Read Acoustics in Architecture text version

NSCA University at infoComm08

20 June 2008 Las Vegas, Nevada

Acoustics In Architecture (NW012)

Steven J. Thorburn, PE, CTS-D, CTS-I Thorburn Associates, Inc [email protected] www.TA-Inc.com

Corporate Office: Regional Office: Regional Office:

Castro Valley, California Burbank, California Raleigh Durham, North Carolina

Tel: 510-886-7826 Tel: 818-569-0234 Tel: 919-463-9995

Firm Profile THE COMPANY

Thorburn Associates (TA) is a full service Acoustical Consulting and Technology Design and Engineering firm. TA was founded in 1992 by principals who have consulted on and managed over 2000 projects. We provide a full range of services which allow the client, architect, or end-user a single point of contact during design and construction. Our staff is comfortable providing traditional design or design/build services and is quite experienced with the partnering process.

PHILOSOPHY

At TA we do whatever it takes to help make your project a success. Our consultants stay up-to-date on the latest technologies; develop in-house procedures to insure the quality of our work, such as custom computer programs to improve efficiency and provide quality control for redundant calculations. We utilize the latest automated equipment, such as the current release of AutoCAD with relational database overlays to produce design documents. Our office computers are fully networked. From design through construction, TA has the experience, knowledge and technology to make your project a success. Extensive laboratory and electronic test equipment allow us to efficiently document all aspects of acoustic designs. Our engineers can also create a BinauralizationTM model (room simulation) which allows you to "hear" how your facility will sound before it is built. Our experience with the construction process provides the practical background experience necessary to recommend acoustical solutions that are both innovative and effective. Our Audiovisual System Design packages are complete and require minimal clarification during the construction phase. A relational database links project details directly to AutoCAD via drawing attributes. Electronic test equipment allows us to document all aspects of the audiovisual system design. This level of detail allows for true competitive bidding from installation contractors. Our knowledge of the construction process provides the background experience necessary to recommend audiovisual solutions that meet your needs. We feel it is imperative that our principals take an active role throughout a project. Only by being directly involved with projects can we be assured that you, our clients, are getting the level of quality you deserve and require.

FACILITY TYPES

Presentation Facilities Training and Board Rooms Conference, Video, and Teleconference Rooms Places of Worship and Theatres Single and Multi-Family Housing Office Buildings, Research Facilities Theme Parks and Destination Resorts Commercial and Retail Buildings Educational Facilities Hospitals and Medical Facilities

AWARDS

TA principals have received three awards from the International Communications Industries Association: Professional Education and Training Committee Award, 1996-97 First Place - Systems and Facilities Design, 1991, project: CSA Audiovisual Presentation Studio Award for Systems and Facilities Design, 1990, project: City of Fremont's Council Chambers Audiovisual Upgrade Themed Entertainment Association THEA Award: Awarded Themed Entertainment Association THEA Outstanding Achievement Award for Paramount's King's Island "Tomb Raider: The Ride" 2002 Universal Studios "Amazing Adventures of Spiderman," 2000 Universal Studios "Islands of Adventure," 2000 Columbus Center of Science and Technology (COSI), audio, video and control system engineering services and acoustical design 2000 Building of America Award, 2007, project: The Mountain View Senior Center Northern California Region's Most Important New Construction/ Renovation, 2007, project: San Francisco Federal Office Building, General Service Administration AIA Winner of Architecture & Excellence Award, 2007, project: Plaza Apartments

Recording, Broadcast and PostProduction Studios Hotels and Casinos Planetariums Large Format Theatres Libraries Community Center

CONSULTING SERVICES

Room Acoustics and Sound Isolation Audiovisual and Sound System Design Room Modeling Mechanical Noise and Vibration Control Environmental Acoustics and Traffic Noise Studies Construction Administration Expert Testimony Presentation Lighting

WBE STATUS

Small Business: Certified as a Small Business (SBE) with the State of California Registered as a Historically Underutilized Business with the State of North Carolina (HUB) Women Owned Business (WBE): California Public Utilities Clearinghouse

INTERNET ADDRESS

www.TA-Inc.com or email us at: [email protected]

Corporate Office: Regional Office: Regional Office:

Castro Valley, California Burbank, California Raleigh Durham, North Carolina

Tel: 510-886-7826 Tel: 818-569-0234 Tel: 919-463-9995

Related Services

The following acoustic and audiovisual system design issues are typically found or required when we work on the following building types: Performance and Entertainment Facilities, Office Buildings, Research Laboratories, Medical Facilities, Libraries, Government and University Buildings, Film and Video Studios, Luxury Hotels, and Places of Worship.

Architectural Acoustic Design

Conceptual and Detailed Architectural Acoustic Design Acoustical Analysis of Existing Facilities Speech Intelligibility, Speech Privacy within Rooms Reverberation and Clarity of Sound Reflection, Diffusion, and Absorption of Sound Aspect Ratios to Promote Excellent Room Acoustics Room Modeling Floor/Ceiling and Wall Details to Prevent Noise Transmission Window and Door Selections to Meet Sound Isolation Criteria Interior and Exterior Noise from Affecting Adjacent Spaces Vibration Isolation Industrial Noise Control Mechanical Systems, Plumbing Systems Ventilation Systems - Duct Rumble, Diffuser Hiss, Rooftop Units Central Plants Sound System Design Video System Design Video Information Systems Foreground and Background Music Systems Video and Film Projection Systems Facility Master Plans for Growth and Expansion Equipment Evaluation, System Adjustment Control Systems Network System Infrastructure Design Traffic Noise Studies Highway, Aircraft, and Railroad Noise Site Evaluations and Surveys Sound and Vibration Testing Bid Management/Contractor Selection Cost/Change Control On-site Observation/Quality Control Schedule Management Submittal Reviews/Requests for Information Performance Testing/Training Construction Defects Sound Isolation Traffic Noise

Sound Isolation

Mechanical Noise Control

Audiovisual System Engineering

Data/Telecom Environmental Noise Abatement

Construction Administration

Expert Testimony

Corporate Office: Regional Office: Regional Office:

Castro Valley, California Burbank, California Raleigh Durham, North Carolina

Tel: 510-886-7826 Tel: 818-569-0234 Tel: 919-463-9995

Steven J. Thorburn, PE, CTS-D, CTS-I Principal

EDUCATION

Michigan Technological University B.S. Electrical Engineering Major: Electroacoustics B.S. Liberal Arts Major: Theatre and Lighting Design

AREAS OF EXPERTISE

Mr. Thorburn practices acoustical consulting and audiovisual system design in the following areas:

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PROFESSIONAL EXPERIENCE

Projects he has managed and consulted on include:

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PROFESSIONAL LICENSES

Mr. Thorburn is a registered Engineer in the following states: CA: MN: NC: AZ: MI: E.E. 13159 WA: P.E. 213389 OH: P.E. 25217 SC: P.E. 34990 IL: P.E. 46612 OR: P.E. 37191 E.E. 65890 P.E. 21186 062 - 054816 P.E. 669501

architectural acoustics mechanical noise control audiovisual, sound and control systems video and teleconference systems construction administration

Wilmington Convention Center ­ Wilmington, NC New London Presbyterian Church ­ New London, PA Lockheed Martin Aeronautics Company ­ Various Locations Nissan North America, Corporate Headquarters ­ Franklin, TN Lotte World ­ Seoul, Korea Stanford University - Graduate School of Business, Stanford, CA Arizona Mills IMAX Theatre ­ Tucson, AZ University of North Carolina, Chapel Hill, Dental Science Building ­ Chapel Hill, NC Sioux Falls Historic Courthouse and Law Library, Sioux Falls, S.D. Harveys Resort Hotel/Casino, South Lake Tahoe, NV Wachovia Bank ­ Charlotte, NC Cisco Systems Executive Briefing Center, Santa Clara, CA Sutter Medical Center, Sacramento ­ Sacramento, CA PG&E Pacific Energy Center, San Francisco, CA Durham County Justice Building ­ Durham, NC Knott's Camp Snoopy Amusement Park, Bloomington, MN Demsey E. Benton & E.M. Johnson Water Treatment Plant ­ Wake County, NC Cold Canyon Landfill/Sort Facility, San Luis Obispo, CA Kaiser - Geary Campus Medical Office Building, San Francisco, CA Minnesota Zoo - 3-D Theatre, Minneapolis, MN University of Illinois, Various Projects ­ Urbana, IL Alta Bates Medical Center - Conference and Education Center, Berkeley, CA

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Mr. Thorburn has served as project manager and consultant on over 1800 different projects. He is active in projects which require both acoustical and audiovisual system design services. His dual degrees from Michigan Technological University in theatre design and electrical engineering enable him to coordinate technical requirements involved in the construction bid process with practical issues required by the end-users. His projects have included presentation and conference facilities, government and university buildings, film and video studios, luxury hotels, libraries, churches, medical facilities, performing arts centers, recording facilities, and entertainment facilities. Mr. Thorburn was responsible for developing the International Communications Industries Association's Design Consultant's Council. He regularly attends conferences, trade shows, and product exhibitions which allow him to recommend the most cost-effective yet functional products to meet his client's needs. Manufacturers often ask for his input on the 'next generation' of A/V system components.

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TECHNICAL PUBLICATIONS and LECTURES

Mr. Thorburn frequently teaches seminars and lectures on both acoustical consulting and audiovisual system design. His most recent national presentations include:

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AIA Continuing Education System: Essentials of Acoustics: Theory and Hands-on Applications; Presentation Facility Design and Audiovisual Considerations, 2006 ICIA Institute Seminars, 1995-2006, Facilities and Systems Design ICIA Institute Seminar, 1996-2006, Presentation Facilities Design, ICIA Install School 1995-2001 ICIA Design School 1998-2006

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He is also a regular contributor to industry publication, Systems Contractor News.

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AWARDS

Mr. Thorburn has received the following awards from the International Communications Industries Association:

·

PROFESSIONAL SOCIETIES

· · · · · · ·

·

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Professional Education and Training Committee Award, 1996-1997. Systems and Facilities Design Award, First Place, 1991, project: CSA Audiovisual Presentation Studio. Systems and Facilities Design Award, 1990, project: City of Fremont Council Chambers Audiovisual Upgrade.

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Giant Screen Cinema Association Acoustical Society of America National Council of Acoustical Consultants National Society of Professional Engineers Institute of Electrical and Electronic Engineers International Communications Industries Association Audio Engineering Society American Institute of Architects

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Corporate Office: Regional Office: Regional Office:

Castro Valley, California Burbank, California Raleigh Durham, North Carolina

Tel: 510-886-7826 Tel: 818-569-0234 Tel: 919-463-9995

Acoustics In Architecture

Welcome To: Acoustics In Architecture

Steven J. Thorburn PE, CTS-D, CTS-I Thorburn Associates, Inc.

San Francisco, California Raleigh Durham, North Carolina Los Angeles, California

Slide 1

Acoustics In Architecture -- 2008

Acoustics In Architecture

Description:

Gain a greater understanding of the issues that should be addressed when developing the acoustical design of rooms like a large boardroom or a 300-seat auditorium/lecture room. All aspects of room acoustics will be discussed and reviewed including reverberation criteria, the even distribution of low frequency room modes, wall constructions to control noise, absorption, echo control, diffusion and more. A detailed workbook will be provided to all attendees.

Note! This is an intermediate session that addresses just the physical construction of rooms. We will not be going over any systems applications, no mics, no loudspeakers! If you are looking for the integration of systems into rooms this session is not for you! The acoustical design goal of any room is to make sure the room sounds good without any audio systems!

Slide 2

Acoustics In Architecture -- 2008

House Keeping

Restrooms ADA issues Lots of goodies to download

Slide 3

Acoustics In Architecture -- 2008

TA Copyright 2008 Corporate Office: Regional Office: Regional Office: Castro Valley, California Burbank, California Raleigh-Durham, North Carolina Tel: 510-886-7826 Tel: 818-569-0234 Tel: 919-463-9995

Acoustics In Architecture

Slide 4

Acoustics In Architecture -- 2008

The Seminar

Review Board Room

Sound Isolation Room Modes Room Acoustics

300 Seat Auditorium

Mechanical Noise Control Room Acoustics Reverberation Time

Questions and Answers

Slide 5

Acoustics In Architecture -- 2008

What Is Sound?

Pressure fluctuation with two components

Frequency Level

Slide 6

Acoustics In Architecture -- 2008

TA Copyright 2008 Corporate Office: Regional Office: Regional Office: Castro Valley, California Burbank, California Raleigh-Durham, North Carolina Tel: 510-886-7826 Tel: 818-569-0234 Tel: 919-463-9995

Acoustics In Architecture

What Is Frequency?

Pitch/tone Pure tone

Tuning fork

Number of cycles per second = frequency

Hertz(Hz)

Slide 7

Acoustics In Architecture -- 2008

Pure Tone Sound Wave

A sound made up of a single frequency. Wave Length

Slide 8

Acoustics In Architecture -- 2008

Propagation of Sound

(1) Wavelength

Slide 9

Acoustics In Architecture -- 2008

TA Copyright 2008 Corporate Office: Regional Office: Regional Office: Castro Valley, California Burbank, California Raleigh-Durham, North Carolina Tel: 510-886-7826 Tel: 818-569-0234 Tel: 919-463-9995

Acoustics In Architecture

Piano Frequency

31.5 63 125 250 500 1000 2000 4000

TROMBONE CELLO VIOLIN

1 OCTAVE

CDEFGAB

7 OCTAVES

Slide 10

Acoustics In Architecture -- 2008

What is loudness

Pitch/tone Pure tone

Tuning fork

Number of cycles per second = frequency

Hertz(Hz)

Slide 11

Acoustics In Architecture -- 2008

Sound Chart

Slide 12

Acoustics In Architecture -- 2008

TA Copyright 2008 Corporate Office: Regional Office: Regional Office: Castro Valley, California Burbank, California Raleigh-Durham, North Carolina Tel: 510-886-7826 Tel: 818-569-0234 Tel: 919-463-9995

Acoustics In Architecture

Narrow Band Data

80

SOUND PRESSURE LEVEL, dB

70 60 50 40 30 20 10

31

63 125 250 500 1K 2K 4K 8K

OCTAVE BAND CENTER FREQUENCIES, Hz

Slide 13

Acoustics In Architecture -- 2008

Octave Band (OB)

Every time we double the frequency, we have an octave. To make acoustical analysis, sound was divided into bands.

Centered on:

31.5, 63, 125, 250, 500, 1000, 2000, 4000, 8000, 16000 Hz.

Slide 14

Acoustics In Architecture -- 2008

1/3 Octave Band

These bands can be further split down into other bands. 1/3 octave are the most common.

63 Hz OB is made up of:

50, 63, 80 Hz 1/3 OB

Slide 15

Acoustics In Architecture -- 2008

TA Copyright 2008 Corporate Office: Regional Office: Regional Office: Castro Valley, California Burbank, California Raleigh-Durham, North Carolina Tel: 510-886-7826 Tel: 818-569-0234 Tel: 919-463-9995

Acoustics In Architecture

Octave Band Data

80

SOUND PRESSURE LEVEL, dB

70 60 50 40 30 20 10

31

63 125 250 500 1K 2K 4K 8K

OCTAVE BAND CENTER FREQUENCIES, Hz

Slide 16

Acoustics In Architecture -- 2008

Weighting

Flat Loudness dBA dBC

Slide 17

Acoustics In Architecture -- 2008

101 Acoustics You Passed

Slide 18

Acoustics In Architecture -- 2008

TA Copyright 2008 Corporate Office: Regional Office: Regional Office: Castro Valley, California Burbank, California Raleigh-Durham, North Carolina Tel: 510-886-7826 Tel: 818-569-0234 Tel: 919-463-9995

Acoustics In Architecture

Board Room

Sound Isolation Room Modes Room Acoustics

Slide 19

Acoustics In Architecture -- 2008

Sound Isolation

Sound Isolation ­ Keeping unwanted sound out of a room or keeping loud events in a room from impacting other spaces Walls Floor Ceiling Doors / Windows Penetrations

Slide 20

Acoustics In Architecture -- 2008

Sound Isolation

Sound is blocked by partitions with mass. Sound can be blocked by two light weight partitions separated by a large air space.

Slide 21

Acoustics In Architecture -- 2008

TA Copyright 2008 Corporate Office: Regional Office: Regional Office: Castro Valley, California Burbank, California Raleigh-Durham, North Carolina Tel: 510-886-7826 Tel: 818-569-0234 Tel: 919-463-9995

Acoustics In Architecture

Sound Impinging on a Structure

Ii Ia Ir

Slide 22

It

Acoustics In Architecture -- 2008

Sound Isolation

Sound Isolation ­ Sometimes called Noise Reduction or Noise Control Source ­ How Loud Path - (what we are solving for) Receiver ­ How Quiet

Slide 23

Acoustics In Architecture -- 2008

Sound Isolation

Source ­ How Loud Fan or Mechanical Data ­ 1/1 Octave bands Traffic Noise ­ broadband dBA Occupant noise - measure

Slide 24

Acoustics In Architecture -- 2008

TA Copyright 2008 Corporate Office: Regional Office: Regional Office: Castro Valley, California Burbank, California Raleigh-Durham, North Carolina Tel: 510-886-7826 Tel: 818-569-0234 Tel: 919-463-9995

Acoustics In Architecture

Sound Isolation

How Loud Should the Room Be ­ this is usually addressed in NC / PNC / RC ­ I use NC. More later on this for the Auditorium

Slide 25

Acoustics In Architecture -- 2008

Noise Criteria Curves (NC)

80

SOUND PRESSURE LEVEL, dB

70 60 50 40 30 20 10 NC-65 NC-60 NC-55 NC-50 NC-45 NC-40 NC-35 NC-30 NC-25 NC-20 NC-15

Kitchens, Shops, Computer Rooms -- Moderately fair listening conditions

Lobbies, Labs, Open Plan Offices -- For fair listening conditions Large Offices, Reception Areas, Restaurants -- For moderately good listening conditions Private Offices, Classrooms, Libraries -- For good listening conditions Auditoriums, Theatres, Conference Rooms -- For very good listening conditions Concert Halls, Studios, Churches -- For excellent listening conditions

31

63 125 250 500 1K

2K 4K 8K

OCTAVE BAND CENTER FREQUENCIES, Hz Slide 26

Acoustics In Architecture -- 2008

Sound Isolation

So what wall do we use:

Let's assume we have a fan room next to the board room. The manufacturer tells us that the casing radiated noise levels are:

63 78 125 80 1/1 Octave Band (Hz), Sound Levels (dB) 250 500 1K 2K 76 68 62 54 4K 46 8K 42

Source (Fan)

Slide 27

Acoustics In Architecture -- 2008

TA Copyright 2008 Corporate Office: Regional Office: Regional Office: Castro Valley, California Burbank, California Raleigh-Durham, North Carolina Tel: 510-886-7826 Tel: 818-569-0234 Tel: 919-463-9995

Acoustics In Architecture

Sound Isolation

Source ­ Path = Receiver or Source ­ Receiver = Path Required

Source (Fan) Receive (NC-30) Difference S-R 63 78 57 21 125 80 48 32 1/1 Octave Band (Hz), Sound Levels (dB) 250 500 1K 2K 76 68 62 54 41 35 31 29 35 33 31 25 4K 46 28 18 8K 42 27 15

·Sound Power ·Room Effect

Slide 28

Acoustics In Architecture -- 2008

Room Factor

We could use:

Lp = Lw + 10 Log10

(

4 Q + a 2 4r

)

Lp = sound-pressure level at a distance r from the source, dB Re 2 x 10-5 N/m2 Lw = sound-power of the source, dB Re 10-12 W Q = source directivity in its proposed configuration a = room absorption, m2 (sabins) r = distance from source, m

Slide 29

Acoustics In Architecture -- 2008

Transmission Loss (TL)

A measurement of how much sound energy is reduced in transmission through materials.

Slide 30

Acoustics In Architecture -- 2008

TA Copyright 2008 Corporate Office: Regional Office: Regional Office: Castro Valley, California Burbank, California Raleigh-Durham, North Carolina Tel: 510-886-7826 Tel: 818-569-0234 Tel: 919-463-9995

Acoustics In Architecture

Sound Isolation

Hunt for walls with matching TL

Source (Fan) Receive (NC-30) Difference S-R TL item 11 Appendix B-1 63 78 57 21 ?? ?? 125 80 48 32 32 0 1/1 Octave Band (Hz), Sound Levels (dB) 250 500 1K 2K 76 68 62 54 41 35 31 29 35 33 31 25 42 54 53 54 7 21 22 29 4K 46 28 18 52 34 8K 42 27 15 ?? ??

·TL tests limited to 100 (Hz) 1/3 OB ·TL tests limited to 4k (Hz) 1/3 OB ·Use data referenced from a Lab!

Slide 31

Acoustics In Architecture -- 2008

Sound Transmission Class (STC)

1/3 octave band transmission loss. Noise reduction corrected to standard room.

Slide 32

Acoustics In Architecture -- 2008

Sound Transmission Class (STC)

Nr = TL + 10 Log TL = A2 = S =

Slide 33

A2

S

Sound Transmission Loss of Barrier Absorption in Receiving Room (Sabine) Surface Area of Barrier (ft2)

Acoustics In Architecture -- 2008

TA Copyright 2008 Corporate Office: Regional Office: Regional Office: Castro Valley, California Burbank, California Raleigh-Durham, North Carolina Tel: 510-886-7826 Tel: 818-569-0234 Tel: 919-463-9995

Acoustics In Architecture

STC 45 Wall Detail

Seal Airtight

SECTION

Gypsum Board (1 & 1)

PLAN VIEW

Metal Stud

Batt Insulation

SECTION

Seal Airtight

Slide 34

Acoustics In Architecture -- 2008

STC 50 Wall Section

Slide 35

Acoustics In Architecture -- 2008

STC 55 Wall Detail

Seal Airtight

SECTION

Gypsum Board (2 & 2)

PLAN VIEW

Metal Stud

Batt Insulation

SECTION

Seal Airtight

Slide 36

Acoustics In Architecture -- 2008

TA Copyright 2008 Corporate Office: Regional Office: Regional Office: Castro Valley, California Burbank, California Raleigh-Durham, North Carolina Tel: 510-886-7826 Tel: 818-569-0234 Tel: 919-463-9995

Acoustics In Architecture

STC 65 Wall Detail

Seal Airtight

SECTION

Gypsum Board (2 & 2) Airspace Metal Stud

PLAN VIEW

Batt Insulation

SECTION

Seal Airtight

Slide 37

Acoustics In Architecture -- 2008

Composite TL

A chain is only as strong as its weakest link.

Slide 38

Acoustics In Architecture -- 2008

Transmission Loss -- 50 dB

ALL BRICK - COMPOSITE TL 50 dB

100 dB

50 dB

Slide 39

Acoustics In Architecture -- 2008

TA Copyright 2008 Corporate Office: Regional Office: Regional Office: Castro Valley, California Burbank, California Raleigh-Durham, North Carolina Tel: 510-886-7826 Tel: 818-569-0234 Tel: 919-463-9995

Acoustics In Architecture

Transmission Loss -- 29 dB

1/8 GLASS - COMPOSITE TL 29 dB

100 dB

71 dB

Slide 40

Acoustics In Architecture -- 2008

Transmission Loss -- 26 dB

1/4 GLASS - COMPOSITE TL 26 dB

100 dB

74 dB

Slide 41

Acoustics In Architecture -- 2008

Transmission Loss -- 23 dB

1/2 GLASS - COMPOSITE TL 23 dB

100 dB

77 dB

Slide 42

Acoustics In Architecture -- 2008

TA Copyright 2008 Corporate Office: Regional Office: Regional Office: Castro Valley, California Burbank, California Raleigh-Durham, North Carolina Tel: 510-886-7826 Tel: 818-569-0234 Tel: 919-463-9995

Acoustics In Architecture

Transmission Loss -- 20 dB

ALL GLASS - COMPOSITE TL 20 dB

100 dB

80 dB

Slide 43

Acoustics In Architecture -- 2008

Composite TL

Composite TL = 10 Log TL = S =

S ( S )

Transmission Loss (dB) Surface Area (ft2) Sound Transmission Coefficient

=

Slide 44

Acoustics In Architecture -- 2008

Composite TL

Brick

TL = 10 Log 50 = 10 Log 5 = Log

Glass

Slide 45

1

1 1

1

TL = 10 Log 20 = 10 Log 2 = Log

= 10 5 = 10 -5

1

1 1

1

= 10 2 = 10 -2

Acoustics In Architecture -- 2008

TA Copyright 2008 Corporate Office: Regional Office: Regional Office: Castro Valley, California Burbank, California Raleigh-Durham, North Carolina Tel: 510-886-7826 Tel: 818-569-0234 Tel: 919-463-9995

Acoustics In Architecture

Composite TL

Composite TL = 10 Log

= 10 Log = 10 Log

S ( S )

100 (10-5 x 87.5 + 10-2 x 12.5) 100 (12.6 x 10-2 )

= 10 Log (800) = 10 x 2.9031 = 29dB

Slide 46

Acoustics In Architecture -- 2008

Leaks

Slide 47

Acoustics In Architecture -- 2008

Ducts

Slide 48

Acoustics In Architecture -- 2008

TA Copyright 2008 Corporate Office: Regional Office: Regional Office: Castro Valley, California Burbank, California Raleigh-Durham, North Carolina Tel: 510-886-7826 Tel: 818-569-0234 Tel: 919-463-9995

Acoustics In Architecture

Big Pipe

Slide 49

Acoustics In Architecture -- 2008

Outlet

Slide 50

Acoustics In Architecture -- 2008

Acoustical Doors and Windows

Slide 51

Acoustics In Architecture -- 2008

TA Copyright 2008 Corporate Office: Regional Office: Regional Office: Castro Valley, California Burbank, California Raleigh-Durham, North Carolina Tel: 510-886-7826 Tel: 818-569-0234 Tel: 919-463-9995

Acoustics In Architecture

Acoustical Doors

Jamb and Head

Solid Core Wood Door Floor

Slide 52

Acoustics In Architecture -- 2008

Acoustical Doors

Slide 53

Acoustics In Architecture -- 2008

Slide 54

Acoustics In Architecture -- 2008

TA Copyright 2008 Corporate Office: Regional Office: Regional Office: Castro Valley, California Burbank, California Raleigh-Durham, North Carolina Tel: 510-886-7826 Tel: 818-569-0234 Tel: 919-463-9995

Acoustics In Architecture

Sound Isolation

So what wall do we use:

Let's assume we do not want to have people hear what is going on inside the room as they eavesdrop in the hall!

Source (Teleconference) 63 65 125 74 1/1 Octave Band (Hz), Sound Levels (dB) 250 500 1K 2K 78 80 79 75 4K 68 8K 60

Slide 55

Acoustics In Architecture -- 2008

Sound Isolation

Source ­ Path = Receiver or Source ­ Receiver = Path Required

Source (Teleconference) Receive (NC40) Difference S-R 63 65 64 1 125 74 57 17 1/1 Octave Band (Hz), Sound Levels (dB) 250 500 1K 2K 78 80 79 75 50 45 41 39 28 35 38 36 4K 68 38 30 8K 60 37 23

Slide 56

Acoustics In Architecture -- 2008

Boardroom Room Acoustics

Boardrooms are really too small for Reverberation Time Calculations (diffuse field) Goals

Even Room Modes Mixing Up Finishes

Slide 57

Acoustics In Architecture -- 2008

TA Copyright 2008 Corporate Office: Regional Office: Regional Office: Castro Valley, California Burbank, California Raleigh-Durham, North Carolina Tel: 510-886-7826 Tel: 818-569-0234 Tel: 919-463-9995

Acoustics In Architecture

Reverberation Field

Where the room (building space) limits the fall off of sound.

i.e. Sound levels stop falling off by 6 db every time the distance is doubled.

As more sound-absorbing treatment is used, the reduction of sound level with distance becomes more like the reduction outdoors, but there is a point of diminishing returns.

Slide 58

Acoustics In Architecture -- 2008

Sound Fields

L p (dB)

6 dB per Doubling of Distance Near Field Free Field Reverberant Field

Log (Distance)

Slide 59

Acoustics In Architecture -- 2008

What Is a Room Mode?

A standing wave The wave length is evenly divisible by the room's dimensions Low Frequency Issue (< 400 Hz)

Slide 60

Acoustics In Architecture -- 2008

TA Copyright 2008 Corporate Office: Regional Office: Regional Office: Castro Valley, California Burbank, California Raleigh-Durham, North Carolina Tel: 510-886-7826 Tel: 818-569-0234 Tel: 919-463-9995

Acoustics In Architecture

Standing-Wave Pattern

Rope

Node

Antinode

Slide 61

Acoustics In Architecture -- 2008

Standing-Wave Pattern

Air

Node

Antinode

back

Slide 62

Acoustics In Architecture -- 2008

Various Recommended Room Proportions

2.8 2.6 2.4 2.2 2.0 1.8 1.6 1.4 1.2 1.0 Slide 63 1.2 1.4 1.6 1.8 2.0 2.2

(Ref. R.H. Bolt)

Divide the shortest of the height, width or length into the other two! 12 x 18 x 24 feet or meters = 1:1.5:2 (1:1.5:2)

Acoustics In Architecture -- 2008

TA Copyright 2008 Corporate Office: Regional Office: Regional Office: Castro Valley, California Burbank, California Raleigh-Durham, North Carolina Tel: 510-886-7826 Tel: 818-569-0234 Tel: 919-463-9995

Acoustics In Architecture

Good Room Mode Ratios

1 1 1 1 : : : : 1.3 : 1.6 1.4 : 2 1.6 : 2.2 1.8 : 2.2

Slide 64

Acoustics In Architecture -- 2008

Room Mode Calculation

fN =

C 2

( N )2 + ( N )2 + ( N )2 L L L

x y z x y z

Frequency N = Mode L = Length C = Speed of Sound

Slide 65

fN =

Acoustics In Architecture -- 2008

Room Mode Calculation

For a Room 12 x 18 x 24, the first 3 Modes are? fN =

1128 2 1 0 0 ( 12 ) + ( 18 ) + ( 24 )

2 2 2

= = =

fN =

1128 2

0 1 0 ( 12 ) + ( 18 ) + ( 24 )

2 2

2

fN =

1128 2

0 0 1 ( 12 ) + ( 18 ) + ( 24 )

2 2

2

Slide 66

Acoustics In Architecture -- 2008

TA Copyright 2008 Corporate Office: Regional Office: Regional Office: Castro Valley, California Burbank, California Raleigh-Durham, North Carolina Tel: 510-886-7826 Tel: 818-569-0234 Tel: 919-463-9995

Acoustics In Architecture

Types Of Room Modes

Axial ­ Two Surfaces Tangential ­ Four Surfaces Oblique ­ Six Surfaces

Slide 67

Acoustics In Architecture -- 2008

Schroeder Cutoff Frequency

is the frequency above which the standing waves are that closely spaced that they do not substantially affect the sound, it is the frequency above which there are more than three modal frequencies within the bandwidth (1/3 octave band) of every mode. It depends on Volume and Reverberation Time which influences the bandwidth of the modal frequencies. The larger the room or the shorter the reverberation time the lower the Schroeder frequency. A lower Schroeder frequency will cause the frequency to smooth over a wider frequency range.

Slide 68

Acoustics In Architecture -- 2008

Board Room ­ Room Acoustics

Generally not an issue Treat one wall (>150 sf) with 1 to 2 inch thick sound absorbing panels Treat two walls (>250 sf) Chair Rail To Ceiling At Least 50% of Ceiling ATC To Small for RT60 (>10,000 c.f. start doing RT60 cals)

Acoustics In Architecture -- 2008

Slide 69

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Acoustics In Architecture

Questions and Answers

Slide 70

Acoustics In Architecture -- 2008

Mechanical Noise Control Room Acoustics Reverberation Time

Slide 71

Acoustics In Architecture -- 2008

Things to Avoid in Large Room Design

Echoes Flutter Echoes Sound Focusing Sound Shadows Excessive Reverberation Background Noise

Slide 72

Acoustics In Architecture -- 2008

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Acoustics In Architecture

Echoes

Strong refection well above reverberant decay. We can start to hear echoes at 35 milliseconds. (Haus effect)

Possible Echo

Sound Pressure

Echo

0

t

Acoustics In Architecture -- 2008

Slide 73

Flutter Echoes

A series of echoes between parallel surfaces

SOURCE

Slide 74

Acoustics In Architecture -- 2008

Sound Focusing

Effects of curved surfaces

S1 S

Slide 75

Acoustics In Architecture -- 2008

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Acoustics In Architecture

Sound Shadows

Seats that do not have full exposure to the reverberant field, such as under balconies, or in wing areas of asymmetric meeting rooms.

Slide 76

Acoustics In Architecture -- 2008

Excessive Reverberation

Too much acoustical energy will cause muddiness and affect speech intelligibility.

Slide 77

Acoustics In Architecture -- 2008

Background Noise

Let's make it so quiet we can hear a pin drop.

Slide 78

Acoustics In Architecture -- 2008

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Acoustics In Architecture

Background Noise

NC -- Noise Criteria is a family of curves established in 1957. The amount of noise that a mechanical system makes in a room. Equal loudness curves which take into account that we do not perceive the magnitude of the low frequency noise levels.

Slide 79

Acoustics In Architecture -- 2008

Noise Criteria Curves (NC)

80

SOUND PRESSURE LEVEL, dB

70 60 50 40 30 20 10 NC-65 NC-60 NC-55 NC-50 NC-45 NC-40 NC-35 NC-30 NC-25 NC-20 NC-15

Kitchens, Shops, Computer Rooms -- Moderately fair listening conditions Lobbies, Labs, Open Plan Offices -- For fair listening conditions Large Offices, Reception Areas, Restaurants -- For moderately good listening conditions Private Offices, Classrooms, Libraries -- For good listening conditions Auditoriums, Theatres, Conference Rooms -- For very good listening conditions Concert Halls, Studios, Churches -- For excellent listening conditions

31

63 125 250 500 1K

2K 4K 8K

OCTAVE BAND CENTER FREQUENCIES, Hz Slide 80

Acoustics In Architecture -- 2008

Noise Criteria Chart

80

SOUND PRESSURE LEVEL, dB

70 60 50 40 30 20 10 NC-65 NC-60 NC-55 NC-50 NC-45 NC-40 NC-35 NC-30 NC-25 NC-20 NC-15

Extremely Noisy Very Noisy Moderately Noisy to Noisy Very Quiet to Quiet

31

63 125 250 500 1K

2K 4K 8K

OCTAVE BAND CENTER FREQUENCIES, Hz Slide 81

Acoustics In Architecture -- 2008

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Acoustics In Architecture

Fan Location

Always over your room You want it as far away as possible

Slide 82

Acoustics In Architecture -- 2008

Duct System

Supply Return Lined Silencers Diffusers

Slide 83

Acoustics In Architecture -- 2008

Slide 84

Acoustics In Architecture -- 2008

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Acoustics In Architecture

Slide 85

Acoustics In Architecture -- 2008

Slide 86

Acoustics In Architecture -- 2008

Roof Top Fan Systems

Fan Supply Duct Control Unit

Return

Silencer

Diffuser

Slide 87

Acoustics In Architecture -- 2008

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Acoustics In Architecture

HVAC Noise Control

Fan Split

Diffuser

Slide 88

Acoustics In Architecture -- 2008

Slide 89

Acoustics In Architecture -- 2008

HVAC Noise Control

Silencer Fan Split

Diffuser

Slide 90

Acoustics In Architecture -- 2008

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Acoustics In Architecture

Ducts

Main Duct Branch Duct

Secondary Branch Duct

Dampers Diffuser

Slide 91

Acoustics In Architecture -- 2008

Vibration Isolation

AIRBORNE SOUND

Equipment Near Columns

Rigid Base Vibration Isolators

Transmitted Noise and Vibration is Reduced

Slide 92

Acoustics In Architecture -- 2008

Vibration Isolation

Slide 93

Acoustics In Architecture -- 2008

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Acoustics In Architecture

Vibration Isolation

Slide 94

Acoustics In Architecture -- 2008

Plumbing Isolation

Slide 95

Acoustics In Architecture -- 2008

Plumbing Isolation

Slide 96

Acoustics In Architecture -- 2008

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Acoustics In Architecture

Plumbing Isolation

Slide 97

Acoustics In Architecture -- 2008

Electrical Isolation

Slide 98

Acoustics In Architecture -- 2008

Room Acoustics

Absorption Reverberation Reflections

Slide 99

Acoustics In Architecture -- 2008

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Acoustics In Architecture

Absorption

NRC -- Noise Reduction Coefficient The mathematical average of the absorption coefficient of the 250, 500, 1000, and 2000 Hz octave bands. Has nothing to do with noise reduction.

Slide 100

Acoustics In Architecture -- 2008

ABSORPTION -- NRC

NRC 1.00

Totally Absorptive

Slide 101

Acoustics In Architecture -- 2008

ABSORPTION -- NRC

NRC 1.00 NRC 0.00

Totally Absorptive

Totally Reflective

Slide 102

Acoustics In Architecture -- 2008

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Acoustics In Architecture

Effect of the Mounting Condition

1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 125 250 500 1K 2K 4K NRC

Slide 103

Acoustics In Architecture -- 2008

Effect of the Mounting Condition

1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 125 250 500 1K 2K 4K NRC

Slide 104

Acoustics In Architecture -- 2008

ASTM Mounting Conditions

Slide 105

Acoustics In Architecture -- 2008

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Acoustics In Architecture

ASTM Mounting Conditions

Slide 106

Acoustics In Architecture -- 2008

Effects of Mounting Conditions on Absorption

Slide 107

Acoustics In Architecture -- 2008

Effects of Mounting Conditions on Absorption

Slide 62/63

Slide 108

Acoustics In Architecture -- 2008

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Acoustics In Architecture

Effects of Mounting Conditions on Absorption

Slide 109

Acoustics In Architecture -- 2008

Effects of Mounting Conditions on Absorption

Slide 110

Acoustics In Architecture -- 2008

Wave Length

Wavelength =

Speed of Sound Frequency

Speed of sound 1128 ft/s (343 m/s) Frequency (cycles per second) Wavelength's notation is

=

Slide 111

Lambda

Acoustics In Architecture -- 2008

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Acoustics In Architecture

Slide 112

Acoustics In Architecture -- 2008

NRC Calculation

Heavy Carpet 250 = 0.06 500 = 0.14 1000 = 0.37 2000 = 0.60 NRC = 0.30

Slide 113

Acoustics In Architecture -- 2008

NRC Calculation

Low Frequency Absorption 250 = 0.90 500 = 0.80 1000 = 0.50 2000 = 0.40 NRC = 0.65

Slide 114

Acoustics In Architecture -- 2008

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Acoustics In Architecture

Reverberation

NRC Absorption Types of Materials Mounting of Materials Location

Slide 115

Acoustics In Architecture -- 2008

Suggested Reverberation Times

`Dead' spaces (sound decays rapidly) `Live' spaces (sound persists) MUSIC

Symphonic (classical to romantic) Semi-classical concerts,chorus,(using sounds system) Churches Cathedrals

SPEECH & MUSIC

Multipurpose auditoriums High school auditorium Small theaters Cinema Lecture and conference rooms

SPEECH

Intimate drama Elementary classrooms Recording and broadcasting studio

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

2.2

2.4

2.6

Reverberation time (sec)

Slide 116

Acoustics In Architecture -- 2008

Reflected Sound in a Treated Room

Reverberation

60 dB

time

Slide 117

Acoustics In Architecture -- 2008

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Acoustics In Architecture

Reflected Sound in a Treated Room

Reverberation

60 dB

time

Slide 118

Acoustics In Architecture -- 2008

Reflected Sound in a Treated Room

Reverberation

60 dB

time

Slide 119

Acoustics In Architecture -- 2008

Reflected Sound in a Treated Room

Reverberation

60 dB

time

Slide 120

Acoustics In Architecture -- 2008

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Acoustics In Architecture

RT 60 Equation

V T = 0.049 a

Where: T = reverberation time required for sound to decay 60 dB after the source has stopped (s) V = room volume (ft3) a = total ft2 of room absorption (sabins, so named to honor W.C. Sabine)

It should not be used for recording studios or anechoic chambers, which have extremely high ratios of absorption to room volume. In these cases, the Eyring formula should be used.

Slide 121

Acoustics In Architecture -- 2008

RT 60 Calculation

Compute the surface areas S.

ceiling S = 60 x 35 = 2100 ft2 walls S = 2 x 35 x 15 = 1050 ft2 S = 2 x 60 x 15 = 1800 ft2 floor S = 60 x 35 = 2100 ft2

Slide 122

Acoustics In Architecture -- 2008

RT 60 Calculation

Compute the total room absorption a using a =SSa.

S a (sabins) ceiling 2100 x 0.04 = 84 walls 2850 x 0.30 = 855 floor 2100 x 0.10 = 210 Total a = 1149 sabins

Slide 123

Acoustics In Architecture -- 2008

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Acoustics In Architecture

Let's Do an RT60 Calc!

Slide 124

Acoustics In Architecture -- 2008

RT60 Goal ­ 0.8 to 1.0 Seconds

(slide 119)

Slide 125

Acoustics In Architecture -- 2008

Floor Plan

Total Square Feet: 2895

675

1575

335 310

Slide 126

Acoustics In Architecture -- 2008

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Acoustics In Architecture

Ceiling Plan

2585

315

Slide 127

Acoustics In Architecture -- 2008

West Elevation

320

760

Slide 128

Acoustics In Architecture -- 2008

East Elevation

480

Slide 129

Acoustics In Architecture -- 2008

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Acoustics In Architecture

North Elevation

265

350

725

Slide 130

Acoustics In Architecture -- 2008

South Elevation

744

494

Slide 131

Acoustics In Architecture -- 2008

Mixing Acoustical Finishes

Slide 132

Acoustics In Architecture -- 2008

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Acoustics In Architecture

Direct, Early, and Reverberant Sound

First Reflection

Direct

Slide 133

Acoustics In Architecture -- 2008

Direct, Early, and Reverberant Sound

Impulse Direct Sound

Sound Pressure

t0 t1 t2

First Reflection

0

Early Sound

t

Slide 134

Acoustics In Architecture -- 2008

Reflections

Reflective surface will absorb no wave energy Returns all energy back to the space it came from Reflective acoustic surface: concrete wall

Acoustics In Architecture -- 2008

Slide 135

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Acoustics In Architecture

Reflection

Slide 136

Acoustics In Architecture -- 2008

Reflection ( x > 4 )

x>4

Flat sound-reflecting panel

r i

Reflected sound path

Slide 137

Acoustics In Architecture -- 2008

Reflection of Sound

S

Flat Surface acts like a mirror.

Slide 138

Acoustics In Architecture -- 2008

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Acoustics In Architecture

Reflection of Sound

S1 S

Concave Surface concentrates sound in the region S .

1

Slide 139

Acoustics In Architecture -- 2008

Reflection of Sound

S

Convex Surface scatters sound.

Slide 140

Acoustics In Architecture -- 2008

Absorption

Conversion of sound energy to heat Common acoustically absorptive material: fiberglass insulation

Slide 141

Acoustics In Architecture -- 2008

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Acoustics In Architecture

Absorption

Slide 142

Acoustics In Architecture -- 2008

Diffusion

Combination of sound waves Increases distribution of the direction of sound Diffused sound energy is distributed in time

Slide 143

Acoustics In Architecture -- 2008

Diffusion

Slide 144

Acoustics In Architecture -- 2008

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Acoustics In Architecture

Diffusion ( x = )

Diffusing panel (typical length and width surface dimensions are 3 ft to 10 ft with random depths (x) of 6 in to 2 ft)

x=

Diffused sound paths

Slide 145

Acoustics In Architecture -- 2008

Reflection of Sound

S

Rough Surface leads to diffuse reflection.

Slide 146

Acoustics In Architecture -- 2008

Questions and Answers

Slide 147

Acoustics In Architecture -- 2008

TA Copyright 2008 Corporate Office: Regional Office: Regional Office: Castro Valley, California Burbank, California Raleigh-Durham, North Carolina Tel: 510-886-7826 Tel: 818-569-0234 Tel: 919-463-9995

Acoustics In Architecture

Slide 148

Acoustics In Architecture -- 2008

Thank You!

Acoustics In Architecture

Download Handout (10 Meg) at www.TA-Inc.com/nsca.htm [email protected]

Steven J. Thorburn PE, CTS-D, CTS-I Thorburn Associates, Inc.

San Francisco, California Raleigh Durham, North Carolina Los Angeles, California

Slide 149

Acoustics In Architecture -- 2008

TA Copyright 2008 Corporate Office: Regional Office: Regional Office: Castro Valley, California Burbank, California Raleigh-Durham, North Carolina Tel: 510-886-7826 Tel: 818-569-0234 Tel: 919-463-9995

FAN

COPYRIGHT

C 2004

Corporate Office: Regional Office: Regional Office:

Castro Valley, California Burbank, California Morrisville, North Carolina

Tel: 510-886-7826 Tel: 818-569-0234 Tel: 919-463-9995

Appendix A-7

`

Corporate Office: Regional Office: Regional Office

Castro Valley, California Burbank, California Raleigh-Durham, North Carolina

Tel: 510-886-7826 Tel: 818-569-0234 Tel: 919-463-9995

Appendix A-7

`

Corporate Office: Regional Office: Regional Office

Castro Valley, California Burbank, California Raleigh-Durham, North Carolina

Tel: 510-886-7826 Tel: 818-569-0234 Tel: 919-463-9995

Appendix A-13

`

Corporate Office: Regional Office: Regional Office

Castro Valley, California Burbank, California Raleigh-Durham, North Carolina

Tel: 510-886-7826 Tel: 818-569-0234 Tel: 919-463-9995

Appendix A-13

`

Corporate Office: Regional Office: Regional Office

Castro Valley, California Burbank, California Raleigh-Durham, North Carolina

Tel: 510-886-7826 Tel: 818-569-0234 Tel: 919-463-9995

Appendix A-20

`

Corporate Office: Regional Office: Regional Office

Castro Valley, California Burbank, California Raleigh-Durham, North Carolina

Tel: 510-886-7826 Tel: 818-569-0234 Tel: 919-463-9995

Appendix A-20

`

Corporate Office: Regional Office: Regional Office

Castro Valley, California Burbank, California Raleigh-Durham, North Carolina

Tel: 510-886-7826 Tel: 818-569-0234 Tel: 919-463-9995

`

Project Name:

Run Description:

Room Volume (ft^3) 1/1 OCTAVE BAND ABSORPTION AREA ft^2 MATERIAL 63 125 250 500 1000 2000 4000 8000 63 125 250 500 1/1 OCTAVE BAND ABSORPTION 1000 2000 4000 8000

SURFACE

Corporate Office: Regional Office: Regional Office TOTAL ABSORPTION AVG. ABSORPTION RT60 -- SABINE

Castro Valley, California Burbank, California Raleigh-Durham, North Carolina

Appendix A-26

Tel: 510-886-7826 Tel: 818-569-0234 Tel: 919-463-9995

`

Project Name:

Run Description:

Room Volume (ft^3) 1/1 OCTAVE BAND ABSORPTION AREA ft^2 MATERIAL 63 125 250 500 1000 2000 4000 8000 63 125 250 500 1/1 OCTAVE BAND ABSORPTION 1000 2000 4000 8000

SURFACE

Corporate Office: Regional Office: Regional Office TOTAL ABSORPTION AVG. ABSORPTION RT60 -- SABINE

Castro Valley, California Burbank, California Raleigh-Durham, North Carolina

Appendix A-26

Tel: 510-886-7826 Tel: 818-569-0234 Tel: 919-463-9995

`

Project Name:

Run Description:

Room Volume (ft^3) 1/1 OCTAVE BAND ABSORPTION AREA ft^2 MATERIAL 63 125 250 500 1000 2000 4000 8000 63 125 250 500 1/1 OCTAVE BAND ABSORPTION 1000 2000 4000 8000

SURFACE

Corporate Office: Regional Office: Regional Office TOTAL ABSORPTION AVG. ABSORPTION RT60 -- SABINE

Castro Valley, California Burbank, California Raleigh-Durham, North Carolina

Appendix A-26

Tel: 510-886-7826 Tel: 818-569-0234 Tel: 919-463-9995

`

Project Name:

Run Description:

Room Volume (ft^3) 1/1 OCTAVE BAND ABSORPTION AREA ft^2 MATERIAL 63 125 250 500 1000 2000 4000 8000 63 125 250 500 1/1 OCTAVE BAND ABSORPTION 1000 2000 4000 8000

SURFACE

Corporate Office: Regional Office: Regional Office TOTAL ABSORPTION AVG. ABSORPTION RT60 -- SABINE

Castro Valley, California Burbank, California Raleigh-Durham, North Carolina

Appendix A-26

Tel: 510-886-7826 Tel: 818-569-0234 Tel: 919-463-9995

TRANSMISSION LOSS DATA FOR COMMON BUILDING ELEMENTS Transmission Loss (dB)

STC IIC

Building Construction Walls 2-6'** Monolithic 1. 3/8-in plywood (1 lb/ft2) 2. 26-gauge sheet metal (1.5 lb/ft2) 3. 1/2-in gypsum board (2 lb/ft2) 4. 2 layers ½" gypsum board, laminated w/ joint compound (4 lb/ft2) 5. 1 /32-in sheet lead (2 lb/ft2) 6. Glass-fiber roof fabric (37.5 oz/yd2)

125Hz 250Hz 500Hz 1000Hz 2000Hz 4000Hz Rating

Rating*

14 12 15 19 15 6

18 14 20 26 21 9

22 15 25 30 27 11

20 21 31 32 33 16

21 21 33 29 39 20

26 25 27 37 45 25

22 20 28 31 31 16

Interior: 7. 2 by 4 wood studs 16 in oc with 17 ½" gypsum board both sides (5 lb/ft') 8. Construction no. 7 with 2-in glass 15 fiber insulation in cavity 9. 2 by 4 staggered wood studs 16 in 23 oc each side with 1/2-in gypsum board both sides (B lb/fl2) 10.Construction no. 9 with 2 1 /4-in 29 glass fiber insulation in cavity 11.2 by 4 wood studs 16 in oc with 32 5/8-ingypsum board both sides, one side screwed to resilient channels. 3-in glass-fiber insulation in cavity ( 7 lb/fi2) 12.Double row of 2 by 4 wood studs 31 16 in oc with 3/8-in gypsum board on both sides of construction. 9-in glass-fiber insulation in cavity (4 lb/ft2) 13. 6-in dense concrete block, 3 cells, 37 painted (34 lb/fi2) 14.8-in lightweight concrete block, 34 3 cells, painted (38 lb/ft2) 15.Construction no, 14 with expanded 34 mineral loose fill in cells 16.6-in lightweight concrete block with 35 1/2-in gypsum board supported by resilient metal channels on one side, other side painted (26 lb/ft2)

31 30 28 38 42

33 34 39 45 52

40 44 46 52 58

38 46 54 58 53

36 41 44 50 54

33 37 39 48 52

44

55

62

67

65

54

36 40 40 42

42 44 46 50

49 49 52 64

55 59 60 67

58 64 66 65

45 49 51 53

Appendix B-1

`

Corporate Office: Regional Office: Regional Office

Castro Valley, California Burbank, California Raleigh-Durham, North Carolina

Tel: 510-886-7826 Tel: 818-569-0234 Tel: 919-463-9995

Transmission Loss (dB)

STC IIC

Building Construction

125Hz 250Hz 500Hz 1000Hz 2000Hz 4000Hz Rating

Rating

17.2 1/2-in steel channel studs 24 in oc with 5/8-in gypsum board both sides (6 lb/ft2) 18.Construction no. 17 with 2-in glass-fiber insulation in cavity 19.3 5/8-in steel channel studs 16 in oc with 1/2-in gypsum board both sides (5 lb/fi2) 20.Construction no.19 with 3-in mineral fiber insulation in cavity 21.2 1/2-in steel channel studs 24 in oc with two layers 5/8-in gypsum board one side, one layer other side (8 lb/ft2) 22.Construction no. 21 with 2-in glass fiber insulation in cavity 23. 3 5/8-in steel channel studs 24 in oc with two layers 5/8-in gypsum board both sides ( 1 1 lb/ft2) 24.Construction no. 23 with 3-in mineral fiber insulation in cavity Exterior: 25. 4 1 /2-in face brick (50 lb/ft2) 26.Two wythes of 4 1 / 2-in face brick 2-in airspace with metal ties (100 lb/fl2) 27.Two wythes of plastered 4 1/2-in brick, 2-in airspace with giass-fiber insulation in cavity 28.2 by 4 wood studs 16 in oc with 1" stucco on metal lath on outside and 1/2-in gypsum board on inside (8 lb/ft2) 29.6-in solid concrete with 1 / 2-in plaster both sides (80 lb/ft2)

22 26 26 28 28

27 41 36 45 31

43 52 43 54 46

47 54 51 55 51

37 45 48 47 53

46 51 43 54 47

39 45 43 48 44

31 34 38

43 41 52

55 51 59

58 54 60

61 46 56

51 52 62

51 48 57

32 37 43 21

34 37 50 33

40 47 52 41

47 55 61 46

55 62 73 47

61 67 78 51

45 50 59 42

39

42

50

58

64

67

53

Floor-Ceilings'2.3 30. 2 by 10 wood joists 16 in oc with 23 1/2- in plywood subfloor under 25/32-in oak on floor side, and 5/8-in gypsum board nailed to joists on ceiling side ( 10 lb / ft2) 31.Construction no. 30 with 5/8-in 30 gypsum board screwed to resilient channels spaced 24 in oc perpendicular to joists

32

36

45

49

56

37

32

35

44

50

54

60

47

Appendix B-2

`

Corporate Office: Regional Office: Regional Office

Castro Valley, California Burbank, California Raleigh-Durham, North Carolina

Tel: 510-886-7826 Tel: 818-569-0234 Tel: 919-463-9995

Transmission Loss (dB)

STC IIC

Building Construction 32.Construction no. 31 with 3-in glass fiber insulation in cavity 33, 4-in reinforced concrete slab (54 lb/ft2) 34.14-in precast concrete tees with 2-in concrete topping on 2-in slab (75lb/ ft2) 35.6-in reinforced concrete slab (75 lb /ft2) 36.6-in reinforced concrete slab with 3/4-in T&G wood flooring on 1 1/2 by 2 wooden battens floated on 1-in glass fiber (83 lb/ft2) 37.18-in steel joists 16 in oc with I 5/8-inconcrete on 5/8-in plywood under heavy carpet laid on pad, and 5/8-in gypsum board attached to joists on ceiling side (20 lb/ft2)

125Hz 250Hz 500Hz 1000Hz 2000Hz 4000Hz Rating 36 48 39 38 38 40 42 45 43 44 45 45 50 52 52 52 56 52 59 55 58 57 60 67 60 64 66 68 72 65 49 44 54 55 55

Rating

27

37

45

54

60

65

47

Roofs2 38.3 by 8 wood beams 32 in oc with 29 2 by 6 T&G planks, asphalt felt built-up roofing, and gravel topping 39.Construction no. 38 with 2 by 4s 35 16 in oc between beams, 1/2-in gypsum board supported by metal channels onceiling side with 4-in glass-fiber insulation in cavity 40.Corrugated steel, 24 gauge with 17 1 3/8-in sprayed cellulose insulation on ceiling side ( 1.8 lb/ft') 41.2 1/2-in sand and gravel concrete 32 (148 lb/fil) on 28 gauge corrugated steel supported by 14-in-deep steel bar joists with 1/2-in gypsum plaster on metal lath attached to metal furring channels 13 1/2 in oc on ceiling side (41 lb/ft2) Doors2 42. Louvered door, 25 to 30 % open 10

33 42

37 49

44 62

55 67

63 79

43 53

22 46

26 45

30 50

35 57

41 61

30 49

12 19 22 31

12 23 25 31

12 18 19 31

12 17 20 39

11 21 29 43

12 19 21 34

43.1 3/4-in hollow-core wood door, no 14 gaskets, 1/4-in air gap at sill (1.5 lb/fil) 44.Construction no 43 with gaskets 19 and drop seal 45.1 3/4-in solid-core wood door with 29 gaskets and drop seal (4.5 lb/ft2)

Appendix B-3

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Transmission Loss (dB)

STC IIC

Building Construction

125Hz 250Hz 500Hz 1000Hz 2000Hz 4000Hz Rating

Rating

46. 3/4-in hollow-core 16 gauge steel 23 door, glass-fiber filled, with gaskets and drop seal ( 7 lb/ft2) Glass2 47. 1/8-inmonolithic float glass (1.4 lb/ft2) 48.1/4-inmonolithic float glass (2,9 lb/ft2) 49.1/2-in insulated glass: 1/8 + 1/8" double glass with 1/4-in airspace (3.3 lb/ft2) 50.1 / 4- + 1 /8-in double glass with 2-in airspace 51.Construction no. 50 with 4-in airspace 52.1/4-in laminated glass, 30-mil plastic interlayer (3.6 lb/ft2) 53. Double glass: 1/4-in laminated + 3/16-in monolithic glass with 2-in airspace (5.9 lb/ft2) 54.Double glass: 1/4-in laminated + 3/ 16-in monolithic glass with 4-in airspace (5.9 lb/ft2) 55.Double glass: 1/4-in laminated + 1/4-in laminated with 1/2-in airspace (7.2 lb/ft2) 18 25 21 18 21 25 25 36 21

28

36

41

39

44

38

21 28 26 31 32 28 34 37 30

26 31 24 35 42 32 44 48 40

31 34 33 42 48 35 47 51 44

33 30 44 44 48 36 48 50 46

22 37 34 44 44 43 55 58 57

26 31 28 39 43 35 45 48 42

*IIC (impact isolation class) is a single number rating of the impact sound transmission performance of a floor ceiling construction tested over a standard frequency range. The higher the IIC the more efficient the construction will be for reducing impact sound transmission. INR (impact noise rating) previously was used as the single number rating of impact noise isolation. To convert the older INR data to IIC, ad 51 to the INR number. **A wide range of TL and STC performance can be achieved by gypsum wallboard constructions. Refer to ASTM E 90 laboratory report and literature from manufacturers for specific details such as type of gypsum board; gauge, width and spacing of steel studs; glass-fiber or mineral-fiber insulation thickness and density; and complete installation recommendations.

Appendix B-4

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SOUND ABSORPTION DATA FOR COMMON BUILDING MATERIALS AND FURNISHINGS Sound Absorption Coefficient Material Walls(i-3.9.12) Sound-Reflecting: 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. Brick, unglazed Brick, unglazed and painted Concrete, rough Concrete block, painted Gass, heavy (large penes) Glass, ordinary window Gypsum board, 1/2 in thick (nailed to 2 X 4s, 16 in oc) Gypsum board, 1 layer, 5/8 in thick (screwed to 1 x 3s, 16 in oc with airspaces filled with fibrous insulation) Construction no. 8 with 2 layers of 5/8-in-thick gypsum board Marble or glazed tile Plaster on brick Plaster on concrete block (or 1 in thick on lath) Plaster on lath Plywood, 3/8-in paneling Steel Venetian blinds, metal Wood, 1/4-in paneling, with airspace behind Wood, 1-in paneling with airspace behind 0.02 0.01 0.01 0.10 0.18 0.35 0.29 0.55 0.28 0.01 0.01 0.12 0.14 0.28 0.05 0.06 0.42 0.19 0.02 0.01 0.02 0.05 0.06 0.25 0.10 0.14 0.12 0.01 0.02 0.09 0.10 0.22 0.10 0.05 0.21 0.14 0.03 0.02 0.04 0.06 0.04 0.18 0.05 0.08 0.10 0.01 0.02 0.07 0.06 0.17 0.10 0.07 0.10 0.09 0.04 0.02 0.06 0.07 0.03 0.12 0.04 0.04 0.07 0.01 0.03 0.05 0.05 0.09 0.10 0.15 0.08 0.06 0.05 0.02 0.08 0.09 0.02 0.07 0.07 0.12 0.13 0.02 0.04 0.05 0.04 0.10 0.07 0.13 0.06 0.06 0.07 0.03 0.10 0.08 0.02 0.04 0.09 0.11 0.09 0.02 0.05 0.04 0.03 0.11 0.02 0.17 0.06 0.05 0.05 0.00 0.05 0.05 0.05 0.15 0.05 0.10 0.10 0.00 0.05 0.05 0.05 0.15 0.10 0.10 0.10 0.10 NRC 125Hz 25OHz 50OHz 10OOHz 20OOHz 40OOHz Number*

Sound-Absorbing: 19. 20. Concrete block, coarse Lightweight drapery, 10 oz/yci2, on wall flat on wall Note:Sound-reflecting at most frequencies.) Mediumweight drapery, 14 oz/yd2, draped to half area (i.e., 2 ft of drapery to 1 ft of wall) Heavyweight drapery, 18 oz/yd2, Draped to half area 0.36 0.03 0.44 0.04 0.31 0.11 0.29 0.17 0.39 0.24 0.25 0.35 0.35 0.15

21. 22.

0.07 0.14

0.31 0.35

0.49 0.55

0.75 0.72

0.70 0.70

0.60 0.65

0.55 0.60

Appendix B-5

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Sound Absorption Coefficient Material NRC 125Hz 25OHz 50OHz 10OOHz 20OOHz 40OOHz Number*

23.

24. 25. 26, 27.

Fiberglass fabric curtain, 8 1 /2oz/yd2, draped to half area (Note: The deeper the airspace behind the drapery (up to 12 in), the greater the low-frequency absorption.) Shredded-wood fiberboard, 2 in thick on concrete (mtg. A) Thick, fibrous material behind open facing Carpet, heavy, on 5/8-in perforated mineral fiberboardwith airspace behind Wood, 1/2-in paneling, perforated 3/16-in-diameterholes, 1 1 % open area, with 2 1/2-in glass fiber in airspace behind

0.09

0.32

0.68

0.83

0.39

0.76

0.55

0.15 0.60 0.37 0.40

0.26 0.75 0.41 0.90

0.62 0.82 0.63 0.80

0.94 0.80 0.85 0.50

0.64 0.60 0.96 0.40

0.92 0.38 0.92 0.30

0.60 0.75 0.70 0.65

Floors(9, 1 11) Sound-Reflecting: 28. Concrete or terrazzo 29. Linoleum, rubber, or asphalt tile on concrete 30. Marble or glazed tile 31. Wood 32. Wood parquet on concrete Sound-Absorbing: 33. Carpet, heavy, on concrete 34. Carpet, heavy, on foam rubber 35. Carpet, heavy, with impermeable latex backing on foam rubber 36. Indoor-outdoor carpet Ceilings(6. 8-10) ** Sound-Reflecting: 37. Concrete 38. Gypsum board, 1/2 in thick 39. Gypsum board, 1 / 2 in thick, in suspension system 40. Plaster on lath 41. Plywood, 3/8 in thick 0.01 0.29 0.15 0.14 0.28 0.01 0.10 0.10 0.10 0.22 0.02 0.05 0.05 0.06 0.17 0.02 0.04 0.04 0.05 0.09 0.02 0.07 0.07 0.04 0.10 0.02 0.09 0.09 0.03 0.11 0.00 0.05 0.05 0.05 0.15 0.01 0.02 0.01 0.15 0.04 0.02 0.08 0.08 0.01 0.01 0.03 0.01 0.11 0.04 0.06 0.24 0.27 0.05 0.02 0.03 0.01 0.10 0.07 0.14 0.57 0.39 0.10 0.02 0.03 0.01 0.07 0.06 0.37 0.69 [email protected] 0.20 0.02 0.03 0.02 0.06 0.06 0.60 0.71 0.48 0.45 0.02 0.02 0.02 0.07 0.07 0.65 0.73 0.63 0.65 0.00 0.05 0.00 0.10 0.05 0.30 0.55 0.35 0.20

Appendix B-6

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Sound Absorption Coefficient Material NRC 125Hz 25OHz 50OHz 10OOHz 20OOHz 40OOHz Number*

Sound-Absorbing: 42. 43. 44. 45. 46. 47. 48. 49. 50. Acoustical board, 3/4 in thick, 0.76 in suspension system (mtg. E) Shredded-wood fiberboard, 2 in thick 0.59 on lay-in grid (mtg. E) Thin, porous sound bsorbing material, 0.10 3/4 in thick (mtg. B) Thick, porous sound-absorbing material, 0.38 2 in thick(mtg. B), or thin material with airspace behind (mtg. D) Sprayed cellulose fibers, 1 in thick. 0.08 on concrete (mtg A) Glass-fiber roof fabric, 12 oz/yd' 0.65 0.71 Glass-fiber roof fabric, 37 1/2 oz/yd2 0.38 (Note: Sound-reflecting at most frequencies.) Polyurethane foam, 1 in thick, 0.07 open cell, reticulated Parallel glass-fiberboard panels, 0.07 1 in thick by 18 in deep, spaced 18 in apart, suspended 12 in below ceiling Parallel glass-fiberboard panels, 0.10 1 in thick by 18 in deep, spaced 6 1/2 in apart, suspended 12 in below ceiling

(1. 5.7.91)

+

0.93 0.51 0.60 0.60 0.29 0.82 0.23 0.11 0.20

0.83 0.53 0.80 0.78 0.75 0.86 0.17 0.20 0.40

0.99 0.73 0.82 0.80 0.98 0.76 0.15 0.32 0.52

0.99 0.88 0.78 0.78 0.93 0.62 0.09 0.60 0.60

0.94 0.74 0.60 0.70 0.76 0.80 0.06 0.85 0.67

0.95 0.65 0.75 0.75 0.75 0.15 0.30 0.45

51.

0.29

0.62

1.12

1.33

1.38

0.85

Seats and Audience 52. 53. 54. 55. 56. 57.

Fabric well-upholstered seats, with perforated seat pans Leather-covered upholstered seats, unoccupied++ Audience, seated in upholstered seats' Congregation, seated in wooden pews Chair, metal or wood seat, unoccupied Students, informally dressed, seated in tablet-arm chairs

0.19 0.44 0.39 0.57 0.15 0.30

0.37 0.54 0.57 0.61 0.19 0.41

0.56 0.60 0.80 0.75 0.22 0.49

0.67 0.62 0.94 0.86 0.39 0.84

0.61 0.58 0.92 0.91 0.38 0.87

0.59 0.50 0.87 0.86 0.30 0.84

Openings(9)# 58. Deep balcony, with upholstered seats 59. Diffusers or grilles, mechanical system 60. Stage 0.50-1.00 0.15-0.50 0.25-0.75

Appendix B-7

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Sound Absorption Coefficient Material NRC 125Hz 25OHz 50OHz 10OOHz 20OOHz 40OOHz Number*

Miscellaneous(3,9. 11) 61. 62. 63. 64. 65. 66. Gravel, loose and moist, 4 in thick Grass, marion bluegrass, 2 in high Snow, freshly fallen, 4 in thick Soil, rough Trees, balsam firs, 20 ft ground area per tree, 8 ft high Water surface (swimming pool) 0.25 0.11 0.45 0.15 0.03 0.01 0.60 0.26 0.75 0.25 0.06 0.01 0.65 0.60 0.90 0.40 0.11 0.01 0.70 0.69 0.95 0.55 0.17 0.02 0.75 0.92 0.95 0.60 0.27 0.02 0.80 0.99 0.95 0.60 0.31 0.03 0.70 0.60 0.90 0.45 0.15 0.00

*NRC (noise reduction coefficient) is a single-number rating of the sound absorption coefficients of a material. It is an average that only includes the coefficients ih the 250 to 2000 Hz frequency range and therefore should be used with caution. **Refer to manufacturer's catalogs for absorption data which should be from up-to-date tests by independent acoustical laboratories according to current ASTM procedures. +Coefficients are per square foot of seating floor area or per unit. Where the audience is randomly spaced (e.g., courtroom, cafeteria), mid-frequency absorption can be estimated at about 5 sabins per person. To be precise, coefficients per person must be stated in relation to spacing pattern. ++The floor area occupied by the audience must be calculated to include an edge effect at aisles. For an aisle bounded on both sides by audience, include a strip 3 ft wide; for an aisle bounded on only one side by audience, include a strip 1 1/2 ft wide. No edge effect is used when the seating abuts walls or balcony fronts (because the edge is shielded). The coefficients are also valid for orchestra and choral areas at 5 to 8 ft2 per person. Orchestra areas include people, instruments, music racks, etc. No edge effects are used around musicians. #Coefficients for openings depend on absorption and cubic volume of opposite side.

Appendix B-8

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NOISE LEVEL DATA FOR COMMON SOURCES Sound Pressure Level (dB) Example Source Home Alarm clock at 4 to 9 ft (ringing) Electric shaver at 1 '/2 ft Vacuum cleaner at 3 ft Garbage disposal at 2 ft Clothes washer at 2 to 3 ft (wash cycle) Toilet (refilling tank) Whirlpool , six nozzles (filling tub) Window air-conditioning unit Telephone at 4 to 13 ft TV at 10 ft Stereo (teenager listening level) Stereo (adult listening level) Violin at 5 ft (fortissimo) 92 Normal conversational speech At three feet Outdoors Birds at 10 ft Cicadas Large dog at 50 ft (barking) Lawn mower at 5 ft Pistol shot at 250 ft (peak impulse levels) Surf at 10 to 15 ft (moderate seas) Wind in trees (10 mi/h) Transportation Large trucks at 50 ft (55 mi/h) Passenger car at 50 ft (55 mi/h) Motorcycle at 50 ft (full throttle w/o baffle) Snowmobile at 50 ft Train at 100 ft (pulling hard) Train siren at 50 ft Car horn at 15 ft Commercial turbofan airplane @ 1 mi from takeoff flight path) Military helicopter at 500 ft (single engine, medium size) 83 72 95 65 95 88 .. 77 92 85 70 95 82 102 90 .. 82 89 83 67 91 84 94 110 .. 82 83 85 66 91 75 90 110 92 78 81 81 67 91 78 86 107 95 70 76 76 66 87 77 87 100 90 56 72 72 59 87 79 83 91 80 .. 62 65 54 85 69 79 78 60 .. 51 86 71 95 85 94 109 97 79 80 .. .. .. 85 .. 71 .. .. .. 50 87 .. 72 .. .. .. 58 86 .. 70 .. .. .. 68 84 83 71 33 .. 35 70 81 91 67 35 50 51 64 74 99 64 37 52 54 52 70 102 58 37 54 48 48 72 106 54 35 57 57 72 86 106 78 43 .. 59 48 64 59 50 68 64 .. 49 60 56 .. 46 58 66 83 65 55 65 64 41 62 72 66 .. 57 48 49 69 69 59 53 68 65 44 64 83 75 .. 62 55 62 73 56 59 54 69 56 56 67 82 72 91 63 62 60 79 55 58 57 71 53 68 70 82 70 91 57 62 64 73 50 54 56 71 48 73 68 80 66 87 48 70 60 73 50 50 57 68 44 69 63 75 64 83 40 50 59 72 49 46 52 65 37 83 39 60 48 79 .. 80 68 81 69 62 63 74 59 83 74 86 75 66 63 63Hz 125Hz 250Hz 500Hz 1000Hz 2000Hz 4000Hz 8000Hz dBa

Appendix B-9

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Interiors Amplified rock music Performance (lg. arena) Audiovisual room Auditorium (applause) Classroom Computer equipment room Dog kennel Gymnasium Kitchen Laboratory Library Mechanical equipment room Music practice room Racquetball court Reception and lobby area Teleconference 116 85 60 60 78 .. 72 86 65 60 87 90 82 60 65 117 89 68 66 75 .. 78 85 70 63 86 94 85 66 74 119 92 75 72 73 90 84 79 73 66 85 96 50 72 78 116 90 79 77 78 104 89 78 75 67 84 96 85 77 80 118 89 85 74 80 106 86 77 72 64 83 96 83 74 79 115 87 84 68 78 101 80 72 69 58 82 91 75 68 75 109 85 75 60 74 89 72 65 65 50 50 91 68 60 68 102 50 65 50 70 79 64 57 61 40 78 90 62 50 60 121 94 88 78 84 108 90 81 77 68 88 100 86 78 83

Note: Sources for noise level data include Journal of Acoustical Society of America, Sound and vibration, Noise Control Engineering Journal, and technical publications of the U.S. Environmental Protection Agency and National Bureau of Standards (U.S.)

Appendix B-10

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MECHANICAL EQUIPMENT NOISE LEVEL DATA

Sound Pressure Level (dB) 3 ft. from equipment Equipment Absorption machine Axial fan Boiler Centrifugal fan Chiller, centrifugal Compressor, air Condenser Cooling tower Fan coil unit Induction unit PTAC Pump Rooftop unit Warm-air furnace Reference "Noise from Construction Equipment and Operations, Building Equipment, and Home Appliances," U.S. Environmental Protection Agency, NTID 300.1, Washington, December 1971. 63 Hz 91 98 92 86 80 86 99 102 57 57 64 75 95 65 125Hz 250Hz 500Hz 1000Hz 2000Hz 4000Hz 8000Hz dBA 86 99 92 95 85 84 92 102 55 58 64 80 93 65 86 99 89 89 87 86 90 97 53 56 65 82 89 59 86 98 86 90 87 87 90 94 50 54 56 87 85 53 83 97 83 87 90 86 89 90 48 45 53 86 80 48 80 95 80 82 98 84 85 88 42 40 48 80 75 45 77 91 77 76 91 80 76 84 38 35 44 77 69 39 72 87 74 77 87 75 68 79 32 33 37 75 66 30 8 102 89 92 100 91 92 97 53 54 59 89 87 57

From: "Architectural Acoustics" by David Egan

r:\market\aia-csi class\appendix\appendix b.doc

Appendix B-11

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L w = 10

W log W0

where Lw =sound power level (dB) W = sound power (W) Wo = reference sound power (W, usually taken as 10-12 W) Note: Lw is used by testing laboratories to rate a sound source independently of its environment. Noise Reduction:

NR = LI - L2

where NR = noise reduction, or the difference in sound levels between two conditions (dB) LI = sound level under one condition, usually taken as the higher value (dB) L2 = sound level under another condition (dB)

NR = 10 log I1 I2

where NR = [see formula (6)] l1 = sound intensity under one condition (W/M2) l2 = sound intensity under another condition (W/M2)

Sound Source Under Free Field Conditions: Outdoors

I=

W

4d 2

where l = sound intensity (W/ M2) W = sound power (W) = 3.14 d = distance from sound source (m) If distance is given in feet, use l= W/4 d2 X 10.76 Inverse-Square Law:

Appendix C-2

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I1 d2 = I2 d1

( )

2

where l1 = sound intensity at distance di (W/M2) l2 = sound intensity at distance d2 (W/M2) d = [see formula (8)]

NR = 20 log d 2 d1

where NR = noise reduction (dB) d2 = distance from sound source at one location (ft or m) d1= distance from sound source at another location (ft or m) Note: The sound level is decreased outdoors by 6 dB for each doubling of distance from a point source because 20 log (2) = 20 (0.3) = 6 dB. For line sources, use 1 0 log in formula.

r:\market\aia-csi class\appendix\appendix c.doc

Appendix C-3

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Sound Source in Reverberant Field: Indoors

where a = total room absorption at given frequency (sabins) S= surface area (ft2) a = sound absorption coefficient at given frequency (decimal percent)

where l = sound intensity in reverberant field (W/M2) W = sound power (W) a = total room absorption (sabins) If absorption is calculated in M2, use l = W/I a.

where l1 = sound intensity in reverberant field at total room absorption a, (W/M2) l2= sound intensity in reverberant field at total room absorption a2 (W/M2) a = [see formula (11)

where NR room noise reduction in reverberant field (dB) a2 = total room absorption after treatment (sabins) a1 = total room absorption before treatment (sabins)

Appendix C-4

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Appendix C Summary of Useful Formulas General

Character:

Tp =

1 f

where TP = period of one complete vibration (s) f = frequency (Hz)

=

c f

where = wavelength (ft) c = speed of sound in air (ft/s f = frequency (Hz) Magnitude:

L I = 10 log

I I0

where L1 = sound intensity level (decibels, abbreviated dB) l= sound intensity (watts / meter squared, abbreviated WM2) l0 = reference sound intensity (W/M2, usually taken as 10-12 W/M2 or the equivalent 10-16 W/CM2)

L P = 20 log

P P0

where Lp = sound pressure level (Db P = sound pressure (newtons / meter squared, abbreviated N / M2, or pascals, abbreviated Pa) P0 = reference sound pressure (N/M2, always taken as 0.00002 N/M2) Note: Lp may be considered equal to L1 in most architectural acoustics situations.

Appendix C-1

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LP = LW ­ 10 log a + 16

where Lp = sound pressure level (dB) Lw =sound power level (dB) a = [see formula (11)] Sabine Formula:

where T = reverberation time, or time required for sound to decay 60 dB after source has stopped (s) V = room volume (ft3) a= [see formula (11)] Eyring Formula:

where T =reverberation time (s) V =room volume (ft3) S = total surface area (ft2) mean sound absorption coefficient (decimal percent) Note: Use the constant 0. 16 instead of 0.05 where absorption is calculated in metric sabins (surface areas in M2). In large.rooms, add air absorption to denominator of T formulas. Noise Reduction Coefficient. with result rounded to nearest 18) 0.05 increment

where NRC = noise reduction coefficient (decimal percent) a = sound absorption coefficient (decimal percent)

Appendix C-5

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Sound Transmission Through Common Barrier

TL = L1 ­ L2

where TL = sound transmission loss (dB) LI = sound level in laboratory source room (dB) L2 = sound level in laboratory receiving room (dB)

where TL = sound transmission loss (dB) = sound transmission coefficient (no units) Composite TL:

where TL = sound transmission loss of composite barrier (dB) ÓS = S1 + S2 +. . .+Sn= total surface area of barrier (ft2)

S = S1 + 2S2 +nSn

= sum of sound transmission coefficients of each part of barrier times the respective areas (ft2) Homogeneous Materials:

TL = 20 + 20 log G

where TL = sound transmission loss at 500 Hz (dB) G = surface density (lb/ft2)

where NR = LI - L2 = noise reduction, or difference in sound levels, between rooms (dB) TL = sound transmission loss of common barrier (dB) a2 = absorption in receiving room (sabins) S = surface area of common barrier (ft2)

Appendix C-6

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Mechanical System Noise and Vibrations Vibration Isolation:

where fn = natural or resonant frequency of isolator (Hz) y = spring static deflection (in) Lined Duct: where A = attenuation for lined duct (dB/ft) a = sound absorption coefficient of duct liner (decimal percent) P = perimeter of rectangular duct (in) S = cross-sectional open area of duct (in2) SoundSystems Loudspeaker-to-Listener Distance: where d = maximum loudspeaker-to-listener distance (ft) Q = loudspeaker directivity (no units) V = room volume (ft3) T = reverberation time (s) Distributed Loudspeakers for Seated Audience:

S=

where S = spacing between loudspeakers (ft) H = floor-to-ceiling height (ft) Background Masking:

Appendix C-7

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SUMMARY OF USEFUL FORMULAS 393 where S = spacing between loudspeakers (ft) D = plenum depth (ft) H = floor-to-ceiling height (ft) Miscellaneous Vibrating Panels: 170 fr @wd where fr = resonant frequency (Hz) w = surface weight of panel (lb/ft2) d = depth of airspace behind panel (in) Perforated Facings: 40-P (30) D where f, = critical frequency (Hz) P = open area (percent) D = hole diameter (in) (29)

Double Walls: 170 fo (GI X G2) d + G2 (31

where fo = mass-air-mass resonant frequency (Hz) GI = weight of panel layers on one side (lb/ft2) G2 = weight of panel layers, on opposite side (lb/ft2) d = thickness of cavity insulation times F2 plus cavity depth not containing insulation (in)

Appendix C-8

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394 SUMMARY OF USEFUL FORMULAS Outdoor Barriers: A 10 log H2 + 10 log f - 17 (32)

R where A = attenuation for thin-wall barrier (dB) H = height of barrier above line of sight between source and receiver (ft) R = distance from source (or receiver) to barrier (ft) Note: Use smaller of the two distances. f = frequency (Hz) Ceiling Height for Auditoriums: H = 20T (33)

where H = average ceiling height for auditorium with upholstered seats and absorptive rear wall (ft) T = mid-frequency reverberation time (s)

From: "Architectural Acoustics" by David Egan r:\market\aia-csi class\appendix\appendix c.doc

Appendix C-9

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Corporate Office: Regional Office: Regional Office

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APPENDIX D: DEFINITION OF TERMS

Acoustical Terms

Absorption A totally absorptive material will not reflect any energy back into the room. In the case of a sound wave, the sound will cease to exist. Energy can neither be created nor destroyed, but it can be converted from one form to another. Absorption is the conversion of sound energy to heat. Acoustical Material Any material considered in terms of its acoustical properties. Commonly and especially, a material designed to absorb sound. Airborne Sound Sound that arrives at the point of interest, such as one side of a partition, by propagation through air. Airflow Resistance The quotient of the air pressure difference across a specimen divided by the volume velocity of airflow through the specimen. The pressure difference and the volume velocity may be either steady or alternating. Anechoic Echo free; an anechoic room is one whose walls, ceiling, and floor are covered with sound absorbing material, usually in the shape of wedges. Arithmetic Mean Sound Pressure Level Of several related sound pressure levels measured at different positions or different times, or both, in a specified frequency band. The sum of the sound pressure levels divided by the number of levels. NOTE - The arithmetic mean sound pressure level is sometimes used to approximate the average sound pressure level. The accuracy of this approximation depends upon the range of sound pressure levels. Average Sound Pressure Level Of several related sound pressure levels measured at different positions or different times, or both, in a specified frequency band, ten times the common logarithm of the arithmetic mean of the squared pressure ratios from which the individual levels were derived. NOTE - An average sound pressure level obtained by integrating and averaging during certain time periods is often called equivalent sound pressure level and, when A-weighted, equivalent sound level. Background or Ambient Noise Level Ambient noise level is defined as the sound level that is typically observed on the measurement instrument, in the absence of individual identifiable acoustical events that are usually far from the listener. Noise from all sources unrelated to a particular sound that is the object of interest. Background noise may include airborne, structureborne, and instrument noise. The composite of airborne sound from many sources near and far associated with a given environment. No particular sound is singled out for interest. Characteristic Impedance of the Medium The specific normal acoustic impedance at a point in a plane wave in a free field. It is a pure specific resistance since the sound pressure and the particle velocity are in phase and it is equal in magnitude to the product of the density of the medium and the speed of sound in the medium. Community Noise Equivalent Level (CNEL) A descriptor for the 24-hour A-weighted average noise level. The CNEL concept accounts for the increased acoustical sensitivity of people to noise during the evening and nighttime hours. Sound levels during the hours from 7:00 p.m. to 10:00 p.m. are penalized 5 dB; sound levels during the hours from 10:00 p.m. to 7:00 a.m. are penalized 10 dB. A 10 dB increase in sound level is perceived by people to be twice as loud. Cutoff Frequency Of an anechoic wedge or set of wedges, the lowest frequency above which the normal incidence sound absorption coefficient is at least 0.990. Damp To cause a loss or dissipation of the oscillatory or vibrational energy of an electrical or mechanical system.

Appendix D-1

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Day/Night Noise Level (DNL) The Day/Night Noise Level is the sound level which corresponds to average human sensitivity to sound levels in decibels. DNL encompasses several parameters including amplitude in decibels which corresponds to loudness, time averaging and increased sensitivity to noise at night and the frequency or pitch at which sound occur. More specifically, the DNL sound level corresponds to an energy average during a 24-hour period. The nighttime hours from 10 pm to 7 am are twice as sensitive, that is, with a 10 decibel penalty applied, due to increased human sensitivity during the night. The DNL is an A-weighted sound level. A-weighting is a filter which is applied to the microphone signal which approximates human sensitivity to different frequencies, i.e., pitch. Human hearing is most sensitive in the speech range and least sensitive at low frequencies. The units of the day/night (DNL) sound level are dBA. dB(A) A-weighted sound pressure level (or noise level) represents the noisiness or loudness of a sound by weighting the amplitudes of various acoustical frequencies to correspond more closely with human hearing. A 10-dB (decibel) increase in noise level is perceived to be twice as loud. A-weighting is specified by the U.S. EPA, OSHA, Caltrans, and others for use in noise measurements. dB(C) C-weighted sound pressure level (or noise level) represents the "overall" or wideband measurement of sound level. The response is fairly uniform from 50 to 5000 Hz, therefore C-weighting more accurately measures the overall acoustic energy, without regard to how humans actually hear. Decay Rate The rate of decrease of sound pressure level after the source of sound has stopped: for vibration, the rate of decrease of vibratory acceleration, velocity, or displacement level after the excitation has stopped. Decibel (dB) the term used to identify ten times the common logarithm of the ratio of two like quantities proportional to power or energy. One decibel corresponds to a power ratio of 10 0.1 and n decibels corresponds to a power ration of (10 0.1) n. The term used to identify ten times the common logarithm of the ratio of two like quantities proportional to power or energy. (See level, sound transmission loss.) Thus, one decibel corresponds to a power ratio of 100.1 and n decibels corresponds to a power ratio of (100.1)n. NOTE - Since the decibel expresses the ratio of two like quantities, it has no dimensions. It is, however, common practice to treat "decibel" as a unit as, for example, in the sentence, "The average sound pressure level in the room is 45 decibels." Diffraction A change in the direction of propagation of sound energy in the neighborhood of a boundary discontinuity, such as the edge of a reflective or absorptive surface. Diffuse Sound Field the sound in a region where the intensity is the same in all directions and at every point. Diffusion A diffuse field is a combination of sound waves that are scattered in direction and time. Diffusion is the most significant of the three tools because of two important components. First, diffusion simultaneously increases the distribution of, and modifies the direction of sound without removing energy from within the space (spatial response). Second, diffused sound energy is distributed in time (temporal response). The listeners perception of an expanded space is created by the combination of spatial and temporal components. Plastic grills are placed in front of fluorescent tubes to evenly distribute their light throughout the room. That is the spatial aspect of diffusion. Direct Sound Field The sound that arrives directly from a source without reflection. Echo A long delayed, distinct reflections of sufficient sound level to be clearly heard above the general reverberation as a repetition of the original sound. Field Impact Insulation Class (FIIC) A single figure rating which quantifies the property of a floor/ceiling construction to reduce footfall-generated noise as measured in the field. Increasing IIC values correspond to improved impact insulation. Field Sound Transmission Class (FSTC) A single-figure rating which quantifies the sound insulation properties of a partition as measured in the field. Numerically, STC represents the number of decibels of speech sound reduction from one side of the partition to the other. The STC is intended for use when speech and office noise constitute the principal noise problem. Increasing FSTC values corresponds to improved sound insulation. Sound transmission class calculated in accordance with Classification ASTM E 413 using values of field transmission loss.

Appendix D-2

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Room Criterion Curves (RC) A series of curves of octave-band sound spectra in a system for rating the noisiness of an occupied indoor space. The RC Curve represents a close approximation of a well balanced, bland sounding spectrum and can be used to maintain background sound levels for masking or other purposes. An optimum balance in sound quality is achieved by approximately the shape of the curve to within +/- 2 dB over the entire frequency range. If low frequency levels (31.5 to 250 Hz) exceed the design curve by 5 dB, the sound is likely to be rumbly; exceeding the design curve by 5 dB at the high frequencies (2000 to 4000 Hz) will cause the sound to be hissy. Sabin [L2] The unit of measure of sound absorption in the inch-pound system. Sones A unit of loudness expressed on a linear scale. An approximate equivalence between sones and the Aweighted sound level 10 feet from a sound source is: 1 sone = 20 dB; 2 sones = 30 dB; 4 sones = 40 dB; 32 sones = 70 dB, etc. Sound Absorption (1) the process of dissipating sound energy. (2) the property possessed by materials, objects and structures such as rooms of absorbing sound energy. (3) A; [L2]; metric sabin-in a specified frequency band, the measure of the magnitude of the absorptive property of a material, an object, or a structure such as a room. NOTE - Sound energy passing through a wall or opening may be regarded as being absorbed in certain calculations. Sound Absorption Coefficient Of a surface, in a specified frequency band, the measure of the absorptive property of a material as approximated by the method of Test Method ASTM C 423. Ideally, the fraction of the randomly incident sound power absorbed or otherwise not reflected. Sound Attenuation The reduction of the intensity of sound as it travels from the source to a receiving location. Sound absorption is often involved as, for instance, in a lined duct. Spherical spreading and scattering are other attenuation mechanisms. Sound Energy Energy added to an elastic medium by the presence of sound, consisting of potential energy in the form of deviations from static pressure and of kinetic energy in the form of particle velocity. Sound Exposure Level (SEL), LAE That constant level in dBA which, lasting for one second, has the same amount of acoustic energy as a given A-weighted noise event. Sound Insulation The capacity of a structure to prevent sound from reaching a receiving location. Sound energy is not necessarily absorbed; impedance mismatch, or reflection back toward the source, is often the principal mechanism. NOTE - Sound insulation is a matter of degree. No partition is a perfect insulator of sound. Sound Intensity The quotient obtained when the average rate of energy flow in a specified direction and sense is divided by the area, perpendicular to that direction, through or toward which it flows. The intensity at a point is the limit of that quotient as the area that includes the point approaches zero. Sound Isolation The degree of acoustical separation between two locations, especially adjacent rooms. NOTE - This qualitative term may be used in lieu of the more quantitative term noise reduction. Sound isolation is achieved by using sound-insulating or sound-attenuating elements. Sound Level Of airborne sound, a sound pressure level obtained using a signal to which a standard frequencyweighting has been applied. NOTE I-Three standard frequency-weightings designated A. B. and C are defined in ANSI SI.4, Specification for Sound Level Meters. NOTE 2 - The frequency-weighting and method of averaging must be specified unless clear from the context. Sound Power In a specified frequency band, the rate at which acoustic energy is radiated from a source. In general, the rate of flow of sound energy, whether from a source, through an area, or into an absorber.

Appendix D-5

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Field Transmission Loss, FTL Sound transmission loss measured in accordance with ASTM E 336. Flanking Paths Indirect paths through which sound energy can bypass constructions and seriously degrade the transmission loss (TL) rating of that construction. Example flanking paths are open ceiling plenums and attics, continuous side walls and floors, air duct and pipe penetrations, joist and crawl spaces. Flanking paths can be prevented by careful design of all connections, penetrations, and adjacent framing systems. Flanking Transmission Transmission of sound from the source to a receiving location by a path other than that under consideration. Flutter Echo Can be heard as a "rattle" or "clicking" from a hand clap. May be present in small rooms or narrow spaces with parallel walls. Can be effectively controlled with sound absorbing materials. Frequency The rate of repetition of a periodic event. Sound in air consists of a series of compressions and rarefactions due to air particles set into motion by a vibrating source. The frequency of this sound wave is determined by the number of times per second a given air molecule vibrates around its neutral position. The greater the number of complete vibrations (cycles) the higher the frequency. The unit of frequency is the hertz (Hz). Impact Isolation Class (IIC) The Impact Isolation Class is single figure rating which quantifies impact noise on a floor through a ceiling, such as that produced by foot-falls. A standardized device generates the impact sound by dropping 5 hammers which impart a known energy into the floor/ceiling construction. The resulting sound pressure level is measured in the receiving room below in frequency bandwidths comparable to those used in sound transmission loss measurements. The procedure and curve fitting are defined in ASTM Standard E492. Increasing IIC values correspond to improved impact insulation. A single-number rating derived from measured values of normalized impact sound pressure levels in accordance with Annex Al of Method ASTM E 492. It provides an estimate of the impact sound insulating performance of a floor-ceiling assembly. INCE Institute of Noise Control Engineering Insertion Loss (IL) Of a silencer or other sound-reducing element, in a specified frequency band, the decrease in sound power level, measured at the location of the receiver, when a sound insulator or a sound attenuator is inserted in the transmission path between the source and the receiver. Leq The equivalent steady-state A-weighted sound level that, in a stated period of time, would contain the same acoustic energy as the time-varying sound level during the same time period. Level (L) Ten times the common logarithm of the ratio of a quantity proportional to power or energy to a reference quantity of the same kind. (See sound power level, sound pressure levels) The quantity so obtained is expressed in decibels. Level Reduction (LR) In a specified frequency band, the decrease in sound pressure level, measured at the location of the receiver, when a barrier or other sound-reducing element is placed between the source and the receiver. NOTE - Level reduction is a useful measure in circumstances when measures of transmission loss, insertion loss, or noise reduction are not possible. Metric Sabin, [L ] The unit of measure of sound absorption in the metre-kilogram-second system of units. Noise Criteria (NC) Noise Criteria ratings approximate the human perception of "noisiness" within buildings. The NC rating is based on 8 octave band sound pressure level measurements in which building machinery normally produce sound which can be annoying to the occupants. These eight measurements are compared with a family of curves. The highest curve under which all the data fall is the rating. This rating is not applicable to pure tones where a penalty must be added since they are perceived to be more "noisy." High NC ratings are louder and an increase by 10 points approximates a doubling of perceived loudness. Noise Isolation Class (NIC) The noise isolation Class is a single number rating describing the attenuation of sound through building partitions. The rating is derived from measured values of noise reduction between two enclosed spaces that are connected by one or more paths. In general, the more massive a material or construction, the higher its NIC rating. A single-number rating calculated in accordance with Classification ASTM E 413 using measured values of noise reduction. It provides an estimate of the sound isolation between two enclosed spaces that are acoustically connected by one or more paths. Noise Reduction (NR) In a specified frequency band, the difference between the average sound pressure levels measured in two enclosed spaces or rooms due to one or more sound sources in one of them. NOTE - It is implied that in each room there is a meaningful average level: that is, that in each room the individual observations are randomly distributed about the average value, with no systematic variation with position within

Appendix D-3 2

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the permissible measurement region. Noise reduction becomes meaningless and should not be used in situations where this condition is not met. Noise Reduction Coefficient (NRC) The NRC is intended as a single-number rating of the sound-absorbing efficiency at mid-frequencies. It is not, as its name implies, the difference in sound levels between two conditions or between rooms. It is the numerical average of the sound absorption coefficients at 250, 500, 1000, and 2000 Hz for a specific material and mounting condition. A single-number rating derived from measured values of sound absorption coefficients in accordance with 11.7 of Test Method ASTM C 423. It provides an estimate of the sound absorptive property of an acoustical material. Noise Sources Anything that is not part of the experience that is being tested. This would include but is not limited to adjacent building systems, mechanical equipment, ride equipment, adjacent show audio or effects, traffic noise, and the natural environment (rain). Normal Incidence Sound Absorption Coefficient Of a surface, at a specified frequency, the fraction of the perpendicularly incident sound power absorbed or otherwise not reflected. Normalized Noise Isolation Class (NNIC) A single-number rating calculated in accordance with Classification ASTM E 413 using measured values of normalized noise reduction. (See normalized noise reduction.) Normalized Noise Reduction (NNR) Between two rooms, in a specified frequency band, the value that the noise reduction in a given field test would have if the reverberation time in the receiving room were 0.5 s. NNR is calculated as follows: NNR = NR + 10 log (T/0.5) where: NR = noise reduction, dB and T = reverberation time in receiving room, s. NOTE - The normalized noise reduction is intended to approximate the noise reduction that would exist between two ordinarily furnished rooms. Outdoor-Indoor Transmission Loss (OITL) Of a building facade, in a specified frequency band, ten times the common logarithm of the ratio of the airborne sound power incident on the exterior of the facade to the sound power transmitted by the facade and radiated to the interior. The quantity so obtained is expressed in decibels. Percentile Level, L(N),(T) That noise level in dBA exceeded for N% of the measurement time T. Pink Noise Noise with a continuous frequency spectrum and with equal power per constant percentage bandwidth. For example, equal power in any one-third octave band. Pitch The subjective response of human hearing to frequency. Low frequencies generally are considered "boomy" and high frequencies "screechy" or "hissy". Preferred Noise Criteria (PNC) Revisions of NC Curves used for similar situations in rating the noise environments of indoor spaces. Developed to answer objections regarding the adequacy of NC Curves at the low and high frequencies; they are based on both the preferred speech-interference level and the loudness level. Receiving Room In architectural acoustical measurements, the room in which the sound transmitted from the source room is measured. Reflection A perfectly reflective surface will absorb no wave energy, but return all that energy back to the space it came from. The sound wave (traveling toward the reflective surface) can be simplified as a straight line (black line). The reflected wave (gray line) will leave the surface at an opposite and equal angle. A mirror is a reflective surface for light energy. Shinning a beam of light into a mirror will demonstrate the same behavior as sound striking an acoustically reflective surface. One example of a very reflective acoustic surface is a concrete wall. Reverberant Sound Field The sound in an enclosed or partially enclosed space that has been reflected repeatedly or continuously from the boundaries. Reverberant Sound Sound that builds up and decays gradually and can be "stored" in a room for an appreciable time. Reverberation The persistence of sound in an enclosed or partially enclosed space after the source of sound has stopped: by extension, in some contexts, the sound that so persists. Reverberation Room A room so designed that the reverberant sound field closely approximates a diffuse sound field, both in the steady state when the sound source is on, and during decay after the source of sound has stopped. Reverberation Time(RT60 ) The time required for the stored or reverberant sound to decrease by 60 dB.

Appendix D-4

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Sound Power Level, Lw Of airborne sound, ten times the common logarithm of the ratio of the sound power under consideration to the standard reference power of 1 pW. The quantity so obtained is expressed in decibels. NOTE - The pressures are squared because pressure squared. rather than pressure, is proportional to power or energy. Sound Pressure A fluctuating pressure superimposed on the static pressure by the presence of sound. In analogy with alternating voltage its magnitude can be expressed in several ways, such as instantaneous sound pressure or peak sound pressure, but the unqualified term means root-mean-square sound pressure. In air, the static pressure is barometric pressure. Sound Transmission Class (STC) A single-number rating used to compare walls, floor-ceiling assemblies and doors for their sound-insulating properties with respect to speech and small appliance noise. The STC is derived from laboratory measurements of sound transmission loss across a series of 16 tests bands. A single-number rating calculated in accordance with Classification ASTM E 413 using values of sound transmission loss. It provides an estimate of the performance of a partition in certain common sound insulation problems. Sound Transmission Coefficient In a specified frequency band, the fraction of the airborne sound power incident on the partition that is transmitted by the partition and radiated on the other side. NOTE - Unless qualified, the term denotes the value obtained when the specimen is exposed to a diffuse sound field as approximated, for example, in reverberation rooms meeting the requirements of Test Method ASTM E 90. Sound Transmission Loss (TL) Of a partition, in a specified frequency band, ten times the common logarithm of the ratio of the airborne sound power incident on the partition to the sound power transmitted by the partition and radiated on the other side. The quantity so obtained is expressed in decibels. NOTE - Unless qualified, the term denotes the sound transmission loss obtained when the specimen is exposed to a diffuse sound field as approximated, for example, in reverberation rooms meeting the requirements of Test Method ASTM E 90. A measurement, in decibels, of how much sound energy is reduced by transmission through materials. In general, the more massive a material the higher its TL Structureborne Sound Sound that arrives at the point of interest, such as the edge of a partition, by propagation through a solid structure. Thermal Insulation A material or assembly of materials used primarily to provide resistance to heat flow. Unit measurement, a precisely specified quantity in terms of which the magnitudes of other quantities of the same kind can be stated. Vibration Isolation A reduction, attained by the use of a resilient coupling, in the capacity of a system to vibrate in response to mechanical excitation. White Noise Noise with a continuous frequency spectrum and with equal power per unit bandwidth. For example. equal power in any band of 100-Hz width.

Appendix D-6

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