Technology in Architecture Lecture 19 Sound Privacy Sound Privacy Enhancement Sound Privacy Reduction Structure Borne Sound

Sound Privacy

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

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

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

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 A Room B SPL=70 NC1=35 SPL=40 SPL=40 NC2=25 Privacy Maintained TL=30 TL=30 Privacy Violated Sectional View

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)

Sound Privacy—Example 1 For each frequency: If SPL-NR ≤ NCmax privacy achieved If SPL-NR > NCmax privacy violated

Sound Privacy Enhancement

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

Sound Privacy Reduction

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

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

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

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

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

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

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

Structure-Borne Noise

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

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

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

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

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

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