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LEED v4
Commercial Interiors
Indoor Environmental Quality

Acoustic performance

LEED CREDIT

CI-v4 EQc9: Acoustic performance 2 points

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SPECIAL REPORT

LEEDuser expert

Ken Shook

LEED AP BD+C

Longman Lindsey
Partner

SPECIAL REPORT

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Frank advice from LEED experts

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Credit language

USGBC logo

© Copyright U.S. Green Building Council, Inc. All rights reserved.

Intent

To provide workspaces and classrooms that promote occupants’ well-being, productivity, and communications through effective acoustic design.

Requirements

For all occupied spaces, meet the following requirements, as applicable, for HVAC background noise, sound isolation, reverberation time, and sound reinforcement and masking.

HVAC Background Noise

Achieve maximum background noise levels from heating, ventilating, and air conditioning (HVAC) systems per 2011 ASHRAE Handbook, HVAC Applications, Chapter 48, Table 1; AHRI Standard 885-2008, Table 15; or a local equivalent. Calculate or measure sound levels.

For measurements, use a sound level meter that conforms to ANSI S1.4 for type 1 (precision) or type 2 (general purpose) sound measurement instrumentation, or a local equivalent.

Comply with design criteria for HVAC noise levels resulting from the sound transmission paths listed in ASHRAE 2011 Applications Handbook, Table 6; or a local equivalent.

Sound Isolation

Meet the composite sound transmission class (STCC) ratings listed in Table 1, or local building code, whichever is more stringent.

Table 1. Minimum composite sound transmission class ratings for adjacent spaces

Adjacency combinations STCC
Residence (within a multifamily residence), hotel or motel room Residence, hotel or motel room 55
Residence, hotel or motel room Common hallway, stairway 50
Residence, hotel or motel room Retail 60
Retail Retail 50
Standard office Standard office 45
Executive office Executive office 50
Conference room Conference room 50
Office, conference room Hallway, stairway 50
Mechanical equipment room Occupied area 60
Reverberation Time

Meet the reverberation time requirements in Table 3 (adapted from Table 9.1 in the Performance Measurement Protocols for Commercial Buildings1).

Table 2. Reverberation time requirements
Room type Application T60 (sec), at 500 Hz, 1000 Hz, and 2000 Hz
Apartment and condominium < 0.6
Hotel/motel Individual room or suite < 0.6
Meeting or banquet room < 0.8
Office building Executive or private office < 0.6
Conference room < 0.6
Teleconference room < 0.6
Open-plan office without sound masking < 0.8
Open-plan office with sound masking < 0.8
Courtroom Unamplified speech < 0.7
Amplified speech < 1.0
Performing arts space Drama theaters, concert and recital halls Varies by application
Laboratories Testing or research with minimal speech communication < 1.0
Extensive phone use and speech communication < 0.6
Church, mosque, synagogue General assembly with critical music program Varies by application
Library   < 1.0
Indoor stadium, gymnasium Gymnasium and natatorium < 2.0
Large-capacity space with speech amplification < 1.5
Classroom < 0.6
Sound Reinforcement and Masking Systems

Sound Reinforcement
For all large conference rooms and auditoriums seating more than 50 persons, evaluate whether sound reinforcement and AV playback capabilities are needed.

If needed, the sound reinforcement systems must meet the following criteria:

  • Achieve a speech transmission index (STI) of at least 0.60 or common intelligibility scale (CIS) rating of at least 0.77 at representative points within the area of coverage to provide acceptable intelligibility.
  • Have a minimum sound level of 70 dBA and must
  • Maintain sound-level coverage within +/–3 dB at the 2000 Hz octave band throughout the space.

Masking Systems
For projects that use masking systems, the design levels must not exceed 48 dBA. Ensure that loudspeaker coverage provides uniformity of +/–2 dBA and that speech spectra are effectively masked.


1 Adapted from ASHRAE (2007d), ASA (2008), ANSI (2002), and CEN (2007)

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What does it cost?

Cost estimates for this credit

On each BD+C v4 credit, LEEDuser offers the wisdom of a team of architects, engineers, cost estimators, and LEED experts with hundreds of LEED projects between then. They analyzed the sustainable design strategies associated with each LEED credit, but also to assign actual costs to those strategies.

Our tab contains overall cost guidance, notes on what “soft costs” to expect, and a strategy-by-strategy breakdown of what to consider and what it might cost, in percentage premiums, actual costs, or both.

This information is also available in a full PDF download in The Cost of LEED v4 report.

Learn more about The Cost of LEED v4 »

Frequently asked questions

Is it possible to pursue this as an Innovation credit in a Core & Shell project?

The answer to this question is available to LEEDuser premium members. Start a free trial »

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Our project has small meeting rooms in an open-office plan. This situation appears to require an STC of 50. However, this level seems to be (unrealistically) high, especially considering the doors in the wall partition. STC 50 with a (closed) wall can be achieved, but even high STC doors won't achieve an STC of more than 45. Would this mean that the credit is not achievable?

The answer to this question is available to LEEDuser premium members. Start a free trial »

(If you're already a premium member, log in here.)

Sound transmission requirements for adjacency combinations are listed in Reference Guide Table 1, but not all combinations are included. For example, an STC rating requirement is not provided for conference room and standard/executive office adjacency. Is sound transmission compliance achieved by addressing only project applicable adjacency combinations listed in Table 1?

The answer to this question is available to LEEDuser premium members. Start a free trial »

(If you're already a premium member, log in here.)

Are we required to have an acoustical consultant in order to attempt this credit?

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See all forum discussions about this credit »

Documentation toolkit

The motherlode of cheat sheets

LEEDuser’s Documentation Toolkit is loaded with calculators to help assess credit compliance, tracking spreadsheets for materials, sample templates to help guide your narratives and LEED Online submissions, and examples of actual submissions from certified LEED projects for you to check your work against. To get your plaque, start with the right toolkit.

LEEDuser expert

Ken Shook

LEED AP BD+C

Longman Lindsey
Partner

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USGBC logo

© Copyright U.S. Green Building Council, Inc. All rights reserved.

Intent

To provide workspaces and classrooms that promote occupants’ well-being, productivity, and communications through effective acoustic design.

Requirements

For all occupied spaces, meet the following requirements, as applicable, for HVAC background noise, sound isolation, reverberation time, and sound reinforcement and masking.

HVAC Background Noise

Achieve maximum background noise levels from heating, ventilating, and air conditioning (HVAC) systems per 2011 ASHRAE Handbook, HVAC Applications, Chapter 48, Table 1; AHRI Standard 885-2008, Table 15; or a local equivalent. Calculate or measure sound levels.

For measurements, use a sound level meter that conforms to ANSI S1.4 for type 1 (precision) or type 2 (general purpose) sound measurement instrumentation, or a local equivalent.

Comply with design criteria for HVAC noise levels resulting from the sound transmission paths listed in ASHRAE 2011 Applications Handbook, Table 6; or a local equivalent.

Sound Isolation

Meet the composite sound transmission class (STCC) ratings listed in Table 1, or local building code, whichever is more stringent.

Table 1. Minimum composite sound transmission class ratings for adjacent spaces

Adjacency combinations STCC
Residence (within a multifamily residence), hotel or motel room Residence, hotel or motel room 55
Residence, hotel or motel room Common hallway, stairway 50
Residence, hotel or motel room Retail 60
Retail Retail 50
Standard office Standard office 45
Executive office Executive office 50
Conference room Conference room 50
Office, conference room Hallway, stairway 50
Mechanical equipment room Occupied area 60
Reverberation Time

Meet the reverberation time requirements in Table 3 (adapted from Table 9.1 in the Performance Measurement Protocols for Commercial Buildings1).

Table 2. Reverberation time requirements
Room type Application T60 (sec), at 500 Hz, 1000 Hz, and 2000 Hz
Apartment and condominium < 0.6
Hotel/motel Individual room or suite < 0.6
Meeting or banquet room < 0.8
Office building Executive or private office < 0.6
Conference room < 0.6
Teleconference room < 0.6
Open-plan office without sound masking < 0.8
Open-plan office with sound masking < 0.8
Courtroom Unamplified speech < 0.7
Amplified speech < 1.0
Performing arts space Drama theaters, concert and recital halls Varies by application
Laboratories Testing or research with minimal speech communication < 1.0
Extensive phone use and speech communication < 0.6
Church, mosque, synagogue General assembly with critical music program Varies by application
Library   < 1.0
Indoor stadium, gymnasium Gymnasium and natatorium < 2.0
Large-capacity space with speech amplification < 1.5
Classroom < 0.6
Sound Reinforcement and Masking Systems

Sound Reinforcement
For all large conference rooms and auditoriums seating more than 50 persons, evaluate whether sound reinforcement and AV playback capabilities are needed.

If needed, the sound reinforcement systems must meet the following criteria:

  • Achieve a speech transmission index (STI) of at least 0.60 or common intelligibility scale (CIS) rating of at least 0.77 at representative points within the area of coverage to provide acceptable intelligibility.
  • Have a minimum sound level of 70 dBA and must
  • Maintain sound-level coverage within +/–3 dB at the 2000 Hz octave band throughout the space.

Masking Systems
For projects that use masking systems, the design levels must not exceed 48 dBA. Ensure that loudspeaker coverage provides uniformity of +/–2 dBA and that speech spectra are effectively masked.


1 Adapted from ASHRAE (2007d), ASA (2008), ANSI (2002), and CEN (2007)

Cost estimates for this credit

On each BD+C v4 credit, LEEDuser offers the wisdom of a team of architects, engineers, cost estimators, and LEED experts with hundreds of LEED projects between then. They analyzed the sustainable design strategies associated with each LEED credit, but also to assign actual costs to those strategies.

Our tab contains overall cost guidance, notes on what “soft costs” to expect, and a strategy-by-strategy breakdown of what to consider and what it might cost, in percentage premiums, actual costs, or both.

This information is also available in a full PDF download in The Cost of LEED v4 report.

Learn more about The Cost of LEED v4 »

In the end, LEED is all about documentation. LEEDuser’s Documentation Toolkit, for premium members only, saves you time and helps you avoid mistakes with:

  • Calculators to help assess credit compliance.
  • Tracking spreadsheets for materials purchases.
  • Spreadsheets and forms to give to subs and other team members.
  • Guidance documents on arcane LEED issues.
  • Sample templates to help guide your narratives and LEED Online submissions.
  • Examples of actual submissions from certified LEED projects.

Is it possible to pursue this as an Innovation credit in a Core & Shell project?

The answer to this question is available to LEEDuser premium members. Start a free trial »

(If you're already a premium member, log in here.)

Our project has small meeting rooms in an open-office plan. This situation appears to require an STC of 50. However, this level seems to be (unrealistically) high, especially considering the doors in the wall partition. STC 50 with a (closed) wall can be achieved, but even high STC doors won't achieve an STC of more than 45. Would this mean that the credit is not achievable?

The answer to this question is available to LEEDuser premium members. Start a free trial »

(If you're already a premium member, log in here.)

Sound transmission requirements for adjacency combinations are listed in Reference Guide Table 1, but not all combinations are included. For example, an STC rating requirement is not provided for conference room and standard/executive office adjacency. Is sound transmission compliance achieved by addressing only project applicable adjacency combinations listed in Table 1?

The answer to this question is available to LEEDuser premium members. Start a free trial »

(If you're already a premium member, log in here.)

Are we required to have an acoustical consultant in order to attempt this credit?

The answer to this question is available to LEEDuser premium members. Start a free trial »

(If you're already a premium member, log in here.)

LEEDuser expert

Ken Shook

LEED AP BD+C

Longman Lindsey
Partner

See all LEEDuser forum discussions about this credit » Subscribe to new discussions about CI-v4 EQc9