IEQc7.1 requires that HVAC designs meet the requirements of ASHRAE Standard 55-2004, which deals with thermal comfort of building occupants. Specifically, ASHRAE 55 requires project teams to evaluate the ability of building systems to stay within a comfortable range of air temperatures, radiant temperatures, humidity, and air speeds during design weather conditions.
In most cases, designing a system that complies with ASHRAE-55 is standard practice and documentation is the only LEED-specific requirement for achieving the credit, so it should cost very little to earn. Earning this credit also sets the stage for you to earn IEQc7.2: Thermal Comfort—Verification.
Meeting this credit in naturally conditioned spaces is tricky, because it’s hard to ensure that thermal conditions remain within the requisite range. It’s really only possible in a few specific climatic regions with especially temperate conditions.
Mixed-mode spaces have a better chance. That is, naturally ventilated buildings can still meet the requirements of ASHRAE-55 if heating and cooling systems can keep indoor conditions comfortable year-round.
Certain spaces, such as greenhouses, gymnasiums, warehouses or manufacturing facilities often operate outside of the ranges defined by ASHRAE-55, which can put the project in conflict with designing either mechanical and passive systems that meet the credit requirements. If you have these spaces in your project, check with GBCIThe Green Building Certification Institute (GBCI) manages Leadership in Energy and Environmental Design (LEED) building certification and professional accreditation processes. It was established in 2008 with support from the U.S. Green Building Council (USGBC). on whether you can earn the credit through an alternative compliance path.
Regardless of the project type, considering target thermal comfort conditions—and designing to meet those conditions—early in the process is very helpful.
While the credit requirements, and the referenced ASHRAE standard, have not changed from older versions of LEED, the documentation requirements for the credit are now more stringent. Completing the new LEED Online credit form requires greater attention to detail and more supporting calculations, which set a higher bar for coordination among team members.
International projects can choose to demonstrate compliance with ISO 7730: 2005 and CEN Standard EN 15251: 2007, or another local equivalent if appropriate. Those following ISO 7730 and CEN Standard EN 15251 should provide the same level of documentation to meet the credit, including PMV or PPD calculations and an evaluation of local thermal comfort criteriaComfort criteria are specific design conditions that take into account temperature, humidity, air speed, outdoor temperature, outdoor humidity, seasonal clothing, and expected activity. (ASHRAE 552004).
Supply air volume (CFM) is different from linear air speed measured in feet per minute (FPM). Linear air speed in FPM is relevant to comfort requirements. This information can be derived from the diffuser throw value.
You can establish compliance based on an alternative method to ASHRAE-55 by identifying an equivalent source of thermal comfort recommendations (from an industry group or a specialized ASHRAE design guide).
For spaces such as warehouses that are not normally conditioned for comfort, the project team may include one or more of the following design alternatives: radiant flooring; circulating fans; passive systems, such as nighttime air, heat venting, or wind flow; localized active cooling (refrigerant or evaporative-based systems) or heating systems; or localized, hard-wired fans that provide air movement for occupants' comfort. See LEED InterpretationLEED Interpretations are official answers to technical inquiries about implementing LEED on a project. They help people understand how their projects can meet LEED requirements and provide clarity on existing options. LEED Interpretations are to be used by any project certifying under an applicable rating system. All project teams are required to adhere to all LEED Interpretations posted before their registration date. This also applies to other addenda. Adherence to rulings posted after a project registers is optional, but strongly encouraged. LEED Interpretations are published in a searchable database at usgbc.org. #10279 for more details.
Areas with a metabolic rate outside of 1.0-1.3 need to use a different tool to show compliance with ASHRAE-55 for that space. For spaces with metabolic rates below 1.0, utilize a tool like this one from UC–Berkeley rather than following the graphical method.
ASHRAE-55 was designed to accommodate activities up to 2.0 MET, but it’s possible to have higher MET levels in your project if you have a kitchen, fitness center, gymnasium, or warehouse. If this is the case, refer to LEED interpretation #10279 for guidance.
Most spaces with MET levels above 2.0 need to meet the cooling and humidity temperature set points for spaces with MET levels of 2.0 in order to meet the intent of EQc7.1.
In order to demonstrate compliance, project teams need to complete one of the following options:
According to the IEQ Space Matrix, spaces can be excluded from this credit if they’re non-regularly occupied and not normally comfort conditioned. For example, the storage area of a warehouse that’s accessed only intermittently is a good candidate for exclusion. However, any space that building occupants are expected to spend fifteen minutes or more at a time can’t be exempted.
The mechanical engineer and architect review ASHRAE-55 along with the credit requirements in the context of the project. ASHRAE-55 requires that you establish a comfort zone based on several variables that affect occupant comfort, and design mechanical systems to create thermal conditions within the comfort zone in each occupied space. Comfort zone calculations are based on the following variables:
Identify any unique programming or climate conditions that might make it tricky to get the credit. Fitness rooms, gyms, natatoriums, or very humid climates often create conditions that require special consideration.
Consider whether mechanical or natural ventilation will be used. When considering natural ventilation systems, review ASHRAE-55 section 5.3 for a description of the relevant requirements.
Include credit requirements in the Owner's Project Requirements for the commissioning credits EAp1 and EAc3.
Consider design implications of credit requirements early in program development. For example, if you are in a humid climate you may need additional dehumidification, which will affect your mechanical space requirements.
Consider how credit requirements will affect energy use and occupant experience, and whether programming is consistent with this credit. This credit is particularly worthwhile for any indoor environment in which occupant productivity is of key importance, and where occupants will benefit from optimized indoor thermal conditions.
Consider pursuing IEQc7.2: Thermal Comfort—Verification in combination with this credit. IEQc7.2 requires an occupant comfort survey after occupancy.
In order to achieve IEQc7.2, you have to achieve IEQc7.1, and you will have to install a permanent monitoring system to provide ongoing feedback about thermal conditions. If you are only pursuing IEQc7.1, there is no requirement for a permanent monitoring system. Residential projects cannot earn IEQc7.2.
This credit is generally a low- or no-cost credit. When it does add significant costs, that’s usually because it wasn’t considered early enough, so more equipment has to be added to provide, for example, additional dehumidification. An added cost like that could be prevented by designing the right system early in the schematic design.
In climates where either heating or cooling predominate, or in very humid climates, meeting ASHRAE-55 year-round might require additional system components. For example, spaces that may not otherwise be cooled—like gymnasiums—may need dehumidification or cooling systems to meet the ASHRAE-55 comfort criteria year-round.
It is always important to consider building orientation, the heat-island effect, insulation levels and other design considerations that will have a direct effect on thermal conditions and on the energy consumed to achieve those conditions, but these are not variables that are used as inputs for establishing a thermal comfort zone in ASHRAE-55, so they don’t directly affect whether or not you achieve this credit.
Review how building systems might contribute to or hinder achievement of this credit and review site-specific conditions that will affect building conditioning.
Determine which HVAC system types (mechanical, mixed mode, or natural) and system components can best meet the credit requirements and review any special programming requirements for ventilation, humidity and thermal conditions. For example, consider whether in-floor radiant heating is preferable to forced-air systems and which are best suited to a project’s programming and budget, and confirm that the system will be capable of operating within the established comfort zone.
When beginning to consider thermal conditioning systems, review which system types will not only meet credit requirements, but will balance performance, efficiency and cost while creating an optimal thermal environment in the given climatic region. In some regions, direct evaporative cooling may be an appropriate option, while in others dehumidification may be needed to meet the credit requirements. Review the feasibility of natural ventilation systems versus mechanical systems and consider their effect on energy use, programming, and credit achievement.
Review ASHRAE-55 section 6.1.1 to understand the credit documentation requirements. Assess these inputs:
Review how thermal controls and operable windows affect credit requirements. Projects in very temperate climates may meet the credit requirements through the use of operable windows exclusively, as long as mean monthly outdoor temperatures are between 50°F–92°F. See ASHRAE-55 section 5.3 for details.
Include credit-related information in the Basis of Design for the commissioning credits EAp1 and EAc3. At a minimum this should include:
Don’t assume that projects in Southwestern or other dry climates will automatically meet the humidity requirements of ASHRAE-55. These climates may have a significant number of days in which operating conditions will exceed the ASHRAE-55 requirements for humidity. Refer to the National Climatic Data Center for regional weather data (see Resources).
Natural ventilation designs are more significantly affected by climate and weather than mechanical systems. Although the methodology and inputs for documenting compliance are the same as for mechanical systems, in certain regions project teams using passive systems may have difficulty meeting ASHRAE-55 due to program constraints or seasonal temperatures that are outside of the prescribed range of 50°F–92°F.
Provide occupant controls for each individual space and avoid trying to normalize conditions in large areas or zones of a building. Separate controls will make it easier to achieve the credit in all spaces and improve occupant comfort while reducing unneeded energy use. For example, if there are ten adjacent offices, provide controls for each office separately. This strategy can also help you earn IEQc6.2: Controllability of Systems—Thermal Comfort. Added controls may increase upfront costs, but reduced energy consumption should help offset those costs.
Examine operating conditions to confirm how likely you are to meet the credit requirements.
Pick the best calculation method for demonstrating credit achievement. Document IEQc7.1 using a Predicted Mean Vote/Predicted Percentage of Dissatisfied (PMV/PPD) calculation, ASHRAE comfort tool, or a psychrometric comfort zone chart from ASHRAE-55. The method you pick will likely be determined by the preference and past experience of the mechanical engineer. (See the Resources tab for software options).
Include the following inputs on the LEED Online credit form:
Make design adjustments to meet credit requirements during design development, keeping in mind the potential impacts on energy use.
Make sure that HVAC engineers track and reconfirm credit-compliant operating ranges through the design development phase.
Make sure that the Basis of Design for commissioning reflects compliance with credit requirements and includes design assumptions and load calculations.
Provide ample thermal controls for building occupants. This will increase comfort and occupant satisfaction and will keep operating conditions within the prescribed ranges of ASHRAE-55.
Occupant access to thermal controls can help to meet the credit requirements on a space-by-space basis while increasing energy efficiency (by preventing conditioning of a whole HVAC zone rather than individual spaces) and increasing occupant satisfaction by giving people greater control over their thermal conditions. Increasing occupant satisfaction will help projects that are attempting IEQc7.2.
Variables like clothing levels and metabolic rates are not compliant or non-compliant, but are used instead to determine what appropriate operating ranges will be for a space. You have to show that your HVAC systems will create conditions within these operating ranges.
Confirm required calculations based on the finalized design by using a PMV/PPD calculation, the ASHRAE comfort tool, or psychrometric zone chart.
Complete all required LEED documentation and upload to LEED Online:
Include ASHRAE-55 related performance requirements in the construction specifications.
Provide LEED documentation requirements in the specifications, including the LEED requirements for information contained in O&M manuals and designating the contractor as the signatory for this credit.
Include LEED references in the drawings and specifications where appropriate.
Make sure that contractor-related LEED documentation requirements and activities are in the specifications so that they are accounted for in estimates and bids.
You might want to defer documenting this credit until the construction submittal to confirm the appropriate system installation and inclusion of the required O&M information.
Develop the Systems Manual, O&M manual, or equivalent. Ensure that the O&M manual includes the following:
The contractor is the signatory for this credit, and has to confirm compliance with the bullets above and sign off on this credit.
Be certain that the commissioning agent reviews the OPR and BOD and confirms that system design and installation will meet the credit requirements for operating ranges.
Set up building operations training to ensure that on-going operation of HVAC systems will meet ASHRAE-55, using the O&M manual for reference.
Encourage general contractors and mechanical contractors, commissioning agents and building operators to review O&M materials and maintenance procedures together to confirm that system performance and maintenance meets the original design intent.
Set up training with O&M staff on proper operating procedures.
Excerpted from LEED 2009 for New Construction and Major Renovations
To provide a comfortable thermal environment that promotes occupant productivity and well-being.
Design heating, ventilating and air conditioning (HVAC) systems and the building envelope to meet the requirements of one of the options below:
Meet the requirements of ASHRAE Standard 55-2004, Thermal Comfort Conditions for Human Occupancy (with errata but without addenda1). Demonstrate design compliance in accordance with the Section 6.1.1 documentation. Projects outside the U.S. may use a local equivalent to ASHRAE Standard 55-2004 Thermal Comfort Conditions for Human Occupancy Section 6.1.1. [India ACP: Thermal Comfort]
Projects outside the U.S. may earn this credit by designing heating, ventilating and air conditioning (HVAC) systems and the building envelope to meet the requirements of International Organization for Standardization (ISO) 7730: 2005 Ergonomics of the thermal environment, Analytical determination and interpretation of thermal comfort using calculation of the PMV and PPD indices and local thermal comfort criteriaComfort criteria are specific design conditions that take into account temperature, humidity, air speed, outdoor temperature, outdoor humidity, seasonal clothing, and expected activity. (ASHRAE 552004); and CEN Standard EN 15251: 2007, Indoor environmental input parameters for design and assessment of energy performance of buildings addressing indoor air quality, thermal environment, lighting and acoustics.
1 Project teams wishing to use ASHRAE approved addenda for the purposes of this prerequisite may do so at their discretion. Addenda must be applied consistently across all LEED credits.
Projects in India may meet the desired comfort criteria specified in the following as a local equivalent to ASHRAE 55-2004:
Establish comfort criteriaComfort criteria are specific design conditions that take into account temperature, humidity, air speed, outdoor temperature, outdoor humidity, seasonal clothing, and expected activity. (ASHRAE 552004) according to ASHRAE 55-2004 (with errata but without addenda) that support the desired quality and occupant satisfaction with building performance. Design the building envelope and systems with the capability to meet the comfort criteria under expected environmental and use conditions. Evaluate air temperature, radiant temperature, air speed and relative humidity in an integrated fashion, and coordinate these criteria with IEQ Prerequisite 1: Minimum IAQIndoor air quality: The quality and attributes of indoor air affecting the health and comfort building occupants. IAQ encompasses available fresh air, contaminant levels, acoustics and noise levels, lighting quality, and other factors. Performance, IEQ Credit 1: Outdoor Air Delivery Monitoring, and IEQ Credit 2: Increased Ventilation.
This updated version of the spreadsheet categories dozens of specific space types according to how they should be applied under various IEQ credits. This document is essential if you have questions about how various unique space types should be treated. Up to date, 2nd Edition.
This spreadsheet categories dozens of specific space types according to how they should be applied under various IEQ credits. This document is essential if you have questions about how various unique space types should be treated. This is the 1st edition.
This ASHRAE standard defines the criteria for human comfort that is followed to design mechanical systems.
Information about the ASHRAE Thermal Comfort tool with ordering information.
Information about how to use psychrometric charts.
Download free psychrometric chart software.
Free, easy-to-use program from UCLA that displays climate data in the form of psychrometric charts, among others.
The National Climatic Data Center provides regional weather data that you can use to assess your climate relative to ASHRAE-55 requirements.
These sample documents, from a LEED for Schools 2009 project in Mass., demonstrate how to document that the project meets the thermal comfort design requirements of ASHRAE 55. LEEDuser thanks Christopher Schaffner of The Green Engineer for providing this sample.
Sample LEED Online forms for all rating systems and versions are available on the USGBC website.
Documentation for this credit can be part of a Design Phase submittal.
Kindly clarify the following query regarding Thermal Comfort Design Alternative Compliance Path for projects in India.
In ACP it is said that projects shall meet the desired comfort conditions as specified in National Building Code of India (NBC).
1. For mechanically conditioned buildings, NBC 2005 Part 8, Section 3 - Table 2
2. For naturally conditioned buildings, NBC 2005 Part 8, Section 1 - Table 9
As per NBC, for mechanically ventilated industry and other specific applications, the design conditions shall be per user’s requirement. So, can we consider that the designed condition meets the requirement of Thermal Comfort Design credit even if doesn’t comply with ASHRAE 55 standard. The design condition for the space is 32±1 0C and 65% RH.
I'm currently working on a project of a huge office building with a small area for retail and a restaurant. The restaurant has a commercial kitchen which, per LEED interpretationLEED Interpretations are official answers to technical inquiries about implementing LEED on a project. They help people understand how their projects can meet LEED requirements and provide clarity on existing options. LEED Interpretations are to be used by any project certifying under an applicable rating system. All project teams are required to adhere to all LEED Interpretations posted before their registration date. This also applies to other addenda. Adherence to rulings posted after a project registers is optional, but strongly encouraged. LEED Interpretations are published in a searchable database at usgbc.org. 10279, needs to comply with ASHRAE 55 - 2004 for thermal comfort design (to achive the IEQc7.1 point). As per section 188.8.131.52 of ASHRAE 55 - 2004 (Computer Model Method for General Indoor Application), I'm using the berkeley.edu comfort tool.
However and unlike other spaces, I understand that the air temperature and mean radiant temperature are far from being similar one to another for this specific case.
1_ What input data for air temperature and for mean radiant temperature should I use for a typical commercial kitchen?
2_ Can anyone advise me on a reliable source for this values?
Thnaks in advance!
We've struggled with this situation as well. The credit language says you're supposed to consider radiant temperature asymmetry which usually gets ignored. The actual cooking surface temperatures introduce radiant asymmetry to the occupants which leads us to believe that the only way to document air temperature and MRT is with a CFD analysis.
There's actually an ASHRAE research project which suggests that ASHRAE 55 is not appropriate for commercial kitchens. ( http://www.tandfonline.com/doi/abs/10.1080/10789669.2013.840494 )
In any case, we've been successful with an alternative compliance approach for the kitchen area. Following LI #10279, we had the engineers provided a narrative describing how the Kitchen systems have been designed to maintain acceptable comfort conditions to meet the credit intent.
"The design of the HVAC system for the kitchen in the XXX Dining Hall used a different approach than the rest of the building because it operates separately from the other spaces. A 100% outdoor air makeup unit provides effective ventilation and includes a hot water heating coil that will maintain space temperature heating set points as needed.
During design, the team and the building owner determined that a cooling system would not be required for the dining hall kitchen. Due to the negative pressurization of the kitchen from the hoods and dishwasher exhaust, air will be drawn in from adjacent spaces on the open cooking line and the dish room to provide cooling. At full operating conditions, expected heat gains in the space from people and lighting will be offset by the amount of air being drawn in. It is estimated that the temperature of the kitchen will be slightly higher than the temperature of surrounding spaces in the summer months when usage is low. "
I've got a project with the same issues. I am not sure if I get you right. I would think as well that the cooking equipment's surface temperature needs to be included, which would require CFD.
In you alternative compliance path, did you include a CFD or just the sample language above? What was the temperature of the adjacent spaces? Was that language above accepted by reviewers or did you submit more complex calculations as well?
Do elevators halls need to be vefified for thermal comfort?,
My understanding is that they are "not regularly occupied" spaces, so they don´t, please I will appreciatte any discussion on this affirmation,
I don't think it is necessary to ventilate for thermal comfort per say, but you should check the ventilation requirement as per ASHRAE 62.1 for circulations.
Thank you for your response,
We did, we are supplying fresh air in rates calculated by ASHRAE 62.1, but this outdoor air is not cooled nor heated,
So, we can say we are ok with IEQ_c7.1?
No, it seems you also need to comply with the thermal comfort requirement for this space also. I recommend you download a tool called SpaceMatrix, and there you can see what requirements apply to each space.
As of now we are using berkeley.edu/comfort tool for thermal comfort compliance for both A/c & Non A/c area
But we use PMV method for A/c area and adaptive method for Non A/c area (Ventilation area) because we don't have RH & air speed details for ventilation area
1.Is it correct to use Adaptive method for ventilation areas
2.Can we enter space temperature as operative temperature in above tool
3.If the Adaptive method is not applicable means which area can be used in adaptive methods
Kindly advise how to use this tool for both A/c and Non A/c area
What are the suitable spaces for PMV & Adaptive methods respectively
awaiting for you reply
Generally passively conditioned areas can only comply by the adaptive method as too many hours will fall out of range using conventional approaches.
Operative Temperature is not the same as Space Temperature, but it may be close enough, unless you are doing something unusual.
we are using (http://smap.cbe.berkeley.edu/comforttool) this link for thermal comfort results but we use PMV method for A/c areas and Adaptive method for ventilated areas (due to lack of date such as RH and airspeed)
1.Is it correct to use adaptive method for ventilation area (Non A/c)
2.Can we use space temperature as operative temperature
3.if the adaptive method is not used means, what is suitable usage area for adaptive method
Kindly advise which method(PMV & Adaptive) is correct for which area (Ac & Non - Ac)
I had a comment on a LEED review in IEQc7.1 to provide a summary table which lists the heating and cooling design parameters used for each space type and the Room Input Reports for each space type. My question is, what is a Room Input Report and what should it look like?
Interesting, I have not seen that asked for yet on projects I have worked on. Basically, this credit requires you to design to meet the comfort conditions of various space types, and to give what those parameters should be. A Room Input Report would come from the energy model, showing all the information used for each space in the model...including the set points used in the simulation. So they are basically asking you to prove that you used the set points that you claim for this credit in the energy model. Make sense really.
Does raise the question (and I would like Marcus to chime in if he monitors this thread), could you make a case (or are you allowed) to have different set points between the baseline and the design models? I always thought that the set points had to be the same, but if you made changes in your design to provide comfort in a wider range of temperatures, could you claim that in the performance?
It sounds like perhaps the compliance option selected was load calculations and what the reviewer needs to see is that the appropriate occupancy levels and occupant loads (sensible and latent heat gains) were used for sizing the equipment. As for what report should be submitted, it depends on the software used, but typically this information can be found in the room input summary reports (as noted in the comment).
As for the question for Marcus, he is busy (and limits his efforts to the EA credits) so the quick answer is that you are correct - the space temperature settings in the energy models must be the same in the Baseline and Proposed case. Any savings associated with a wider comfort range would need to be submitted as an exceptional calculation.
My project is a Housing Authority remodel that has to meet Energy Star, thus be ASHRAE 55 compliant. Of course our budget is limited, but we are reusing perimiter HW finned tube in one of the buildings and adding Cooling only PTACs. The other building is EBB heat and adding PTACs as well. All apartments are one-bedroom and the PTAC will be placed in the living room with the intent that the adjacent bedroom is conditioned by the living room unit (remember budget constraints!). Fresh air is either windows or a central unit dumping into the corridors. My questions are as follows:
1.) Can I even do this with a PTAC and then if so can I do it with a single PTAC serving 2 rooms? It is definitely individual control, but multiple rooms, air speeds, humidity, etc are what they are based on the unit running per room temps.
2.) Am I reading correctly that radiant systems prevent me from using operative temps all together?
3.) If so, what programs are best recommended to figuring Mean Radiant Temps? (I do not believe my typical load program gives me this data)
I think you have a more basic issue. If you are relying on the windows for ventilation, the GBCIThe Green Building Certification Institute (GBCI) manages Leadership in Energy and Environmental Design (LEED) building certification and professional accreditation processes. It was established in 2008 with support from the U.S. Green Building Council (USGBC). reviewers will only grant this credit if you can show comfort and ventilation can be met at the same time (i.e. with the windows open).
David, I agree with Christopher's comment in terms of your first issue to address. However, it sounds like you may have a central ventilation system using corridor pressurization. In that case, I'll address your items 2 and 3.
2) If you have radiant heating/cooling, then you cannot assume that the operative temperature is equal to the space air temperature -- see ASHRAE 55 Appendix C. The operative temperature must then be calculated using the formula in Appendix C using the air temperature and mean radiant temperature (MRT).
You've described the heating as HW finned tube and EBB and the cooling as PTACs, which are all either free or forced convection. Do you have any radiant heating or cooling?
3) I use the ASHRAE Thermal Comfort Tool (purchase from ASHRAE, discount for members) which does include a MRT calculator. I don't know if any other software tools have the same. The CBE Thermal Comfort Tool requires manual input of either the operative temperature or air temperature and MRT.
You could also do a manual MRT calculation using the equations provided in Chapter 9 of the ASHRAE Fundamentals Handbook -- there is one for seated and one for standing occupants.
1.What is a MET rate for Sewing machine workers (Jeans cloth stitching)
2.Is it acceptable to get this credit using Design alternative (HVLS Fans or Evaporative Cooler)
3.How we achieve this credit for ventilated Office spaces (MET - 1)
1. Probably between 1.2 and 2.0, depending on whether they are seated or standing. Look at ASHRAE 55 Appendix A for a good table of MET rates. Pick the one that most closely fits.
2. If the comfort conditions can be met, the technology does not matter.
3. You need to be able to show that space conditions fall within the comfort zone. Not sure what you are asking exactly - read the tips above.
In ASHRAE 55, Section 5.3 Optional Method for Naturally Conditioned, it mentions that "There must be no mechanical cooling system for the space".
We are working on a residential project where each apartment has its individual conditioning system, it provides heating and cooling, but the ventilation is through operable windows.
Are we not elegible for this credit because of the conditions?
Your are not eligible to comply using Section 5.3. As the standard states, when a building has no mechanical cooling "occupant's thermal responses...may differ from thermal responses in buildings with centralized HVAC systems". Since your building has cooling, one would not expect this adaptive thermal comfort effect.
You can still show compliance following the mechanical cooling pathway. (i.e. the standard path)
Thank you Christopher, this helps a lot!
I have the annual hourly mean radiant temperature results (from the energy model simulation). I'm wondering what MRT you have used in the past if you have all of these figures? How do you choose the MRT figure when you have all this data available for the entire year?
You probably have more info than you need to document the credit. ASHRAE 55 uses the "operative temperature", which is a combination of air temperature, mean radiant temperature (MRT) and other factors. Unless you've got a space with a MET rate above 2.0, showing that air temperature and humidity stay within the comfort zone is usually sufficient to document the credit.
I have read the definition of inactive storage in the space-matrix spreadsheat. However, it is not clear to me if I can consider a storage space that is used once a week as "inactive storage".
By the name "inactive storage" it sounds like it can be excluded. You should look at what kind of activity and occupancy occurs when it is "used once a week", and confirm that it is not a regularly occupied space.
Thanks Christopher, they take aggregate material out of this room to make concrete strength tests.
You'll need to make a better argument than that if you want to exclude the space.
"they" - how many people? How long are they in there? How often?
You need to prove that the space is not "regularly occupied". The definition of regularly occupied is an area "where workers are seated or standing as the work inside a building". If it is part of someone's regular job to spend time inside this room it is "regularly occupied" and must be included.
Does anyone know if is OK to adhere to ASHRAE 55-2013 instead of ASHRAE 55-2004?
LEED InterpretationLEED Interpretations are official answers to technical inquiries about implementing LEED on a project. They help people understand how their projects can meet LEED requirements and provide clarity on existing options. LEED Interpretations are to be used by any project certifying under an applicable rating system. All project teams are required to adhere to all LEED Interpretations posted before their registration date. This also applies to other addenda. Adherence to rulings posted after a project registers is optional, but strongly encouraged. LEED Interpretations are published in a searchable database at usgbc.org. #10416 allows ASHRAE Standard 55-2013 to be used for both LEED 2009 and LEED v4. I'm in Canada, and there is a similar interpretation (CIRCredit Interpretation Ruling. Used by design team members experiencing difficulties in the application of a LEED prerequisite or credit to a project. Typically, difficulties arise when specific issues are not directly addressed by LEED information/guide #859) that allows LEED Canada projects to adopt more recent versions of ASHRAE standards and applicable addenda for any credit.
Our project is sewing factory It is not fully conditioned (A/C & Ventilation)
1.A/c for Office area
2.Fans (Exhaust, Fresh air, HVLS fans) for Production area
We use HVLS fans for lieu of A/c
Is it possible to attend this credit using HVLS fans in Ventilated Areas
HVLS fans are Circulating fans are not
It sounds like you might have a hard time complying. What are the temperature and humidity conditions in the production area?
Temperature is about 31 deg C and above and MET rate is 2+
Is it possible to get this credit using Design alternative (MET - above 2)
31 C = 88 deg F. That's warm. With a MET rate of 2 I don't see how you can possibly comply. What you have is a literal sweat shop.
My project has apartments and penthouses on the top. Engineers design VRF with thermostat and residents can control their comfort thermally. I'm wondering how to document for this credit: do I just need to write a narrative that thermostat is available in every room and residents can control air speed, humidity, temperature to match their clothes and activities in the room so resident can have the best thermal comfort. Or I have to show PMV/PPD result for residents. If I have to do so, I will use thermal calculation tool for appartment as a whole or for every single room (bedroom, living room, kitchen room.
You should be able to comply. Either do a calc for a typical unit, or show that the MET rate allows you to use the "standard" comfort zone, and that the VRFs can meet temperature and humidity requirements.
Should also document the air speed - VRFs can be "blowy"
We have a fully naturally ventilated open cafeteria (No walls, only roof mounted on top of columns) that is occupied only for max about 2 hrs a day during 1hr lunch break and two tea breaks.
Do you think we should include this space in thermal comfort documentation or can we exclude it due to very low usage?
You are correct that this area may be excluded, but not for the stated reason. As described, the cafeteria is not an interior so ASHRAE 55-2004 does not apply. Section 2.3 states, "This standard specifies thermal environmental conditions...in indoor spaces designed for human occupancy..." I suggest you identify the space as exterior, explain the intended use and occupant expectations for an exterior cafeteria and this should satisfy the intent of the credit as well as the reviewer.
Thank you very much.
So how do you define an interior space? Have you come across any standard definition or is it a subjective judgement? For example if we have half walls instead of no walls at all, does that become an interior space? Or if we have 3 sides fully open with no walls and one side has a wall with standard window, is that an interior space or exterior space?
Each of the ASHRAE standards has a definitions section (Section 3) and typically words defined in this section are italicized. There is no definition for interior or indoor space in either ASHRAE 55 or 62.1, but 90.1 defines a space as a fully y enclosed space. Without walls, the area is not a space. Your description seems to align with what I would call a pavilion (with or without the knee walls) which is definitely exterior space. If there were folding solid doors that could be open, the space would be considered to be interior and you would have to include the space. If the doors were only there for security purposes during unoccupied periods, you could argue that the space is not enclosed when occupied.
Hi there, I'm working on a office project with Chilled beams and Displacement ventilationA system in which air slightly cooler than the desired room temperature is introduced at floor level and is lifted up by warmer air to exhaust outlets at the ceiling, increasing air circulation and removal of pollutants.. We are planning to do CFD simulations to analyse radiant temperature asymmetry , drafts vertical air temperature difference, etc. Would this be enough to document compliance with this credit?
The CFD will show temperature and air speed, but you also need to show that those conditions fall in the comfort zone based on activity and clothing expected.
I am dealing with a complex commercial center containing a indoor ski center and a ice rink, which clearly fall outside of the comfortable zone of ASHRAE 55. The feedback from GBCIThe Green Building Certification Institute (GBCI) manages Leadership in Energy and Environmental Design (LEED) building certification and professional accreditation processes. It was established in 2008 with support from the U.S. Green Building Council (USGBC). required us to provide DESIGN strategies to improve thermal comfort and meet the intent of this credit. Does anybody know any design strategies that can be applied to ski center and ice rink?
Design recommendations for ice rinks are included in the 2015 ASHRAE Applications Handbook, Chapter 5 (as well as earlier versions), but indoor ski centers seem be too new/uncommon to have standard design recommendations. However, it would seem reasonable that the same criteria (or similar) would apply for both since they depend on keeping the space cold enough to maintain snow/ice and the occupants have an expectation of cold conditions within the space. Describing how the design aligns with the recommendations in the handbook or similar generally accepted standard should suffice. Also LEED InterpretationLEED Interpretations are official answers to technical inquiries about implementing LEED on a project. They help people understand how their projects can meet LEED requirements and provide clarity on existing options. LEED Interpretations are to be used by any project certifying under an applicable rating system. All project teams are required to adhere to all LEED Interpretations posted before their registration date. This also applies to other addenda. Adherence to rulings posted after a project registers is optional, but strongly encouraged. LEED Interpretations are published in a searchable database at usgbc.org. 10279, although not specifically related to your issue touches on spaces that are not generally comfort conditioned. Keep in mind that different explanations may be required for spectator areas; the activity level is different and often radiant heat is provided for additional spectator comfort.
I agree with Cam that first looking for guidance from ASHRAE on what would be the standard of care for that kind of application. From personal experience with ice rinks or hockey arenas, it is all about humidity control. This is both for the ice and the spectators. Radiant heat works to help around the outside of the ice, but you have to control the humidity to feel comfortable.
I am dealing with a complex commercial center that contains a ski center and a ice rink, which clearly fall outside of the comfortable zone of ASHRAE 55. The feedback from GBCIThe Green Building Certification Institute (GBCI) manages Leadership in Energy and Environmental Design (LEED) building certification and professional accreditation processes. It was established in 2008 with support from the U.S. Green Building Council (USGBC). requires us to provide DESIGN strategies to improve thermal comfort and meet the intent of this credit. Does anybody know any design strategies that can be applied to ski center and ice rink?
I am working on a project in Dubai, the design engineer has performed a psychrometric analysis using 46.0°C (DB) and 29°C (WB) for climatic design cooling conditions. The project space is cooling only, as there are no heating requirements in Dubai. How would this be documented on the LEED IEQc7.1 form? Would we use the dry bulb or wet bulb temperature for the cooling climatic design condition? Do we leave the heating design condition field blank, and write a narrative explaining the extreme climate where the project is located?
In a current project in Nigeria there's no heating requirement. We filled the cooling design condition in the heating section as well and commented this in special circumstances.This was ok for the reviewer.
The temperature that should be entered is the Dry Bulb temperature. A brief narrative including the average low temperature should confirm that no heating is required.
Thank you for the feedback Jens and Cam!
We wish to pursue the credits IEQ 7.1 & 7.2 , the space is auditorium seating with a dance floor for Wedding .(Area - 5300 sq ft , Occupancy 370 People), having office spaces on other floors . Location - Cincinnati Ohio
1. What MTR should to be assumed .? Not sure of the % time for standing, seating and dancing. My MTR is going above 2.0, How to show the thermal comfort in that case.
There is a cafeteria where the HVAC designer of record intends to have it naturally conditioned. According to ASHRAE 55-2004, naturally conditioned spaces must be equipped with operable windows that open to the outdoors and are readily adjustable by the occupants of the space.
The cafeteria in question is equipped wtih operable windows. Nevertheless, the resultant indoor operative temperature will likely be beyond the acceptable band in figure 5.3 of the standard.
Is supplemental evaporative cooling, which counts chiefly on fans, together with evaporation effect of water, construed as a viable alternative for naturally conditioned spaces?
Thank you very much in advance.
Recently, i am working for a complex commercial project including a ice rink and a ski centre.
These two spaces are acturally very special, whether we can exclude them when we consider thermal comfort ?
Leanne, to my knowledge there is no exclusions in the credit, even though ASHRAE 55 has definite limits. So if the space falls outside of ASHRAE, then you must demonstrate comfort in some other way, either by standard of care, studies that might substantiate conditions, or something else. You might find some industry standard that addresses what the standard of comfort is. However, this is not a sure thing at all.
But short answer is no, you cannot exclude any space to get the credit.
Maybe use this and build a custom ensemble with very high CLO ( thick jacket, long johns, etc.) http://smap.cbe.berkeley.edu/comforttool
I think with high CLO and high MET you can be comfortable even in cold areas. This tool might help make the case to the LEED reviewers but it only goes down to dry bulb temperatures of 10 degrees C/ 50 degrees F. http://smap.cbe.berkeley.edu/comforttool A mechanical engineer can probably get more into the logic behind all that. Definitely provide a written explanation of your strategy with your preliminary LEED design submittal. We've had to provide a lot of back up data on our projects with Natatoriums because of the unique space conditions.
I'm looking for clarification on how to handle air speed for floor 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. at the perimeter of a large lobby space. At these locations the air speed will be high but the majority of the lobby space and where most occupants are will be low velocity. Should the air velocity be based more on this area w/ most traffic/occupants rather than at the perimeter?
Also, there are large amounts of glazing and not sure if calculation of mean radiant temperature is typically required in such cases?
In lobbies it is often quite difficult to specify where people will be. I would position them in the most typical positions for the evaluation. This will then allow you to determine the velocity of the air where they are.
Radiant mean temperature is absolutely required, which is why you have most likely positioned the 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. to be at the perimeter. So, you will have to evaluate that issue, and air is often difficult to provide this comfort. We have seen radiant floors used in heating climates to great affect in these kinds of spaces where more conventional radiation would not be allowed for aesthetic reasons. While I have not gotten to do this myself, I think the same floor tubing could be used to provide a cool slab in summer too, but you have to be very careful to control the temperature to stay above the dew point of the air. I have heard of this working in coordination with the air quite well, just not on a project that I have been directly involved with.
The project I'm working on is an ice-cream factory which will have staff working for short spells (but more than 15min) in spaces cooled to down to -40C. This is obviously outside the range of ASHRAE 55-2004 but I would like to know if it is still possible to get compliance if local regulations regarding workspace environments are met?
The project is in South Africa and there is a local regulation called the "Environmental regulation for workplaces" which is enforced by the Department of Labour. It specifies the amount of time that staff may work in sub-zero temperatures and the type of protective clothing that must be worn.
Do you know if this credit is achievable?
If so, how should it be done?
Many thanks for any advice you can offer.
Interesting question. This would definitely deserve a conference call with the reviewer team even before you submit. I know of cases where there are situations that ASHRAE 55 does not apply, and GBCIThe Green Building Certification Institute (GBCI) manages Leadership in Energy and Environmental Design (LEED) building certification and professional accreditation processes. It was established in 2008 with support from the U.S. Green Building Council (USGBC). has accepted alternative ways or practices to show compliance. Your logic seems good, but having that conference call would be the best way to move forward.
You should also take a look at LEED InterpretationLEED Interpretations are official answers to technical inquiries about implementing LEED on a project. They help people understand how their projects can meet LEED requirements and provide clarity on existing options. LEED Interpretations are to be used by any project certifying under an applicable rating system. All project teams are required to adhere to all LEED Interpretations posted before their registration date. This also applies to other addenda. Adherence to rulings posted after a project registers is optional, but strongly encouraged. LEED Interpretations are published in a searchable database at usgbc.org. 10279. Although it is primarily about spaces with elevated metabolic rates, it touches on compliance for spaces that are not normally comfort conditioned and could be helpful.
Short answer is that I think you cannot meet the credit.
We are looking for some advices on thermal comfort compliance upon IEQc7.1.
Our project is an industrial building with office and production spaces located in climate zoneOne of five climatically distinct areas, defined by long-term weather conditions which affect the heating and cooling loads in buildings. The zones were determined according to the 45-year average (1931-1975) of the annual heating and cooling degree-days (base 65 degrees Fahrenheit). An individual building was assigned to a climate zone according to the 45-year average annual degree-days for its National Oceanic and Atmospheric Administration (NOAA) Division. 6. There are heating and ventilation systems provided for the winter. For the summer it is designed that these ventilation systems to operate based on Outdoor air (100%) only. No cooling coils are provided. All spaces have operable windows, but without any control on their functioning.
While applying the ASHRAE Std. 55- 2010 Comfort Tool software, we are facing the following problems:
1.) Since there is no cooling system for the summer, the spaces presumably are understood as naturally conditioned. However we cannot use the 5.3. Optional Method as the building doesn’t meet all necessary requirements – the lowest outdoor temperature is -15.9 F and we have activities with MET>1.3. The question for this issue is: For the summer period, what space temperature should we enter in the Comfort Tool software and what MRT value?
2.) In the production spaces, the metabolic rate is greater than 2.0 MET. Is there some trade-off for these type of spaces and should we present the program output for them, although they don’t meet the requirements of the standard?
I hate to be a downer, but if you do not have cooling or active natural ventilation, then you cannot show compliance to ASHRAE 55. There are some methods to show intent (such as exercise areas where the MET rate is higher than ASHRAE covers), but if you are not going to do natural ventilation, then I would not pursue this credit.
For projects with MET over 2.0 you may use LEED InterpretationLEED Interpretations are official answers to technical inquiries about implementing LEED on a project. They help people understand how their projects can meet LEED requirements and provide clarity on existing options. LEED Interpretations are to be used by any project certifying under an applicable rating system. All project teams are required to adhere to all LEED Interpretations posted before their registration date. This also applies to other addenda. Adherence to rulings posted after a project registers is optional, but strongly encouraged. LEED Interpretations are published in a searchable database at usgbc.org. 10279. The interpretation aligns with the "Use of Metabolic rate Data" on ASHRAE 55 2004 's page 17.
I have a couple of questions regarding this credit:
a) How can I convert the air velocity at the diffuser outlet to the air velocity reaching the occupant, knowing that an open plan office will have several desks and some occupants will be closer to the diffuser than others? Do I take average location in the middle of the room?
b) The 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. for my project are located just below the ceiling level (around 9 feet above floor) whereas I need to report the air speed at the seating level of occupants (3 feet above floor). Do you think diffuser manufacturers will have these values / conversion formulas?
c) The Mechanical Engineer confirmed that this is a typical project with a typical HVAC design strategy. Can I assume that the air speed is 40 feet per minute (as a default value) without further documentation to the USGBC, given that they don't ask for any documentation?
For a typical project in an office building with typical HVAC design, yes, I believe it is probably acceptable to presume the air speed is 40 fpm.
If you want to analyze it more completely, then you can read the introductory information in a diffuser catalog like Titus to evaluate air flow patterns and throws / air velocity at various distances, heights, and supply air temperatures.
What ended up happening on your project? Did you have to provide justification for the 40 fps?
I am completing documentation for a dormitory that has a Summer/Winter operative temperature of 75/70, respectively. RH is 55, air velocity is 40 FPM.
Rooms with a 1.2 MET or lower are all noncompliant (or 1.2 MET and .5 CLO, which is also noncompliant). In order to comply, it appears my only options are to raise the CLO level or the operative temperature of the space (I think I can't change the activity level since, no matter what, the space use remains the same). Here are my questions:
1. Provided I supply a narrative stating clothing assumptions and these clothing assumptions are logical (not requiring occupants to wear a jacket in the summer, for instance) using the values provided for garments in ASHRAE 55, can I simply raise the CLO levels in the spaces (or come up with a 'standard' project CLO that passes in all spaces and I can then apply to each space for each season?)?
2. If I adjust the operative temperature of the space I'm assuming that if, for instance, I am cooling below the project setpoint we have designed to in order to pass, would I be required to provide calculations proving that the extra cooling required is achievable by the system and equipment provided in the space? The same question would go for spaces where the temperature required for comfort exceeds the design heating setpoint for the project.
3. Is it possible to adjust both values in order to change each as little as possible and remain as close to the ASHRAE standard number and the design setpointsSetpoints are normal operating ranges for building systems and indoor environmental quality. When the building systems are outside of their normal operating range, action is taken by the building operator or automation system. in the project? Would each assumption for CLO in the summer and winter have to be a global change, or can each space use a different CLO level even though they all exist within the same building?
This brief guide introduces some of the key variables involved in designing for thermal comfort.
Principal & Founder
The Green Engineer, Inc.
LEEDuser is produced by BuildingGreen, Inc., with YR&G authoring most of the original content. LEEDuser enjoys ongoing collaboration with USGBC. Read more about our team
Copyright 2016 – BuildingGreen, Inc.