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  1. Comfort
  2. Internally generated noise

Internally generated noise

Features>Comfort>75. Internally generated noise

75. Internally generated noise

Intent: 

To reduce acoustic disruptions and increase speech privacy by creating an acoustic plan and limiting internal noise levels.

Electronics, HVAC systems, mechanical equipment and other noise-emitting office devices, as well as occupants themselves can be major sources of indoor noise. As offices and workspaces are increasingly designed to promote employee interaction, occupants can experience decreased levels of privacy and acoustic comfort, especially when users with different job types share a space. Office noise can lead to decreased productivity, especially in open-plan offices where aural distractions and interruptions from other employees are frequent. Additionally, studies show that exposure to noise generated within the building can lead to reduced concentration and mental arithmetic performance, and increased distraction due to reduced speech privacy.

Part 1: Acoustic Planning

An acoustic plan is developed that identifies the following:

a.90 Loud and quiet zones.
b. Noisy equipment in the space.
Part 2: Mechanical Equipment Sound Levels

The mechanical equipment system meets the following requirements once interior build-out is complete in the following spaces:

a.90 Open office spaces and lobbies that are regularly occupied and/or contain workstations: maximum noise criteria (NC) of 40.
b.90 Enclosed offices: maximum noise criteria (NC) of 35.
c. Conference rooms and breakout rooms: maximum noise criteria (NC) of 30 (25 recommended).
d.90 Teleconference rooms: maximum noise criteria (NC) of 20.
Part 3: Mechanical Equipment Sound Levels in Sensitive Rooms

The following requirement is met in the bedrooms, dining rooms, living rooms, and studies:

a.131 The maximum background noise level in the home or unit due to interior noise sources (HVAC systems, lighting, and other building services operating simultaneously) is less than or equal to 40 dBA, based on the peak Leq.
Part 4: Best-Practice HVAC Installation

The following requirements are met:

a.131 Ducts are securely attached with no loose connections between sections.
b.131 Fan housing is securely anchored.
c.131 Damper flaps fully close, without any visible airspaces around the perimeter of the flap.
Part 5: HVAC Sound Ratings

The following requirements are met in all bedrooms, dining rooms, living rooms, and studies for all fans except HVAC air handlers and remote-mounted fans that are located outside habitable spaces with at least 1.2 m [4 ft] of ductwork between the fan and the intake grill:

a.131 Intermittent ventilation fans with a maximum rated airflow at or below 11 m³/min [400 cfm] have a maximum sound rating of 1.5 sones.
b.131 Continuous ventilation fans have a maximum sound rating of 0.7 sones.
Part 6: Noise Criteria in Schools

Each regularly occupied space must meet the following noise criteria while unoccupied, as measured in the geometric center of the room:

a.125 Classrooms: less than 35.
Part 7: Disruptive Music Limitation

If music is played in the space, sound levels may not exceed the following:

a.173 7 decibels over the ambient sound level measured a minimum of 15 ft [4.5 m] outside of the entrance to the space.
Nervous
Endocrine
Cardiovascular

Applicability Matrix

Core & Shell New & Existing Buildings New & Existing Interiors
Part 1: Acoustic Planning - P P
Part 2: Mechanical Equipment Sound Levels O P P
Commercial Kitchen Education Multifamily Residential Restaurant Retail
Part 1: Acoustic Planning P P - P P
Part 2: Mechanical Equipment Sound Levels - P - - -
Part 3: Mechanical Equipment Sound Levels in Sensitive Rooms - - O - -
Part 4: Best-Practice HVAC Installation - - O - -
Part 5: HVAC Sound Ratings - - O - -
Part 6: Noise Criteria in Schools - P - - -
Part 7: Disruptive Music Limitation - - - P -

Verification Methods Matrix

Letters of Assurance Annotated Documents On-Site Checks
PART 1 (Protocol)
Acoustic Planning 		Architect
PART 2 (Performance)
Mechanical Equipment Sound Levels 		Performance Test
PART 3 (Performance)
Mechanical Equipment Sound Levels in Sensitive Rooms 		Performance Test
PART 4 (Design)
Best-Practice HVAC Installation 		Contractor
PART 5 (Design)
HVAC Sound Ratings 		MEP
PART 6 (Performance)
Noise Criteria in Schools 		Performance Test
PART 7 (Design)
Disruptive Music Limitation 		Performance Test

90

U.S. General Services Administration Center for Workplace Strategy Public Buildings Service. Sound Matters: How to Achieve Acoustic Comfort in the Contemporary Office. Washington, D.C.: 2012: 11, 29, 32, 33, 36.
75.1.a

The General Services Administration's Sound Matters recommends to carefully consider the effect on neighboring workstations when locating supporting activities, i.e. copier rooms, coffee bars, entries to conference rooms.
75.2.b

The General Services Administration's Sound Matters recommends a background noise maximum of NC 35 for private offices.
75.2.d

The General Services Administration's Sound Matters recommends a background noise maximum of NC 20 for teleconference facilities.
75.2.a

The General Services Administration's Sound Matters recommends a background noise maximum of NC 40 for open plan workspaces.
125

ASHRAE. Noise and Vibration Control. In Owen M, ed. ASHRAE Handbook - HVAC Applications. 2011 ed. Atlanta, GA: ASHRAE; 2011.
75.6.a

ASHRAE recommends a noise criteria (NC) less than 35 in school classrooms.
131

U.S. Green Building Council. Pilot Credit: Acoustic Comfort. http://www.usgbc.org/node/4631859?return=/credits. Published 2013. Accessed December 10, 2014.
75.3.a

The LEED v4 credit for Acoustic Comfort for homes sets 2 options for the LEED point, one of which requires that the max. background noise level due to interior noise sources cannot exceed 40 dBA based on peak hr Leq tested in acoustically sensitive rooms.
75.4.a

The LEED v4 credit for Acoustic Comfort for homes sets 2 options for the LEED point, one of which requires that ducts are securely attached with no loose connections between sections of ductwork.
75.4.b

The LEED v4 credit for Acoustic Comfort for homes sets 2 options for the LEED point, one of which requires that the fan housing is securely anchored.
75.4.c

The LEED v4 credit for Acoustic Comfort for homes sets 2 options for the LEED point, one of which requires that damper flaps close fully, with no visible airspaces around the flap.
75.5.a

The LEED v4 credit for Acoustic Comfort for homes sets 2 options for the LEED point, one of which requires that intermittent fans have a max. sound rating of 1.5 sones (unless their max. rated airflow exceeds 400 cfm) in acoustically sensitive rooms.
75.5.b

The LEED v4 credit for Acoustic Comfort for homes sets 2 options for the LEED point, one of which requires that continuous ventilation fans have a max. sound rating of 1.5 sones in acoustically sensitive rooms.
173

New York City Department of Environmental Protection. A Guide to New York City's Noise Code. http://www.nyc.gov/html/dep/pdf/noise_code_guide.pdf. Published 2014. Accessed April 16, 2015.
75.7.a

The NYC DEP's Guide to the NYC Noise Code states that music heard on the street may not exceed 7 decibels over the ambient sound level, as measured on the street or public right-of-way 15 ft or more from the source from 10PM-7AM.
Features>Comfort>75. Internally generated noise