Ministry of Municipal Affairs PROPOSED CHANGE TO THE 2012 BUILDING CODE O. REG. 332/12 AS AMENDED CHANGE NUMBER: SOURCE: B-09-11-01 Ontario-NBC CODE REFERENCE: Division B / 9.11. DESCRIPTION OF THE PROPOSED AMENDMENT The proposed change introduces a new sound transmission metric and additional guidance on the new metric. This section has also been restructured. EXISTING 2012 BUILDING CODE PROVISION(S) Section 9.11. Sound Control 9.11.1. Sound Transmission Class Rating (Airborne Sound) 9.11.1.1. Determination of Sound Transmission Class Ratings (1) Sound transmission class ratings shall be determined in accordance with ASTM E413, Classification for Rating Sound Insulation, using results from measurements in accordance with, (a) ASTM E90, Laboratory Measurement of Airborne Sound Transmission Loss of Building Partitions and Elements, or (b) ASTM E336, Measurement of Airborne Sound Attenuation Between Rooms in Buildings. (See Appendix A.) 9.11.2. Required Sound Control Locations (Airborne Sound) 9.11.2.1. Minimum Sound Transmission Class Ratings (1) Except as provided in Sentence (2), every dwelling unit and every suite in hotels shall be separated from every other space in a building in which noise may be generated, by an assembly providing a sound transmission class rating of at least 50, measured in accordance with Subsection 9.11.1. or as listed in Tables 1 and 2 of MMAH Supplementary Standard SB-3, Fire and Sound Resistance of Building Assemblies. (2) Where a dwelling unit or suite in a hotel is adjacent to an elevator shaft or a refuse chute, the separating assembly shall have a sound transmission class rating of at least 55, measured in accordance with Subsection 9.11.1. or as listed in Tables 1 and 2 of MMAH Supplementary Standard SB-3, Fire and Sound Resistance of Building Assemblies. Page 1 Copyright Queen s Printer for Ontario 2016
9.11.2.2. Building Services in an Assembly (1) Building services located in an assembly required to have a sound transmission class rating shall be installed in a manner that will not decrease the required rating of the assembly. A-9.11.1.1.(1) Sound Transmission Class Ratings. The specified STC rating of 50 is considered the minimum acceptable value, but many builders prefer to design for STC 55 or more in high quality accommodation. Another reason to choose assemblies rated higher than STC 50 is that the STC ratings of assemblies are based on laboratory tests, but the sound transmission of any assembly as constructed in the field may be significantly less than its rating. This can be due to sound leaks, departures from design, poor workmanship or indirect (flanking) transmission paths overlooked in design. To provide a margin of safety to compensate for these, builders often select wall and floor systems that have been rated at least 5 points higher than the design STC rating in laboratory tests. Sound leaks can occur where one wall meets another, the floor, or the ceiling. Leaks may also occur where the wall finish is cut for the installation of equipment or services. Avoid back-to-back electrical outlets or medicine cabinets. Carefully seal cracks or openings so structures are effectively airtight. Apply sealant below the plates in stud walls, between the bottom of drywall sheets and the structure behind, around all penetrations for services and, in general, wherever there is a crack, a hole or the possibility of one developing. Sound-absorbing material inside a well-designed wall decreases sound transmission. It has another advantage; it also helps to reduce the effects of leaks due, perhaps, to poor workmanship. Indirect or flanking transmission arises where the parts of a building are rigidly connected together and where cavities in hollow walls or floors, or continuous lightweight layers connect apartments. Sound travels in cavities, as vibration along surfaces and through walls, ceilings and floors to adjacent rooms. Many paths other than the direct one through the party wall or floor may be involved. To achieve good sound insulation, transmission along flanking paths must be minimized by introducing breaks and resilient connections in the construction. Some examples of bad and good details are shown in Figure 9.11.1.1.(1). Figure A-9.11.1.1.(1) Cross Section Through Wall/floor Junctions Impact Noise Changes to construction should not be made without consultation with someone competent in the field of acoustical design. Adding extra layers of drywall to walls in an attempt to reduce sound transmission, can actually increase it if done incorrectly. For example, attaching drywall on resilient channels directly to an existing wall or ceiling usually increases low frequency sound transmission. Adding an additional layer of drywall inside a double layer wall will also seriously increase sound transmission. Adding blocking inside walls to reduce the risk of fire spread should be done so it does not increase vibration transmission from one part of a wall or floor to the other. To verify that acoustical privacy is being achieved, a field test can be done at an early stage in the construction; ASTM E336, Measurement of Airborne Sound Attenuation Between Rooms in Buildings will give a complete measurement. A simpler and less expensive method is ASTM E597, Determining a Single Number Rating of Airborne Sound Insulation in Multi Unit Building Specifications. The rating provided by this test is usually within 2 points of the STC obtained from
ASTM E336. It is useful for verifying performance and finding problems during construction. Alterations can then be made prior to project completion. Impact Noise Section 9.11. has no requirements for control of impact noise transmission. Footstep and other impacts can cause severe annoyance in multi-family residences. Builders concerned about quality and reducing occupant complaints will ensure that floors are designed to minimize impact transmission. A recommended criterion is that bare floors (tested without a carpet) should achieve an impact insulation class (IIC) of 55. Some lightweight floors that satisfy this requirement may still cause complaints about low frequency impact noise transmission. Adding carpet to a floor will always increase the IIC rating but will not necessarily reduce low frequency noise transmission. Good footstep noise rejection requires fairly heavy floor slabs or floating floors. Most frequently used methods of test for impact noise are ASTM E492, Laboratory Measurement of Impact Sound Transmission Through Floor-Ceiling Assemblies Using The Tapping Machine, or ASTM E1007, Field Measurement of Tapping Machine Impact Sound Transmission Through Floor-Ceiling Assemblies and Associated Support Structures. Machinery Noise Elevators, garbage chutes, plumbing, fans, and heat pumps are common sources of noise in buildings. To reduce annoyance from these, they should be placed as far as possible from sensitive areas. Vibrating parts should be isolated from the building structure using resilient materials such as neoprene or rubber. PROPOSED CODE CHANGE Revise Section 9.11 as follows: Section 9.11. Sound Transmission Control 9.11.1. Sound Transmission Class Rating (Protection from Airborne SoundNoise) 9.11.21.1. Minimum Sound Transmission Class RatingsRequired Protection (1) Except as provided in Sentence (2), and (3), every a dwelling unit and every suite in hotels shall be separated from every other space in a building in which noise may be generated, by an assembly providing a sound transmission class rating of at least 50, measured in accordance with Subsection 9.11.1. or as listed in Tables 1 and 2 of MMAH Supplementary Standard SB-3, Fire and Sound Resistance of Building Assemblies. (a) separating assembly and adjoining constructions that, which together provide an apparent sound transmission class rating (ASTC) of not less than 47, or(b) a separating assembly providing a sound transmission class (STC) rating of at least 50 and adjoining constructions that conform to Article 9.11.1.4. (2) In a house, each dwelling unit shall be separated from every other space in the house in which noise may be transmitted by, (a) construction (i) whose joist spaces are filled with sound-absorbing material of not less than 150 mm nominal thickness, (ii) whose stud spaces are filled with sound-absorbing material, (iii) having a resilient channel on one side of the separation spaced 406 or 610 mm o.c., and (iv) having not less than 12.7 mm thick gypsum board on ceilings and on both sised of walls, or Copyright Queen s Printer for Ontario 2015 Page 3
(b) (c) construction providing a sound transmission class of not less than 43, or a separating assembly and adjoining constructions, which together provide an apparent sound transmission class (ASTC) rating of not less than 40. (23) Where a dwelling unit or suite in a hotel is adjacent to an elevator shaft or a refuse chute, the Construction separating a dwelling unit or suite in a hotel from an elevator shaft or refuse chute assembly shall have a sound transmission class (STC) rating of at least 55., measured in accordance with Subsection 9.11.1. or as listed in Tables 1 and 2 of MMAH Supplementary Standard SB-3, Fire and Sound Resistance of Building Assemblies. 9.11.1.12. Determination of Sound Transmission Class Ratings (1) The Ssound transmission class ratings shall be determined in accordance with ASTM E413, Classification for Rating Sound Insulation, using results from measurements carried out in accordance with ASTM E 90, Laboratory Measurement of Airborne Sound Transmission Loss of Building Partitions and Elements. (a) ASTM E90, Laboratory Measurement of Airborne Sound Transmission Loss of Building Partitions and Elements, or (b) ASTM E336, Measurement of Airborne Sound Attenuation Between Rooms in Buildings. (See Appendix A.) (2) Apparent sound transmission class (ASTC) ratings of sound transmission between adjoining spaces in a building shall be determined (a) determined in accordance with ASTM E 413, Classification for Rating Sound Insulation, using results from measurements carried out in accordance with ASTM E 336, Measurement of Airborne Sound Attenuation between Rooms in Buildings, or (b) calculated in accordance with Article 5.9.1.3. or Article 5.9.1.4. 9.11.1.3. Compliance with Required Ratings (1) Compliance with STC ratings shall be demonstrated through, (a) measurements carried out in accordance with Sentence 9.11.1.2.(1), or (b) construction of separating assemblies conforming to Tables 1 or 2 of MMAH Supplementary Standard SB-3, Fire and Sound Resistance of Building Assemblies, as applicable. (2) Compliance with ASTC ratings shall be demonstrated by (a) measurement or calculation according to Sentence 9.11.1.2.(2), or (b) construction of separating assemblies conforming to Tables 1 or 2 of MMAH Supplementary Standard SB-3, Fire and Sound Resistance of Building Assemblies, as applicable, that have a sound transmission class rating of not less than 50 in conjunction with flanking assemblies constructed in accordance with Article 9.11.1.4. (see Appendix A). 9.11.1.4. Adjoining Constructions (See Appendix A) (1) This Article applies where the required protection is provided in accordance with Clause 9.11.1.1.(1)(b) and compliance is demonstrated in accordance with Clause 9.11.1.3.(2)(b). (2) Flanking wall assemblies connected to a separating floor or ceiling assembly shall be constructed with (a) concrete or concrete block having a mass per area greater than 200 kg/m 2, or (b) gypsum board finish that (i) is supported on wood or steel framing, and (ii) ends or is interrupted where it meets the structure of the separating floor or ceiling assembly. (3) Flanking wall and ceiling assemblies connected to a separating wall assembly shall be constructed with, (a) concrete or concrete block having a mass per area greater than 300 kg/m 2, or Copyright Queen s Printer for Ontario 2015 Page 4
(b) gypsum board finish that (i) is supported on wood or steel framing, and (ii) ends or is interrupted where it meets the structure of the separating wall assembly or, for double-stud walls, where it meets the space between the two lines of studs. (4) Flanking floor assemblies connected to a separating wall assembly shall be, (a) constructed (i) with concrete having a mass per area greater than 300 kg/m 2, or be constructed (ii) in accordance with Section 9.16., or (b) supported on joists or trusses that are not continuous across the junction and are covered with floor treatments in accordance with Table 9.11.1.4. for the applicable wall construction. Table 9.11.1.4. Floor Treatments for Flanking Wood-Framed Floor Assemblies in Horizontally Adjoining Spaces Forming Part of Sentence 9.11.1.4.(4) Type of Separating Wall Assembly with STC 50 from MMAH Supplementary Standard SB-3 Fire and Sound Resistance of Building Assemblies Minimum Requirements for Floor Treatments Applied Over Subfloor of Wood- Framed Flanking Floor Assemblies on Both Sides of Floor/Wall Junction W5, W6, W10, W12 (staggered studs) wood strip flooring not less than 16 mm thick aligned parallel to separating wall, or one layer OSB or plywood not less than 15.5 mm thick plus finished flooring, or one additional material layer plus finished flooring having a combined mass per area not less than 8 kg/m² (1) W4, W11 (staggered studs) one layer of OSB or plywood not less than 12.5 mm thick plus hardwood strip flooring not less than 19 mm thick aligned parallel to separating wall, or one additional material layer plus finished flooring having a combined mass per area 16 kg/m² (1) W8, W9 (staggered studs) concrete or gypsum concrete topping not less than 19 mm thick bonded to the subfloor plus finished flooring, or one additional material layer plus finished flooring having a combined mass per area not less than 32 kg/m² (1) Copyright Queen s Printer for Ontario 2015 Page 5
Type of Separating Wall Assembly with STC 50 from MMAH Supplementary Standard SB-3 Fire and Sound Resistance of Building Assemblies Minimum Requirements for Floor Treatments Applied Over Subfloor of Wood- Framed Flanking Floor Assemblies on Both Sides of Floor/Wall Junction W13, W14, W15 (double stud walls) Where a continuous subfloor or other rigid materials at the floor/wall junction provide structural connection between the two rows of studs in the separating wall:, hardwood strip flooring not less than 16 mm thick aligned parallel to separating wall, or one layer OSB or plywood not less than 15.5 mm thick plus finished flooring, or one additional material layer plus finished flooring having a combined mass per area not less than 8 kg/m² (1) B1 to B10 any finished flooring Notes to Table 9.11.1.4.: (1) See Appendix A 9.11.2.1. Minimum Sound Transmission Class Ratings (1) Except as provided in Sentence (2), every dwelling unit and every suite in hotels shall be separated from every other space in a building in which noise may be generated, by an assembly providing a sound transmission class rating of at least 50, measured in accordance with Subsection 9.11.1. or as listed in Tables 1 and 2 of MMAH Supplementary Standard SB-3, Fire and Sound Resistance of Building Assemblies. (2) Where a dwelling unit or suite in a hotel is adjacent to an elevator shaft or a refuse chute, the separating assembly shall have a sound transmission class rating of at least 55, measured in accordance with Subsection 9.11.1. or as listed in Tables 1 and 2 of MMAH Supplementary Standard SB-3, Fire and Sound Resistance of Building Assemblies. 9.11.2.2. Building Services in an Assembly (1) Building services located in an assembly required to have a sound transmission class rating shall be installed in a manner that will not decrease the required rating of the assembly. A-9.11.1.1.(1) Sound Transmission Class Ratings. Airborne Sound Airborne sound is transmitted between adjoining spaces directly through the separating wall, floor and ceiling assemblyies and via the junctions between these separating assemblies and the flanking assemblies. Copyright Queen s Printer for Ontario 2015 Page 6
The Sound Transmission Class (STC) rating describes the performance of the separating wall or floor/ceiling assembly, whereas the Apparent Sound Transmission Class (ASTC) takes into consideration the performance of the separating element as well as the flanking transmission paths. Therefore, from the occupants point of view, the best indicator of noise protection between the two spaces is the ASTC rating. As a key principle, it is important to follow a whole system approach when designing or constructing assemblies that separate dwelling units because the overall sound performance of walls and floors is also influenced by fire protection measures and the structural design of the assemblies. Likewise, changes to the construction of assemblies to meet sound transmission requirements may have fire and structural implications. Another key principle is that enhancing the performance of the separating element does not automatically enhance the system s performance. For horizontally adjoining spaces, the separating assembly is the intervening wall and the pertinent flanking surfaces include those of the floor, ceiling, and side wall assemblies that have junctions with the separating wall assembly, normally at its four edges. For each of these junctions, there are a set of sound transmission paths. Figure A-9.11.-A illustrates the horizontal sound transmission paths at the junction of a separating wall with flanking floor assemblies. Figure A-9.11.-A Horizontal Sound Transmission Path IMAGE N/A For vertically adjoining spaces, the separating assembly is the intervening floor/ceiling and the pertinent flanking surfaces include those of the side wall assemblies in the upper and lower rooms that have junctions with the separating floor/ceiling assembly at its edges, of which there are normally four. For each of these junctions, there is a set of sound transmission paths. Figure A-9.11.-B illustrates the vertical sound transmission paths at the junction of a separating floor/ceiling assembly with two flanking wall assemblies. Figure A-9.11.-B Vertical Sound Transmission Path IMAGE N/A Control of sound leaks The specified STC rating of 50 is considered the minimum acceptable value, but many builders prefer to design for STC 55 or more in high quality accommodation. Another reason to choose assemblies rated higher than STC 50 is that the STC ratings of assemblies are based on laboratory tests, but the sound transmission of any assembly as constructed in the field may be significantly less than its rating. This can be due to sound leaks, departures from design, poor workmanship or indirect (flanking) transmission paths overlooked in design. To provide a margin of safety to compensate for these, builders often select wall and floor systems that have been rated at least 5 points higher than the design STC rating in laboratory tests. The metrics used to characterize the sound transmission performance of assemblies separating dwelling units do not account for the adverse effects of air leaks in those assemblies, which can transfer sound. Sound leaks can occur where onea wall meets another wall, the floor, or the ceiling. Leaks may alsothey can also occur where the wall finish is cut for the installation of equipment or services. The following are examples of measures for controlling sound leaks: Avoid back-to-back electrical outlets or medicine cabinets; Carefully seal cracks or openings so structures are effectively airtight; Apply sealant below the plates in stud walls, between the bottom of drywallgypsum board sheets and the structure behind, around all penetrations for services and, in general, wherever there is a crack, a hole or the possibility of one developing; Copyright Queen s Printer for Ontario 2015 Page 7
include Ssound-absorbing material inside a well-designedthe wall decreases sound transmissionif not already required. It has another advantage; it also helps to reduce the effects of leaks due, perhaps, to poor workmanship. The reduction of air leakage is also addressed to some extent by the smoke tightness requirements in the Code. The calculation of and laboratory testing for STC and ASTC ratings are performed on intact assemblies having no penetrations or doors. When measuring ASTC ratings in the field, openings can be blocked with insulation and drywall. Indirect or flanking transmission arises where the parts of a building are rigidly connected together and where cavities in hollow walls or floors, or continuous lightweight layers connect apartments. Sound travels in cavities, as vibration along surfaces and through walls, ceilings and floors to adjacent rooms. Many paths other than the direct one through the party wall or floor may be involved. To achieve good sound insulation, transmission along flanking paths must be minimized by introducing breaks and resilient connections in the construction. Some examples of bad and good details are shown in Figure 9.11.1.1.(1). Figure A-9.11.1.1.(1) Cross Section Through Wall/floor Junctions Impact Noise Changes to construction should not be made without consultation with someone competent in the field of acoustical design. Adding extra layers of drywall to walls in an attempt to reduce sound transmission, can actually increase it if done incorrectly. For example, attaching drywall on resilient channels directly to an existing wall or ceiling usually increases low frequency sound transmission. Adding an additional layer of drywall inside a double layer wall will also seriously increase sound transmission. Adding blocking inside walls to reduce the risk of fire spread should be done so it does not increase vibration transmission from one part of a wall or floor to the other. To verify that the required acoustical privacyperformance is being achieved, a field test can be done at an early stage in the construction; ASTM E336, Measurement of Airborne Sound Attenuation Between Rooms in Buildings will gives a complete measurement. A simpler and less expensive method is presented in ASTM E597, Determining a Single Number Rating of Airborne Sound Insulation for Use in Multi-Unit Building Specifications. The rating provided byderived from this test is usually within 2 points of the STC obtained from ASTM E336. It is useful for verifying performance and finding problems during construction. Alterations can then be made prior to project completion. Impact Noise Section 9.11. has no requirements for the control of impact noise transmission. However, Ffootstep and other impacts can cause severe annoyance in multi-family residences. Builders concerned about quality and reducing occupant complaints will ensure that floors are designed to minimize impact transmission. A recommended criterion is that bare floors (tested without a carpet) should achieve an impact insulation class (IIC) of 55. Some lightweight floors that satisfy this requirement may still causeelicit complaints about low frequency impact noise transmission. Adding carpet to a floor will always increase the IIC rating but will not necessarily reduce low frequency noise transmission. Good footstep noise rejection requires fairly heavy floor slabs or floating floors. Impact noise requirements are being considered for inclusion in future editions of the OBC. Copyright Queen s Printer for Ontario 2015 Page 8
The Mmost frequently used test methods of test for impact noise are ASTM E492, Laboratory Measurement of Impact Sound Transmission Through Floor-Ceiling Assemblies Using The Tapping Machine, or ASTM E1007, Field Measurement of Tapping Machine Impact Sound Transmission Through Floor-Ceiling Assemblies and Associated Support Structures. Machinery Noise Elevators, garbage chutes, plumbing, fans, and heat pumps are common sources of noise in buildings. To reduce annoyance from these, they should be placed as far as possible from sensitive areas. Vibrating parts should be isolated from the building structure using resilient materials such as neoprene or rubber. A-9.11.1.3. Control of Airborne Noise in Buildings. Tables 1 and 2 of MMAH SB-3 Fire and Sound Resistance of Building Assemblies present separating assemblies that comply with Subsection 9.11. However, selecting an appropriate separating assembly is only one part of the solution for reducing airborne sound transmission between adjoining spaces: to fully address the sound performance of the whole system, flanking assemblies must be connected to the separating assembly in accordance with Article 9.11.1.4. A-9.11.1.4 Adjoining Constructions. Tables A-9.11.1.4.-A to A-9.11.1.4.-D present generic options for the design and construction of junctions between separating and flanking assemblies. Constructing according to these options is likely to meet or exceed an ASTC rating of 47. Other designs may be equally acceptable if their sound resistance can be demonstrated to meet the minimum ASTC rating or better on the basis of tests referred to in Article 9.11.1.2., or if they comply with Subsection 5.8.1. However, some caution should be applied when designing solutions that go beyond the options provided in these Tables: for example, adding more material to a wall could negatively impact its sound performance or have no effect at all. Table A-9.11.1.4.-A presents compliance options for the construction of separating wall assemblies with flanking floor, ceiling and wall assemblies in horizontally adjoining spaces. Copyright Queen s Printer for Ontario 2015 Page 9
Table A-9.11.1.4.-A Options for the Design and Construction of Junctions and Flanking Surfaces Between Separating Wall Assemblies in Horizontally Adjoining Spaces for Compliance with Clause 9.11.1.1.(1)(b) Type of Separating Wall Assembly with STC 50 from Table 1 of MMAH SB-3 Fire and Sound Resistance of Building Assemblies Options for Design and Construction of Junctions and Flanking Surfaces (1) to Address Horizontal Sound Transmission Paths Bottom Junction (between separating wall and flanking floors) Top Junction (between separating wall and flanking ceiling) Side Junctions (between separating wall and flanking walls) W4, W5, W6 (single stud) W8, W9, W10, W11, W12 (staggered studs) for additional material layer and finished flooring, see Table 9.11.1.4. subfloor on both sides of wall is plywood, OSB, waferboard (15.5 mm thick) or tongue and groove lumber ( 17 mm thick) floor is framed with wood joists, wood I-joists or wood trusses spaced 400 mm o.c., with or without absorptive material (2) in cavities floor joists or trusses are oriented parallel to separating wall (non-loadbearing case) or perpendicular to separating wall but are not continuous across junction (loadbearing case) ceiling is framed with wood joists, wood I-joists, or wood trusses, with or without absorptive material (2) in cavities ceiling joists or trusses are oriented perpendicular to separating wall but are not continuous across junction (loadbearing case) or parallel to junction (non-loadbearing case) gypsum board ceiling is fastened directly to bottom of ceiling framing or on resilient metal channels (3) Example Showing Side View of Bottom and Top Junctions gypsum board on flanking walls ends or is cut at separating wall and is fastened directly to framing or on resilient metal channels (3) flanking wall is framed with single row of wood studs, staggered studs on a single 38 mm x 140 mm plate, or 2 rows of 38 mm x 89 mm wood studs on separate 38 mm x 89 mm plates, with or without absorptive material (2) in cavities flanking wall framing is structurally connected to separating wall and terminates where it butts against framing of separating wall or is continuous across junction Example Showing Plan View of Side Junctions Copyright Queen s Printer for Ontario 2015 Page 10
Type of Separating Wall Assembly with STC 50 from Table 1 of MMAH SB-3 Fire and Sound Resistance of Building Assemblies Options for Design and Construction of Junctions and Flanking Surfaces (1) to Address Horizontal Sound Transmission Paths Bottom Junction (between separating wall and flanking floors) Top Junction (between separating wall and flanking ceiling) Side Junctions (between separating wall and flanking walls) W13, W14, W15 for additional material layer and finished flooring, see Table 9.11.1.4. subfloor on both sides of wall is plywood, OSB, waferboard (15.5 mm thick) or tongue and groove lumber ( 17 mm thick) floor is framed with wood joists, wood I-joists or wood trusses spaced 400 mm o.c., with or without absorptive material (2) in cavities floor joists or trusses are oriented parallel to separating wall (non-loadbearing case) or perpendicular to separating wall but are not continuous across junction (loadbearing case) near leaf of separating wall is supported on designated joist wood joists, wood I-joists or wood trusses are oriented perpendicular or parallel to separating wall, with or without absorptive material (2) in cavities joist framing at junction is supported on near leaf of separating wall gypsum board ceiling panels end at wall framing and are fastened directly to bottom of ceiling framing or on resilient metal channels (3) Example Showing Side View of Bottom and Top Junctions flanking wall framing is fastened to adjacent leaf of separating wall flanking wall is framed with single row of wood studs, staggered studs on a single 38 mm x 140 mm plate, or 2 rows of 38 mm x 89 mm wood studs on separate 38 mm x 89 mm plates, with or without absorptive material (2) in cavities gypsum board panels on flanking walls ends or is cut at framing of separating wall and is fastened on resilient metal channels (3) or directly to framing of flanking wall if that framing and any sheathing are not continuous across the junction Example Showing Plan View of Side Junctions Copyright Queen s Printer for Ontario 2015 Page 11
Type of Separating Wall Assembly with STC 50 from Table 1 of MMAH SB-3 Fire and Sound Resistance of Building Assemblies Options for Design and Construction of Junctions and Flanking Surfaces (1) to Address Horizontal Sound Transmission Paths Bottom Junction (between separating wall and flanking floors) Top Junction (between separating wall and flanking ceiling) Side Junctions (between separating wall and flanking walls) S1 to S15 F1 concrete floor assembly from Table 9.10.3.1.-B with mass per area not less than 300 kg/m 2 (e.g. normal-weight concrete with average thickness of 130 mm) with or without an additional material layer or finished flooring F1 concrete floor assembly from Table 9.10.3.1.-B with mass per area not less than 300 kg/m 2 (e.g. normal-weight concrete with average thickness of 130 mm) with or without gypsum board ceiling suspended below concrete floor Example Showing Side View of Bottom and Top Junctions flanking wall framing is structurally connected to separating wall and terminates where it butts against framing of separating wall or is continuous across junction gypsum board on flanking walls ends or is cut at separating wall and is fastened directly to framing or on resilient metal channels (3) flanking wall consists of steel framing (loadbearing or non-loadbearing steel studs) or concrete blocks with mass per area not less than 200 kg/m 2 (e.g. normal-weight hollow core concrete block units (4) with a gypsum board lining supported on framing providing a cavity not less than 50 mm deep) with or without absorptive material (2) in cavities behind gypsum board of flanking walls Example Showing Plan View of Side Junctions B1 to B10 same options as stated above for walls S1 to S15 same options as stated above for walls S1 to S15 junction at top of concrete block assembly is loadbearing or non-loadbearing resilient joint same options as stated above for walls S1 to S15 Example Showing Side View of Bottom and Top Junctions Examples Showing Plan View of Side Junctions Copyright Queen s Printer for Ontario 2015 Page 12
Notes to Table A-9.11.1.4.-A: (1) See also Table A-9.11.1.4.-B. (2) Sound absorptive material is porous (closed-cell foam was not tested) and includes fibre processed from rock, slag, glass or cellulose fibre with a maximum density of 32 kg/m3. See Notes (3) and (6) of Table 1 and Note (4) of Table 2 of MMAH SB- 3 Fire and Sound Resistance of Building assemblies for additional information. (3) Resilient metal channels are formed from steel having a maximum thickness of 0.46 mm (25 gauge) with slits or holes in the single leg between the faces fastened to the framing and to the gypsum board (see Figure A-9.10.3.1.-D). ASTM C 754, Installation of Steel Framing Members to Receive Screw-Attached Gypsum Panel Products, describes the installation of resilient metal channels. (4) Normal-weight concrete block units conforming to CSA A165.1, Concrete Block Masonry Units, have aggregate with a density not less than 2 000 kg/m3; 190 mm hollow core units are 53% solid, providing a wall mass per area over 200 kg/m2; 140 mm hollow core units are 75% solid, providing a wall mass per area over 200 kg/m2. Table A-9.11.1.4.-B presents options for improving the sound performance of separating wall systems beyond that achieved by implementing the options presented in Table A-9.11.1.4.-A. The suggested performance improvement options are listed in order of approximate acoustic priority and are interdependent, i.e., if options at the top of the list are not implemented, then options at the bottom of the list will have much lesser effect. Table A-9.11.1.4.-B Options for the Construction of a Separating Wall System to Further Improve the Sound Insulation Performance Achieved with the Options in Table A-9.11.1.4.-A Type of Separating Wall Assembly with STC 50 from Table 1 of MMAH SB-3 Fire and Sound Resistance of Building Assemblies W4, W5, W6, W8, W9, W10, W11, W12 W13, W14, W15 Performance Improvement Options for Junctions Between Separating Walls and Flanking Floor/Ceiling Assemblies Increase mass per area of additional material layer and finished flooring over subfloor (e.g. concrete or gypsum concrete topping) Choose separating wall assembly with higher STC rating Orient floor and ceiling joists parallel to separating wall (non-loadbearing case) Add resilient layer under additional material layer over subfloor or between additional material layer and finished flooring Support gypsum board panels of ceiling on resilient metal channels (1) Support gypsum board panels of flanking walls on resilient metal channels (1) If seismic or other structural requirements permit, choose a fire block detail at floor/wall junction in accordance with Subsection 9.10.16. that does not provide a rigid connection between the two rows of framing of the separating wall (e.g. subfloor not continuous across junction and semi-rigid fibre insulation board filling the gap in accordance with Article 9.10.16.3.). In this case, an additional material layer would not be necessary. Also, choose separating wall assembly with higher STC rating (e.g. more absorptive material (2) in cavities and/or more gypsum board). If having a rigid structural connection at the floor/wall junction (such as subfloor continuous across the junction) is required for seismic or other structural reasons, obtain a higher ASTC rating as follows: Increase combined mass per area of additional material layer over subfloor and finished flooring (e.g. concrete or gypsum concrete topping) Choose separating wall assembly with higher STC rating (e.g. more absorptive material (2) and/or more gypsum board) Support gypsum board panels of ceiling on resilient metal channels (1) Support gypsum board panels of flanking walls on resilient metal channels (1) Add resilient layer under additional material layer over subfloor or between additional material layer and finished flooring Copyright Queen s Printer for Ontario 2015 Page 13
Type of Separating Wall Assembly with STC 50 from Table 1 of MMAH SB-3 Fire and Sound Resistance of Building Assemblies S1 to S15 B1 to B10 Performance Improvement Options for Junctions Between Separating Walls and Flanking Floor/Ceiling Assemblies Choose separating wall assembly with higher STC rating Increase thickness of concrete floor slab and/or add material layer and finished flooring over subfloor Add gypsum board ceiling on framing supported under the floor above, with cavity not less than 100 mm deep Add resilient layer under additional material layer over subfloor or between additional material layer and finished flooring Support gypsum board panels of flanking walls on resilient metal channels (1) if steel studs are loadbearing type Choose separating wall assembly with higher STC rating Add gypsum board ceiling supported below concrete floor with cavity not less than 100 mm deep and sound absorptive material (2) in cavity Increase thickness of concrete floor slab and/or add material layer and finished flooring over subfloor Add resilient layer under additional material layer over subfloor or between additional material layer and finished flooring and increase mass per area of additional material layer and finished flooring (e.g. floating concrete or gypsum concrete topping) Support gypsum board panels of flanking walls on resilient metal channels (1) if steel studs are loadbearing type Notes to Table A-9.11.1.4.-B: (1) Resilient metal channels are formed from steel having a maximum thickness of 0.46 mm (25 gauge) with slits or holes in the single leg between the faces fastened to the framing and to the gypsum board (see Figure A-9.10.3.1.-D). ASTM C 754, Installation of Steel Framing Members to Receive Screw-Attached Gypsum Panel Products, describes the installation of resilient metal channels. (2) Sound absorptive material is porous (closed-cell foam was not tested) and includes fibre processed from rock, slag, glass or cellulose fibre with a maximum density of 32 kg/m 3. See Notes (3) and (6) of Table 1 and Note (4) of Table 2 of MMAH SB-3 Fire and Sound Resistance for Existing Buildings for additional information. Table A-9.11.1.4.-C presents compliance options for the construction of separating floor/ceiling assemblies with flanking wall assemblies in vertically adjoining spaces. Copyright Queen s Printer for Ontario 2015 Page 14
Table A-9.11.1.4.-C Options for the Design and Construction of Junctions and Flanking Surfaces Between Separating Floor/Ceiling Assemblies in Vertically Adjoining Spaces for Compliance with Clause 9.11.1.1.(1)(b) Type of Separating Floor/Ceiling Assembly with STC 50 from Table 2 of MMAH SB-3 Fire and Sound Resistance of Building Assemblies F1 (with or without gypsum board ceiling) Options for Design and Construction of Junctions and Flanking Surfaces (1) to Address Vertical Sound Transmission Paths Junctions with Flanking Steel-Framed Walls floor ends at flanking wall assembly (T-junction) or extends beyond it (cross-junction) steel framing of flanking walls is loadbearing or non-loadbearing, with a single row of steel studs, staggered studs, or 2 rows of studs, with studs spaced not less than 400 mm o.c., with or without absorptive material (2) in cavities flanking wall structure is fastened to separating concrete floor but is not continuous across junction gypsum board on flanking walls is not continuous across junction and is fastened directly to wall framing or on resilient metal channels (3) Junctions with Flanking Concrete Walls floor ends at flanking wall assembly (T-junction) or extends beyond it (cross-junction) one wythe of concrete blocks with mass per area not less than 200 kg/m 2 (e.g. normal-weight hollow core concrete block units (4) ) loadbearing (solid) or non-loadbearing (resilient) junction between top of flanking concrete block wall and floor structure gypsum board lining is supported on wood or steel framing providing a cavity not less than 50 mm deep, with or without absorptive material (2) in cavities gypsum board on flanking walls is not continuous across junction and is fastened directly to wall framing or on resilient metal channels (3) F8 to F38 Junctions with Flanking Loadbearing or Non-Loadbearing Walls wood studs of flanking wall are 38 mm x 89 mm or 38 mm x 140 mm and spaced 400 mm or 600 mm o.c. flanking wall framing consists of single row of wood studs, staggered studs on a single 38 mm x 140 mm plate, or 2 rows of 38 mm x 89 mm wood studs on separate 38 mm x 89 mm plates, with or without absorptive material (2) in wall cavities gypsum board on flanking walls ends or is cut near floor framing and is fastened directly to wall framing or supported on resilient metal channels (3) Example Showing Side View of Junctions in Flanking Loadbearing Wall Example Showing Side View of Junctions in Flanking Non-Loadbearing Wall Notes to Table A-9.11.1.4.-C: (1) See also Table A-9.11.1.4.-D. (2) Sound absorptive material is porous (closed-cell foam was not tested) and includes fibre processed from rock, slag, glass or cellulose fibre with a maximum density of 32 kg/m 3. See Notes (3) and (6) of Table 1 and Note (4) of Table 2 of MMAH SB-3 Fire and Sound Resistance of Building assemblies for additional information. Copyright Queen s Printer for Ontario 2015 Page 15
(3) Resilient metal channels are formed from steel having a maximum thickness of 0.46 mm (25 gauge) with slits or holes in the single leg between the faces fastened to the framing and to the gypsum board (see Figure A-9.10.3.1.-D). ASTM C 754, Installation of Steel Framing Members to Receive Screw-Attached Gypsum Panel Products, describes the installation of resilient metal channels. (4) Normal-weight concrete block units conforming to CSA A165.1, Concrete Block Masonry Units, have aggregate with a density not less than 2 000 kg/m 3 ; 190 mm hollow core units are 53% solid, providing a wall mass per area over 200 kg/m 2 ; 140 mm hollow core units are 75% solid, providing a wall mass per area over 200 kg/m 2. Table A-9.11.1.4.-D presents options for improving the sound performance of separating floor/ceiling assemblies beyond that achieved by implementing the options presented in Table A-9.11.1.4.-C. The suggested performance improvement options are listed in order of approximate acoustic priority and are interdependent, i.e., if options at the top of the list are not implemented, then options at the bottom of the list will have much lesser effect. Table A-9.11.1.4.-D Options for the Construction of a Separating Floor System to Further Improve the Sound Insulation Performance Achieved with the Options in Table A-9.11.1.4.C. Type of Separating Floor Assembly with STC 50 from Table 2 of MMAH SB-3 Fire and Sound Resistance of Building Assemblies F1 (with or without gypsum board ceiling) F8 to F38 Performance Improvement Options for Junctions Between Separating Floors and Flanking Wall Assemblies Add heavier additional material layer over subfloor and/or resilient layer under additional material layer or between additional material layer and finished flooring Add gypsum board ceiling supported at least 100 mm below concrete floor with minimal structural connection (e.g. ceiling framing supported resiliently) and sound absorptive material (1) in cavity Support gypsum board of flanking walls of lower room on resilient metal channels (2) (if framed with loadbearing studs) Add heavier additional material layer over subfloor and/or resilient layer under additional material layer or between additional material layer and finished flooring Add more/heavier gypsum board to ceiling and increase spacing of resilient metal channels (2) to 600 mm o.c. Support gypsum board of flanking loadbearing walls of lower room on resilient metal channels (2) Support gypsum board on flanking non-loadbearing walls of lower room on resilient metal channels (2) Notes to Table A-9.11.1.4.-D: (1) Sound absorptive material is porous (closed-cell foam was not tested) and includes fibre processed from rock, slag, glass or cellulose fibre with a maximum density of 32 kg/m 3. See Notes (53) and (86) of Table 9.10.3.1.-A1 and Note (54) of Table 9.10.3.1.-B2 of MMAH SB-3 Fire and Sound Resistance of Building Assemblies for additional information. (2) Resilient metal channels are formed from steel having a maximum thickness of 0.46 mm (25 gauge) with slits or holes in the single leg between the faces fastened to the framing and to the gypsum board (see Figure A-9.10.3.1.-D). ASTM C 754, Installation of Steel Framing Members to Receive Screw-Attached Gypsum Panel Products, describes the installation of resilient metal channels. Copyright Queen s Printer for Ontario 2015 Page 16
A-Table 9.11.1.4. Floor Treatments. The sound insulation performance of lightweight framed floors can be improved by adding floor treatments, i.e., additional layers of material over the subfloor (e.g. concrete topping, OSB or plywood) and finished flooring or coverings (e.g., carpet, engineered wood). Table A-Table 9.11.1.4. presents the mass per area values based on thickness and density of a number of generic floor treatment materials (the values for proprietary products may be different; consult the manufacturer s current data sheets for their products values). Table A-Table 9.11.1.4. Mass per Area of Floor Treatment Materials Floor Treatment Material Thickness, mm Density, kg/m³ Mass per Area, kg/m 2 Materials Typically Having a Mass per Area Less Than 8 kg/m² Medium-density fibreboard (MDF) 2.9 6.1 790 810 2.3 5.0 Plywood generic softwood 12.5 13.3 15.5 16.3 450 500 5.6 6.6 7.0 8.1 Ceramic tile 8.4 700 1 000 5.9 8.4 Materials Typically Having a Mass per Area Greater Than 8 kg/m² but Less Than 16 kg/m² Particleboard 11.3 19.2 Medium-density fibreboard (MDF) Oriented strandboard (OSB) 13.9 21.1 14.3 15.8 17.3 18.8 710 755 640 755 600 680 8.1 14.5 8.9 15.9 8.6 10.7 10.4 12.8 Plywood generic softwood 25.5 450 500 11.5 13.1 Materials Typically Having a Mass per Area Greater Than 16 kg/m² but Less Than 32 kg/m² Medium-density fibreboard (MDF) 25.0 32.1 640 740 16.0 23.7 Materials Typically Having a Mass per Area Greater Than 32 kg/m² Concrete 40.0 50.0 Gypsum concrete 25.0 2 015 2 380 1 840 1 870 80.6 119.0 46.1 46.7 RATIONALE FOR CHANGE Problem/General Background The requirements in the Building Code with regard to sound transmission are based on the best available information at the time they were introduced. The requirements focus on the laboratory rating of the separating assembly, rather than performance of the system. Advances in the field of acoustical research now make it clear that this falls well short of achieving a level of performance consistent with the objectives of the Code. The current provisions encourage an over-simplified design approach that results in frequent investment in the wrong elements and most importantly fail to provide a functional requirement that establishes a minimum acceptable performance necessary to satisfy the Objective OH3 Noise Protection. Copyright Queen s Printer for Ontario 2015 Page 17
Justification/Explanation This proposed change would harmonize requirements with the model National Building Code of Canada. Switching from the current STC rating to the Apparent Sound Transmission Class (ASTC) rating would address the minimum performance of the complete system without over-design and with minimal implication to the scope of the OBC and enforcement. Specifically: 9.11.1.1 - This Article was brought to the beginning of the Section because it contains the actual required ratings and deemed-to-comply constructions and clarifies the application for each required rating. An ASTC rating has been added as an option to the requirements for secondary suites in Sentence 9.11.1.1.(2) because this will allow the use of the simplified and detailed calculation methods in Part 5. A rating of STC 43 and ASTC 40 can be considered as roughly equivalent because it is unlikely that the current performance (STC 43) would be further compromised through flanking contributions through commonly constructed walls- floorand ceiling assemblies. The STC rating required between elevator shafts and dwelling units in Sentence 9.11.1.1.(3) will remain unchanged because there are currently no metrics that address noise generated by elevators. Increasing the criteria for a required (airborne) STC rating as is currently done in the Building Code was considered better than no requirement at all. Addressing the protection of occupants from elevator noise through ASTC would therefore also not be an improvement over requiring an STC rating. 9.11.1.2. - This Article describes acceptable measurement and calculation methods for the ratings used in this Section. The field measurement standard has been deleted as an option to determine the STC because it is virtually impossible to isolate the direct sound transmission of the separating assembly from the overall sound experienced in the receiving room. Sentence 9.11.1.2.(2) introduces two acceptable ways to determine an ASTC rating either by an in-situ test or by calculating. 9.11.1.3. - This new Article specifies all available and acceptable compliance methods including deemed-tocomply methods involving the looking up of ratings for assemblies constructed according to generic specifications. While the lookup method for an STC (Sentence 1) results in an actual single number rating, the lookup method for an ASTC (Sentence 2) results in specifications for acceptable construction of direct and flanking assemblies without a single number rating. 9.11.1.4. - This Article allows the use of the STC metric to comply with the requirements for dwelling units. The requirements address three deemed- to-comply scenarios: Flanking walls attached to a separating floor or ceiling Flanking walls or ceilings attached to a separating wall, and Flanking floor assemblies attached to a separating wall The article also addresses the fact that flanking contributions through concrete assemblies are negligible in most cases. Problems could arise where concrete block is too light or in some cases for concrete basement slabs. Copyright Queen s Printer for Ontario 2015 Page 18