1. Modular Walls and Acoustics

2. Overview Interest and use of modular walls is growing rapidly due to its inherent flexibility and sustainability Other than cost, concerns about about noise and speech privacy is the biggest barrier to closing the sale

3. Bottom Line  Poor acoustics can ruin a good design even if the walls aren’t the problem  Fixing an acoustic problem after construction is costly  Unacceptable noise levels can result in discomfort and lost productivity  Architects and designers are being held accountable for acoustic issues

4. What You Need to Know  Basic principals of acoustics  Causes of acoustical problems  Truth about acoustical ratings  Steps to improve acoustics  How to handle objections

5. Noise Distractions Research as recently as 1998* showed that open plan office noise reduces the productivity of knowledge workers (people trying to manipulate words or numbers in their brains, for example to write a report or plan) by a staggering 66%! * Banbury, S. and Berry, D. C. (1998), Disruption of office-related tasks by speech and office noise.

6. Speech Privacy *UCB Center for The Built Environment Occupant surveys administered by CBE typically find that acoustics is the leading source of workplace dissatisfaction. This acoustic dissatisfaction is frequently related to speech privacy— overhearing unwanted conversations, or feeling that one is overheard. In one study of seven office buildings, as many as 72% of respondents were dissatisfied with speech privacy in their workplace.

7. STC and NRC STC NRC Sound Transmission Class: Ratings of a wall’s ability to block sound Noise Reduction Coefficient: Ratings of a wall’s ability to absorb sound

8. Numbers Don’t Lie… STC Number Ratings: 25 Normal speech easily understood 30 Normal speech audible but unintelligible 35 Loud speech audible & understandable 38 Normal speech inaudible 38 Loud speech audible but not understandable 40 Loud speech audible but unintelligible 45 Loud speech barely audible 50 Shouting barely audible 55 Shouting not audible

9. …Or Do They STC are measured in specially constructed acoustical chambers, and field conditions such as lack of adequate sealing, back-to-back electrical boxes, flanking paths can diminish acoustical performance. The as-built 'field-STC' (FSTC) is usually much lower than the laboratory-measured STC. A wall with an STC rating of 45, which has a hole of only 0.001% of the total wall area, is reduced to an effective STC of almost 40. *National Research Council Canada

10. The Little Big Difference Changes in STC RatingChanges in Apparent Loudness +/- 1Almost imperceptible +/- 3Just perceptible +/- 5Clearly noticeable +/- 10Twice (or half) as loud Changes in STC Rating in Apparent Loudness: +/- 1Almost imperceptible +/- 3Just perceptible +/- 5Clearly noticeable +/- 10Twice (or half) as loud

11. Absorptive Ratings A material with an NRC of.80 will absorb 80% of the sound that comes into contact with it and reflect 20% of the sound back into the space. Brick.00-.03 Wood.05-.15 Heavy Carpet.30-.55 18oz Drapery.60-.65 Fiberglass 3.5”.80-.90 NRC Ratings

12. A Numbers Gam e NRC provides no information on how absorptive a material is in the upper and lower frequencies. Averaging Allows For Different Materials To Have The Same Rating But Different Frequency Bias NRC does not have any relevance to the materials barrier affect (STC rating ).

13. Sound Masking  Uniform, non disturbing sound  Masks targeted frequencies  Enhances privacy & confidentiality  Reduces stress & complaints  HIPA and GBLA compliance

14. Improve Your Ratings Decouple walls Add length to the ventilation Insulate the wall Insulate the ceiling plenum Seal all flanking paths Minimize parallel hard walls Add sound masking

15. Thank You! Mark Bassil President 917-697-5418 Copyright © 2010 – MAI – All Rights Reserved