Apparent wood elements and acoustic performance – Feedback from Adivbois CLT building mockup Catherine Guigou-Carter 1 Health and Comfort Department, CSTB 24 Rue Joseph Fourier, 38400 Saint Martin d’Hères, France Nicolas Balanant 2 CERQUAL Qualitel Certification 28 Rue du Rocher, 75008 Paris, France Jean-Luc Kouyoumji 3 FCBA Allée de Boutaut, 33000 Bordeaux, France

ABSTRACT The acoustic performance of a CLT based building mockup was investigated within the scope of AdivBois acoustic technical commission with the objective of defining wood building constructions fulfilling requirements. The CLT based building is a three floor construction, with four rooms on each level. Acoustic measurements from junction characterization to air-borne and impact sound insulations have been performed. Apparent wood is supposed to have positive effect on health and well-being on building occupants. This paper concentrates of the effect of apparent wood on the acoustic performance : the apparent wood can be either the underside of the CLT floor (i.e., no suspended ceiling) or posts and beams possibly continuous between different rooms. The measured results are discussed with respect to prediction. A simple approach to take into account the through beams or posts is proposed. Recommendations concerning apparent wood elements in buildings are imparted.

1. INTRODUCTION

Wood fixes CO2 during its growth. The new French environmental regulation RE2020, for new buildings applicable from January 1, 2022, promotes the use of renewable materials to store carbon. Used as structural element in construction, where its lifespan is around 100 years, wood is an interesting source of carbon capture. The development of wood in the construction and renovation of buildings is also recognized by the French public authorities as an effective means of contributing to the objectives of the National Low Carbon Strategy.

In addition, to achieve the carbon objectives of the Paris 2024 Olympic and Paralympic Games aligned with the Paris Agreement, many projects are developed in wood.

1 catherine.guigou@cstb.fr 2 n.balanant@cerqual.fr 3 jean-luc.kouyoumji@fcba.fr

If the lightweight aspect of wood is appreciated for elevations and extensions, in multi-storey buildings, the predictability of the acoustic and vibration performance of lightweight structures requires special know-how. Behavior at low frequencies and flanking transmissions must be monitored with care. Fortunately, research has made much progress in recent years, particularly in France due to the momentum generated within the framework of the ADIVBois project. The aim of the ADIVBois association is to help removing technical and regulatory obstacles and to share the expertise acquired in the field of high-rise wooden constructions, with project owners, project managers and companies. The technical working groups of ADIVBois have carried out work in recent years on the aspects of structure, envelope, fire safety and acoustics.

Regarding the acoustic investigation, a laboratory test campaign on the CLT floor was carried out by CSTB in 2018. Then, the project for a life-size mockup of a multi-storey wooden construction was launched at the FCBA in 2019. This new project managed by FCBA was baptized “ADIVBois Acoustic Mockup”; it brings together CSTB, CERQUAL and FCBA.

This three-level wooden mockup with four rooms per level was built on the FCBA site in Bordeaux. The mockup is intended to study the floors, the flanking transmissions, and the transmissions via the wooden supporting elements such as posts and beams. 2. Laboratory measurements

Laboratory tests have been undertaken with the aim of providing designers of high-rise wooden buildings with examples of separating floors likely to comply with both French regulatory requirements in terms of construction rules, as well as comfort criteria proposed by ADIVBois for dwellings configuration. The following component performances have been retained as a first step

• R w +C  58 dB for airborne sound insulation • L n,w ≤ 52 dB et L n,w + C I50-2500 ≤ 52 dB for impact sound insulation Floor solutions with exposed wood on the underside have been investigated, although this configuration is also subject to fire safety constraints and the need to treat flanking transmissions with regard to acoustics. Many floor configurations based on 140 mm thick CLT wood panels, and integrating different types of floating systems and suspended ceilings were also considered.

2.1. CLT floors with apparent underside Several flooring solutions with exposed wood on the floor underside have been tested. Table 1 presents these configurations and their corresponding acoustic performance.

It should be noted that the configurations tested do not achieve the targeted performance levels, particularly with regard to impact sound insulation, without the use of a floor covering. A flexible floor covering with a performance of ∆L w  18 dB on a 140 mm thick concrete floor (with in particular ∆L  7 dB at 50 Hz) nevertheless allows the first two floors A and B of Table 1 (point supported screed configuration and gravel configuration) to meet the targeted acoustic objectives.

The tests carried out were limited to floor solutions with a thickness of around 30 cm because the elevation constraint is particularly strong for the construction of high buildings. Solutions with concrete fill or honeycomb with granules, for adding mass could achieve the targeted acoustic performance, but this would require increasing the thicknesses of the floor.

Figure 1 illustrates the performance of floors in terms of airborne sound insulation and impact sound insulation in one-third octave bands between 50 and 5000 Hz.

Table 1: Acoustic performance of CLT floors with apparent underside.

Description Composition Performance

A

1 – CLT panel 140 mm 2 – Insulation material 80 mm

R w +C = 59 dB

L n,w = 56 dB L n,w +C I50-2500 = 54 dB

3 – Wood support 100 mm

4 – Resilient pad 5 – Concrete screed 50 mm

B

1 – CLT panel 140 mm 2 – Gravel 80 mm (106 kg/m²)

R w +C = 66 dB

L n,w = 53 dB L n,w +C I50-2500 = 54 dB

3 – Resilient layer 15 mm 4 – Concrete screed 60 mm

C

1 – CLT panel 140 mm 2 – Concrete fill 60 mm (120 kg/m²)

R w +C = 55 dB

L n,w = 64 dB L n,w +C I50-2500 = 63 dB

3 – Resilient layer 30 mm 4 – Concrete screed 60 mm

D

1 – CLT panel 140 mm 2 – Honeycomb core 60 mm including

R w +C = 58 dB

L n,w = 59 dB L n,w +C I50-2500 = 62 dB

aerated concrete granules (87 kg/m²)

3 – Resilient layer 30 mm 4 – Concrete screed 60 mm

Figure 1: Acoustic performance of CLT floors with apparent underside.

2.2. CLT with suspended ceiling Several floor solutions with suspended ceiling have also been tested; the plenum is 100 mm filled with 80 mm thick glass wool. Table 2 shows these configurations and the corresponding acoustic performance. The ceiling is mounted on rigid hangers except for one configuration (floor G) which used resilient hangers.

The configuration with cement screed on thin resilient layer does not meet the targeted performance in terms of impact sound insulation for a suspended ceiling integrating 2 BA13 plaster boards (floor E); this floor requires acoustic floor finishing to achieve all requirements. However, the similar configuration for a suspended ceiling integrating 2 BA18 plaster boards (floor F) meets the performance objectives without floor finishing.

Configurations with dry screed make it possible to achieve the targeted performance objectives (floors G and H) without floor finishing. Floor G incorporating weighting granules in a honeycomb core is associated with the best performance but its thickness of around 37 cm is relatively large and therefore penalizing.

Figure 2 illustrates the performance of floors incorporating a suspended ceiling of airborne sound insulation and impact sound insulation for one-third octave bands between 50 and 5000 Hz.

Table 2: Acoustic performance of CLT floors with suspended ceiling.

Description Composition Performance

E

1 – CLT panel 140 mm 2 – Thin resilient layer 2 mm

R w +C  65 dB

L n,w = 54 dB L n,w +C I50-2500 = 55 dB

3 – Concrete screed 50 mm 4 – Suspended ceiling with 2 BA13

with 80 mm of glass wool

F

1 – CLT panel 140 mm 2 – Thin resilient layer 2 mm

R w +C  69 dB

L n,w = 51 dB L n,w +C I50-2500 = 51 dB

3 – Concrete screed 50 mm 4 – Suspended ceiling with 2 BA18

with 80 mm of glass wool

G 1 – CLT panel 140 mm 2 – Dry floating floor made of 25 mm

R w +C  64 dB

board and 10 mm of mineral wool as

L n,w = 50 dB L n,w +C I50-2500 = 52 dB

resilient layer 3 and 4 – Suspended ceiling with 2 BA18 with 80 mm of glass wool

H 1 – CLT panel 140 mm 2 – Honeycomb core 60 mm including

aerated concrete granules (87 kg/m²) 3 – Dry floating floor made of 25 mm

R w +C  73 dB

L n,w = 37 dB L n,w +C I50-2500 = 48 dB

board and 10 mm of mineral wool as

resilient layer 4 and 5 – Suspended ceiling with 2 BA18 with 80 mm of glass wool

It should be added that the results highlighted positive effects of the floor finishing (such as plastic floor covering) on the impact sound insulation at low frequencies which were not expected. In particular, when the plastic floor covering used during the tests is placed on a cement screed, it

provides a reduction in impact sound levels, including at low frequencies, whereas it tends to increase them very slightly on dry floating systems tested. Also, more work on the effects of floor finishing (such as tiles, parquet, soft plastic covering) must be carried out in order to extend the validity of the floor system configurations with respect to the targeted performances.

Figure 2: Acoustic performance of CLT floors with suspended ceiling. 3. BUILDING MEASUREMENTS

The construction of the “ADIVBois Acoustic Mockup” and the measurements carried out on it were intended in particular to show the in situ influence of the various components of the floors (screeds, suspended ceilings, floor finishing, etc.) and to check the suitability of the method for predicting building performance based on component performance. In addition, the study of acoustic transmission with respect to exposed posts and beams and its influence on acoustic insulation was also one of the aims of this investigation.

Finally, this work must lead to the proposal of constructive solutions allowing the respect of the targeted acoustic performances.

3.1. Description

The prototype, or “ADIVBois Acoustic Mockup” is a three storey wooden structure building comprising 4 rooms on each floor, including 2 rooms with an overall surface area of approximately 14 m² each, and 2 rooms with an overall surface area of approximately 19.8 m² each. The following building performance corresponding to a dwelling configuration with the entry level of the NF Habitat certification has been selected:

• D nT,w +C  53 dB for airborne sound insulation • L’ nT,w ≤ 55 dB et L’ nT,w + C I50-2500 ≤ 55 dB for impact sound insulation Two different floor types have been implemented

• Floor 1 with apparent underside (corresponding to Floor type B of previous section) • Floor 2 with suspended ceiling (corresponding to Floor type E of previous section) Two types of vertical wall were mounted: the first is based on a 140 mm thick CLT panel and the second corresponds to a 180 mm thick double frame plasterboard based separating wall (denoted SAD180 in the rest of the paper). The façades are standard lightweight wood frame wall with an independent interior lining (composed of 2 BA13 plasterboards on an independent metal frame with 45 mm mineral wool).

Figure 3 illustrates this structure and localizes the different walls and floors implemented.

“SUS EEERREORSEGROREEER

Lightweight separating wall

Floor 2 Type E Rooms S13, S14, S23, S24 50 mm screed on thin resilient

SAD180

layer CLT 140 mm Suspended ceiling : air 20 mm,

glass wool 80 mm, 2 BA13

Floor 1 Type B Rooms S11, S12, S21, S22 60 mm screed on 15 mm mineral

wool resilient layer

80 mm Gravel

CLT 140 mm

Separating wall

Separating wall

2 BA13 45 mm mineral wool and 35 mm air gap

2 BA13 45 mm mineral wool and 35 mm air gap

CLT 140 mm 45 mm mineral wool and 35 mm air gap

CLT 140 mm 45 mm mineral wool and 35 mm air gap

2 BA13

2 BA13

Figure 3: Construction principle of the “ADIVBois Acoustic Mockup”.

The results presented in the following sections compare the acoustic performance of the building with respect to exposed wood elements, on the basis of measurements and predictions according to the EN ISO 12354-1 and -2 standards [1]. These predictions are based on the performance of the components measured in the laboratory (or the AcouBat software database for the lightweight SAD 180 wall) and on the vibration attenuations at the junctions measured on this mockup.

Regarding the acoustic measurements, different teams participated; the FCBA team used the in- situ engineering measurement method (EN ISO 16283 standards [2]) and the other teams the survey method (EN ISO 10052 standard [3] and the French Acoustic Measurement Guide [4]). In the following tables presenting the measured performance, the result in brackets denotes the one obtained with the survey measurement method.

Preliminary results were presented in 2021 [5] and more complete measurement results relative to the prediction method in a companion paper [6].

3.2. Comparison between measured and predicted acoustic performance Figure 4 shows the acoustic performance measured between rooms with floors with a visible underside.

Airborne sound insulation D nT,w +C

Impact sound insulation

Floor junctions

including resilient layer

L’ nT,w / L’ nT,w +C I50-2500

Figure 4: Acoustic performance measured between rooms for floor with visible underside.

For the vertical transmission, the performance targets are reached by means of the floor weighted down by a layer of gravel and covered with a floating screed on mineral wool.

For the horizontal transmission, the desired performance is also achieved by means of junctions providing relatively high vibration attenuation K ij for the floor/floor path: K Ff = 21 dB in average value for one-third octaves between 250 and 1000 Hz according to the EN ISO 10848 [7]. This significant vibration attenuation K Ff is obtained with a CLT floor which is not continuous: the floor is supported on a supporting beam (section of size 80 mm x 200 mm) on one side of the CLT wall and on an angle iron on the other side. Furthermore, resilient materials are included between the floor and the supporting elements on the wall for the floor of the intermediary level (1 st level).

These measurements show that the effect of resilient materials is rather limited on the overall results. Indeed, the vertical airborne sound insulation measurements D nT,A between rooms S01/S02, and between rooms S11/S12, are rather similar (respectively D nT,A = 62 and 63 dB) whereas these insulations are essentially due to the transmission path through the exposed floor underside in the ceiling of these rooms.

In addition, the impact sound insulation performance is slightly improved between rooms S11/S12 and room S21/S22 (respectively L' nT,w /L' nT,w +C I50-2500 = 31/36 and 40/38 dB). The difference observed is not necessarily due to the resilient elements present at the junctions, because the lightweight SAD180 wall on the 2 nd floor (top level) reduces the vibration isolation of the junction for the floor/floor path. In the presence of a separating CLT wall, the impact sound levels could have been similar.

Table 3 compares the predicted and measured performance. The indication "RdS" corresponds to the implementation of a plastic floor finishing as described in the previous section. The predicted performance is globally in line with that measured for the vertical transmission. The predicted performance overestimates the performance measured in the horizontal transmission for impact sound insulation; however, the impact sound insulation level for these horizontal transmissions is low and do not represent an issue due to the non-continuous floor configuration.

Table 3: Acoustic performance between rooms for floor with visible underside

– Measurement and Prediction.

Rooms Prediction (dB) Measurement (dB)

D nT,A L’ nT,w L’ nT,w +C I50-2500 D nT,A L’ nT,w L’ nT,w +C I50-2500 S11/S01 56 53 53 56(56) -(52) -(52) S11(RdS ) /S01 - 46 51 - -(47) -(50) S12/S02 58 53 53 59(-) 51(51) 55(53) S12(RdS ) /S02 - 46 51 - -(49) -(54) S21/S11 58 53 54 55(52) 52(53) 55(54) S21(RdS ) /S11 - 46 51 - -(49) -(51) S11/S12 64 20 31 63(62) 31(34) 36(37) S21/S22 61 10 30 57(-) 40(39) 38(42)

Based on the results obtained, it remains difficult to conclude on the benefit of a resilient element at the junction. On the other hand, junctions with low attenuation (between 0 and 5 dB for example) would not make it possible to meet the objectives because the flanking transmissions by the floors would then be too high.

3.3. Exposed wooden elements in a lightweight partition In this section, the effect of an exposed wooden post or beam in the lightweight plasterboard separating wall (SAD180) between rooms S13/S14 as well as between rooms S23/S24, is investigated. The central wooden post of these walls has a section of 200 mm x 200 mm. Between rooms S13 and S14, there are 2 visible posts, one in the middle and one at the end of the partition, i.e. a linear of 2x2.5 m, as well as a 5.5 m long beam at the top of the separating partition. Figure 5

shows rooms S14 and S24 with exposed beam and post elements; the view of rooms S13 and S23 would be identical. Figure 6 presents the enclosure type applied on the middle post in the lightweight plasterboard separating wall; similar enclosures (45 mm mineral wool with 2 layers of BA13 plaster boards on an independent metallic frame, i.e., same type as the interior lining mounted on the façade) are used to encase the beams and posts

S23/S24

S13/S14

Figure 5: View of the premises with the exposed post/beam type elements (before enclosure).

Figure 6: Description of the enclosure for the post in the middle of a lightweight wall.

Initially, the acoustic measurements were carried out with these posts and beams exposed then in a second time theses posts and beams were encased. Figure 7 shows the airborne sound insulation obtained for the configurations considered. The influence of the sound transmission by the visible wooden elements, on the measurements performed before and after enclosing them, can clearly be observed. Sound transmission through the exposed wooden structure induces a limit in the airborne sound insulation above the one-third octave band of 500 Hz. The shape of the predicted airborne sound insulation spectrum is close to that of the measurements when the wooden elements are enclosed (non-exposed).

In order to take into account the sound transmission through the wooden post in the predictions, a simple approach is proposed. An airborne sound insulation D n,e of 62 dB for all one-third octave bands between 50 and 5000 Hz (corresponding to a performance D n,e,w +C of 62 dB) for a length of 1 m of exposed beam or exposed post both in the emission and in the reception room for a maximum excitation surface (unfolded surface) of 200 mm x 1 m.

This simple approach effectively limits the airborne sound insulation expected above the one- third octave band of 500 Hz; the predicted performance with exposed wood elements is then in line with that measured without enclosure.

Table 4 reports the associated performances in terms of the D nT,A index. It should be noted that the effect of the exposed wood elements is overestimated by the prediction in terms of overall index (7 and 4 dB) compared to the measurements (2-3 dB and 1 dB). This is mainly due to the overestimated airborne sound insulation predicted in the low frequency range (transmission associated to the façade path) that strongly affects the D nT,A index in the case without exposed wood elements.

S13-S14

S23-S24

Figure 7: Acoustic performance to airborne noise between rooms for a SAD180 wall and effect of

exposed post/beam type elements.

Table 4: Airborne sound insulation with exposed wooden elements in light wall – Prediction and

measurement.

Rooms Prediction

Measurement

D nT,A (dB)

D nT,A (dB) S13/S14 – with exposed wood elements 52 52(51) S23/S24– with exposed wood elements 53 54(53) S13/S14 – without exposed wood element 59 54(54) S23/S24 – without exposed wood element 57 55(-)

3.3. Exposed central wooden post The lightweight SAD180 wall between rooms S13 and S14 is then removed as well as the one between S23 and S24; thus 2 large, superposed volumes are obtained (denoted S13+S14 and S23+S24), with a central post of section 200 mm x 200 mm on two levels and 2.5 m high on each floor. Measurements were carried out in particular with enclosure of this post (enclosure of the same type as the lining on the façade, on the post on both levels) and without enclosure (partial enclosure correspond to the enclosure being only on the post on one level).

It is proposed to evaluate the effect of this central column on the basis of a flanking airborne sound insulation of a specific element, D n,f following the expression :

S e ref post S r ref post

S e post S r post ) , (1)

D n,f post = D n,f ref post + 10 log (

The reference post corresponds to the central post with a section of 200 mm x 200 mm and 2.5 m high in the 2 rooms, corresponding to that of rooms S13+S14 and S23+S24. This reference pole is associated with a performance of 55 dB in terms of D n,f,w +C.

Figure 8 below shows the D n,f of the reference post and its effect on the airborne sound insulation expected between S13+S14 and S23+S24. The presence of the exposed wood post is clear on the airborne noise insulation starting at the one-third octave band of 630 Hz.

It should be noted that the partial enclosure of the post (enclosure in lower room S13+S14 only) behaves almost like the complete enclosure of the post (enclosure in the 2 rooms S13+S14 and S23+S24).

MEITTITITITITITENITGT)

The expected airborne sound insulation without exposed wood element overestimates the measured one above the one-third octave band of 800 Hz; the presence of a leak or another parasitic path, or the limitation in terms of measurements could explain this behavior.

Table 5 reports the associated performances in terms of overall D nT,A index. It should be noted that the airborne sound insulation D nT,A is reduced by 3 dB for the prediction as for the measurements due to the exposed post. In these large volumes (more than 100 m 3 ), the airborne sound insulation in the presence of the exposed post (D nT,A of 57 dB) remains above the regulatory threshold (D nT,A of 53 dB). Partial enclosure is equivalent to full enclosure in terms of D nT,A performance.

S13+S14 – S23+S24

D n,f reference central post

Figure 8: Acoustic performance to airborne noise between superposed rooms with central wood

post.

Table 5: Effect of exposed central wood post between superposed rooms – Prediction and

measurement.

Rooms S13+S14 – S23+S24 Prediction

Measurement

D nT,A (dB)

D nT,A (dB) Without enclosure (exposed wood central post) 57 58(57) With partial enclosure - 61(60) With complete enclosure 60 61(60)

3.3. Exposed corner wooden post Based on the approach proposed in the previous section, it is possible to take into account the effect of the columns located in the room corners, that are found on the different levels. Thus, Equation (1) can be used taking into account the emission (collection) and reception (radiation) surface of the corner post.

The corner posts of the model have the dimensions of 240 mm x 320 mm and are partially covered by the facade linings; it will be considered that only a quarter of their surface is exposed.

The case of airborne sound transmission between rooms S01 and S11 including the effect of a corner post on the facade is shown in Figure 9. In terms of global index (see Table 6), the prediction is associated with only 1 dB difference due to the post (55 dB with exposed post and 56 dB without post) while the measurements rather give a difference of 3 dB (58 and 61 dB).

The results for the airborne sound transmission between rooms S04 and S14 (Figure 9) seem to show that the transmission by the corner post is not in this case the main transmission causing the

performance to drop at medium and high frequency: the presence of the central post in the lightweight SAD wall also plays a role. The same types of results are found for the airborne sound transmission between rooms S03 and S13. In terms of global index (see Table 6), the prediction is associated with a 6 dB difference due to the exposed wood elements, which is globally in line with the measurements (control method) with a difference of 5 dB. Additional investigations would be necessary to identify the different transmission paths and confirm the proposed predictive approach for the exposed wood posts.

S04 – S14

S01 – S11

Figure 9: Acoustic performance to airborne noise between superposed rooms with corner wood

post.

Table 6 : Effect of exposed corner wood posts – Prediction and measurement.

Rooms Prediction

Measurement

D nT,A (dB)

D nT,A (dB) S01/S11 – with exposed wood elements 55 -(58) S01/S11 – without exposed wood element 56 -(61) S04/S14 – with exposed wood elements 54 -(53) S04/S14 – without exposed wood element 60 60(58) 4. CONCLUSIONS

The construction and acoustic investigation of the “ADIVBois Acoustic Mockup” have enabled a significant advance in the understanding of the acoustics of wooden constructions, in particular that of high-rise buildings made of cross laminated wooden panels (CLT).

All the data collected made it possible to verify and determine constructive solutions, integrating floors with and without a suspended ceiling.

In addition, it has been shown that wooden structural elements can remain visible and be located between rooms subject to certain conditions. A first approach to take exposed wooden posts into account in the calculations is proposed with acoustic insulation D n,e for the visible elements integrated in a lightweight wall and with a flanking insulation D n,f for the running elements between two rooms. These principles definitely deserve further study to explain certain observed behaviors and to extend the values to other sections of posts and beams.

Nevertheless, it should be added that these exposed wooden elements (posts and beams) can pose an acoustic problem for the occupants, because they constitute the main transmission of noise from

500 Hz and correspond to an identifiable propagation path which could be considered annoying. Therefore, such exposed elements are not recommended in bedrooms.

The consideration of apparent CLT wall was also evaluated in this study on the basis of the prediction model. These configurations of exposed walls deserve to be studied in more detail and especially to be evaluated in-situ on the “ADIVBois Acoustic Mockup”.

Finally, it must be emphasized that the constructive solutions, in particular with respect to the exposed wood elements, must be adapted according to the constraints linked to the risk of fire, the building structure and insurance aspects.

The full reports of this study are undergoing final review and should be available soon. It is expected that the “ADIVBois Acoustic Mockup” will remain for testing other constructive solutions. 5. ACKNOWLEDGEMENTS

The authors would like to thank ADIVBois, CODIFAB and the French Nouvelle-Aquitaine region for the financial support provided to this project.

In addition, the authors would particularly like to thank the various contributors who participated free of charge in this study, in particular the companies that provided materials, the acoustic design offices and industrial acousticians who carried out additional acoustic measurements and finally the members of the ADIVBois acoustic working group for their contributions and constructive exchanges. 6. REFERENCES

1. EN ISO 12354 Building acoustics - Estimation of acoustic performance of buildings from the

performance of elements - Part 1: Airborne sound insulation between rooms and Part 2 : impact sound insulation between rooms (2017) 2. EN ISO 16283 Acoustics - Field measurement of sound insulation in buildings and of building

elements – Part 1 : airborne sound insulation (2014) and Part 2 : impact sound insulation (2020) 3. EN ISO 10052 Acoustics - Field measurements of airborne and impact sound insulation and of

service equipment sound - Survey method (2021) 4. Guide de mesures acoustiques, Version août 2014 (in French), https://www.ecologie.gouv.fr/sites/default/files/dgaln_guide_mesures_acoustiques_aout_2014.pdf 5. C. Guigou Carter, C., Kouyoumji, J.-L., Balanant, N., De Bastiani, B., Acoustic performance of

a CLT-based 3 floor building mockup, Proceedings of Euronoise 2021 , October 2021. 6. C. Guigou Carter, C., Balanant, N., Kouyoumji, J.-L., Building acoustic performance prediction

– Feedback from Adivbois CLT building mockup, Proceedings of Internoise 2022 , August 2022 7. EN ISO 10848 Acoustics - Laboratory and field measurement of flanking transmission for

airborne, impact and building service equipment sound between adjoining rooms (2017)