1 / 39

Technology in Architecture

Technology in Architecture. Lecture 17 Noise Reduction by Absorption Sound Paths Sound Isolation Sound Privacy Structure Borne Sound. Noise Reduction by Absorption. Increased absorption reduces ambient noise. S: p. 771, F.18.2. Noise Reduction by Absorption. 69 db.

spencer
Télécharger la présentation

Technology in Architecture

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Technology in Architecture Lecture 17 Noise Reduction by Absorption Sound Paths Sound Isolation Sound Privacy Structure Borne Sound

  2. Noise Reduction by Absorption Increased absorption reduces ambient noise S: p. 771, F.18.2

  3. Noise Reduction by Absorption 69 db Reverberation increases ambient sound levels S: p. 798 F.19.1

  4. Sound Paths Air-Borne Sound Structure-Borne Sound S: p. 806, F.19.10

  5. Sound Transmission Barriers reduce sound transmission to reduce noise intrusion S: p. 807, F.19.11

  6. Air-Borne Sound Transmission Loss (TL): sound energy lost through a construction assembly S: p. 813, F.19.17

  7. Noise Reduction Combined effect of TL and absorption NR=TL-10 Log (S/AR) NR: noise reduction (db) TL: transmission loss (db) S: area of barrier wall (ft2) AR: total absorption of receiving room (sabins, ft2)

  8. Noise Reduction Example What is the noise reduction at 500 hz between two rooms separated by a 2x4 stud wall with ½” gyp. bd. on each side. Receiving room absorption: 450 sabins, ft2 Separation wall: 10’ x 20’

  9. Noise Reduction Example Find TL500 TL500=35 db S: p. 813, F.19.17

  10. Noise Reduction Example Find NR500 NR500=TL500-10 Log (S/AR) =35-10 Log (200/450) =35-10 Log (0.444) =35-10(-0.35) =35+3.5=38.5 say 39db

  11. Sound Transmission Class Sound Transmission Class (STC): defines overall transmission loss across center band frequencies Barrier STC Descriptor/ Application Ranking 25 Poor/1 Space divider 30 Fair/2 Room divider 35 Very Good/4 Offices near quiet space 42-45 Excellent/5 Party walls 46-50 Total Privacy/6 Quiet next to noisy from S: p. 828. T.19.6

  12. Sound Transmission Class STC can be compromised by: • Combination with lesser sound barriers • Gapsin construction “An air path is a good sound path”

  13. Sound Transmission Class STC of a wall assembly 2x4 stud with gyp. Bd. S: p.1712, Index K.1

  14. Sound Transmission Class Wall assembly description 2x4 stud with gyp. bd. S: p. 1716, Table K.3

  15. Sound Transmission Class Wall assembly selection TL data 2x4 stud with gyp. bd. S: p. 1713, Index K.2

  16. Sound Transmission Class Floor assembly follows same process S: p. 1724, Index L.1

  17. Noise Criteria Noise Criteria (NC): accepted noise level for a given space. Defined for center band frequencies 62.5 125 250 500 1000 2000 4000

  18. Noise Criteria Curves Accepted noise level for a given space. S: p. 759, F.17.17

  19. Noise Criteria Noise Criteria for various applications S: p.831, T.19.8

  20. Sound Privacy Privacy is affected by initial sound source, TL, NC and absorbtion Room B Room A SPL NC1 NC2 Privacy Violated TL TL Privacy Maintained Sectional View

  21. Sound Privacy—Example 1 Room A: NC500=35 Room B: NC500=25 Room B Room A SPL=70 NC1=35 SPL=40 SPL=40 NC2=25 Privacy Violated TL=30 TL=30 Privacy Maintained Sectional View

  22. Noise Criteria Curves Privacy is affected by background noise level NC 35 @ 500 hz Max SPL500=40 db S: p. 759, F.17.17

  23. Sound Privacy—Example 1 Room A: NC500=35, SPL500 ≤ 40 db Room B: NC500=25, SPL500 ≤ 31 db Initial check based on TL alone Room B Room A SPL=70 NC1=35 SPL=40 SPL=40 NC2=25 Privacy Violated TL=30 TL=30 Privacy Maintained Sectional View

  24. Sound Privacy—Example 1 Combine effect of TL and absorption for final analysis NR=TL-10 Log (S/AR) NR: noise reduction (db) TL: transmission loss (db) S: area of barrier wall (ft2) AR: total absorption of receiving room (sabins, ft2)

  25. Sound Privacy—Example 1 For each frequency: If SPL-NR ≤ NCmaxprivacy achieved If SPL-NR > NCmaxprivacy violated

  26. Sound Privacy Enhancement TL data can be enhanced by standard enhancements Wood stud wall (STC 35) • Add gyp bd to one side +2 db • Add gyp bd to both sides +4 db • Double thickness insulation +6 db • Staggered studs +9 db • Double studs +13 db from S: p. 816, T.19.1

  27. Sound Privacy Reduction Privacy is diminished by flanking noise, weaker STC constructions and/or gaps S: p. 825, F.19.34

  28. Sound Privacy Privacy diminished by weaker STC constructions S: p. 817, F.19.22

  29. Sound Privacy—Example 1 A 100 ft2 wall assembly has TL=50 [excellent] What is the overall TL if a 20 ft2 door with TL=20 is part of the wall? S: p. 817, F.19.22

  30. Sound Privacy—Example 1 S1= 100 ft2 S2= 20 ft2 S2/S1=20/100=20% TL1-TL2=50-20=30 db TL1-TLC=23 TLC=TL1-23=27 db [fair-poor] S: p. 817, F.19.22

  31. Sound Privacy Privacy diminished by construction gaps S: p. 817, F.19.23

  32. Sound Privacy—Example 2 A 10x10 (100 ft2) wall assembly has TL=35 [very good] What is the overall TL if a 1/16” gap exists along each vertical edge? S: p. 817, F.19.23

  33. Sound Privacy—Example 2 S1= 14400 in2 S2= 15 in2 S2/S1=15/14400=0.1% TL1=35 db TLC=29 db [fair-poor] S: p. 817, F.19.23

  34. Sound Transmission Reduction Impact Isolation Structural isolation Flexible connections Spring mounts Inertial dampening S: p. 845, F.19.47

  35. Sound TransmissionReduction– Floors Sound Transmission Class (STC) Impact Isolation Class (IIC) S: p.1726, Index L.3

  36. Impact Isolation Class—Enhancements Construction Tectonics S: p. 842, F.19.43

  37. Impact Isolation Class—Enhancements Resilient Floor Finishes: • 1/16” vinyl tile 0 db • 1/8” linoleum or rubber tile 4 +/- 1 db • ¼” cork tile 10 +/- 2 db • Low pile carpet on fiber pad 12 +/- 2 db • Low pile carpet on fiber pad 18 +/- 3 db • High pile carpet on foam pad 24 +/- 3 db from S: p. 843

  38. Mechanical Isolation Moving parts (vibration sources) eliminated by mechanical isolation S: p. 851, F.19.54

More Related