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Technology in Architecture. Lecture 15 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 B. Room A. SPL. NC 1. NC 2. Privacy Violated. TL. TL.
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Technology in Architecture Lecture 15 Sound Privacy Sound Privacy Enhancement Sound Privacy Reduction Structure Borne Sound
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
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
Noise Criteria Curves Privacy is affected by background noise level NC 35 @ 500 hz Max SPL500=40 db S: p. 749, 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 B Room A SPL=70 NC1=35 SPL=40 SPL=40 NC2=25 Privacy Violated TL=30 TL=30 Privacy Maintained 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 ≤ NCmaxprivacy achieved If SPL-NR > NCmaxprivacy 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. 806, T.9.1
Sound Privacy Reduction Privacy is diminished by flanking noise, weaker STC constructions and/or gaps S: p. 816, F.19.35
Sound Privacy Privacy diminished by weaker STC constructions S: p. 807, 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. 807, 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. 807, F.19.22
Sound Privacy Privacy diminished by construction gaps S: p. 807, 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. 807, 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. 807, F.19.23
Sound Paths Structure-Borne Sound S: p. 796, F.19.10
Sound Transmission Reduction Impact Isolation Structural isolation Flexible connections Spring mounts Inertial dampening S: p. 835, F.19.47
Sound TransmissionReduction– Floors Sound Transmission Class (STC) Impact Isolation Class (IIC) S: p.1688, Index L.3
Impact Isolation Class—Enhancements Construction Tectonics S: p. 832, F.19.43
Impact Isolation Class—Enhancements Resilient Floor Finishes: • 1/8” linoleum or rubber tile 4 +/- 2 db • Low pile carpet on fiber pad 12 +/- 2 db • High pile carpet on foam pad 24 +/- 3 db from S: p. 833-4
Mechanical Isolation Moving parts (vibration sources) eliminated by mechanical isolation S: p. 841, F.19.54