J. NEGREIRA DIVISION OF ENGINEERING ACOUSTICS, LUND UNIVERSITY

Transcription

1 Flanking Transmission J. NEGREIRA DIVISION OF ENGINEERING ACOUSTICS, LUND UNIVERSITY

2 Outline Introduction Flanking transmission SS-EN Examples Summary

3 References: SS-EN series SS-EN :2000, Building Acoustics Estimation of acoustic performance of buildings from the performance of elements Part 1: Airborne sound insulation between rooms (2000). SS-EN :2000, Building Acoustics Estimation of acoustic performance of buildings from the performance of elements Part 2: Impact sound insulation between rooms (2000). SS-EN :2000, Building Acoustics Estimation of acoustic performance of buildings from the performance of elements Part 3: Airborne sound insulation against outdoor sound (2000). SS-EN :2000, Building Acoustics Estimation of acoustic performance of buildings from the performance of elements Part 4: Transmission of indoor sound to the outside (2000). SS-EN :2000, Building Acoustics Estimation of acoustic performance of buildings from the performance of elements Part 5: Sound levels due to service equipment (2000). SS-EN :2000, Building Acoustics Estimation of acoustic performance of buildings from the performance of elements Part 6: Sound absorption in enclosed spaces (2000).

4 Introduction (I) Sound transmission Airborne Structure-borne Transmission paths Direct transmission (D) Flanking paths (F i ) Flanking: cause of problems related with acoustic comfort Difference between lab and in-situ measurements ~4 db» Estimation methods described in SS-EN 12354:2000 Acoustic performance as sum of individual contributions

5 Introduction (II) t i Laboratory measurements good control just direct transmission In reality, more transmission paths d f dt it Direct Flanking Parts added to wall (windows, doors, leaks ). May be included in τ d Indirect transmission between rooms (ducts, suspended ceiling )

6 Introduction (III) d f d Dd n Fd f m Df k Ff NOTES: The sketch only indicates first-order paths; paths involving one element in the sending room, one junction or connection and one element in the receiving room. // The number of elements n, m and k are normally 4. // Main contributions are normally the Ff paths.

7 Outline Introduction Flanking transmission SS-EN Examples Summary

8 Flanking transmission reduction index (I) Apparent sound reduction index (13 paths) R w log R Dd, w n F f 1 R Ff, w n f 1 R Df, w n F 1 R Fd, w If only Ff paths are assumed: R w log R d, R w f, w

9 Flanking transmission reduction index (II) Flanking sound reduction index R ij (approximation given in the standard SS-EN 12354:2000) R R i, w j, w s R f R ij w ij, w Kij log, 2 l0 lij S R i & R j : sound reduction index of flanking element i and j K ij : vibration reduction index (junction dependent) S s : floor / wall surface l 0 = 1m l ij : junction common length NOTES: K ij is related to the vibrational power transmission over a junction between structural elements under diffuse field conditions, normalised in order to make it an invariant quantity (independent of the energy losses). This quantity can be taken from Annex E of SS-EN // An additional term +ΔR ij would be added to the right hand side of the equation to account for improvement of sound reduction due to aditional linings (here is omitted).

10 Flanking transmission reduction index (III) Vibration reduction indexes K ij SS-EN :2000 (Annex E)

11 Flanking transmission reduction index (IV) Vibration reduction indexes K ij SS-EN :2000 (Annex E)

12 Flanking transmission reduction index (V) Vibration reduction indexes K ij SS-EN :2000 (Annex E)

13 Flanking transmission reduction index (VI) Vibration reduction indexes K ij SS-EN :2000 (Annex E)

14 Outline Introduction Flanking transmission SS-EN Calculation Examples Design Summary

15 Calculation example (SS-EN :2000)

16 Calculation example (SS-EN :2000)

17 Design example: Decoupling Structural Elements

18 Design example: Timber Volume Elements

19 Design example: Elastic Interlayers

20 Outline Introduction Flanking transmission SS-EN Examples Summary

21 Summary Flanking transmission R w R, total w C R w log R Dd, w n F f 1 R Ff, w n f 1 R Df, w n F 1 R Fd, w C Li Ri log i R w R R i, w j, w Ss R f R ij w ij, w Kij log, 2 l0 lij

22 Thank you for your attention!