BUILDING PHYSICS SOLID TIMBER MANUAL 2.0
BUILDING PHYSICS © Binderholz GmbH & Saint-Gobain Rigips Austria GesmbH 1st edition, May 2019 All information in this document reflects the latest state of development and has been prepared for you according to the best of knowledge and good faith. As we always strive to offer the best possible solutions for you, we reserve making changes due to improvements in terms of application or production technology. Assure yourself that you have the most recent edition of this document available. Printing errors cannot be ruled out. This publication is targeted at trained specialists. The illustrations of executing activities contained in this document are not understood as processing instructions, unless expressly marked as such. Renderings and sectional views of the individual assemblies are not depicted on scale; they merely serve as illustration. Our products and systems are matched to each other. Their interaction has been confirmed by internal and external testing. All information is generally based on the exclusive use of our products. Unless described otherwise, the information does not permit any conclusions as to the combinability with third-party systems or exchangeability of individual parts by external products; to this end, no warranty can be extended or liability accepted. Please also note that our business relationships are exclusively subject to our general terms of sale, delivery and payment (GTC) in the current version. You can receive our GTC on request or find them online at www.binderholz.com and www.rigips.com. We are looking forward to a pleasant cooperation and wish you great success with all of our system solutions. Publisher Binderholz GmbH and Saint-Gobain Rigips Austria GesmbH Technical implementation Dipl.-Ing. (FH) Tim Sleik, Dipl.-Ing. Christian Kolbitsch and Dipl.-Ing. (FH) Jens Koch Graphic implementation Advertising Agency Goldfeder − Jasmin Brunner Photos binderholz, Rigips Austria, Rothoblaas, Getzner Werkstoffe HOTLINES: Binderholz Bausysteme GmbH Saint-Gobain Rigips Austria GesmbH Tel. +43 6245 70500 Tel. +43 1 616 29 80-517 www.binderholz.com www.rigips.com
BUILDING PHYSICS CONTENT Sound insulation 6 Air-borne sound insulation 6 Structure-borne sound / footfall sound 7 Flanking transmission / secondary sound paths 7 Planning information for sound insulation 8 Improvement possibilities to reduce the flank sound transmission 9 CLT BBS ceiling in visual surface quality – optimisation of the flank transmission of the ceiling support on an apartment partition wall 11 Sound insulation of components without secondary paths as calculation basis 13 Flank insulation values Rij,w to be considered 15 Calculation of the air-borne sound insulation value R’w in consideration of the secondary paths 17 Vertical sound transmission via the apartment separating ceiling 17 Secondary paths to be considered for vertical footfall sound transmission 20 List of formulas on sound insulation 22 Table of abbreviations, sound insulation 23 Heat insulation / Humidity regulation 26 Winter heat insulation 26 Summer heat insulation 27 Humidity regulation 28 Building physical parameters of CLT BBS 29 Fire protection 32 Fire resistance of components 32 Fire behaviour of building materials 33 binderholz CLT BBS in the event of a fire 34 Fire stops in timber construction 36 Fire protection evaluation of component joints 37 List of figures 38 Sources 39
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5 SOUND INSULATION
BUILDING PHYSICS 6 SOUND INSULATION Sound insulation serves the purpose of protecting people adequately from noise in social rooms. In timber construction, the components always comprise multiple layers. This way, the sound encounters multiple resistances on its path in between the individual components. While the sound insulation of single-layer components is based exclusively on their mass and flexural stiffness, smart multi-layer structures with decoupled layers and hollow space insulating materials can reach steady sound insulating values with substantially lesser masses. The construction situation is decisive for the evaluation of sound insulation. This means that given the requirements of sound insulation, a separating component must always be evaluated including the secondary sound paths. binderholz CLT BBS In solid timber structures, foremost the total thickness of the cross laminated timber CLT BBS, its surface weight and flexural stiffness play an essential role for the sound insulation of the basic component (without further layers). Generally, the complete component (wall, ceiling, roof) is supplemented by additional layers (façade, installation level, floor structure, etc.) The sound insulation of the complete component is significantly improved by additional cladding. Components made of CLT BBS are made of modular elements. The modular connections required due to the structure are tested comprehensively for sound insulation and designed so that they do not have any negative effects on the indicated sound insulation value. For the use of CLT BBS as separating ceiling or partition wall in a residential unit, component assemblies have been developed in the course of comprehensive testing at the ift Rosenheim that meet the relevant requirements for sound insulation. The measuring results illustrate clearly that these optimised assemblies also withstand comparisons to reinforced concrete walls and notably so with one-fifth of the mass. Rigips dry construction systems Layers with large surface measures, for example, plasterboards have a positive effect on sound insulation. By additionally mounting an installation level, a flexible shell is created that substantially increases sound insulation in high and medium frequency ranges. Here, flexible bearing profiles such as RigiProfil as well as heavy flexible panelling, e.g. Rigips fire protection plates should be used and the largest possible shell spacing should be ensured. Air-borne sound insulation A structure is excited to oscillate during sound transmission. In the case of multi-layer structures, the insulating material in the hollow space affects the coupling of the individual layers and the sound distribution inside of the hollow space. The rated sound insulation value R’w [dB] indicates the sound insulation of a component between two rooms including secondary sound paths (see Figure 1). The sound insulation of multi-layer components depends on the characteristics of each individual layer and on the interaction of all layers. The properties of the individual layers depend on their surface measure (mass inertia) and flexural stiffness. For example, the sound insulation can be improved by mounting an installation level in addition, which consists of plasterboards, meaning a flexible layer with large surface measure. The sound insulation can be improved, for example, by • a reduction of the surface connecting points of the individual layers (paying attention to statically required spacing); • use of flexible bearing profiles such as spring rails, metal stand flexible shells; • use of heavy flexible panelling such as plasterboards; • use of soft insulating material in hollow spaces; • increasing the shell spacing. Figure 1 – The ceiling test bench in the sound testing lab and arrangement of the measuring instruments
BUILDING PHYSICS 7 Structure-borne sound / footfall sound Structure-borne sound is induced in a component through mechanical stimulation (see Figure 2). Footfall sound is a structure-borne sound that is caused, for example, by children jumping around or knocking. The disruptive sound is mechanically induced directly into the ceiling and deflected to the neighbouring rooms. The insulation of a ceiling is marked by the rated standard footfall sound level L’nT,w [dB]. Consideration of the construction situation including the secondary sound paths is indicated here by the line. For the measurement of footfall sound, the ceiling in the transmitting room is excited by a standard hammer mill and the sound level generated is measured in the receiving room. The lower the level, the better the rating of the ceiling for insulating footfall sound. The assembly to be selected decisively depends on • the dynamic stiffness s’ of the sound insulation panels, • the masses of the floor screed or unfinished ceiling, • the reinforcement of the unfinished ceiling. The weaker the dynamic stiffness s’ the better the footfall sound insulation (the permissible load of the footfall sound insulation must be observed). It is essentially attempted to prevent or minimise the induction of footfall sound into the structure and its transfer and deflection in the form of airborne noise. The deflection to the receiving room can be reduced by means of facing formwork. Figure 2 – Reduction of structure-borne sound Source: HFA planning brochure “Ceiling structures for multi-storey timber construction”, 2009 Flanking transmission / secondary sound paths Besides the separating component, also all flanking building parts are involved in the sound insulation between two rooms. The separating component is just one of the many transmission paths. For separating components with high sound insulation, the sound is transmitted for the most part via the flanking ceilings, roofs, interior and exterior walls. To optimise the sound insulation of components, it must be aimed for the lowest possible transmission via secondary paths. The extent of the transmission via secondary paths depends on the concrete construction situation. The forwarding of the sound is structurally prevented by a bearing on elastic interim layers (see Figure 3). Figure 3 – On the left, Rothoblaas XYLOFON and on the right, Getzner Sylodyn By planning in facing formwork and suspended ceiling structures, these additional measures can be reduced and, in part, they can even be omitted entirely. Source: Planning brochure of Holzforschung Austria The behaviour of solid timber structures is very different from solid mineral construction. Forecast models existing so far do not reflect the actual behaviour of solid timber structures. To be able to reliably fulfil the requirements for sound insulation and suitability for use, the components are frequently overdimensioned through substitute models and simplified conservative approaches and thereby become inefficient. Within the scope of the project “Vibro-acoustics in the planning process for timber structures” that is supported by binderholz and SaintGobain Rigips Austria among others, comprehensive measurements of the sound transmission via flanking components have been conducted (see Figure 4). A prediction model according to DIN EN ISO 12354 was developed, which considers the diverse transmission paths in the construction situation and nonetheless remains applicable for the construction practitioner. The model is being integrated in the new DIN 4109. Reduktion von Körperschall Floor screed TSD boards Filling CLT BBS unfinished ceiling Intermediate layer CLT BBS wall elastic planking Induction Insulation Insulation Deflection Insulation © Rothoblaas © Getzner Werkstoffe
BUILDING PHYSICS 8 The following illustrations show the various secondary sound paths depending on the construction situation: Figure 4 – Schematic diagram of the contributions to the sound transmission in timber construction Source: Vibro-acoustics research project Model for calculation according to DIN EN ISO 12354 The calculation of single-number ratings of the sound insulation, R’w and of the standard footfall sound level L’n,w in construction is based on the transmissions paths shown in Figure 4 according to the following equations: The footfall sound flank path DFf, going into the floor screed and, via the flanking wall in the transmitting room, down into the flanking wall in the receiving room is not considered yet in the normative calculation according to EN 12354. Acoustics predictions were compared to construction site measurements and a substantial effect of this transmission path can be seen (vibro-acoustics research project). In this planning brochure, the corresponding predictive model is described, which is illustrated in detail in the calculation example provided. Planning notes for sound insulation The table below shows recommendations for the sound insulation of apartment ceilings and partition walls for multi-storey buildings for residential housing based on DIN 4109, supplement 2 and respectively ÖNORM B 8115. The data refers to the construction situation including all secondary sound paths. Building part Austria Germany Apartment partition wall D’nT,w ≥ 55 dB R’w ≥ 55 dB Apartment separating ceiling L’nT,w ≤ 48 dB Minimum requirement: L’n,w ≤ 53 dB Enhanced requirement: L’n,w ≤ 46 dB R’w = –10 lg ( 10 – 0,1R w + ∑10– 0,1R ij,w ) with ij = Ff, Fd, Df L’n,w = 10 lg ( 10 0,1L n,w + ∑10 0,1L n,ij,w ) with ij = Df, DFf 1 2 Footfall sound transmission Vertical air-borne sound transmission Horizontal air-borne sound transmission
BUILDING PHYSICS 9 Overview of the built examples in solid timber construction, enhanced requirements for apartment separating ceilings according to DIN 4109, supplement 2 are fulfilled The table below shows structures in finished buildings that fulfil all enhanced requirements for apartment separating ceilings in consideration of all flanking components (vibro-acoustics research project) BV Ceiling Walls Additional measures Prediction Construction measurement 2 80 50 85 200 Concrete floor screed MFT, s’ = 6 MN / m³ Lime chippings CLT BBS 100 mm CLT BBS Elastomer top and bottom R’w = 63.8 dB L’n,w = 42.5 dB R’w = 66 dB L’n,w = 45 dB 3 65 40 90 100 Concrete floor screed MFT, s’ = 6 MN / m³ Lime chippings Glulam 100 mm CLT BBS 12.5 mm Rigips RF fire protection board Elastomer top R’w = 61.3 dB L’n,w = 45.8 dB R’w = 63 dB L’n,w = 45 dB 4 60 40 15 447 Concrete floor screed MFT, s’ = 6 MN / m³ Fibreboard Wood-concrete compound ≥ 100 mm CLT BBS Facing formwork R’w = – dB L’n,w = 44 dB 5 60 40 90 200 Concrete floor screed MFT, s’ = 6 MN / m³ Lime chippings Glulam 2 x 18 mm Rigips RF fire protection board ≥ 100 mm CLT BBS 2 x 18 mm Rigips RF fire protection board K260 encapsulation R’w = 60.9 dB L’n,w = 44.0 dB R’w = 59 dB L’n,w = 43 dB Improvement possibilities to reduce the flank sound transmission Based on the accompanying research project “vibro-acoustics in the planning process for timber structures” and a number of planning brochures as well as specialised lectures, binderholz and Saint-Gobain Rigips Austria gained valuable and practically applicable insights for the planning of solid timber construction that is optimised in terms of sound insulation. In the following, these measures are explained and the positive effects are presented in a comprehensible way by means of a calculation example. Viewed for themselves, CLT BBS solid timber elements for walls and ceilings are rigid discs. This nature of a disc entails that the flanking components made of large-format elements have a poorer effect for the insulation of the flanks than components that consist of CLT BBS 125 elements. For example, the component of a flanking exterior wall consists of many lined-up elements with width of each 1.25 m that are joined with bolts by a wooden riser. The modular panel joint here works like a spring or a separating cut and thereby provides substantial insulation for the flank transmission (see Figure 5). The measurements of the flank insulation value RFf have been conducted with this modular construction method and the assessed values in the calculation example that are more favourable in terms of sound insulation are applicable only when using this construction method. Source: Vibro-acoustics research project Figure 5 – Difference in the flank sound transmission between CLT BBS 125 and the CLT BBS XL large-format panel Large-format board CLT BBS XL CLT BBS 125
BUILDING PHYSICS 10 Flanking CLT BBS walls should be provided with a facing formwork that has decoupling effects (installation level on vibration mounts, shell spacing at least 5 mm or use stand-alone facing formwork – see Figure 6). Figure 6 – Facing formwork working with decoupling effect on one or both sides In the calculation of the sound transmission, the mass of the binderholz cross laminated timber CLT BBS wall and ceiling elements have a strong influence. The measurements show that directly applied plasterboard planking has a positive effect on the flank sound insulation. In detail, this effect is illustrated in the calculation example. Elastomers can be used for the sound decoupling in the case of vertical flank transmission, for example, on the supports of an apartment separating ceiling. The following table shows the improvement of the joint insulation values (input parameters for calculation of the sound insulation value incl. secondary paths R’w – see page 17). Only the upper elastomer has effects on the transmission path Fd and only the bottom elastomer affects the path Df. The paths Ff and DFf are influenced by both elastomers. Arrangement of the elastomers Position Data from the DAGA 2010 conference transcript New measured data top bottom top or bottom ∆Kij = 7 … 10 dB ∆Kij = 4 … 10 dB top and bottom ∆Kij = 8 … 19 dB ∆Kij = 13 … 15 dB Source: Vibro-acoustics research project NOTES The indicated values have a wide spread, as elastomers of different manufacturers have been used in combination with different wall and ceiling structures. The information applies only to decoupled mounting materials (angles with elastomer boards, bolts with lining and elastic insulating washers – see Figure 7). If conventional fasteners are used, the decoupled effect of the elastomer will reduce significantly. In that case, a ∆Kij of 2 to 3 dB can be assessed. Further planning bases for the influence of elastomer bearings with and without consideration of the installed fasteners can be found in the planning brochure of Holzforschung Austria entitled “Roof structures for multi-storey timber construction”. Source: Rothoblaas planning brochure Figure 7 – Decoupled fasteners with elastomer bearings of different manufacturers © Rothoblaas © Getzner Werkstoffe © Rothoblaas
BUILDING PHYSICS 11 CLT BBS ceiling in visual surface quality – optimisation of the flank transmission of the ceiling support on an apartment partition wall CLT BBS ceilings with wooden surface visible on the bottom side contribute to the flank transmission between adjacent rooms (see Figure 8). Current measurements of the flank insulation value RFf have shown that a ceiling reinforcement using filling in combination with a wet screed floor structure results in a substantial improvement of the flank insulation (vibro-acoustics research project). Figure 8 – Different path of the flank sound transmission in the ceiling area A 150-mm thick binderholz CLT BBS 125 ceiling that rests on an 80-mm thick CLT BBS 125 wall results in a measured RFf,w of 44 dB. If an element consisting of 60-mm chipping filling, a 40-mm footfall sound insulation board and 50-mm concrete screed is applied on the 1500mm thick CLT BBS ceiling, the measured RFf,w increases to 61 dB. If a continuity effect of the CLT BBS ceiling is dispensable in terms of structural stability, a separation of the ceiling fields in the axes of the apartment partition walls is an effective measure to improve the flank insulation. With a continuous 150-mm thick CLT BBS 125 ceiling, the measured flank insulation value is RFf 44 dB (as described above); with execution of a separating cut, the measured value for RFf increases to 49 dB. Another possibility to improve the flank insulation is to provide the flanking ceilings with an additional suspended ceiling with direct supports with vibration decoupling (see Figure 9). This way, the energy applied on the CLT BBS ceiling in the transmitting room and the deflection into the receiving room is significantly reduced. Figure 9 – Suspended ceiling with vibration decoupling
BUILDING PHYSICS 12 Example for calculating the sound insulation of a planned construction situation in consideration of secondary sound paths Figure 10 – Illustration of two apartments with apartment partition wall with vibration decoupling MAßSTAB: ail Variante 2 übertragung 1:50 BEARBEITER: andhal DATUM: PLAN-NR.: 21.12.2017 2 HOLZ BAUSYSTEME GmbH -HALVIC-STR. 46 HALLEIN fon +43 6245 70500-00 fax +43 6245 70500-7001 www.binderholz.com bbs@binderholz.com s Apartment separating ceiling Cement screed Footfall sound insulation Chip filling, 50 40 100 bound penetration shielding CLT BBS 5-layered Apartment 1 Apartment 2 150 MAßSTAB: PLANINHALT: Grundriss/Detail Variante 2 PROJEKT: Schall - Flankenübertragung 1:50 BEARBEITER: andhal DATUM: PLAN-NR.: 21.12.2017 2 BINDERHOLZ BAUSYSTEME GmbH SOLVAY-HALVIC-STR. 46 A-5400 HALLEIN fon +43 6245 70500-00 fax +43 6245 70500-7001 www.binderholz.com bbs@binderholz.com Interi r wall 100 15 CLT BBS 5-layered Gypsum fibre boards Interior wall CLT BBS 3-layered Battens on vibration mounts 60 70 Apartment separating wall 2x15 Gypsum fibre boards Battens on vibration mounts 30 70 bound penetration shielding CLT BBS 5-layered Apartment 2 Footfall sound: flank 2 Footfall sound: flank 4 Apartment 1 Apartment 2 120 CLT BBS 5-layered 70 30 2x15 Gypsum fibre boards Battens on vibration mounts 50 Mineral wool 15 Gypsum fibre boards 50 Mineral w ol 150 Footfall sound: flank 1 Footfall sound: flank 3 PLANINHALT: Exterior wall 100 160 40 8 CLT BBS 5-layered Heat insulation Battens with EPDM HPL Interior wall 100 15 CLT BBS 5-layered Gypsum fibre boards Interior wall CLT BBS 3-layered Battens on vibration mounts 60 70 Apartment separating wall 2x15 Gypsum fibre boards Battens on vibration mounts 30 70 15 Gypsum fibre boards Apartment 1 Apartment 2 Footfall sound: flank 2 Footfall sound: flank 4 120 CLT BBS 5-layered 70 30 2x15 Gypsum fibre boards Battens on vibration mounts 50 Mineral wool 15 Gypsum fibre boards 50 Mineral wool Footfall sound: flank 1 Footfall sound: flank 3
BUILDING PHYSICS 13 Sound insulation of components without secondary paths as calculation basis Calculation of R’w from the mass of a single-shell separating component in CLT BBS construction design without facing formwork where no test results are available: Component Component length lf Component layers for the flank sound calculation Rw,r assessed air-borne sound insulation in the flank sound calculation Rw,P tested air-borne sound insulation of the complete component Apartment partition wall 3.14 m 5-layered CLT BBS 120 mm (57.6 kg / m²) without assessed mass increase, planking of CLT BBS decoupled by means of vibration mounts 35.7 dB 69 dB Interior wall 3.12 m 5-layered CLT BBS 100 mm (48 kg / m²) with one-sided planking of 15-mm Rigips RF fire protection board, Additional mass 13.5 kg / m² 36.7 dB - Exterior wall (separating cut on the axis of the apartment partition wall) 3.12 m 5-layered CLT BBS 100 mm (48 kg / m²) with one-sided planking of 15-mm Rigips, RF fire protection board, additional mass 13.5 kg / m² 36.7 dB 47 dB* Apartment separating ceiling Area across the room viewed: Ss = 3.12 m x 3.14 m = 9.8 m² 5-layered CLT BBS 150 mm (72.0 kg / m²) with assessed mass increase from the floor assembly with heavy filling (196.0 kg / m²) results in a total mass of 268 kg / m² 57.1 dB Rw,P = 77 dB Ln,w,P = 38 dB * The value was measured with 90 mm CLT BBS and 12.5 mm Rigips RF fire protection board Horizontal sound transmission through the apartment partition wall Calculation of the sound insulation value in consideration of the secondary paths The measured sound insulation value R’w of the apartment partition wall (complete assembly R’w = 69 dB) can be inserted directly in the formula below: The flank insulation values Rij,w are to be calculated: R’w = 32.05 * log ( m'element ) – 18.68 + Kwall type with Kwall type = – 2 dB for large-format elemente 1 R’w = –10 lg ( 10 – 0,1R w + ∑10– 0,1R ij,w ) 1 R ij,w = ( R i,w+ R j,w ) / 2 + ∆R ij,w + K ij + 10 lg ( Ss / lolf ) 3
BUILDING PHYSICS 14 Explanation regarding the joint insulation value Kij Numerous Kij values were measured in the research project “Vibro-acoustics in the planning process for timber structures”. In addition, measured data of comparable assemblies from different European institutes have been compiled and assessed. The analysis in the table below shows the median values of the joint insulation values for various joint situations. Case Joint type Transmission direction Joint insulation value 1 “Vertical transmission” Path Ff KFf = 20 dB 2 “Horizontal transmission” Path Ff Ceiling, continuous KFf = 3 dB 3 “Horizontal transmission” Path Ff Ceiling, separated KFf = 12+10lg(m2' / m1') 4 “Mixed transmission” Path Df and Fd KFd = 14 dB KDf = 14 dB 5 “Horizontal transmission” Paths Ff, Df, Fd Walls of BBS 125 KFf = 12 dB KDf = KFd = 16 dB Figure 11 – Flank sound transmission with CLT BBS 125 elements In the structure consisting of CLT BBS 125, always 1.25-mm wide wall elements are lined up side-by-side and joined with a wooden riser, which has an acoustic effect like a separating cut (see Figure 11). Consequently, not case 1 must be expected for KFf with a continuous flanking wall, but the more favourable case 3. This was proven by means of the measurements in the course of the aforementioned research project. Likewise based on the acoustically favourable construction design using CLT BBS 125 elements, the RFf measuring results show that with the execution of a separating cut in the flanking wall on the partition wall axis, the KFf value from case 1 must be used in the calculation for this case. NOTE These projections with favourable effects on sound insulation can be chosen only when the exterior wall does not consist of large-format elements. Furthermore, any potentially existing direct planking on the interior side of the flanking wall must not extend beyond the partition wall.
BUILDING PHYSICS 15 Flank insulation values Rij,w to be considered 1. Flank of apartment partition wall – exterior wall RFf,w: Sound transmission into the flanking wall and out of the flanking wall again into the receiving room RF,w = 36.7 dB Rf,w = 36.7 dB ∆RFf,w = 0 dB (no facing formwork present) KFf = 20 dB (case 1 based on the modular construction method with 125 cm wide CLT BBS wall elements) Ss = 8.6 m² lo = 1.0 m lf = 2.75 m Calculation result: RFf,w = 61.6 dB RDf,w: Sound transmission into the partition wall and out of the flanking exterior wall again into the receiving room RD,w = 35.7 dB (calculation based on the mass of the unfinished CLT BBS 125 wall elements, 12 cm thickness) Rf,w = 36.7 dB ∆RDf,w = 18 dB (improvement value of a one-sided facing formwork on vibration mounts with double 12.5 mm planking on CLT BBS 125 wall, 90 mm thickness, measuring results from binderholz / Rigips) KDf = 16 dB (case 5) Ss = 8.6 m² lo = 1.0 m lf = 2.75 m Calculation result: RFd,w = 75.1 dB RFd,w: Sound transmission into the flanking exterior wall and out of the partition wall again into the receiving room For the calculation, the path Fd is set equal to Df: RFd,w = 75.1 dB 2. Flank of apartment partition wall – interior wall RFf,w: Sound transmission into the abutting interior wall and out of the abutting interior wall again into the receiving room RF,w = 36.7 dB Rf,w = 36.7 dB ∆RFf,w = 0 dB (no facing formwork present) KFf = 20 dB (case 1 based on the modular construction method with 125 cm wide CLT BBS wall elements) Ss = 8.6 m² lo = 1.0 m lf = 2.75 m Calculation result: RFf,w = 61.6 dB RDf,w: Sound transmission into the partition wall and out of the abutting interior wall again into the receiving room RD,w = 35.7 dB (calculation based on the mass of the unfinished CLT BBS 125 wall elements, 12 cm thickness) Rf,w = 36.7 dB ∆RDf,w = 18 dB (improvement value of a one-sided facing formwork on vibration mounts with double 12.5 mm planking on CLT BBS 125 wall, 90 mm thickness, measuring results from binderholz / Rigips) KDf = 16 dB (case 5) Ss = 8.6 m² lo = 1.0 m lf = 2.75 m Calculation result: RDf,w = 75.2 dB RFd,w: Sound transmission into the abutting interior wall and out of the partition wall again into the receiving room For the calculation, the path Fd is set equal to Df: RFd,w = 75.2 dB
BUILDING PHYSICS 16 3. Flank of apartment partition wall – ceiling RFf,w: Sound transmission into the flanking ceiling and out of the flanking ceiling again into the receiving room RF,w = 57.1 dB Rf,w = 57.1 dB ∆RFf,w = 0 dB (no suspended ceiling present) KFf = 5,3 dB (case 3, m1’ = 268 kg / m², m2’ = 57.6 kg / m²) Ss = 8.6 m² lo = 1.0 m lf = 3.14 m Calculation result: RFf,w = 66.8 dB RDf,w: Sound transmission into the partition wall and out of the flanking ceiling again into the receiving room RD,w = 35.7 dB (calculation based on the mass of the unfinished CLT BBS 125 wall elements, 12 cm thickness) Rf,w = 57.1 dB ∆RDf,w = 18 dB (improvement value of a one-sided facing form- work on vibration mounts with double 12.5 mm plank- ing on CLT BBS 125 wall, 90 mm thickness, measuring results from binderholz / Rigips) KDf = 14 dB (case 4) Ss = 8.6 m² lo = 1.0 m lf = 3.14 m Calculation result: RDf,w = 82.8 dB RFd,w: Sound transmission into the flanking ceiling and out of the partition wall again into the receiving room For the calculation, the path Fd is set equal to Df: RFd,w = 82.8 dB 4. Flank of apartment partition wall – floor The related secondary paths ij = Ff, Df, Fd are not considered, since the sound transmission is prevented structurally by • heavy floor assemblies with concrete floor screed • correct installation of the apartment partition wall, as shown in the cut, on the unfinished ceiling using the screed rim insulating strip
BUILDING PHYSICS 17 Calculation of the air-borne sound insulation value R’w with consideration of the secondary paths Based on the above described individual values, the following can be calculated by means of the formula R’w: According to DIN 4109, 2 dB must be considered as forecast unreliability for the air-borne sound: R’w = 57.3 dB – 2 dB = 55.3 dB > measured R’w = 55 dB Proof of the air-borne sound is thereby provided. REMARK regarding RDf and RFd These flank insulation values are far above the value of the flank paths RFf due to the decoupled insulation levels. For simplification, this path can be neglected in the execution of double-sided installation levels (stand-alone or on vibration mounts) on the apartment partition wall or on the interior side on the flanking wall. In the calculation example shown above, the difference when neglecting these flank paths is +0.3 dB for R’w . Vertical sound transmission via the apartment separating ceiling Footfall sound transmission in consideration of secondary paths The measured standard footfall sound level of the apartment partition wall (complete assembly Rw = 69 dB) can be inserted directly in the formula below: The footfall sound flank transmissions on the path Df and DFf are to be calculated: The lab value for the flank transmission of the footfall sound on the path Df is to be calculated according to the following formula: R’w = –10 log(10 -0,1×69 + 10-0,1×61,6 + 10-0,1×75,1 + 10-0,1×75,1 + 10-0,1×61,6 + 10-0,1×75,1 + 10-0,1×75,1 + 10-0,1×66,8 + 10-0,1×82,8 + 10-0,1×82,8 ) = 57.3 dB 1 L’n,w = 10 lg(10 0,1L n,w + ∑10 0,1L n,ij,w) 2 Ln,Df,w = Ln,Df,lab,w – ∆Kij – ∆Rj,w – 10lg (Ss / (lo lf)) Ln,DFf,w = Ln,DFf,lab,w – ∆Kij – ∆Rij,w – 10lg (Ss / ( lo lf)) 4 5 L’n,Df,lab,w = 10 lg(10 0,1(L n,w + K 1 ) – 10 0,1L n,w) 6
BUILDING PHYSICS 18 The factor K1 required for this purpose besides the rated standard footfall sound level L n,w can be found in the following table as dependent on the construction variant: Corrective summand K1 for consideration of the flank transmission on the path Df. Wall arrangement in the receiving room Ceiling assembly CLT BBS ceiling CLT BBS wall K1 = 4 dB The lab value for the flank transmission of the footfall sound on the path DFf, Ln,DFf,lab,w is shown shaded in grey in the right column of the table below, as dependent on the wall structure and floor assembly. In the table that applies under lab conditions, the value was referred to as Ln,DFf,w. Wall assembly in the transmitting and receiving room Floor screed assembly Footfall sound transmission on the paths Dd + Df: Ln,w + K1 in dB 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 >5 Ln,DFf,w in dB a) ZE / HWF 11 10 10 9 8 7 6 5 5 4 4 3 3 2 2 1 1 1 1 1 1 0 n = 1 46 b) ZE / MF 10 10 9 8 7 6 5 5 4 4 3 3 2 2 1 1 1 1 1 1 0 0 n = 7 45 σ σ = 1.5 c) TE 8 7 6 5 5 4 4 3 3 2 2 1 1 1 1 1 1 0 0 0 0 0 n = 6 42 σ σ = 0.9 Floor screed assembly: a) ZE / HWF mineral-bound screed or cast asphalt on soft fibre timber footfall sound insulation boards Rim insulating strips: > 5 mm mineral fibre or PE-foam rim strips b) ZE / MF mineral-bound screed or cast asphalt on soft fibre or PST footfall sound insulation boards Rim insulating strips: > 5 mm mineral fibre or PE-foam rim strips c) TE dry screed on mineral fibre, PST or soft fibre timber footfall sound insulation boards Rim insulating strips: > 5 mm mineral fibre or PE-foam rim strips
BUILDING PHYSICS 19 With these formulas and the related tables shown, the vertical footfall sound transmission in consideration of secondary paths can now be calculated for the illustrated planning example. In this process, respectively the two flank paths Df and DFf must be examined for all four walls of the analysed room, from which eight values result for Ln,ij,w. The following plan excerpt (see Figure 12) shows the analysed room with the flanking walls to be considered for the footfall sound transmission. Figure 12 – Optimised apartment partition wall for the prevention of flank sound transmission PLANIN Gru PROJE Sch Exterior wall 100 160 40 8 CLT BBS 5-layered Heat insulation Battens with EPDM HPL Inter 100 15 Interior wall CLT BBS 3 Battens o 60 70 Apartment separating wall 2x15 Gypsum fibre boards Battens on vibration mounts 30 70 15 Gypsum fibre boards Apartment 1 Apartment 2 Footfall sound: flank 2 Footfall sound: flank 4 120 CLT BBS 5-layered 70 30 2x15 Gypsum fibre boards Battens on vibration mounts 50 Mineral wool 15 Gypsum f 50 Mineral w Footfall sound: flank 1 Footfall sound: flank 3
BUILDING PHYSICS 20 Secondary paths to be considered for vertical footfall sound transmission 1. Flank ceiling – apartment partition wall Ln,w = 38 dB Ss = 9.8 m² lf = 3.14 m K1 = 4 dB (from Table 1, CLT BBS 125 ceiling in visual surface quality, CLT BBS 125 walls in visual surface quality or directly planked without consideration of potentially planned facing formwork / installation levels) Ln,Df,lab,w = 39.8 dB (calculation according to formula 6) Ln,DFf,lab,w = 45 dB (from Table 2, CLT BBS 125 ceiling in visual sur- face quality, floor assembly with concrete screed and mineral fibre footfall sound insulation boards, rim insulation strips always required) ∆Kij = 0 dB (no elastomer at the top) ∆Kij = 3 dB (elastomer at the bottom, effective for both flank paths) ∆Rij,w = 18 dB (improvement value of a one-sided facing form work on vibration mounts with double 12.5 mm plank- ing on CLT BBS 125 wall, 90 mm thickness, measuring results from binderholz / Rigips) Calculation result: Ln,Df,w = 13.9 dB Ln,DFf,w = 14.1 dB 2. Flank ceiling – interior wall Ln,w = 38 dB Ss = 9.8 m² lf = 3.12 m K1 = 4 dB (corresponding to flank 1) Ln,Df,lab,w = 39.8 dB (corresponding to flank 1) Ln,DFf,lab,w = 45 dB (corresponding to flank 1) ∆Kij = 0 dB (no elastomer at the top) ∆Kij = 3 dB (elastomer at the bottom, effective for both flank paths) ∆Rij,w = 0 dB (no facing formwork planned) Calculation results: Ln,Df,w = 31.8 dB Ln,DFf,w = 37.0 dB 3. Flank ceiling – interior wall Ln,w = 38 dB Ss = 9.8 m² lf = 3.14 m K1 = 4 dB (corresponding to flank 1) Ln,Df,lab,w = 39.8 dB (corresponding to flank 1) Ln,DFf,lab,w = 45 dB (corresponding to flank 1) ∆Kij = 0 dB (no elastomer at the top) ∆Kij = 3 dB (elastomer at the bottom, effective for both flank paths) ∆Rij,w = 15 dB (improvement value of a one-sided facing form- work on vibration mounts with single 15 mm planking on CLT BBS 125 wall, 90 mm thickness, measuring results from binderholz / Rigips) HolzBauSpezial confer- ence transcript) Calculation results: Ln,Df,w = 16.9 dB Ln,DFf,w = 22.1 dB 4. Flank ceiling – interior wall Ln,w = 38 dB Ss = 9.8 m² lf = 3.12 m K1 = 4 dB (corresponding to flank 1) Ln,Df,lab,w = 39.8 dB (corresponding to flank 1) Ln,DFf,lab,w = 45 dB (corresponding to flank 1) ∆Kij = 0 dB (no elastomer at the top) ∆Kij = 3 dB (elastomer at the bottom, effective for both flank paths) ∆Rij,w = 0 dB (no facing formwork planned) Calculation results: Ln,Df,w = 31.8 dB Ln,DFf,w = 37.0 dB
BUILDING PHYSICS 21 5. Calculation of the footfall sound transmission in consideration of secondary paths Calculation L’n,w by means of the following formula According to DIN 4109, 3 dB must be considered as forecast unreliability for the footfall sound: L’n,w = 43,0 dB + 3 dB = 46.0 dB ≤ measured L’n,w = 46 dB Proof of the footfall sound is thereby provided. Remarks regarding the calculation example Since the scientifically proven calculation described here differs from the requirements of DIN 4109, the proof for the separating ceiling must be rendered by means of a construction measurement. Simplified in-situ correction: for the calculation, the lab values L’n,w and R’w of the direct transmission are converted to match the construction situation by means of the structure-borne sound resounding period of the ceiling in the lab, Ts,lab, and at the construction site, Ts,situ. The effect of the in-situ correction (measured examples from the vibro-acoustics research project) is not considered in this calculation example; it results in a change of the calculated R’w or L’n,w values of an averaged ± 1 to 2 dB. L’n,w = 10log(10 0,1×38 + 100,1×13,9 + 100,1×14,1 + 100,1×31,8 + 100,1×37,0 + 100,1×16,9 + 100,1×22,1 + 100,1×31,8 + 100,1×37,0 ) = 43.0 dB 2 R’Dd = R’situ = R’lab – 10lg(Ts,situ /Ts,lab) or L’n,Dd = L’n,situ = L’n,lab + 10lg(Ts,situ /Ts,lab) 7 8
BUILDING PHYSICS 22 List of formulas on sound insulation 1 R’w [dB] Rated construction sound insulation value of a separating component (requirement for Germany) in installed condition with secondary paths 2 L’n,w [dB] Standard footfall sound level (requirement for Germany) in installed condition with secondary paths 3 R ij,w Calculated flank insulation value of a separating component for the individual secondary sound paths with ij = Df, Fd, Ff 4 Ln,Df,w [dB] Footfall sound flank transmission on the path Df, converted to the construction situation 5 Ln,DFf,w [dB] Footfall sound flank transmission on the path DFf, converted to the construction situation 6 Ln,Df, lab w [dB] Lab value of the footfall sound flank transmission on the path Df 7 R’Dd Calculated sound insulation value of a separating component (requirement for Germany) with secondary paths and with in-situ correction 8 L’n,Dd Calculated standard footfall sound level of a separating ceiling (requirement for Germany) with secondary paths and with in-situ correction
BUILDING PHYSICS 23 Table of abbreviations, sound insulation Rw [dB] Rated sound insulation value of a component without secondary sound paths Ln,w [dB] Rated standard footfall sound level of a component without secondary sound paths Ri,w [dB] Air-borne sound insulation value of the flanking component in the transmitting room Rj,w [dB] Air-borne sound insulation value of the flanking component in the receiving room ∆Rij,w [dB] Improvement value of the flank sound insulation (air-borne sound and footfall sound) achieved through installation levels or stand-alone facing formwork Ss [m²] Surface of the separating component lo [m] Reference length 1.0 m lf [m] Length of the butt joint of the flanking component to the separating component [m] Kij [dB] Joint insulation values for calculation of the flank insulation value Rij,w ∆Kij [dB] Improvement of the footfall sound flank transmission achieved through decoupling elastomers K1 [dB] Factor to calculate the footfall sound flank transmission on the path Df K2 [dB] Factor to calculate the footfall sound flank transmission on the path DFf Ln,DFf,lab,w [dB] Lab value of the footfall sound flank transmission on the path DFf D’nT,w [dB] Rated standard sound level difference of a separating component (requirement for Austria) in the built-in condition with secondary paths; resounding period in the receiving room is considered in it L’nT,w [dB] Standard sound level of a separating ceiling (requirement for Austria) in the built-in condition with secondary paths; resounding period in the receiving room is considered in it m1' [kg / m²] Assessable surface measures of the flanking component (without the mass of potential facing formwork or suspended elements) for the calculation of the joint insulation value Kij m2' [kg / m²] Assessable surface measures of the separating component (without the mass of potential facing formwork or suspended elements) for the calculation of the joint insulation value Kij
24 HEAT INSULATION
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BUILDING PHYSICS 26 HEAT INSULATION / HUMIDITY REGULATION Winter heat insulation Heat insulation in construction above ground level covers all measures to avoid a need for heating during the winter and cooling during the summer. At the same time, more comfort because of a pleasant room climate and the related significant relief for the environment are key points. With insufficient heat insulation, uncomfortable and unhygienic room climatic living conditions can set in. Why heat insulation? • To increase comfort. • To prevent illnesses. • To save costs because heating costs can be reduced substantially. • To increase the value of the building (energy costs). • To protect our environment because the CO2 emissions are significantly lowered. binderholz CLT BBS With cross laminated timber CLT BBS, low energy, passive energy and plus energy buildings can be constructed. CLT BBS structures fulfil all customary heat insulation values and create a comfortable and balanced room climate due to their permeable design and their capacity to lower the peak values of the humidity in the room. Since CLT BBS is made of pinewood lamellas, which are subject to strict quality control, the moisture of CLT BBS wood in the condition as delivered is guaranteed to be within a very narrow range at 12 % ± 2 % and a controlled gross density is also assured. For this reason, an improved value for heat conductivity λ of 0.12 W/ mK can be assessed for CLT BBS according to the valid ETA-06 / 0009. Rigips dry construction systems Modern timber structures in the passive and multi-comfort design using systems of Saint-Gobain guarantee the highest measure of quality. A comprehensive product range of Saint-Gobain insulating materials is available for floors, walls, ceilings and roofs. The range includes everything from normal heat insulation to complete system solutions for residential areas and for commercial and public buildings (see example in Figure 13). Mineral fibre insulating materials of Isover with a λ of 0.034 W/ mK and WDV systems of Weber offer the greatest comfort at the lowest insulation thicknesses. Rigips facing formwork and suspended ceiling and roof structures with complete hollow space insulation (for example Isover mineral wool) additionally contribute to the reduction of the U-values of building parts. For the required improvement of the overall energy efficiency also in existing buildings, the dry interior finishing makes one of the most decisive contributions. The energy efficiency of existing buildings can be improved substantially in the finishing of existing roof structures. Besides the short construction periods, the resulting opportunity to update the building technology in the installation levels at the same time represents a particular advantage of dry construction. Moreover, planking with Rigips boards and a volumetric weight of approx. 800 and up to 1200 kg / m² can contribute to increasing the component mass that has a capacity for storing heat and thereby to the summerly comfort. Figure 13 – Exterior wall 22 b
BUILDING PHYSICS 27 Summer heat insulation Summer heat insulation (heat protection) helps limit the heat that is created in the interior of the building through the direct or indirect irradiation of the sun, which is usually largely due to irradiation through the windows, to a bearable measure. This is done primarily by minimising the heat addition from the direct irradiation of the sun, reducing the heat conductivity of wall, roof and ceiling surfaces, and the waste heat of electrical devices and people. Windows without protection from the sun have the biggest effect on the heating of interior rooms. Summer heat insulation is becoming more and more important, in particular in consequence of global climatic change and the trend toward rising temperatures. This is related to the increasing use of air conditioners, which in turn lead to climbing power and respectively energy consumption, and thereby also to increasing CO2 emissions especially in the summer months. This is why summer heat insulation has to be considered already in the building planning phase to avoid that buildings overheat during the summer resulting in uncomfortable room temperatures. In residential buildings room temperatures in an average summer will remain below 27 °C due to nightly ventilation, low heat dissipation of devices, sun shading and heat storage. During heat waves, they are likely to rise somewhat. In offices, temperatures of below 26 °C are aimed for. In this regard, it is particularly important to pay attention, on the one hand, to corresponding sun shading devices that are installed on the outside of the windows, so that the “glasshouse effect” can be prevented and, on the other hand, to especially understanding and considering the summer behaviour of buildings and that of the users. Not only the occurring maximum temperature but also the period during which a certain temperature threshold is exceeded is significant for the user’s subjective perception. The effect of the user behaviour on summerly room temperatures in consideration of various building materials or construction methods applied – light-weight construction, brick construction, concrete construction – has been analysed by measurements in occupied properties within the scope of a research project. Parameters that influence the behaviour of not actively climate-controlled buildings during the summer or the room heating in consequence of summerly irradiation of heat are: • the outdoor climate • the thermal properties of the used components in the exterior area such as surface paint, heat insulation capacity, component assemblies or layer sequence, the capacity to store heat especially of components located on the inside, the overall degree of energy permeation, the size and orientation of the used glazing, existing sun shielding systems and their effects • orientation of the exterior wall surfaces • use of possibilities for night-time ventilation and the sun shielding equipment • release of heat from electrical devices, illumination and people • storage efficiency of items of furniture and structural design The results of the research project show that regardless of the construction method, the building materials used, and the existing thermal storage of the mass in the interior room, it is the user behaviour and foremost incorrect use of ventilation possibilities that has a greater effect on the progression of summer room temperatures. At the same time, the nightly dissipation of heat through windows is decisive for the summertime thermal behaviour of rooms. Ensuring comfort in the living rooms (see Figure 14) during frequently occurring heat periods is a central concern of Saint-Gobain Multikomfort. The aim is to reduce temperature peaks in the summer and increase comfort in the room. The Rigips Alba®balance full-gypsum boards developed for this purpose absorb the room heat that exceeds the comfort zone and release it again when there is sufficient nightly ventilation. Figure 14 – Well-being in the interior space
BUILDING PHYSICS 28 Reasons why rapid air exchanges are incorrectly omitted in the summer: • assumption that ventilation at night is not required in passive houses • risk of falls in children’s rooms (max. tilting of the windows) • reduced ventilation effect because of insect screens • pets (windows are tilted at most) • ground floor apartments (for security reasons, windows are tilted at most) • restriction of the ventilation effect for the apartment because of closed interior doors • noise in the surroundings especially at night In the summer, the daily fluctuations of the outdoor temperature are generally greater than in the winter. Moreover, there is a very high temperature difference on the component surfaces in consequence of the irradiation of the sun. Measures for optimisation: • increasing the heat insulation. • Insulating layers placed on the outside and masses with the capacity of storage have favourable effects on indoor temperatures. • Choice of windows: according to more recent building physical research, the heat permeability of windows has a much greater effect on the interior room temperature than the capacity of the interior masses to store heat. • The kind of the chosen insulating material does not have such decisive importance. Instead, the thickness of the provided insulating layer, as well as the material type and thickness of the cladding facing the interior room are in the foreground of the examinations. • Correct user behaviour: the room climate can be additionally improved by ventilation during the night and keeping windows and doors closed during the day. The results of the scientific studies show that the summer heat insulation can be equated only to limited extent with the components’ storage capacity. With a rising level of heat insulation, the summer temperatures in the room fall to a comfortable measure. CLT BBS elements have a positive effect in this because CLT BBS provides simultaneously good insulation from heat as well as excellent storage capacity. The simulation of a single-family home shows that with increasing heat insulation, temperature exceedances become much less frequent and are by far weaker. The experiences gathered by residents, too, show that comfort and room climate in timber houses are consistently evaluated as being positive also during the summer. Humidity regulation Wood as a natural and replenishable raw material has many positive building physical properties. One is the ability to absorb moisture and release it again. Thus, CLT BBS has a reducing effect on the peak values of humidity in rooms (see Figure 15). At a room temperature of 20 °C and relative humidity of 55 %, 1 m³ CLT BBS stores around 43 litres of water. If the relative humidity changes from 55 % to 65 %, 1 m³ CLT BBS absorbs a rounded 7 litres of water from the room air. Figure 15 – Absorption behaviour of different building materials ABSORPTION PROPERTIES CLT BBS Concrete mortar Humidity (%) 0 20 40 60 80 100 Concrete Brick 35 30 25 20 15 10 5 0 Mass-specific water content (%) -65 -12
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