This pilot credit is based upon the LEED for Schools Enhanced Acoustical Design credit, and has been developed in order to meet the market need for guidance around acousti-cal design in the office and new construction setting.
1. Register for Pilot Credit(s) here. 2. Register a username at LEEDuser.com, and participate in online forum3. Submit feedback survey; supply PDF of your survey/confirmation of completion with credit documentation
Excerpted from LEED Pilot Credit Library
To provide workspaces and classrooms that promote occupants’ well-being, productivity, and communications through effective acoustic design.
For all occupied spacesOccupied Spaces are defined as enclosed spaces that can accommodate human activities. Occupied spaces are further classified as regularly occupied or non-regularly occupied spaces based on the duration of the occupancy, individual or multi-occupant based on the quantity of occupants, and densely or non-densely occupied spaces based upon the concentration of occupants in the space., meet the following requirements as applicable to the space:
Projects that cannot meet sections of the requirements due to limited scope of work or historic preservation requirements must meet at least 3 of the above sections and submit a detailed description justifying design decisions.
Room Noise Levels
Room noise levels from building mechanical systems shall fall within the sound level ranges shown in either the 2011 ASHRAE Handbook, HVAC Applications, Chapter 48, Table 1, or the AHRI Standard 885-2008, Table 15, or local equivalent.
Measurements for room sound levels shall be measured using a sound level meter that conforms to ANSI S1.4 for type 1 (precision) or type 2 (general purpose) sound measurement instrumentation, or local equivalent.
Comply with design criteria for HVAC noise levels in regularly occupied spacesRegularly occupied spaces are areas where one or more individuals normally spend time (more than one hour per person per day on average) seated or standing as they work, study, or perform other focused activities inside a building. resulting from the sound transmission paths listed in Table 6 in the ASHRAE 2011 Applications Handbook or AHRI Standard 885-2008, or local equivalent.
Limiting Reverberation Time and Reverberant Noise Buildup
Meet the reverberationReverberation is an acoustical phenomenon that occurs when sound persists in an enclosed space because of its repeated reflection or scattering on the enclosing surfaces or objects within the space. (ANSI S12.602002) time requirements in the following table, adapted from Table 9.1 in the Performance Measurement Protocols for Commercial Buildings [Adapted from ASHRAE (2007d), ASA (2008), ANSI (2002), and CEN (2007)]:
Paging, Masking and Sound Reinforcement Systems
For projects that use masking systems, meet the following:
The homepage for the LEED Pilot Credit Library. The LEED Pilot Credit Library is intended to facilitate the introduction of new prerequisites and credits to LEED. This process will allow USGBC to test and refine credits through LEED 2009 project evaluations before they are sent through the balloting process for introduction into LEED.
Background for the LEED Pilot Credit Library is provided in this foundational document.
It is correct that sound reinforcement systems are only required fro conference rooms or auditoriums for more then 50 people?
Are masking systems optional in order to comply or mandatory?
We are considering this credit for a New Construction Project. Before making a decision we need to estimate the engineering cost involved for this credit.
I understand that measurements are required once the project is finished. I also understand an analysis is required prior to construction, in order to determine the values that are requried. Does this involve an acoustic simulation or a calculation? What would be the time required for this? I understand that it depends on the size of the project, but I would need some orientation. A full scale acoustic simulation might require a lot more time then a spreadsheet calculation. Could any one give some feedback or orientation? Thanks.
This is a good question. The characteristics of the design necessary to meet the Pilot Credit requirements (e.g., STCSound transmission class (STC) is a single-number rating for the acoustic attenuation of airborne sound passing through a partition or other building element, such as a wall, roof, or door, as measured in an acoustical testing laboratory according to accepted industry practice. A higher STC rating provides more sound attenuation through a partition. (ANSI S12.602002) ratings for partitions), can be developed without measurements. Arriving at composite STC (e.g., wall/window ratios) requires calculations of some level.
ReverberationReverberation is an acoustical phenomenon that occurs when sound persists in an enclosed space because of its repeated reflection or scattering on the enclosing surfaces or objects within the space. (ANSI S12.602002) times can be calculated, or measured after construction. Background noise (ventilation systems) can be calculated.
You are correct in that the level of effort is dependent on the number and type of spaces in the project, some rooms are "typical", while some rooms are unique and require additional efforts.
I hope this helps.
Ethan Salter, PE, LEED AP
Charles M. Salter Associates, Inc.
Thanks for the reply.
You mention that the credit can be achieved without measurements. the credit requirement however says "Measurements for room sound levels shall be measured using a sound level meter ... " Should I understand that measuring is one option to comply, but there exists another option, such as the calculations you mention?
Would it be correct that the engineering effort required to do the calculations would be rather limited ... ?
Our understanding is similar to Ethans above, that a combination of actual sound level measurements and acoustic calculations can be used. This seems more consistent with the credit intent. However, this will need to be clarified with USGBC. For our submission, we completed and uploaded a completed version of the acoustic template from LEED Schools for each regularly occupied space and a acoustic commissioning report for the primary assembly space.
A team that I'm working with would like to know whether or not measurements are required. It is still not clear from this discussion.
Also, is there a template to use for documentation? If so, it would be great if it could be made available on LEEDUser. For instance, may one use the LEED for Schools Enhanced Acoustical Performance, or possibly the Prerequisite template for this credit?
Is this s design or construction credit? From the credit form requirements looks like the NC levels will have to be measured, the rest criteria can be theoretically analysed or modeled. We are at a point to submit for design review;
1. Would it be appropriate to leave this credit for construction submittal when we can make measurements in lieu of modeling
2. What would be appropriated sampling strategy to perform the measurements. We have a hotel project with 127 guest rooms and we are planing to measure only 3 rooms which represent the three typical configurations. We have 7 meetings rooms which are in two typical configurations and we are planing to do two sets of measurements, one for each typical condition. For the admin office and the gym areas we are planing to do two additional sets of measurements and analysis.
This is a design credit. The NC levels can be determined through acoustical analysis of the mechanical system. I would recommend contacting an acoustical consultant to help you finish up the design. If you wait to do measurements, it will be much more difficult to fix any noise issues with the mechanical system.
Thank you for the prompt reply, Nicolas! Waht is interesting is that the latest credit form even specifies the type of sound level meter that will have to be used to demonstrate the room noise levels. The form was updated yesterday March 1, 2012!
While the requirements have changed, the credit submittals still list "Room noise level calculations (NC, RC(N) or dBAA decibel (dBA) is a sound pressure level measured with a conventional frequency weighting that roughly approximates how the human ear hears different frequency components of sounds at typical listening levels for speech. (ANSI S12.602002))". The sound level meter requirements are adhering to ANSI guidelines, so it makes sense that they would be included. Oddly, they also still list speech privacy requirements. So it is possible that the credit will still receive further updates.
We have a clinic project that is seeking LEED HC certification and the credit IEQ c2 is similar to this pilot credit. Background noise, sound isolation, speech privacy are also needed in HC project. We try to pursue this credit but it's hard to meet all the requirements. Does anyone know how to meet the requirements of speech privacy? There are PI, AI, SII, STI but I can't find the construction materials with these coefficients. Then how do I prove the speech privacy of the spaces meet the requirements.
Thanks in advance, any help and suggestions will be appreciated.
You will not find construction materials with coefficients for PI, AI, SII, or STI. In order to meet speech privacy requirements, acoustical testing and/or calculations are required to determine the proper partition construction to meet your goals. I highly recommend that you find an acoustical consultant to assist your team.
James, March 1, 2012 the credit form was updated eliminating the Speech Privacy section! You can download the form from USGBC site. It looks much more straightforward.
Is this ID credit approach asking for an effort substantially above and beyond the enhanced credit for LEED for Schools? Not being an acoustics engineer, it seems there is a dizzying amount of calculations required ("speech privacy analysis?"). Has anyone attempted to undertake this credit? If so, what was your experience?
This credit is a new addition to the Pilot Credit Library, and has not yet been undertaken by any project teams.
The credit was developed in response to the market's request for an acoustic credit for LEED NC which encompasses a wide range of project types. Because the acoustic needs of "New Construction" projects vary, you'll notice there aren't specific criteria ranges listed in the credit. We are essentially asking teams to document the acoustic requirements (reverberationReverberation is an acoustical phenomenon that occurs when sound persists in an enclosed space because of its repeated reflection or scattering on the enclosing surfaces or objects within the space. (ANSI S12.602002) time, background noise, sound isolation, speech privacy) for their specific project and prove how they achieved their stated criteria.
In comparison to LEED for Schools, this credit is on par with the requirements of the Enhanced Acoustical Performance Credit. Both credits require compliance with reverberation time, background noise, and sound isolation. LEED for Schools requires compliance with IIC (impact noise isolation), whereas the NC credit asks teams to comply with speech privacy.
We look forward to hearing how project teams addressed the acoustic issues of their projects, and what improvements to the credit they suggest.
I was part of the design team for a military base NC project, for which this credit was submitted and approved. As required, a narrative was submitted documenting our recommendations for room noise, sound isolation, speech privacy, and reverberationReverberation is an acoustical phenomenon that occurs when sound persists in an enclosed space because of its repeated reflection or scattering on the enclosing surfaces or objects within the space. (ANSI S12.602002) times. There was no sound reinforcement system or sound masking system for this project.
We worked with the mechanical engineer to ensure that the room noise met the design guidelines outlined in Chapter 48, Table 1 of the 2011 ASHRAE Handbook. An acoustical model was used to determine the amount of sound level reduction required to meet these guidelines. Silencers, sound boots, and lined ductwork were the recommended treatments.
For sound isolation, the STCSound transmission class (STC) is a single-number rating for the acoustic attenuation of airborne sound passing through a partition or other building element, such as a wall, roof, or door, as measured in an acoustical testing laboratory according to accepted industry practice. A higher STC rating provides more sound attenuation through a partition. (ANSI S12.602002) rating table shown in the Pilot Credit guidelines was compared to the partition schedule in the architectural drawings. The rooms were grouped by type, and a table showing the STC rating of the enclosing partitions was included in the narrative.
The STC ratings in the previously described table were combined with our modeled background noise levels to provide the speech privacy ratings. These ratings all met Confidential Speech Privacy at loud voice levels.
Most of the rooms in this project were offices or classrooms, which have volumes less than 10,000 cubic feet. NRCNoise reduction coefficient (NRC) is the arithmetic average of absorption coefficients at 250, 500, 1,000, and 2,000 Hz for a material. The NRC is often published by manufacturers in product specifications, particularly for acoustical ceiling tiles and acoustical wall panels. 0.90 acoustical ceiling tile covering all ceiling area not occupied by lighting was recommended in these spaces. There was an auditorium with a volume of 78,000 cubic feet in this project. This room will be primarily used for presentations. For this space an acoustical model was created. We recommended treatment of a percentage of the vertical surface area with acoustical wall panels in addition to acoustical ceiling tile. These treatments reduced the mid-band reverberation time in this space to approximately 0.55 seconds.
In my opinion, the guidelines of this Pilot Credit are appropriate and they are in-line with guidelines we typically try to meet in NC projects. My one recommendation for improvement on the credit would be to incorporate the Speech Privacy Class (SPC) metric into the speech privacy section. This is our preferred metric for determining speech privacy.
Our experience was similar to Nicholas'. Our project involved improvements and refurbishment of an existing office space, so we conducted before and after airborne noise reduction testing to quantify the improvement in noise reduction with the upgraded and changed wall assemblies. Other than that, our calculations and analyses were consistent with a new construction project as opposed to a renovation project.
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