0.53 mm thick and not less than 41.3 mm wide, with legs not less than 33.3 mm long and shall be 12.7 mm less than the assembly height.
6) Corner beads shall
  1. be fabricated of galvanized steel that is not less than 0.41 mm thick,
  2. have legs not less than 31 mm long,
  3. be attached to the wallboard or stud with 25.4 mm screws spaced not more than 300 mm o.c., and
  4. have the attaching fasteners penetrate either another corner bead in multiple layer assemblies or the steel stud member.
7) In a 4-layer system, metal angles shall be fabricated of galvanized steel and shall be not less than 0.46 mm thick with legs not less than 51 mm long.
D-2.6.6. Concrete Filled Hollow Steel Columns
1) A fire-resistance rating, R, is permitted to be assigned to concentrically loaded hollow steel columns that are filled with plain concrete, steel-fibre reinforced concrete or bar-reinforced concrete, that are fabricated and erected within the tolerances stipulated in CSA S16, “Design of Steel Structures,” and that comply with Sentences (2) and (3), provided:
where
C= axial compressive force due to dead and live loads without load factors, kN,
Cmax=
but shall not exceed where
C'r= factored compressive resistance of the concrete core in accordance with CSA S16, “Design of Steel Structures,”
where
a= constant obtained from Table D-2.6.6.A.,
f'c= specified compressive strength of concrete in accordance with CAN/CSA-A23.3, “Design of Concrete Structures,” MPa,
D= outside diameter of a round column or outside width of a square column, mm,
R= specified fire-resistance rating, min, and
KL= effective length of column as defined in CSA S16, “Design of Steel Structures,” mm,
subject to the validity limits stated in Table D-2.6.6.B.
2) A pair of steam vent holes shall be provided at each end of the hollow steel column and at each intermediate floor level, and the holes shall be
  1. not less than 13 mm in diameter,
  2. located on opposite faces, 150 mm above or below a base plate, cap plate or concrete slab,
  3. orientated so that adjacent pairs are perpendicular, and
  4. not obstructed by other building elements.
3) Load application and reaction shall be through end bearing in accordance with CSA S16, “Design of Steel Structures.”
Table D-2.6.6.A.
Values of Constant “a”
Forming part of Article D-2.6.6.
Filling Type

Concrete Type(1)

 Steel Reinforcement Circular Columns Square Columns
PC S n/a 0.070 0.060
FC S ≈ 2% 0.075 0.065
RC S 1.5%-3% 0.080 0.070
RC S 3%-5% 0.085 0.075
PC N n/a 0.080 0.070
FC N ≈ 2% 0.085 0.075
RC N 1.5%-3% 0.090 0.080
RC N 3%-5% 0.095 0.085
Notes to Table D-2.6.6.A.:
(1) See Subsection D-1.4., Types of Concrete.
Table D-2.6.6.B.
Validity Limits
Forming part of Article D-2.6.6.
Parameter Type of Concrete Filling
PC FC RC

fc' (MPa)

20 to 40 20 to 55 20 to 55
D (round) (mm) 140 to 410 140 to 410 165 to 410
D (square) (mm) 140 to 305 102 to 305 175 to 305
Reinforcement (%) n/a ≈ 2% of the concrete mix by mass

1.5% to 5% of cross-sectional area(1)
Concrete Cover (mm) n/a n/a ≥ 25
R (min) ≤ 120 ≤ 180 ≤ 180
KL (mm) 2 000 to 4 000 2 000 to 4 500 2 000 to 4 500

Class(2)

 1, 2 or 3 1, 2 or 3 1, 2 or 3
Notes to Table D-2.6.6.B.:
(1) Limits on size, number and spacing of bars and ties in accordance with CAN/CSA-A23.3, “Design of Concrete Structures.”
(2) Classification of sections in accordance with CSA S16, “Design of Steel Structures.”

D-2.7. Individually Protected Steel Beams

D-2.7.1. Minimum Thickness of Protective Covering
The minimum thickness of protective covering on steel beams exposed to fire on 3 sides for fire-resistance ratings from 30 min to 4 h is shown in Table D-2.7.1.
Table D-2.7.1.
Minimum Thickness of Cover to Individual Protected Steel Beams, mm(1)
Forming part of Article D-2.7.1.
Description of Cover Fire-Resistance Rating
30 min 45 min 1 h 1.5 h 2 h 3 h 4 h

Type S concrete(2) (beam spaces filled solid)

25 25 25 25 32 50 64

Type N or L concrete(2) (beam spaces filled solid)

25 25 25 25 25 39 50

Gypsum-sand plaster on 9.5 mm gypsum lath(3)

 13 13 13 20 — — —
Gypsum-perlite or vermiculite plaster on 9.5 mm gypsum lath(3) 13 13 13 13 25 — —
Gypsum-perlite or gypsum-vermiculite on 12.7 mm gypsum lath(3) 13 13 13 20 25 39 50
Gypsum-perlite or vermiculite plaster on double 12.7 mm gypsum lath(3) 13 13 13 20 25 25 39

Portland cement-sand on metal lath(4)

 23 23 23 — — — —
Gypsum-sand on metal lath(4) (plaster in contact with lower flange) 16 20 25 39 — — —
Gypsum-sand on metal lath with air gap between plaster and lower flange(4) 16 16 16 25 25 — —

Gypsum-perlite or gypsum-vermiculite on metal lath(4)

 16 16 16 23 23 35

48(5)
Notes to Table D-2.7.1.:
(1) Where the thickness of plaster finish applied over gypsum lath is 26 mm or more, the plaster shall be reinforced with wire mesh with 1.57 mm diam wire and 50 mm by 50 mm openings placed midway in the plaster.
(2) Applies to cast-in-place concrete reinforced by 5.21 mm diam wire spaced 200 mm o.c. or 1.57 mm diam wire mesh with 100 mm by 100 mm openings.
(3) Lath held in place by 1.18 mm diam wire wrapped around the gypsum lath 450 mm o.c.
(4) Expanded metal lath 1.63 kg/m2 fastened to 9.5 mm by 19 mm steel channels held in position by 1.19 mm diam wire.
(5) Plaster finish shall be reinforced with wire mesh with 1.57 mm diam wire and 50 mm by 50 mm openings placed midway in the plaster.
D-2.7.2. Types of Concrete
Concrete is referred to as Type S, N or L, depending on the nature of the aggregate used. This is described in Article D-1.4.1.
D-2.7.3. Effect of Plaster
The effect on fire-resistance ratings of the addition of plaster finish to concrete or masonry beam protection is described in Article D-1.7.1.
D-2.7.4. Exceptions
The fire resistance of protected steel beams depends on the means used to hold the protection in place. Because of the importance of this factor, no rating has been assigned in Table D-2.7.1. to masonry units used as protective cover to steel beams. These ratings, however, may be determined on the basis of comparison with column protection at the discretion of the authority having jurisdiction, if satisfactory means of fastening are provided.
D-2.7.5. Beam Protected by a Membrane
A steel beam or steel joist assembly that is entirely above a horizontal ceiling membrane will be protected from fire below the membrane and will resist structural collapse for a period equal to the fire-resistance rating determined in conformance with Subsection D-2.3. The support for this membrane shall be equivalent to that described in Subsection D-2.3. The rating on this basis shall not exceed 1.5 h.

D-2.8. Reinforced Concrete Columns

D-2.8.1. Minimum Dimensions
Minimum dimensions for reinforced concrete columns and minimum concrete cover for vertical steel reinforcement are obtained from Article D-2.8.2. to D-2.8.5., taking into account the type of concrete, the effective length of the column and the area of the vertical reinforcement.
D-2.8.2. Method
1) The minimum dimension, t, in millimetres, of a rectangular reinforced concrete column shall be equal to
  1. 75 f (R + 1) for all Types L and L40S concrete,
  2. 80 f (R + 1) for Type S concrete when the design condition of the concrete column is defined in the second and fourth columns of Table D-2.8.2.,
  3. 80 f (R + 0.75) for Type N concrete when the design condition of the concrete column is defined in the second and fourth columns of Table D-2.8.2., and
  4. 100 f (R + 1) for Types S and N concrete when the design condition of the concrete column is defined in the third column of Table D-2.8.2.
    where
    f= the value shown in Table D-2.8.2.,
    R= the required fire-resistance rating in hours,
    k= the effective length factor obtained from CAN/CSA-A23.3, “Design of Concrete Structures,”
    h= the unsupported length of the column in metres, and
    p= the area of vertical reinforcement in the column as a percentage of the column area.
2) The diameter of a round column shall be not less than 1.2 times the value t determined in Sentence (1) for a rectangular column.
Table D-2.8.2.
Values of Factor f(1)
Forming part of Article D-2.8.2.

Overdesign Factor(2)

Values of Factor f to be Used in Applying Article D-2.8.2.
Where kh is not more than 3.7 m

Where kh is more than 3.7 m but not more than 7.3 m

t is not more than 300 mm,
p is not more than 3%(3)

All other cases(4)
1.00 1.0 1.2 1.0
1.25 0.9 1.1 0.9
1.50 0.83 1.0 0.83
Notes to Table D-2.8.2.:
(1) For conditions that do not fall within the limits described in Table D-2.8.2., further information may be obtained from Reference (7) in Subsection D-6.1.
(2) Overdesign factor is the ratio of the calculated load carrying capacity of the column to the column strength required to carry the specified loads determined in conformance with CAN/CSA-A23.3, “Design of Concrete Structures.”
(3) Where the factor f results in a t greater than 300 mm, the appropriate factor f for “All other cases” shall be applicable.
(4) Where p is equal to or less than 3% and the factor f results in a t less than 300 mm, the minimum thickness shall be 300 mm.
D-2.8.3. Minimum Thickness of Concrete Cover
1) Where the required fire-resistance rating of a concrete column is 3 h or less, the minimum thickness in millimetres of concrete cover over vertical steel reinforcement shall be equal to 25 times the number of hours of fire resistance required or 50 mm, whichever is less.
2) Where the required fire-resistance rating of a concrete column is greater than 3 h, the minimum thickness in millimetres of concrete cover over vertical steel reinforcement shall be equal to 50 plus 12.5 times the required number of hours of fire resistance in excess of 3 h.
3) Where the concrete cover over vertical steel required in Sentence (2) exceeds 62.5 mm, wire mesh reinforcement with 1.57 mm diameter wire and 100 mm openings shall be incorporated midway in the concrete cover to retain the concrete in position.
D-2.8.4. Minimum Requirements
The structural design standards may require minimum column dimensions or concrete cover over vertical steel reinforcement differing from those obtained in D-2.8.2.(1) and D-2.8.2.(2). Where a difference occurs, the greater dimension shall govern.
D-2.8.5. Addition of Plaster
The addition of plaster finish to the concrete column may be taken into account in determining the cover over vertical steel reinforcement by applying the multiplying factors described in Subsection D-1.7. The addition of plaster shall not, however, justify any decrease in the minimum column sizes shown.
D-2.8.6. Built-in Columns
The fire-resistance rating of a reinforced concrete column that is built into a masonry or concrete wall so that not more than one face may be exposed to the possibility of fire at one time may be determined on the basis of cover to vertical reinforcing steel alone. In order to meet this condition, the wall shall conform to Subsection D-2.1. for the fire-resistance rating required.

D-2.9. Reinforced Concrete Beams

D-2.9.1. Minimum Cover Thickness
The minimum thickness of cover over principal steel reinforcement in reinforced concrete beams is shown in Table D-2.9.1. for fire-resistance ratings from 30 min to 4 h where the width of the beam or joist is at least 100 mm.
Table D-2.9.1.
Minimum Cover to Principal Steel Reinforcement in Reinforced Concrete Beams, mm
Forming part of Article D-2.9.1.
Type of Concrete Fire-Resistance Rating
30 min 45 min 1 h 1.5 h 2 h 3 h 4 h
Type S, N or L 20 20 20 25 25 39 50
D-2.9.2. Maximum Rating
No rating over 2 h may be assigned on the basis of Table D-2.9.1. to a beam or joist where the average width of the part that projects below the slab is less than 140 mm, and no rating over 3 h may be assigned where the average width of the part that projects below the slab is less than 165 mm.
D-2.9.3. Beam Integrated in Floor or Roof Slab
For the purposes of these ratings, a beam may be either independent of or integral with a floor or roof slab assembly.
D-2.9.4. Minimum Thickness
Where the upper extension or top flange of a joist or T-beam in a floor assembly contributes wholly or partly to the thickness of the slab above, the total thickness at any point shall be not less than the minimum thickness described in Table D-2.2.1.A. for the fire-resistance rating required.
D-2.9.5. Effect of Plaster
The addition of plaster finish to a reinforced concrete beam may be taken into account in determining the cover over principal reinforcing steel by applying the multiplying factors described in Subsection D-1.7.

D-2.10. Prestressed Concrete Beams

D-2.10.1. Minimum Cross-Sectional Area and Thickness of Cover
The minimum cross-sectional area and thickness of concrete cover over steel tendons in prestressed concrete beams for fire-resistance ratings from 30 min to 4 h are shown in Table D-2.10.1.
Table D-2.10.1.
Minimum Thickness of Concrete Cover over Steel Tendons in Prestressed Concrete Beams, mm(1)
Forming part of Article D-2.10.1.
Type of Concrete

Area of Beam, cm2

 Fire-Resistance Rating
30 min 45 min 1 h 1.5 h 2 h 3 h 4 h
Type S or N 260 to 970 25 39 50 64 — — —
Over 970 to 1 940 25 26 39 45 64 — —
Over 1 940 25 26 39 39 50 77 102
Type L Over 970 25 25 25 39 50 77 102
Notes to Table D-2.10.1.:
(1) Where the thickness of concrete cover over the tendons exceeds 64 mm, a wire mesh reinforcement with 1.57 mm diam wire and 100 mm by 100 mm openings shall be incorporated in the beams to retain the concrete in position around the tendons. The mesh reinforcement shall be located midway in the cover.
D-2.10.2. Minimum Cover Thickness
The cover for an individual tendon shall be the minimum thickness of concrete between the surface of the tendon and the fire-exposed surface of the beam, except that for ungrouted ducts the assumed cover thickness shall be the minimum thickness of concrete between the surface of the duct and the surface of the beam. For beams in which several tendons are used, the cover is assumed to be the average of the minimum cover of the individual tendons. The cover for any individual tendon shall be not less than half the value given in Table D-2.10.1. nor less than 25 mm.
D-2.10.3. Applicability of Ratings
The ratings in Table D-2.10.1. apply to a beam that is either independent of or integral with a floor or roof slab assembly. Minimum thickness of slab and minimum cover to steel tendons in prestressed concrete slabs are contained in Subsection D-2.2.
D-2.10.4. Effect of Plaster
The addition of plaster finish to a prestressed concrete beam may be taken into account in determining the cover over steel tendons by applying the multiplying factors described in Subsection D-1.7.
D-2.10.5. Minimum Cover
1) Except as provided in Sentence (2), in unbonded post-tensioned prestressed concrete beams, the concrete cover to the tendon at the anchor shall be not less than 15 mm greater than the minimum required away from the anchor. The concrete cover to the anchorage bearing plate and to the end of the tendon, if it projects beyond the bearing plate, shall be not less than 25 mm.
2) The requirements in Sentence (1) do not apply to those portions of beams not likely to be exposed to fire (such as the ends and the tops of flanges of beams immediately below slabs).

D-2.11. Glued-Laminated Timber Beams and Columns

D-2.11.1. Applicability of Information
The information in Subsection D-2.11. applies to glued-laminated timber beams and columns required to have fire-resistance ratings greater than those afforded under the provisions of Article 3.1.4.6. of this Code.
D-2.11.2. Method of Calculation
1) The fire-resistance rating of glued-laminated timber beams and columns in minutes shall be equal to
  1. 0.1 fB [4 − 2(B/D)] for beams that may be exposed to fire on 4 sides,
  2. 0.1 fB [4 − (B/D)] for beams that may be exposed to fire on 3 sides,
  3. 0.1 fB [3 − (B/D)] for columns that may be exposed to fire on 4 sides, and
  4. 0.1 fB [3 − (B/2D)] for columns that may be exposed to fire on 3 sides,
    where
    f= the load factor shown in Figure D-2.11.2.-A,
    B= the full dimension of the smaller side of a beam or column in millimetres before exposure to fire [see Figure D-2.11.2.-B],
    D= the full dimension of the larger side of a beam or column in millimetres before exposure to fire [see Figure D-2.11.2.-B],
    k= the effective length factor obtained from CSA O86, “Engineering Design in Wood,”
    L= the unsupported length of a column in millimetres.
2) The factored resistance of a beam or column shall be determined by using the specified strengths in CSA O86, “Engineering Design in Wood.”
Figure D-2.11.2.-A
Factors to compensate for partially loaded columns and beams
Notes to Figure D-2.11.2.-A:
(1)
See D-2.11.2.(2).
Figure D-2.11.2.-B
Full dimensions of glued-laminated beams and columns
Notes to Figure D-2.11.2.-B:
(1)
See D-2.11.2.(2).
(1)See D-2.11.2.(2).
(1)See D-2.11.2.(2).
 

Section D-3. Flame-Spread Ratings and Smoke Developed Classifications

D-3.1. Interior Finish Materials

D-3.1.1. Scope of Information
Tables D-3.1.1.A. and D-3.1.1.B. show flame-spread ratings and smoke developed classifications for combinations of some common interior finish materials. The values are based on all the evidence available at present. Many materials have not been included because of lack of test evidence or because of inability to classify or describe the material in generic terms for the purpose of assigning ratings.
Table D-3.1.1.A.
Assigned Flame-Spread Ratings and Smoke Developed Classifications for Combinations of Wall and Ceiling Finish Materials and Surface Coatings(1)
Forming part of Article D-3.1.1.
Materials Applicable Material Standard Minimum Thickness, mm Surface Coating
Unfinished

Paint or Varnish not more than 1.3 mm Thick, Cellulosic Wallpaper not more than One Layer(2)(3)
Brick, concrete, tile None None 0/0 25/50
Steel, copper, aluminum None 0.33
Gypsum plaster CSA A82.22-M None
Gypsum wallboard CAN/CSA-A82.27-M 9.5 25/50 25/50

ASTM C 1396/C 1396M
Lumber None 16 150/300 150/300

Douglas Fir plywood(4)

 CSA O121 11 150/100 150/300

Poplar plywood(4)

 CSA O153-M

Plywood with Spruce face veneer(4)

 CSA O151

Douglas Fir plywood(4)

 CSA O121 6 150/100 150/100
Fiberboard low density CAN/ULC-S706 11 X/100 150/100
Hardboard        
Type 1 CAN/CGSB-11.3-M 9 150/X

(5)
Standard 6 150/300 150/300
Particleboard

ANSI A208.1

 12.7 150/300

(5)
Waferboard, change beginOSBchange end

CSA O437.0

 — (5) (5)
change beginCAN/CSA-O325change end — change begin(5)change end change begin(5)change end
Notes to Table D-3.1.1.A.:
(1) See D-1.1.1.(5) for standards used to assign flame-spread ratings and smoke developed classifications.
(2) Flame-spread ratings and smoke developed classifications for paints and varnish are not applicable to shellac and lacquer.
(3) Flame-spread ratings and smoke developed classifications for paints apply only to alkyd and latex paints.
(4) The flame-spread ratings and smoke developed classifications shown are for those plywoods without a cellulose resin overlay.
(5) Insufficient test information available.
Table D-3.1.1.B.
Flame-Spread Ratings and Smoke-Developed Classifications for Combinations of Common Floor Finish Materials and Surface Coatings(1)
Forming part of Article D-3.1.1.
Materials Applicable Standard

FSR/SDC(2)
Hardwood or softwood flooring either unfinished or finished with a spar or urethane varnish coating None 300/300
Wool carpet (woven), pile weight not less than 1120 g/m2, applied with or without felt underlay(3) CAN/CGSB-4.129 300/300
Nylon carpet, pile weight not less than 610 g/m2 and not more than 800 g/m2, applied with or without felt underlay(3) CAN/CGSB-4.129 300/500
Nylon carpet, pile weight not less than 610 g/m2 and not more than 1355 g/m2, glued down to concrete CAN/CGSB-4.129 300/500
Wool/nylon blend carpet (woven) with not more than 20% nylon and pile weight not less than 1120 g/m2 CAN/CGSB-4.129 300/500
Nylon/wool blend carpet (woven) with not more than 50% wool, pile weight not less than 610 g/m2 and not more than 800 g/m2 CAN/CGSB-4.129 300/500
Polypropylene carpet, pile weight not less than 500 g/m2 and not more than 1200 g/m2, glued down to concrete CAN/CGSB-4.129 300/500
Notes to Table D-3.1.1.B.:
(1) Tested on the floor of the tunnel in conformance with provisions of CAN/ULC-S102.2, “Test for Surface Burning Characteristics of Flooring, Floor Coverings, and Miscellaneous Materials and Assemblies.”
(2) Flame-Spread Rating/Smoke Developed Classification.
(3) Type 1 or 2 underlay as described in CGSB 4-GP-36M, “Carpet Underlay, Fiber Type.”
D-3.1.2. Ratings
The ratings shown in Tables D-3.1.1.A. and D-3.1.1.B. are arranged in groups corresponding to the provisions of this Code. The ratings apply to materials falling within the general categories indicated.
D-3.1.3. Table Entries
In Tables D-3.1.1.A. and D-3.1.1.B., the first number of each entry relates to flame spread and the second number to smoke developed limit. For example:
25/50 represents a flame-spread rating of 0 to 25 and a smoke developed classification of 0 to 50,
150/300 represents a flame-spread rating of 75 to 150 and a smoke developed classification of 100 to 300, and
X/X applied to walls and ceilings means a flame-spread rating over 150 and a smoke developed classification over 300.
D-3.1.4. Effect of Surface Coatings
Thin surface coatings can modify flame-spread characteristics either upward or downward. Table D-3.1.1.A. includes a number of thin coatings that increase the flame-spread rating of the base material, so that these may be considered where more precise control over flame spread hazard is desired.
D-3.1.5. Proprietary Materials
1) Information on flame-spread rating of proprietary materials and fire-retardant treatments that cannot be described in sufficient detail to ensure reproducibility is available through the listing and labelling services of Underwriters' Laboratories of Canada, Intertek Testing Services NA Ltd., or other recognized testing laboratory.
2) A summary of flame spread test results published prior to 1965 has been prepared by the Institute for Research in Construction of the National Research Council of Canada (see Item (1) in Subsection D-6.1., Fire Test Reports).
D-3.1.6. Limitations and Conditions
1) The propagation of flame along a surface in the standard test involves some finite depth of the material or materials behind the surface, and this involvement extends to the depth to which temperature variations are to be found during the course of the test; for many commonly used lining materials, such as wood, the depth involved is about 25 mm.
2) For all the combustible materials described in Table D-3.1.1.A., a minimum dimension is shown, and this represents the thickness of the test samples on which the rating has been based; when used in greater thicknesses than that shown, these materials may have a slightly lower flame-spread rating, and thinner specimens may have higher flame-spread ratings.
3) No rating has been included for foamed plastic materials because it is not possible at this time to identify these products with sufficient accuracy on a generic basis. Materials of this type that melt when exposed to the test flame generally show an increase in flame-spread rating as the thickness of the test specimen increases.
D-3.1.7. Referenced Standards
In Tables D-3.1.1.A. and D-3.1.1.B., the standards applicable to the materials described are noted because the ratings depend on conformance with these specifications.
 

Section D-4. Noncombustibility

D-4.1. Test Method

D-4.1.1. Determination of Noncombustibility
1) Noncombustibility is required of certain components of buildings by the provisions of this Code, which specifies noncombustibility by reference to CAN/ULC-S114, “Test for Determination of Non-Combustibility in Building Materials.”
2) The test to which reference is made in Sentence (1) is severe, and it may be assumed that any building material containing even a small proportion of combustibles will itself be classified as combustible. The specimen, 38 mm by 51 mm, is exposed to a temperature of 750°C in a small furnace. The essential criteria for noncombustibility are that the specimen does not flame or contribute to temperature rise.

D-4.2. Materials Classified as Combustible

D-4.2.1. Combustible Materials
Most materials from animal or vegetable sources will be classed as combustible by CAN/ULC-S114, “Test for Determination of Non-Combustibility in Building Materials,” and wood, wood fibreboard, paper, felt made from animal or vegetable fibres, cork, plastics, asphalt and pitch would therefore be classed as combustible.
D-4.2.2. Composite Materials
Materials that consist of combustible and noncombustible elements in combination will in many cases also be classed as combustible, unless the proportion of combustibles is very small. Some mineral wool insulations with combustible binder, cinder concrete, cement and wood chips and wood-fibred gypsum plaster would also be classed as combustible.
D-4.2.3. Effect of Chemical Additives
The addition of a fire-retardant chemical is not sufficient to change a combustible product to a noncombustible product.

D-4.3. Materials Classified as Noncombustible

D-4.3.1. Typical Examples
Noncombustible materials include brick, ceramic tile, concrete made from Portland cement with noncombustible aggregate, asbestos cement, plaster made from gypsum with noncombustible aggregate, metals commonly used in buildings, glass, granite, sandstone, slate, limestone and marble.
 

Section D-5. Protection of Openings in Fire-Rated Assemblies

D-5.1. Scope

D-5.1.1. Installation Information
1) The information in D-5. specifies requirements for
  1. the installation of fire doors and fire dampers in gypsum-wallboard-protected stud wall assemblies, and
  2. fire stop flaps for installation in fire-rated membrane ceilings.

D-5.2. Installation of Fire Doors and Fire Dampers

D-5.2.1. References
1) Fire doors and fire dampers in gypsum-wallboard-protected steel stud non-loadbearing walls required to have a fire-resistance rating shall be installed in conformance with Section 9.24. of this Code and the applicable requirements of NFPA 80, “Fire Doors and Other Opening Protectives.”
2) Fire doors and fire dampers in gypsum-wallboard-protected wood stud walls required to have a fire-resistance rating shall be installed in conformance with Section 9.23. of this Code and the applicable requirements of NFPA 80, “Fire Doors and Other Opening Protectives.”

D-5.3. Fire Stop Flaps

D-5.3.1. Construction Requirements
Fire stop flaps shall be constructed of steel not less than 1.5 mm thick, covered on both sides with painted asbestos paper not less than 1.6 mm thick and equipped with pins and hinges of corrosion-resistant material (see Figure D-5.3.1.-A).
Figure D-5.3.1.-A
Typical fire stop flaps
D-5.3.2. Hold-open Devices
Fire stop flaps shall be held open with fusible links conforming to ULC-S505, “Fusible Links for Fire Protection Service,” or other heat-activated devices having a temperature rating approximately 30°C above the maximum temperature that would exist in the system either with the system in operation or shut down.
 

Section D-6. Background Information

D-6.1. Fire Test Reports

Summaries of available fire test information have been published by the Institute for Research in Construction (formerly the Division of Building Research) as follows:
M. Galbreath, Flame Spread Performance of Common Building Materials. Technical Paper No. 170, Division of Building Research, National Research Council Canada, Ottawa, April 1964. NRCC 7820.
M. Galbreath and W.W. Stanzak, Fire Endurance of Protected Steel Columns and Beams. Technical Paper No. 194, Division of Building Research, National Research Council Canada, Ottawa, April 1965. NRCC 8379.
T.Z. Harmathy and W.W. Stanzak, Elevated-Temperature Tensile and Creep Properties of Some Structural and Prestressing Steels. American Society for Testing and Materials, Special Technical Publication 464, 1970, p. 186 (DBR Research Paper No. 424) NRCC 11163.
T.Z. Harmathy, Thermal Performance of Concrete Masonry Walls in Fire. American Society for Testing and Materials, Special Technical Publication 464, 1970, p. 209 (DBR Research Paper No. 423) NRCC 11161.
L.W. Allen, Fire Endurance of Selected Non-Loadbearing Concrete Masonry Walls. DBR Fire Study No. 25, Division of Building Research, National Research Council Canada, Ottawa, March 1970. NRCC 11275.
A. Rose, Comparison of Flame Spread Ratings by Radiant Panel, Tunnel Furnace, and Pittsburgh-Corning Apparatus. DBR Fire Study No. 22, Division of Building Research, National Research Council Canada, Ottawa, June 1969. NRCC 10788.
T.T. Lie and D.E. Allen, Calculation of the Fire Resistance of Reinforced Concrete Columns. DBR Technical Paper No. 378, Division of Building Research, National Research Council Canada, Ottawa, August 1972. NRCC 12797.
W.W. Stanzak, Column Covers: A Practical Application of Sheet Steel as a Protective Membrane. DBR Fire Study No. 27, Division of Building Research, National Research Council Canada, Ottawa, February 1972. NRCC 12483.
W.W. Stanzak, Sheet Steel as a Protective Membrane for Steel Beams and Columns. DBR Fire Study No. 23, Division of Building Research, National Research Council Canada, Ottawa, November 1969. NRCC 10865.
W.W. Stanzak and T.T. Lie, Fire Tests on Protected Steel Columns with Different Cross-Sections. DBR Fire Study No. 30, Division of Building Research, National Research Council Canada, Ottawa, February 1973. NRCC 13072.
G. Williams-Leir and L.W. Allen, Prediction of Fire Endurance of Concrete Masonry Walls. DBR Technical Paper No. 399, Division of Building Research, National Research Council Canada, Ottawa, November 1973. NRCC 13560.
G. Williams-Leir, Prediction of Fire Endurance of Concrete Slabs. DBR Technical Paper No. 398, Division of Building Research, National Research Council Canada, Ottawa, November 1973. NRCC 13559.
A. Rose, Flammability of Fibreboard Interior Finish Materials. Building Research Note No. 68, Division of Building Research, National Research Council Canada, Ottawa, October 1969.
L.W. Allen, Effect of Sand Replacement on the Fire Endurance of Lightweight Aggregate Masonry Units. DBR Fire Study No. 26, Division of Building Research, National Research Council Canada, Ottawa, September 1971. NRCC 12112.
L.W. Allen, W.W. Stanzak and M. Galbreath, Fire Endurance Tests on Unit Masonry Walls with Gypsum Wallboard. DBR Fire Study No. 32, Division of Building Research, National Research Council Canada, Ottawa, February 1974, NRCC 13901.
W.W. Stanzak and T.T. Lie, Fire Resistance of Unprotected Steel Columns. Journal of Structural Division, Proc., Am. Soc. Civ. Eng., Vol. 99, No. ST5 Proc. Paper 9719, May 1973 (DBR Research Paper No. 577) NRCC 13589.
T.T. Lie and T.Z. Harmathy, Fire Endurance of Concrete-Protected Steel Columns. A.C.I. Journal, January 1974, Title No. 71-4 (DBR Technical Paper No. 597) NRCC 13876.
T.T. Lie, A Method for Assessing the Fire Resistance of Laminated Timber Beams and Columns. Can. J. Civ. Eng., Vol. 4, No. 2, June 1977 (DBR Technical Paper No. 718) NRCC 15946.
T.T. Lie, Calculation of the Fire Resistance of Composite Concrete Floor and Roof Slabs. Fire Technology, Vol. 14, No. 1, February 1978 (DBR Technical Paper No. 772) NRCC 16658.

D-6.2. Obsolete Materials and Assemblies

Building materials, components and structural members and assemblies in buildings constructed before 1995 may have been assigned ratings based on earlier editions of the Supplement to the National Building Code of Canada or older reports of fire tests. To assist users in determining the ratings of these obsolete assemblies and structural members, the following list of reference documents has been prepared. Although some of these publications are out of print, reference copies are available at the Institute for Research in Construction, National Research Council Canada, Ottawa, Ont., K1A 0R6.
M. Galbreath, Fire Endurance of Unit Masonry Walls. Technical Paper No. 207, Division of Building Research, National Research Council Canada, Ottawa, October 1965. NRCC 8740.
M. Galbreath, Fire Endurance of Light Framed and Miscellaneous Assemblies. Technical Paper No. 222, Division of Building Research, National Research Council Canada, Ottawa, June 1966. NRCC 9085.
M. Galbreath, Fire Endurance of Concrete Assemblies. Technical Paper No. 235, Division of Building Research, National Research Council Canada, Ottawa, November 1966. NRCC 9279.
Guideline on Fire Ratings of Archaic Materials and Assemblies. Rehabilitation Guideline #8, U.S. Department of Housing and Urban Development, Germantown, Maryland 20767, October 1980.
T.Z. Harmathy, Fire Test of a Plank Wall Construction. Fire Study No. 2, Division of Building Research, National Research Council Canada, Ottawa, July 1960. NRCC 5760.
T.Z. Harmathy, Fire Test of a Wood Partition. Fire Study No. 3, Division of Building Research, National Research Council Canada, Ottawa, October 1960. NRCC 5769.

D-6.3. Assessment of Archaic Assemblies

Information in this document applies to new construction. Please refer to early editions of the Supplement to the National Building Code of Canada for the assessment or evaluation of assemblies that do not conform to the information in this edition of the National Building Code. As with other documents, this Code is revised according to the information presented to the standing committee responsible for its content, and with each update new material may be added and material that is not relevant may be deleted.

D-6.4. Development of the Component Additive Method

The component additive method was developed based upon the following observations and conclusions drawn from published as well as unpublished test information.
Study of the test data showed that structural failure preceded failure by other criteria (transmission of heat or hot gases) in most of the tests of loadbearing wood-framed assemblies. The major contributor to fire resistance was the membrane on the fire-exposed side.
Fire tests of wood joist floors without protective ceilings resulted in structural failure between 8 and 10 min. Calculation of the time for wood joists to approach breaking stress, based upon the charring rate of natural woods, suggested a time of 10 min for structural failure. This time was subtracted from the fire-resistance test results of wood joist floors and the remainder considered to be the contribution of the membrane.
The figures obtained for the contribution of membranes were then applied to the test results for open web steel joist floors and wood and steel stud walls and values of 20 min for the contribution of wood stud framing and 10 min for steel framing were derived.
The fire-resistance rating has been limited to 1.5 h as this method of developing ratings for framed assemblies was new and untried. Although this is the subject of current review, no decision has been made to extend the ratings beyond 1.5 h.
M. Galbreath, G. C. Gosselin, and R. B. Chauhan, Historical Guide to Chapter 2 of the Supplement to the National Building Code of Canada, Committee Paper FPR 1-3, Prepared for the Standing Committee on Fire Performance Ratings, May 1987.
Example showing fire-resistance rating of a typical membrane assembly, calculated using the component additive method.
1 hour Gypsum Board/Wood Stud Interior Partition
A 1 h fire-resistance rating is required for an interior wood framed partition, using 12.7 mm Type X gypsum wallboard.
  1. Since gypsum wallboard is used (D-2.3.4.(2) and Table D-2.3.4.A.) time assigned to 12.7 mm Type X gypsum wallboard membrane on the fire-exposed side of the partition = 25 min
  2. Time assigned to wood framing members at 400 mm o.c. (D-2.3.4.(3) and Table D-2.3.4.C.) = 20 min
  3. Time assigned to insulation, if the spaces between the studs are filled with preformed insulation of rock or slag fibres conforming to CAN/ULC-S702, “Mineral Fibre Thermal Insulation for Buildings,” (D-2.3.4.(4) and Table D-2.3.4.D.) = 15 min
  4. Time assigned to the membrane on the non-fire-exposed side (D-2.3.5.(1)) = 0 min
    Fire-resistance rating = 25 + 20 + 15 = 60 min
 
This Appendix is included for explanatory purposes only and does not form part of the requirements change beginexcept as defined in Division A Sentence 1.1.3.1.(1).change end The bold face reference numbers that introduce each item do not relate to specific requirements in this Division.