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Beyond standard practice
You may assume that good acoustical performance is standard practice and will be delivered by the architect and mechanical engineer, but baseline designs often don’t meet the minimum acoustic requirements of LEED. To achieve this prerequisite you may need the help of an acoustics consultant, especially when project team members don’t have specific experience with acoustical performance. However, the architect or mechanical engineer can perform many of the needed calculations.
Keep background noise out of learning spaces
This prerequisite is intended to keep background noise out of learning spaces and prevent sound generated within a space from reverberating. Although this is a requirement of LEED for Schools projects, other projects can earn an innovation credit by...
Step-by-step credit help
Got the gist of the LEED credit but not sure how to actually achieve it? LEEDuser gives step-by-step help. Members get:
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Credit language straight from USGBC
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Your credit-by-credit reference library
Why waste time chasing down referenced standards and supporting resources when LEEDuser links you directly to the ones you need? LEEDuser has gathered all the best tools out there and organized them by credit for easy reference. Members get links to:
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Documentation Toolkit
In the end, LEED is all about documentation. LEEDuser’s Documentation Toolkit saves you time and helps you avoid mistakes with:
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81 Comments
Example L-16 Narrative
Does anyone have a good example of an L-16 Narrative accepted by USGBC? This is our first LEED project, both architecturally and mechanically. The Example narrative under Documentation Toolkit is outdated and insufficient. We have created a draft outline based on ANSI S12.60, but we really could use some type of reference for comparison.
P.S. No budget for an acoustic consultant. We would if we could.
Ceiling area
We have tectum panels (acoustic/insulation panels) above our beams. Do we have to add additional panels to the wall to make up for the ceiling area occupied by the exposed ceiling structure/beams?
It depends on what approach you want to take in the templates.
If you're going for the "all ceiling area = 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. 0.7 or better approach", then you would need to add panels. If you are willing to make RTReverberation time (RT) is a measure of the amount of reverberation in a space and equal to the time required for the level of a steady sound to decay by 60 dB after the sound has stopped. The decay rate depends on the amount of sound absorption in a room, the room geometry, and the frequency of the sound. RT is expressed in seconds. (ANSI S12.602002) calculations instead, you can make the calculation and you may, or may not, need to add more panels depending on the results.
If the space is greater than 20,000 cu. ft., however, the RT caluclation is your only option.
Submit in Design review but include manuf. cuts in Const Review
The prereq requires manufacturer cut sheets for the accoustic materials. This is a state funded project and we cannot single-source products - we must offer contractors at least 3 manufacturers to select from. We designed according to worst-case scenario of what could be selected. Once construction is done and we have the cutsheets for the actuall products used, I would edit any calcs as needed and provide the supporting cutsheets as part of the Constructin Submittal. If I explain this as part of Special Circumstances, does anyone know why I shouldn't go ahead and submit this as part of the Design Submittal? Or do I have to defer this credit until Construction Submittal since I don't have the cutsheets?
Hi Renee:
I don't think I can help you with this but I'll try to find someone who can. I'm only up on the acoustics requirements...not the submission processes.
Either way would probably work - You could wait until the Construction Phase and submit the final cutsheets, or you could try submitting what documentation you have for the design review.
In this case, you would probably submit the project specifications that clearly state the minimum performance requirements for the various materials, provide cutsheets from the three approved manufacturers to show several product options that meet the requirements, and provide the calculations that meet the requirements using those products.
You may still be asked to defer the credit until construction review, but at least you've had the opportunity to see if there are any other issues raised by the review that you might still have time to correct.
HVAC background noise from Kitchen hoods
We are working on a project which includes 2, 1350sf, culinary classrooms with many industrial cooking equipment in them. The kitchen exhaust rate are as high as 1,000,000 cfh for each of these classroom. The kitchen exhaust are demand controlled and work on a cascade mode with 6 fans.
Would these system be considered HVAC? There is no way to comply with the HVAC 45dBA limit in these classrooms including the kitchen exhausts. The only way around I see would be to include an override switch to turn the exhaust off in case quiet is required.
Hi Rodrigo:
I think you could make the case that these are not HVAC equipment and can be excluded if you can turn them off when they are not needed. My interpretation of LEED's explaination of "HVAC equipment" is equipment used for indoor 'climate control', and not specialty exhaust equipment. If they were designed to be on all the time, however, you might be able to make an argument that they need to be included.
LEED 2009 Music Schools
IEQ p3 is a requirement of LEED for Schools 2009. I would like to see if anyone has worked on documenting compliance for a school under the ANSI standards calculations.
Specifically, it seems rather difficult to achieve this credit in rooms for whicht he primary purpose is music education. The quality of education is inherently linked to the quality of sound in the room. The quality and quantity of materials needed to achieve the required reverb time can have adverse effects on the purpose of these rooms.
Has anyone had similar problems and if so found a soultion acceptable to all parties? We are well aware that LEED does not intend, rightfully so, to allow for every project to achieve every credit. However, to preclude whole projects based on their type, in this case music education, does not seem in keeping with the values set forth.
Hi Brian:
I completely agree. I have not heard of any other compliance approaches, however, that satisfy LEED's understanding of "core learning space" and a musician's actual needs. I hope you bring it to their attention, though! Keep us posted.
ANSI S12.60-2002 vs LEED Template
The ANSI S12.60-2002 standard requires that core learning spacesCore learning spaces are spaces for educational activities where the primary functions are teaching and learning and where good speech communication is critical to a student's academic achievement. These spaces include, but are not limited to, classrooms, enclosed or open plan), instructional pods or activity areas, group instruction rooms, conference rooms, libraries, offices, speech clinics, offices used for educational purposes and music rooms for instruction, practice and performance., between 10,000 and 20,000 cubic feet, have 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 that do not exceed .7 seconds. The LEED template states that
"The project team will demonstrate through calculations based upon the requirements of ANSI Standard S12.60-2002,
that each of the classrooms and core learning spaces has a reverberation
time of 0.6 seconds or less."
It seems that there is a discrepancy between the ANSI standard of .7 seconds and the template. The template requests .6 seconds, which is not what the standard references.
Has there a clarifying position been posted/released on this issue on the part of GBCI/USGBC?
Hi Brian:
I can't find in any of my templates where it says "0.6 seconds or less". All of the ones I've worked on, and the current credit requirements, say that the reverb time needs to meet the ANSI standard. It's possible that it's a new revision and a typo.
If you want a definitive answer, I would ask for clarification. I, personally, would follow the ANSI standard (as that is the original basis for the LEED requirements) and then explain what I did in the comment box.
Simplified Approach
I have a kindergarten, 7440sf, ground level only, all learning spacesCore learning spaces are spaces for educational activities where the primary functions are teaching and learning and where good speech communication is critical to a student's academic achievement. These spaces include, but are not limited to, classrooms, enclosed or open plan), instructional pods or activity areas, group instruction rooms, conference rooms, libraries, offices, speech clinics, offices used for educational purposes and music rooms for instruction, practice and performance. are on perimeter with windows. There is only a small road on the one side about 20 m away. There is no Mechanical Ventilation, just a radiant floor heating. The mechanical room is not adjacent to any learning space. All learning spaces have acoustic ceiling tiles with 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. 0.65, covering >80% of the ceiling. Ceiling height is at about 3.2 meters. The floor is laminated, and has a 8mm (3 inch) wood fiber board "Trittschalldämmung" Step absorption layer.
I've just been told we're not getting the usual acoustics calculation, because it was no longer required. This leaves me to do this on my own.
Q1) will it be accepted to do the calculation for one representative room? (there are 9 "learning" spaces)
Q2) Are other spaces, like corridors to be included?
Any other hints, suggestions and tips are appreciated. Good page btw.
Sorry, I've just checked the data sheet properly. On the data sheet for the acoustic panels it states that when the gap between hard ceiling to bottom of panel is 125 mm (yes) and the insulation is 60 mm (yes), then the 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. is 0.95. I also now under stand that the 20000 cf criteria is per room, not entire facility. that means I could use case 1, option 2. to prove my case. I just need to area weight the NRC value. for that i need a good assumption of the NRC for the normal ceiling tiles with the same ceiling depth and insulation dimensions...any ideas?
Woops! Just got the real value for the 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. of the normal tiles from the manufacturer...0.05. Ouch!
If the 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. compliant area does not cover the ceiling area for spaces < 20,000 cf, can one try with calculations which include walls, floors, windows, etc. to prove RTReverberation time (RT) is a measure of the amount of reverberation in a space and equal to the time required for the level of a steady sound to decay by 60 dB after the sound has stopped. The decay rate depends on the amount of sound absorption in a room, the room geometry, and the frequency of the sound. RT is expressed in seconds. (ANSI S12.602002) are compliant?
Yes, you can with ANSI S12.60-2002.
Hi Jean:
Sorry for the late response.
Yes, you can do individual calculations for 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 in each space instead of designing the ceiling area square footage of 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. 0.7.
I would do a calculation for each space unless they are identical.
Schools 2007 template
We are finishing up reporting on a school addition, and I have a few questions about the template. We are using the "calculation" option for both 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 and 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). In the stc spreadsheet, do you simply leave empty the cells that are n/a? I have the template filled out as complete as seems relevant, but the final page of the template does not show the point to be documented. So I am wondering if I am not filling out the blanks properly. Also the project has a library on the first level and classrooms above. There is no stc adjacency for these two types of spaces (I assume a library is not included because it is a quiet space by nature), so I assume it is not relevant then? Lastly, the library is quite large and falls outside the reverberation volume sizes in the template, does this mean it does not need to be included because of its size and/or type of use?
Hi Keelan:
This response is very deliquent (sorry about that).
Fill out 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) tables as complete as possible. Make sure to include roof, floor/ceiling, and exterior wall assemblies. I'm not sure why the template doesn't show the point documented.
A library is considered a core learning space, so treat the floor/ceiling adjacency as a learning space to learning space situation.
If the library (being a core learning space) is greater than 20,000 cu. ft. 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 would need to be 1.5 seconds or less. You can use the RTReverberation time (RT) is a measure of the amount of reverberation in a space and equal to the time required for the level of a steady sound to decay by 60 dB after the sound has stopped. The decay rate depends on the amount of sound absorption in a room, the room geometry, and the frequency of the sound. RT is expressed in seconds. (ANSI S12.602002) calculation spreadsheet in the template to calculate this.
Sorry again for the delayed response. For some reason I've stopped receiving notification of questions.
Mechanical Equipment - Alternative compliance path
We are currently working on a project wich the HVAC system selected was the split highwall, and there are 3 evaporation machines inside each classroom. The measurement taken inside the classroom has demonstrated a 47dBA level, which do not satisfy the pre-requisite requirements. However, we could not find available on Brazilian market equipments which could satisfy this noise limitation.
Is it possible to attend credit requirements by an alternative compliance path just stating that we could not find better equipments? If not, is it possible to reduce these 47dBa by installing sound absorptive panels inside the room?
Thank you for your time in advance!
Regards
Unfortunately, placing acoustic panels in the room probably won't reduce the noise levels from the mechanical equipment to any significant degree if the spaces are already meeting 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. If it were a highly reverberant room, it might be a little different, but it probably won't do anything for you in this case.
One option that might work would be to hang panels around the unit, making it semi-enclosed. You would need to work with the mechanical engineer to make sure that this wouldn't cause a problem for air flow or heating/cooling, however.
Also, I would try to work with the mechanical contractor or the manufacturer to see what can be done to reduce the noise levels of the installed evaporators. Maybe retrofitting spring or rubber isolators on the fans or reducing the speed that they operate at.
Lastly, I would also make sure that the noise levels were measured correctly. You're only 2 dB(A) off from the requirement. So close! Subjectively, this small of a difference would probably not be noticeable but LEED will probably stick to the 45 dB(A) requirement.
Good luck!
Daniel,
Thank you for your answer and solutions. Our team will have to evaluate deeply this case!
Pre K and K school question
I had perviously contacted GBCI regarding which rating system to use for this project, back in Summer 2010, which is a small Early Childhood Learning Center for 4 and 5 year olds and was told to use the LEED for Schools rating system. However, we have some conditions which make it difficult for us to fully meet the prerequisite requirements of IEQp3 Minimum Acoustical Performance. The biggest issue is that each classroom (there are four (4) total) has an en suite toilet room consisting of two toilet stalls and two sinks. The toilet room does NOT have a door to separate it from the classroom. This is a direct request of the school administration so that if a single child does have to use the toilet room outside of any dedicated "potty time" (there are seevral designated breaks during the day for all students to use the toilet), the teacher can monitor and if need be, assist, the child in the toilet stall, as well as keep an eye -or an ear, on the rest of the children in the classroom. Thus, there is no acoustical separation between the toilet room and the cassroom. There IS however, acoustical separation BETWEEN the toilet rooms in each classroom.
In addition, there are doors between each of the classrooms (the classrooms do not open off a corridor). Sometimes these doors remain closed, and sometimes they remain open, depending on the particular curriculuum being taught at the time. Again, this is part of the teaching "strategy" so to speak; there are times when all the classes are engaged with each other.
We are attmepting to met the requirements of this credit in other ways, such as meeting the minimum SF requirements of acoustical wall/ceiling material equal to the SF of the ceiling (minus lights/diffusersIn an HVAC context, diffusers disperse heating, cooling, or ventilation air as it enters a room, ideally preventing uncomfortable direct currents and in many cases, reducing energy costs and improving indoor air quality (IAQ). In light fixtures, diffusers filter and disperse light. and etc), as well as acoustically handle the HVAC and so forth. However, we are concerned that given the way this school is laid out and the fact that it is primarily early childhood learning, and not technically K-12 but a mix of pre-K and K, and given some of the conflicts we are running into between administrative requests/requirements for the classroom layout and the ANSI standard, that we will not meet this prerequisite and ultimately, not meet LEED.
I was just curious if anyone else had run into a situation such as this, and if so, any advice?
Thanks!
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) requirements you are referring to are in the Enhanced Acoustics credit IEQc9 in LEED for Schools 2009, not the prerequisite. These requirements were moved to the enhanced credit in the 2009 version to allow for open plan classrooms and other owner requested situations you are describing and still meet the prereq.
It sounds like you could meet the prerequisite requirements by designing for 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 and HVAC Background Noise but not the IEQc9 enhanced acoustics credit.
Thanks very much for your feedback and clarfiication Daniel. Re-reading the credit I see that I did indeed misread it and think I have a better handle on it now!
Existing classrooms on an addition
We have a project that is an addition to an existing school. The existing classrooms are included in the LEED boundary, but they have only had minor updates of mechanical systems. Does LEED for Schools 2007 EQ Prerequisite 3 allow for excluding these existing classrooms from 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) requirements?
My guess would be no. I haven't seen anything that would let you exclude them if they are part of the LEED boundary. It would probably be best to check with USGBC on the issue just to be sure.
I would agree with Daniel. LEED's default position would be to include those spaces in all credit and prerequisite requirements. You could conceivably argue for some exception through GBCI.
STC ratings for ceiling and floors?
hi,
We are using LEED for Schools 2007 and am looking for some information on where to find 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 ceiling and floor materials. I have contacted our ceiling rep and have been told that they do not test for STC ratings, only CAC Ratings. Can the CAC rating be used for this prerequisite?
Any information would be helpful!
Thank you!
Hi Tyler:
The short answer is no. 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) of your assembly will have to be estimated using the structure above the ceiling and the ceiling tile below. You might be able to find some documentation with testing done for a similar assembly or you might have to rely on a consultant to help you out with estimating an STC.
The long answer - Ceiling tiles have a Ceiling Attenuation Class (CAC) rating. The rating is used to give an idea about how well ceiling tiles will block sound at a condition where they are installed at a wall that doesn't extend to structure, between two seperate rooms. It doesn't really correlate to an STC rating.
Your STC rating will be mostly determined by the structure above the ceiling like metal deck with concrete on top. This provides the most mass in the assembly and will provide the sound isolation more than the ceiling tile will.
Hope this helps!
Providing supporting info for "common materials" (reverb calcs)
The LEED v3 Reference book provides a table of "common materials". The LEED Online template asks for supporting documentation for all the materials used as an acoustic material finish. If a "common material" doesn't have 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./sound abs coeff. info available can we still use it in the calculation? A gym floor can have VCT, but since it isn't used as an acoustic material and doesn't have NRC ratings, can we not use it in the calcs since the manufacturer doesn't have testing results? If so, what is the point of the "common materials" list?
You should include the surface areas and 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. values for all materials in the room, whether they are "acoustical" or not as all materials absorb sound to some extent and will have an effect on the calculation. For simplicity, I would keep it to the most significant materials in the room as little items will barely make an impact in the calculations. For example, rubber base molding may be in the room, but it's actual significance in the calculation will be negligible.
If you can't find the material you need in the common materials list provided, I would search online. I googled "absorption coefficient common materials" and several good sources came up. For supporting documentation, you could print out the table and attach it, although I've only ever included supporting documentation for actual acoustic products and not common building materials without any review problems.
Case 1 Option 1 - how to group rooms if identical construction?
Has anybody grouped room types for Table IEQp3-1? I am trying to understand exactly how to do this. Simplified scenario: The project has 10 small 100 SF rooms, exactly the same. Do I list the room type, and then the SF for ONE of the rooms (100 SF) or do I list the room type, and then list the COMBINED SF (1000 SF) for all the matching rooms?
If you have 10 rooms exactly the same, you would list them as "Room Type 1", for example, and then report the square footage for just 1 of the rooms (the other 9 would be exactly the same).
"mixed submittal" for EQ pre 3 ?
Curious if anyone has submitted a "mixed submittal" before either during the regular LEED submissions or during an appeal?
The project we're working on - some of the spaces comply with calculations, but not all. We're thinking about testing the non-compliant spaces and submitting both data. (More info from our acoustician below):
All core learning spacesCore learning spaces are spaces for educational activities where the primary functions are teaching and learning and where good speech communication is critical to a student's academic achievement. These spaces include, but are not limited to, classrooms, enclosed or open plan), instructional pods or activity areas, group instruction rooms, conference rooms, libraries, offices, speech clinics, offices used for educational purposes and music rooms for instruction, practice and performance. between 10,000 cu. Ft. and 20,000 cu. Ft. previously met the requirements via the “Calculation” method.
We plan to conduct in situ 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 measurements to verify compliance and it would seem unnecessary to re-confirm the compliant spaces . However, since the submittal form requires an “either or” selection, would we need to measure for both volume sizes or could we just measure for the non-compliant room size?
Hi Candice:
Sorry for the late reply. I haven't heard of anyone doing this and I haven't tried. You could either just proceed with this approach and write up what your intentions are in the Special Circumstances box in the template (personally, I don't see a problem with it) or you could ask USGBC for a definitive answer.
Hope this helps.
Total ceiling area vs "Room Area" in online template
Our ceilings are pretty basic - they are just sloped (from 9' to 11'). I find it odd that the credit calls out for calculations based on the ceiling area, but the online template uses the terminology "Room Area" instead. Since a sloped ceiling would have slightly more SF than the actual room area, does this mean I can't use the template and basically need to recreate the same template and call it an Alt Compliance Path? Has anybody asked clarification from USGBC on this? The online template clearly takes your provided Room Area, deducts your provided Area of Lights, etc to automatically generate the Ceiling Area. Anybody have the same issue?
Hi Renee:
Just input the ceiling area from your sloped ceiling in the box for "Room Area". The template is assuming a flat ceiling.
Daniel
I thought about that, but I wondered if it would cause a problem and result in an inquiry since the Room Area I would insert into the template would not match the SF of the actual room. This particular template isn't linked to another template(thus prohibitting the manual insertion of a different SF for a room), but the reviewer will obviously have access to other floorplans that would clearly show a different SF for the rooms I will list in the template.
I've personally always just inserted the room area, even if the ceiling was slightly sloped, just to make the template work. The sloped ceiling would only add maybe 2-4 extra square feet. I've never had an inquiry *knock on wood*.
I suppose you could do either and then leave a comment at the end of the worksheet explaining your method.
I recieved a response from USGBC!
Issue: Online the Table IEQp3-1 uses the term "Room Area (sf) in the built in template. Is the usage of the term "Room Area" to be taken literally and the online template can only be used by rooms with completely flat ceilings?
Response: Thank you for bringing this to our attention. The issue you mentioned will be corrected in the newest version of the form. In the meantime, please input your ceiling area in the “Room Area” column and explain this issue in the “Special Circumstances” narrative box.
Exclusion of lights, diffusers, grills... and radiant panels?
We have linear radiant panels near our windows and wondered if anybody had been able to justify excluding them from the % of ceiling area that is required to have an 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. of .70 or higher. They are not decorative elements and are providing heating into the room. I just wondered if anyone else has had a similar situation.
Classroom/Lab exhaust fans
For science labs that have room exhaust fans, how are they considered in the context of background noise? Are they excluded because of infrequent use, or are they typically required to be included? Same question for rooms with hoods in the lab. Thanks.
The language used in the background noise requirements is "HVAC systems" but we've taken that to mean the "always running in the background HVAC systems".
If there's a switch the instructor can use to turn the fans on when needed, we're assuming that they can always turn it off if they need it to be more quiet for instruction.
Metal Roof Deck
Does anyone know where I can find sound absorption coefficients for metal roof deck? NOT acoustical metal deck, standard metal deck. No manufacturer I can find publishes them nor are they in the LEED manual or any other acoustical books or websites I've looked at so far.
Absorption coefficients of 0.01 for all octave bands except for 2k, 4k and 8k, which is 0.02.
Credit Calculation Options
Our project's classrooms are all less than 20k cu.ft. and have "clouds" of acoustical ceiling tile (approx. 60% ceiling area) and either drywall soffit (approx 5%) or areas open to structural bar joists, metal deck, ductwork, etc. to be painted out white (approx. 35%). Realistically, the ACT clouds work better than a continuous ceiling because bot sides are providing sound absorption (I would think). We also will have carpet in most classrooms. With the large areas of glazing for daylight on one wall, marker and tack boards on another, and millwork covering a third, we could cover the remaining wall from floor to ceiling (not a realistic idea) with acoustical material and still not quite meet the requirement. Is our only option to perform the calculations under "CASE 2" as would be required for larger classroom spaces? Would this be acceptable to the GBCI reviewers? I don't see anywhere where they state you have your choice of CASE 1 OR 2. I really don't want to try to do the calculations, but since it is a prereq and not an option, do I have any other choices??
Hi Tim:
Once you get into the actual EQp3 template, you will find three options available:
-Complete an 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. Table to show that room materials with NRC 0.7 or higher are equal to or greater than the ceiling area.
-Perform reverb time calculations based on ANSI S12.60-2002
-Perform reberb time measurements after the room is built based on ANSI S12-60.2002
It doesn't sound like the first option is available for you, so you'll have to either make RTReverberation time (RT) is a measure of the amount of reverberation in a space and equal to the time required for the level of a steady sound to decay by 60 dB after the sound has stopped. The decay rate depends on the amount of sound absorption in a room, the room geometry, and the frequency of the sound. RT is expressed in seconds. (ANSI S12.602002) calculations or measurements to satisfy the prereq.
I don't know why all three of these items aren't listed in the LEED documentation but they are found in the template (at least it has been in the most recent projects I have worked on). Another caveat found on the template but not in the documentation reads "NOTE: if the core learning space is: a) not rectilinear, b) has a sloped or non-flat ceiling, or c) has a ceiling height that is 12 feet or more above the finish floor, then only the latter two options are available (ANSI Calculations or Measurements)."
Hope this helps,
Daniel
Daniel,
Thank you for your help on my question and all of the other questions you have helped on this Prereq/Credit.
Since my initial question, "value engineering" has eliminated our ceiling clouds. We can now achieve the requirements for 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 with a combination of suspended acoustical tile ceiling and some tackable acoustical panels to make up the difference for a small drywall soffit area.
Looking at the LEED Online Form for IEQp3, we must also address background noise with either (Path 1) a summary report of calculations based on ASHRAE chapter 47 [Upload L-15], or (Path 2) an acoustical design methodologies description to ensure compliance with ANSI S12.60 for background noise [Upload L-16].
To me, it appears that it would be easier to write a descriptive narrative of the space [L-16] than to perform calculations (No acoustical engineer on this project). Do you know where I can find an example? Am I correct to interpret that there are no required calculations for [l-16]?
The documentation toolkit on this website provides an example from your office (thank you!), but it clearly notes that it is not approved for LEED 2009.
Our mechanical engineering consultants are willing to help, but they continue to remind us that they are not acoustical engineers.
Any suggestions, directions, or examples would be very helpful. Thanks!
I’ve never done the second approach. I've always made the calculations and then provided recommendations to the project team to get the noise levels down to where they were needed.
In any case, a good place to start would be to get a hold of ANSI S-12.60 and follow it’s recommendations where you can, and then write a narrative stating what exactly you did…basically restating the recommendations you incorporated from ANSI in your own words. It doesn’t appear that any calculations are required, just that you follow the recommendations in the ANSI document and then just state what you incorporated into the design.
Hope this helps.
Where does it state that classrooms with sloped ceilings must use the latter two options (ANSI Calculations or Measurements) instead of using the Option 1 - Minimum 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.?
Also, when calculating materials within the room, some of the language within the credit states "specify ceiling and wall finish materials" and other language on this website states "ceiling, wall and floor material." Our classrooms will have carpet - can flooring material be used in the NRC calculations?
Thanks!
Gym Considered Ancillary Learing Space?
Per ANSI Standard S12.60-2002 Acoustical Performance Criteria Definitions I believe a Gym is considered an "ancillary learning space" and is not included as a "core learning space". Does anyone know if a Gym does in fact have to be included as a core learning space for the minimum acoustical performance prereq? Thanks!
There was a typo in the LEED prereq. The Gym is a regularly occupied ancillary learning space, not a core learning space.
The LEED Reference Guide for BD&C 2009 Edition lists the Compliant Space Types for IEQ Credits (specifically for schools) on page 404. The gymnasium is listed as a regularly occupied space: Classroom and Core Learning. This is the way the gym was designated in LEED for Schools v2.0 (2007) and we had to make it comply for EQp3 and EQc8.1-8.2.
My understanding is that this list trumps whatever is in ANSI because this is LEED's designation for all IEQ credits.
I am also interested to know about any documentation that defines a gymnasium as an ancillary space. We have a project with 2 existing gym spaces (originally) constructed with hard surface materials. Meeting a maximum R.T. of 1.5 is somewhat challenging and costly.
This issue was brought up once again on a project that was being funded by a government agency. The GBCI reviewer was insisting that the gymnasium be classified as a core learning space and therefore follow the requirements of IEQp3: Minimum Acoustical Performance. For the definitive word on classifying a gymnasium as an ancillary learning space follow this USGBC link - https://www.usgbc.org/FAQConsolidation/FAQ_Detail.aspx?Id=Q501400000009v...
We finally have an official answer on this issue! Kelly Karmel with Design Balance LLC pointed me to the November 1, 2011 BD+C Addenda (https://www.usgbc.org/ShowFile.aspx?DocumentID=10543, November changes only) or see all addenda at http://www.usgbc.org/DisplayPage.aspx?CMSPageID=2200#BD+C. A new definition for Ancillary Learning SpacesAncillary learning spaces are spaces where good communication is important to a student's educational progress but for which the primary educational functions are informal learning, social interaction or similar activity other than formal instruction. These areas include, but are not limited to, corridors, cafeterias, gymnasia, and indoor swimming pools. and a revised definition for Core Learning SpacesCore learning spaces are spaces for educational activities where the primary functions are teaching and learning and where good speech communication is critical to a student's academic achievement. These spaces include, but are not limited to, classrooms, enclosed or open plan), instructional pods or activity areas, group instruction rooms, conference rooms, libraries, offices, speech clinics, offices used for educational purposes and music rooms for instruction, practice and performance. are included. Gymnasia are listed in the Ancillary Learning Spaces list. The full definition is “Ancillary learning spaces are spaces where good communication is important to a student's educational progress but for which the primary educational functions are informal learning, social interaction or similar activity other than formal instruction. These areas include, but are not limited to, corridors, cafeterias, gymnasia, and indoor swimming pools.”
Mechanical Equipment generated sound levels
We have a schools project that is utilizing heat pumpA type of heating and/or cooling equipment that draws heat into a building from outside and, during the cooling season, ejects heat from the building to the outside. Heat pumps are vapor-compression refrigeration systems whose indoor/outdoor coils are used reversibly as condensers or evaporators, depending on the need for heating or cooling. In the 2003 CBECS, specific information was collected on whether the heat pump system was a packaged unit, residential-type split system, or individual room heat pump, and whether the heat pump was air source, ground source, or water source. units which are located in the individual classrooms in a mechanical closet. In order to meet the prerequisite the noise genreated from the HVAC system has to be below 45 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 manufacturer of the equipment does not have a published noise level to start running calculations. Is there an alternative compliance path such as sound metering?
No, I am not aware of an alternative compliance path in the LEED documentation.
Lights
Does anyone know if you need to subtract the area of the lights in the room from your ceiling area? The example on page 431 of the reference guide does not show any reductions for lighting.
Yes, you would subtract the area for ceiling lights and diffusersIn an HVAC context, diffusers disperse heating, cooling, or ventilation air as it enters a room, ideally preventing uncomfortable direct currents and in many cases, reducing energy costs and improving indoor air quality (IAQ). In light fixtures, diffusers filter and disperse light..
Naturally Ventilated Spaces
Is the requirement to reduce background noise only for noise from HVAC equipment? In naturally ventilated spaces, do we need to account for outside noise? For Credit 9 as well?
The LEED background noise requirement is for "HVAC systems". The referenced ANSI S-12.60 standard has requirements for other exterior noises and their impact on learning spacesCore learning spaces are spaces for educational activities where the primary functions are teaching and learning and where good speech communication is critical to a student's academic achievement. These spaces include, but are not limited to, classrooms, enclosed or open plan), instructional pods or activity areas, group instruction rooms, conference rooms, libraries, offices, speech clinics, offices used for educational purposes and music rooms for instruction, practice and performance. but this is not addressed in the LEED requirements.
I am not familiar enough with Credit 9 to comment on that.
Calculating reverberation time in room with daylight monitor
We are trying to calculate 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 in a classroom which has a daylight monitor in the ceiling. The monitor takes up about 30% the total area of the room Can we regard the "hole" in the ceiling as "air" for calculation purposes, since it does absorb some of the sound?
Hi Caroline:
No, I wouldn't add absorption for air in your calculations. I would include the interior surface materials of the monitor (I'm assuming glass and some amount of hard surfaces like gypsum or wood) and make sure to add the additional volume of the monitor space to the total volume of the classroom for the calculation.
Ok - Am I right in saying that there is no way to enter the data on the form online, and that I will have to do my own spreadsheet for the calculations and submit this through the "alternative compliance path"? This is because the online form does not make provision for entering the dimensions of an irregularly shaped volume. Also, If I do submit a spreadsheet, will the reviewer want the actual spreadsheet (to view the formulas) or will a pdf suffice?
Yes, you are correct. You will have to do your own calculations. I would submit a narrative along with an actual spreadsheet in case they had any questions about the formulas you were using.
LEED for schools 2007 EQp3
We are currently calculating our sound absorption coefficients for LEED for Schools 2007 EQ Prerequsite 3 and have formulated a couple questions.
1: Should we include built-in casework in our calculations? This would include a) subtracting their volume from the total volume of the room, b) including their surface area in the surface area calcuations, and c) determining the sound absorption coefficient for them.
2: Does anyone know of a reference with an expanded list of products and their sound absorption coefficients at 500, 1000, and 2000 Hz.? In addition to those listed in the LEED for Schools reference guide, we need coefficients for whiteboards, smart boards, etc.
Any help you can provide will be greatly appreciated! Thank you for your time in advance.
Hi Breana:
If there is a significant amount of casework, I would include it in the calculations. There is a point, however, where adding or subtracting items in the room will be negligible in determining 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. You might try modeling the room both ways to see if it is really necessary.
Some items like the whiteboards and smartboards simply do not have absorption coefficients because it costs money to get testing and the items aren't considered "acoustical". Similar to the casework, these items are probably negligible in terms of calculating the reverberation time and could be omitted from the calculations. I would just model the walls bare. If there are acoustic tests for items like whiteboards, I am not aware of them.
Hope this helps,
Daniel
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