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

Sound Privacy

Privacy is affected by initial sound source, TL, NC and absorbtion Privacy Maintained Privacy Violated NC 2 SPL NC 1 TL Room A Room B Sectional View

Sound Privacy—Example 1 Room A: NC 500 =35 Room B: NC 500 =25 Privacy Maintained Privacy Violated NC 2 =25 SPL=70 NC 1 =35 TL=30 Room A Room B Sectional View SPL=40

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

Sound Privacy—Example 1 Room A: NC 500 =35, SPL 500 ≤ 40 db Room B: NC 500 =25, SPL 500 ≤ 31 db Initial check based on TL alone Privacy Maintained Privacy Violated NC 2 =25 SPL=70 NC 1 =35 TL=30 Room A Room B Sectional View SPL=40

Sound Privacy—Example 1 Combine effect of TL and absorption for final analysis NR=TL-10 Log (S/A R ) NR: noise reduction (db) TL: transmission loss (db) S: area of barrier wall (ft 2 ) A R : total absorption of receiving room (sabins, ft 2 )

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

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

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 ft 2 wall assembly has TL=50 [excellent] What is the overall TL if a 20 ft 2 door with TL=20 is part of the wall? S: p. 817, F.19.22

Sound Privacy—Example 1 S1= 100 ft 2 S2= 20 ft 2 S2/S1=20/100=20% TL 1 -TL 2 =50-20=30 db TL 1 -TL C =23 TL C =TL 1 -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 ft 2) 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= in 2 S2= 15 in 2 S2/S1=15/14400=0.1% TL 1 =35 db TL C =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 tile0 db 1/8” linoleum or rubber tile4 +/- 1 db ¼” cork tile10 +/- 2 db Low pile carpet on fiber pad12 +/- 2 db Low pile carpet on fiber pad18 +/- 3 db High pile carpet on foam pad24 +/- 3 db from S: p. 843

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