6.5: Acoustic Comfort

(48 points)

GREEN GLOBES #6.5.1 Is the tenant space acoustic design consistent with the intended requirements for the use? 

• Yes (5 points) 
• No (0 points)

Tooltip

A written acoustic control design strategy should be developed to serve as the basis of design for each type of space.

Assessment Guidance

An acoustic control design strategy, and incorporated acoustic control measures, as show in in the construction documents and submittals, will serve as thorough documentation for the Green Globes Assessor.

GREEN GLOBES #6.5.2 Does the space design include the following interior sound control strategies:

Tooltip

“Acoustically separated areas” means an enclosed space that, to function properly, requires separation from other adjacent spaces by wall, floor, and ceiling assemblies that have an STC rating adequate to allow clear, intelligible communication between sender and receiver within the space (e.g. meeting rooms, auditoria, lecture halls, libraries, classrooms, conference rooms, private offices, private rooms in health care facilities, sleeping rooms etc.).

Assessment Guidance

Most of the design decisions and construction procedures for these criteria will be detailed on the architectural drawings. The architect should be made aware if a project is pursuing these criteria early in the design, when space planning is being coordinated. In general, architectural acoustic design attempts to optimize isolation (keeping noise within or preventing it from entering a space) and/or sound quality (judicious use of surfaces, shaping, and finishes to achieve a desired effect). Although these goals often go together, there are many examples where one is targeted with little concern for the other. For example, a mechanical equipment room may be designed with heavy walls, high-quality doors, and structural breaks to keep noise and vibration from being transmitted to occupied spaces; however, the quality of the noise within the mechanical equipment room is perceived as irrelevant and no thought is given to the room finishes or layout with regard to room acoustic response. Similarly, a large space used for a marching band to practice indoors in the event of inclement or uncomfortable weather may incorporate specific architectural features and finishes to provide a good listening environment for the users but there may be little concern about noise leaking out of the building due to its location or the expectations of adjacent users. Designers should remember that not every area that is 'acoustically separated' requires both good isolation and good quality – the requirements depend on whether the room houses sources or receivers, as well as the function of the rooms.

For sub-criteria 6.5.2.2, “mechanical rooms” refers to both mechanical and electrical equipment rooms since electrical equipment can also have high, tonal noise levels.

Entry doors to acoustically sensitive areas are often the weak point in the design of the enclosure. Exterior doors should be vestibules/double-doors or should incorporate bubble/ brush gaskets and/or drop seals. Interior doors should be staggered for rooms opposite each other on the same corridor.

Construction Documents , HVAC design documents required for verification.

References 

• ASHRAE Systems Application Handbook-2007, Chapter 47 
• ANSI S12.60-2010/Part 1 
• ASTM E1374-06

GREEN GLOBES #6.5.2.1 Toilets are located remotely from acoustically separated areas? 

• Yes (2 points) 
• No (0 points) 
• N/A

Tooltip

Mark “N/A” where there are no such areas or restrooms are existing and therefore cannot effectively be acoustically separated from acoustically separated areas due to space configuration limitations.

GREEN GLOBES #6.5.2.2 Acoustically separated areas are located away from noise producing areas such as dance studios, music rooms, cafeterias, indoor swimming pools, mechanical rooms, and gymnasia? 

• Yes (2 points) 
• No (0 points) 
• N/A

Tooltip

Mark “N/A” where there are no such areas or noise producing areas are existing and cannot effectively be acoustically separated from acoustically separated areas due to space configuration limitations.

GREEN GLOBES #6.5.2.3 Entry doors to rooms opposite each other on the same corridor are staggered? 

• Yes (2 points) 
• No (0 points) 
• N/A

Tooltip

Mark “N/A” where there are no such areas.

GREEN GLOBES #6.5.2.4 Through-wall penetrations comply with Annex B of ANSI/ASA S12.60-2010/Part 1?

• Yes (2 points) 
• No (0 points)

GREEN GLOBES #6.5.2.5 Walls separating acoustically separated areas from other areas are constructed full height to underside of the next floor above or the roof deck?

• Yes (2 points) 
• No (0 points)

GREEN GLOBES #6.5.2.6 Walls separating quiet areas from other areas have all joints and penetrations sealed with acoustical sealant?

• Yes (2 points) 
• No (0 points) 
• N/A

Tooltip

Mark “N/A” where there are no such areas.

GREEN GLOBES #6.5.2.7 Areas with high floor impact activities (dance studios, shops, gymnasia, etc.) are not located above acoustically separated areas?

• Yes (2 points) 
• No (0 points) 
• N/A

Tooltip

This is in reference to physical adjacencies of spaces within the overall space plan of a tenant fit-out that is multiple stories. Mark “N/A” where there are no such areas.

GREEN GLOBES #6.5.3 Has an Acoustics Consultant or Acoustician signed off on the design that shows that open office areas conform to ASTM E1573-02 with respect to spatial uniformity, temporal uniformity, spectrum shape, and sound level? 

• Yes (5 points) 
• No (0 points) 
• N/A

Tooltip

Strategies may include minimum 54 inch high open office furniture, high performance ceiling tile 180 Articulation Class (AC), and sound masking. Mark “N/A” where there are no open office areas.

Assessment Guidance

The Green Globes Assessor may request sound level measurements taken at the property line; description of acoustic design strategies and all design targets; FIIC value for flooring assemblies ; acoustic mitigation measures for mechanical equipment and plumbing systems; and Test Report indicating compliance with ANSI S12.60-2010/Part 1.

References 

• ASHRAE Systems Application Handbook-2007, Chapter 47 
• ANSI S12.60-2010/Part 1 
• ASTM E1374-06

GREEN GLOBES #6.5.4 Has an Acoustics Consultant or Acoustician signed off on a design that complies with minimum Sound Transmission Class (STC) ratings of floor/ceiling assemblies, walls and doors between acoustically separated areas (learning spaces), and adjacent spaces as follows and as applicable:

Tooltip

Verify that construction documents include that ambient sound levels in enclosed, occupied spaces fall within specified STC ratings . Review the acoustical analysis prepared by an acoustical designer and the design and construction drawings showing the details required for optimum acoustic performance.

Assessment Guidance

The STC rating indicates the maximum noise reduction performance of an architectural element based on its performance relative to an ideal defined curve but allows for significant deviations within narrow frequency bands. Projects pursuing this criterion should provide acoustical consultant report/diagrams or architectural drawings that detail and describe the STC ratings of walls, floors, ceiling, doors, and windows. STC ratings that meet or exceed the above criteria will count for points.

GREEN GLOBES #6.5.4.1 STC-45 where the adjacent space is a corridor, stair, office, or conference room? 

• Yes (1 points) 
• No (0 points) 
• N/A

Tooltip

Mark “N/A” where there are no such areas.

GREEN GLOBES #6.5.4.2 STC-50 where the adjacent space is a quiet area, speech clinic, health clinic, classroom, or an exterior wall?

• Yes (1 points) 
• No (0 points) 
• N/A

Tooltip

Mark “N/A” where there are no such areas.

GREEN GLOBES #6.5.4.3 STC-50 for doors to quiet areas?

• Yes (1 points) 
• No (0 points) 
• N/A

Tooltip

Mark “N/A” where there are no such areas.

GREEN GLOBES #6.5.4.4 STC-40 for doors to music rooms, cafeterias, natatoria (e.g. swimming pool), or gymnasia?

• Yes (1 points) 
• No (0 points) 
• N/A

Tooltip

Mark “N/A” where there are no such areas.

GREEN GLOBES #6.5.5 Does the Impact Insulation Class (IIC) design of all floor-ceiling assemblies have a minimum rating of IIC-50? 

• Yes (5 points) 
• No (0 points)

Tooltip

Verify that sound transmission from the outside and between rooms and floors will be attenuated, and that primary spaces will be effectively insulated from undesirable impact noise (stairways, mechanical transportation, etc.) when adjacent spaces are fully occupied and being used normally. Check that the appropriate Impact Insulation Class (IIC) values have been specified. Check that engineering design calculations and drawings by a licensed Acoustical Consultant or Acoustician are included.

Assessment Guidance

Since not every state has a separate designation for acoustical engineers and, since few Acoustics Consultants or Acousticians are registered engineers, IIC calculations and drawings should, at minimum, be prepared by a firm that specializes in or has a department that specializes in acoustics.

References 

• ASTM E989-06

GREEN GLOBES #6.5.5.1 Indicate the Impact Insulation Class (IIC) value:

Tooltip

This criterion is informational only and is not scored.

GREEN GLOBES #6.5.6 Has an Acoustics Consultant or Acoustician signed off on a design that shows Reverberation Time (RT) in quiet areas and all other areas where speech intelligibility is important does not exceed the following values as applicable: 

0.6 seconds in spaces less than 10,000 ft3 in volume?

AND 

0.7 seconds in spaces 10,000 - 20,000 ft3 in volume?

AND 

Compliance with Annex C of ANSI/ASA S12.60-2010/Part 1 in spaces larger than 20,000 ft3 in volume? 

• Yes (5 points) 
• No (0 points) 
• N/A

Tooltip

This ensures that room resonance levels support activities such as face-to-face communication, conferences, or individual work. In offices, measures also include: work stations that are zoned and isolated as necessary, and use of sound absorbing materials such as carpeting and acoustic tiles to attenuate noise in office areas. Mark “N/A” for MURBs.

Assessment Guidance

Acoustical Design Documents affixed with professional stamp or signature required for verification.

References 

• ANSI S12.60-2010/Part 1

GREEN GLOBES #6.5.7 Does the predominant lighting type utilize low-noise ballasts in quiet areas and all other areas where speech intelligibility is important? 

• Yes (2 points) 
• No (0 points)

Assessment Guidance

Ballast noise from electromagnetic and electronic ballasts used in fluorescent lighting systems is typically characterized by a “humming” sound. Ballast manufacturers assign a sound rating to their ballasts from “A” through “F”, with “A” being the quietest. Because electronic ballasts have smaller components, they tend to have the lowest sound rating. However, there is no standard for this rating; it is left entirely up to the manufacturers to rate their ballasts. This sound rating can be found listed under the ballast’s specifications. In situations where the required light output necessitates using ballasts with a higher sound rating, the ballasts should be remotely located.

ANSI S12.60-2010/Part 1 covers the acoustical performance criteria, design requirements, and guidelines for permanent schools, though this standard is used for other learning or sound critical spaces as well. Noise from light fixtures or other electrical equipment is not dictated in the standard by ratings or sound levels of the equipment. In order to comply with the standard, the interior-source background noise cannot exceed the limits specified in the table below. Although the table separates sound level limits by HVAC type, the limits include all building services, including lighting. Section 5.2.2.1 of the standard indicates: “The one-hour average A- or C- weighted sound levels of any other building sounds (e.g. lighting) for which sound power data are available, shall be combined on time-means-square basis with calculated one-hour average A- or C- weighted sound level of the HVAC noise before determining conformance. Where sound power data are not available, estimated one-hour average A- or C- weighted sound levels shall be used.” Table 6.5.7: ANSI/ASA S12.60-2010 Noise Limits, are on one-hour average A- and C-weighted sound levels—designated by X/Y in the table below—from sources associated with the building services and utilities.

Beyond the above requirements, ANSI S12.60-2010 has requirements from the tonal sounds generated from building utilities (e.g. ballast noise). Any tonal sounds from lighting ballasts need to be quantified using the methods in ANSI/ASA S1.13-2005 ensuring no “prominent discrete tones.” A prominent discrete tone can be defined as a sound (often perceived as a whine or hum) that can be heard distinctly as a single pitch or a set of pitches. Technically, a prominent discrete tone exists if the one-third octave band sound pressure level in the band with the tone exceeds the arithmetic average of the sound pressure levels of the 2 contiguous one-third octave bands by:

• 5 dB for center frequencies of 500 Hz and above 
• 8 dB for center frequencies between 160 and 400 Hz 
• 15 dB for center frequencies less than or equal to 125 Hz

For compliance with 6.5.7, cut sheets should be provided during the Green Globes Assessor’s review for all ballasts specified on the project showing the manufacturer’s sound rating. A narrative should be provided, justifying areas with ballasts rated lower than “A.”

Additional strategies to mitigate the noise from the electrical system include: 

• Transformers often emit strong tonal noise and vibration characteristics. Identify location of transformers and hang with isolation hangers or mount resiliently. Ensure the feeder enters at the top or side to avoid transmitting vibration to structure. 
• If dimmers are to be employed, use sine-wave dimmers or specify dimmers with high 'rise-times' to avoid having the filaments and fixtures 'sing' when partly loaded. 
• Conduit penetrations at equipment rooms and other noisy spaces should be sealed to the same standard of care and detail as piping and ductwork. 

The assessor may also request sound level measurements taken at the property line; description of acoustic design strategies and all design targets; FIIC value for flooring assemblies ; acoustic mitigation measures for mechanical equipment and plumbing systems; specification which includes Annex E of ANSI S12.60-2010/Part 1; and Test Report indicating compliance with ANSI S12.60-2010/Part 1.

GREEN GLOBES #6.5.8 Does the noise from light fixtures and other electrical fixtures not exceed values indicated in ANSI S12.60-2010/Part 1?

• Yes (2 points) 
• No (0 points)

Assessment Guidance

Ballast noise from electromagnetic and electronic ballasts used in fluorescent lighting systems is typically characterized by a “humming” sound. Ballast manufacturers assign a sound rating to their ballasts from “A” through “F”, with “A” being the quietest. Because electronic ballasts have smaller components, they tend to have the lowest sound rating. However, there is no standard for this rating; it is left entirely up to the manufacturers to rate their ballasts. This sound rating can be found listed under the ballast’s specifications. In situations where the required light output necessitates using ballasts with a higher sound rating, the ballasts should be remotely located.

ANSI S12.60-2010/Part 1 covers the acoustical performance criteria, design requirements, and guidelines for permanent schools, though this standard is used for other learning or sound critical spaces as well. Noise from light fixtures or other electrical equipment is not dictated in the standard by ratings or sound levels of the equipment. In order to comply with the standard, the interior-source background noise cannot exceed the limits specified in the table below. Although the table separates sound level limits by HVAC type, the limits include all building services, including lighting. Section 5.2.2.1 of the standard indicates: “The one-hour average A- or C- weighted sound levels of any other building sounds (e.g. lighting) for which sound power data are available, shall be combined on time-means-square basis with calculated one-hour average A- or C- weighted sound level of the HVAC noise before determining conformance. Where sound power data are not available, estimated one-hour average A- or C- weighted sound levels shall be used.” Table 6.5. 8: ANSI/ASA S12.60-2010 Noise Limits, are on one-hour average A- and C-weighted sound levels—designated by X/Y in the table below—from sources associated with the building services and utilities.

Beyond the above requirements, ANSI S12.60-2010 also has requirements from the tonal sounds generated from building utilities (e.g. ballast noise). Any tonal sounds from lighting ballasts need to be quantified using the methods in ANSI/ASA S1.13-2005 ensuring no “prominent discrete tones.” A prominent discrete tone can be defined as a sound (often perceived as a whine or hum) that can be heard distinctly as a single pitch or a set of pitches. Technically, a prominent discrete tone exists if the one-third octave band sound pressure level in the band with the tone exceeds the arithmetic average of the sound pressure levels of the 2 contiguous one-third octave bands by:

• 5 dB for center frequencies of 500 Hz and above 
• 8 dB for center frequencies between 160 and 400 Hz 
• 15 dB for center frequencies less than or equal to 125 Hz

For compliance with criteria 6.5.8, calculations should be performed by an Acoustical Consultant or Acoustician for all relevant building systems (HVAC, lighting, etc.) sources and paths or testing shall be required for each learning space (or other acoustically sensitive) to ensure that the requirements of Table 6.5.8: ANSI/ASA S12.60-2010 Noise Limits above are met. The testing shall also include provisions for measuring tonal sounds emitted by electrical equipment and lighting fixtures. Annex A of ANSI/ASA S12.60-2010 outlines how to verify the conformance to the standard by field measurements and so should be referenced in the project’s specifications. These test results should be submitted to the Green Globes Assessor prior to the on-site visit for review.

Additional strategies to mitigate the noise from the electrical system include: 

• Transformers often emit strong tonal noise and vibration characteristics. Identify location of transformers and hang with isolation hangers or mount resiliently. Ensure the feeder enters at the top or side to avoid transmitting vibration to structure. 
• If dimmers are to be employed, use sine-wave dimmers or specify dimmers with high 'rise-times' to avoid having the filaments and fixtures 'sing' when partly loaded. 
• Conduit penetrations at equipment rooms and other noisy spaces should be sealed to the same standard of care and detail as piping and ductwork.

The assessor may also request sound level measurements taken at the property line; description of acoustic design strategies and all design targets; FIIC value for flooring assemblies ; acoustic mitigation measures for mechanical equipment and plumbing systems; specification which includes Annex E of ANSI S12.60-2010/Part 1; and Test Report indicating compliance with ANSI S12.60-2010/Part 1.

References 

• ANSI S12.60-2010/Part 1 
• ANSI/ASA S1.13-2005

GREEN GLOBES #6.5.9 Does the layout provide the possibility of designating “Quiet Zones” or “Privacy Areas” for focused, concentrated work and private conversations? 

• Yes (2 points) 
• No (0 points) 
• N/A

Tooltip

Mark “N/A” where there is no need for these zones.

Assessment Guidance

Space planning and programming activities should address the need for specific quiet and privacy areas, allowing streamlined pre-design and design of special acoustical spaces. Space planning and construction documents required for verification.

GREEN GLOBES #6.5.10 Are there small enclosed meeting rooms to take conference calls on speaker phones?

• Yes (2 points) 
• No (0 points)

Assessment Guidance

Construction Documents and/or the assessment site visit will cover the requirements required for verification.

GREEN GLOBES #6.5.11 Is there a sound masking system (white noise) or fabric solution for noise absorption used in open office areas?

• Yes (2 points) 
• No (0 points) 
• N/A

Tooltip

Mark “N/A” where there are no open office areas.

Assessment Guidance

Open office areas can have acoustical problems depending on the design of the building shell, as well as other building structural and occupancy factors, including activities above and below adjacent floors. There may be instances where an acoustical problem will not be identified until construction is complete and furnishings are in place; this situation may require some remedial measures at occupancy. Construction Documents, submittals, testing results, and follow up remedial plays may be required for verification.

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