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LEED v4.1
New Construction
Indoor Environmental Quality
Acoustic Performance

LEED CREDIT

NC-v4.1 EQc9: Acoustic performance 1 point

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SPECIAL REPORT

LEEDuser expert

Ken Shook

LEED AP BD+C

Longman Lindsey
Partner

SPECIAL REPORT

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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 two of the following: HVAC background noise, Sound Transmission, and/or Reverberation time. Meet all three for an exemplary performance point.

Confirm compliance via calculations or measurements in representative rooms, and/or design documentation from a person experienced in the field of acoustics.

HVAC Background Noise

Achieve maximum background noise levels from heating, ventilating, and air conditioning (HVAC) systems per 2015 ASHRAE Handbook-- HVAC Applications, Chapter 48, Table 1 ; AHRI Standard 885-2008, Table 15; or a local equivalent.

If confirming compliance via measurements, use a sound level meter that conforms to ANSI S1.4 for type 1 (precision) or type 2 (general purpose) sound measurement instrumentation, the International Electrotechnical Commission (2013) IEC 61672-1:2013 Electroacoustics – Sound Level Meters – Part 1: Specifications, or a local equivalent.

Comply with design criteria for HVAC noise levels resulting from the sound transmission paths listed in 2015 ASHRAE Handbook—HVAC Applications, Chapter 48, Table 6; or a local equivalent.

Sound Transmission

Categorize all occupied spaces by use and desired level of acoustic privacy.

Meet the composite sound transmission class (STCC) ratings or noise isolation class (NIC) listed in Table 1. For NIC measurements, use ASTM E336-17a or Annex A.3 of ANSI S12.60-2010.

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

Adjacency combinations STC C ** NIC**
Retail Retail 50
Collaborative / multi-use Hallway, stairway 25 20
Private Hallway, stairway 35 30
Confidential Hallway, stairway 40 35
Collaborative / multi-use Collaborative / multi-use 35 30
Collaborative / multi-use Private 45 40
Collaborative / multi-use Confidential 50 45
Private Private 45 40
Private Confidential 50 45
Confidential Confidential 50 45
Conference room Conference room 50 45
Mechanical equipment room* Hallway, stairway 50 45
Mechanical equipment room* Occupied area 60 55

*Minimum STCc or NIC has to be met unless proven that the equipment noise in conjunction with the sound isolation performance of the partitions and doors will not exceed the maximum background noise requirements of the adjacent space.

**If a sound masking system is implemented at a minimum level of 40 dBA, the STCc ratings or NIC values in Table 1 may be lowered by 5 points. This applies to all space types except mechanical equipment rooms. The sound masking system must be designed by an acoustical professional and meet the following criteria:

  • The overall level for sound masking must be set by an acoustical professional and must not exceed 48 dBA in open offices, libraries, cafeterias, corridors/hallways, 45 dBA in enclosed offices, and 42 dBA in conference rooms, and wellness rooms. The combined level of masking and HVAC background noise must not exceed these limits.
  • The system design and commissioning must provide overall level uniformity of +/-1 dBA and one-third octave band uniformity of +/-2 dB from at least 100 to 5,000 Hz when tested according to ASTM E1573-18
  • The sound masking spectrum must conform to the National Research Council of Canada COPE Optimum Masking Spectrum or an alternate spectrum if specified by an acoustical engineer.
Reverberation Time

Meet the reverberation time requirements in Table 2 (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
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

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

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LEEDuser expert

Ken Shook

LEED AP BD+C

Longman Lindsey
Partner

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 two of the following: HVAC background noise, Sound Transmission, and/or Reverberation time. Meet all three for an exemplary performance point.

Confirm compliance via calculations or measurements in representative rooms, and/or design documentation from a person experienced in the field of acoustics.

HVAC Background Noise

Achieve maximum background noise levels from heating, ventilating, and air conditioning (HVAC) systems per 2015 ASHRAE Handbook-- HVAC Applications, Chapter 48, Table 1 ; AHRI Standard 885-2008, Table 15; or a local equivalent.

If confirming compliance via measurements, use a sound level meter that conforms to ANSI S1.4 for type 1 (precision) or type 2 (general purpose) sound measurement instrumentation, the International Electrotechnical Commission (2013) IEC 61672-1:2013 Electroacoustics – Sound Level Meters – Part 1: Specifications, or a local equivalent.

Comply with design criteria for HVAC noise levels resulting from the sound transmission paths listed in 2015 ASHRAE Handbook—HVAC Applications, Chapter 48, Table 6; or a local equivalent.

Sound Transmission

Categorize all occupied spaces by use and desired level of acoustic privacy.

Meet the composite sound transmission class (STCC) ratings or noise isolation class (NIC) listed in Table 1. For NIC measurements, use ASTM E336-17a or Annex A.3 of ANSI S12.60-2010.

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

Adjacency combinations STC C ** NIC**
Retail Retail 50
Collaborative / multi-use Hallway, stairway 25 20
Private Hallway, stairway 35 30
Confidential Hallway, stairway 40 35
Collaborative / multi-use Collaborative / multi-use 35 30
Collaborative / multi-use Private 45 40
Collaborative / multi-use Confidential 50 45
Private Private 45 40
Private Confidential 50 45
Confidential Confidential 50 45
Conference room Conference room 50 45
Mechanical equipment room* Hallway, stairway 50 45
Mechanical equipment room* Occupied area 60 55

*Minimum STCc or NIC has to be met unless proven that the equipment noise in conjunction with the sound isolation performance of the partitions and doors will not exceed the maximum background noise requirements of the adjacent space.

**If a sound masking system is implemented at a minimum level of 40 dBA, the STCc ratings or NIC values in Table 1 may be lowered by 5 points. This applies to all space types except mechanical equipment rooms. The sound masking system must be designed by an acoustical professional and meet the following criteria:

  • The overall level for sound masking must be set by an acoustical professional and must not exceed 48 dBA in open offices, libraries, cafeterias, corridors/hallways, 45 dBA in enclosed offices, and 42 dBA in conference rooms, and wellness rooms. The combined level of masking and HVAC background noise must not exceed these limits.
  • The system design and commissioning must provide overall level uniformity of +/-1 dBA and one-third octave band uniformity of +/-2 dB from at least 100 to 5,000 Hz when tested according to ASTM E1573-18
  • The sound masking spectrum must conform to the National Research Council of Canada COPE Optimum Masking Spectrum or an alternate spectrum if specified by an acoustical engineer.
Reverberation Time

Meet the reverberation time requirements in Table 2 (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
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

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

LEEDuser expert

Ken Shook

LEED AP BD+C

Longman Lindsey
Partner

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