Acoustics Standard Fall 2018, Exams of Microwave Engineering and Acoustics

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Acoustics Standard

Fall 2018

Facilities and Campus Services Facilities Engineering / University Architect / CIT / Engineering &Project Management

Cornell University

272133

• Working Group
  • Matt Reiter, Architectural/Structural Section, FE
  • Liz Kolacki, Senior Mechanical Engineer, FE
  • Andy Page, Manager, Integrated Audio and Video Engineering, CIT
  • Ram Venkat, Senior Project Manager, E & PM
  • J. Shermeta, Associate University Architect, UAO
• Subject Matter Experts
  • Ben Markham, Director, Architectural Acoustics, Acentech
  • Seth Harrison, PE, Senior Associate, Metropolitan Acoustics
  • Mike Tomei, CTS-D/I, Tomei AV Consulting LLC

Developing an Acoustics Standard

• Sound transmits through air and solids
  • Air tightness of a structure offers better isolation
  • Increased structural mass offers better isolation
• Sound competes with (masks) other sounds
  • Quieter spaces are more intelligible but also offer less speech privacy
• Sound bounces around (reverberates) before it

ceases (decays)

• Spaces with less reverberation offer better intelligibility
• Larger spaces are generally more reverberant
• Type of Surface plays a large role
  • hard surfaces increase reverb
  • soft surfaces absorb sound and decrease reverb

Fun Facts – Properties of Sound

RT60 measures reverberation time or the time it takes the original sound to decrease (decay) by 60 dB

Measuring Sound – Reverberation

STI measures speech intelligibility or the

ability to understand what is being said

Measuring Sound – Intelligibility

Seen and Heard: Boston Symphony Hall The Birth of Architectural Acoustics

a·cous·tic noun

plural noun: acoustics

1.the properties or qualities of a room that determine how sound is transmitted in it.

"Symphony Hall has perfect acoustics"

Boston Symphony Hall. McKim, Mead, and White 1900

“Symphony Hall opened on October 15, 1900. Its architects were the distinguished firm of McKim, Mead, and White, who invited a young Harvard physics professor, Wallace Clement Sabine , possibly because of some calculations he had done for Harvard’s Fogg Museum, to advise them about acoustics. His advice is now considered the first truly “scientific” approach to concert-hall acoustics: the “birth of architectural acoustics.” Sabine seemed to have figured out what acoustician Robert Berens (who worked on the recent refurbishment of Symphony Hall) calls the “magic formula” for the effective absorption and reverberation of sound: neither too dry (for lack of reverberation) nor too echoey. As he explained it to me, the sound produced on the stage not only goes directly into the hall but also bounces off everything in sight and earshot — side and rear walls and ceiling — at minutely different times. That combination — the magic formula for absorption and reverberation — is what creates the overall hearing experience. The sound is magical, warm, and vibrant. You can clearly hear the softest pianissimo, the most delicate pizzicato. And its current superb brass section, which for years seemed coarse and blaring, has acquired a new burnished depth along with its familiar power. Everything blooms! Everything sounds! Lloyd Schwartz

• Design
  • Designer established acoustic performance requirements, confirmed with Cornell
  • Designer developed acoustic design details
• Construction
  • Designer provided construction phase oversight
  • Relied on contractor to construct per drawings

Case Study : Hughes Hall Renovation

• Post-Occupancy
  • Complaints from building occupants
  • Acoustic testing performed; results revealed:
    • Incomplete sealing of wall penetration by

contractor

• Low acoustic design of walls, doors and

glazing

• Low acoustic performance due to recessed

toilet accessories and electrical boxes

• Post-Occupancy repairs
  • Wall penetrations are being sealed by

contractor

• Wall construction is being upgraded
• Glazing is being replaced to acoustic glazing

Case Study : Hughes Hall Renovation

• Post-Occupancy
  • None

Case Study : Breazzano Family Center for Business Education

• Design
  • Designer established acoustic performance

requirements, confirmed with Cornell

• Designer developed acoustic design details
• Construction
• Designer provided construction phase oversight
• Relied on contractor to construct per drawings

Case Study : Gates Hall

Challenges at Cornell University

Surfaces

Adjacencies

Challenges at Cornell University

Walls

HVAC

Acoustics in Practice

Partition Schedules

Yale University Design Standards

• Acoustical consultant required for performing arts spaces, drama theaters, and high performance lecture, conference, and seminar rooms.”
• Includes Tables for Noise Control (NC/RC/dbA and for Acoustical Performance NC and NIC)

Precedents & Case Studies

ANSI/ASA S12. “American National Standard Acoustical Performance Criteria, Design Requirements, and Guidelines for Schools”

• “The first and most cost effective step in achieving good noise isolation between learning spaces and other spaces in a school is accomplished in the facility planning stage. This includes optimizing the location of noisy spaces and activities to protect sensitive learning spaces. Where this is not possible, adequate noise isolation is needed.”
• Includes Annexes A – F and Tables for Maximum background noise levels and reverberation times and Minimum STC ratings

General Services Administration (GSA) Facilities Standards for the Public Buildings Service (P100) Chapter 3 and GSA Commissioning Guidelines

• Four key concepts:
  1. Speech Privacy
  2. Background Sound
  3. Equipment Vibration and Reverberation
  4. Exterior Noise
• Acoustical performance will be verified during the commissioning of the building.
• Includes Table 3-2:Acoustics with Maximum Mechanical Noise (RC/NC), Minimum Absorption: Ceiling and Walls (SAA/NRC),

Minimum Noise Isolation (NIC) and

Optimum Reverberation (RT60)