The overall intent of this credit is that all multi-occupant spacesMulti-occupant spaces are places of egress, congregation, or where occupants pursue overlapping or collaborative tasks. Multi occupant spaces may be regularly or non-regularly occupied spaces. (like meeting spaces) must have at least one occupant comfort control. For individual spaces or open-plan offices, at least 50% of occupants must be able to control their individual comfort conditions.
For Core and Shell projects to meet the credit requirements, the owner must provide the flexibility of a demand-controlled system
that provides control capability for 50% of the building occupants, so that the tenant can meet the intent of the credit. Common compliant systems would include under-floor air displacement,
variable refrigerant flow, or sufficient operable windows.
Providing thermal comfort control with operable windows is a common way to earn this credit.The credit defines comfort according to the four primary 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) identified by ASHRAE 55-2004:
A comfort control meeting the credit requirements needs to only address one of these four. Common ways to meet the credit include:
You can meet this credit with either naturally or mechanically ventilated buildings.
Projects using natural ventilation need to provide access to operable windows for at least 50% of occupants. An occupant has access to an operable window if their desk is located within 20 feet of a window to the inside, and 10 feet from side to side.
It is more difficult to achieve credit compliance with mechanical systems like forced air because the controls typically serve a large area. You can provide a greater level of thermal comfort with underfloor air distribution that provide easily controlled diffusers.
For constant-air-volume systems that do not allow individual control, you may need to add an additional unit, such as a reheating coil at the diffuser or perimeter baseboard heating, to achieve the credit’s intent.
For mechanically ventilated spaces, previous LEED-certified projects have complied with the credit by providing occupant controls for heating or cooling only. For example, a building providing controls adjusting heat within a certain temperature range can comply with the credit, even if controls are not providing for the cooling season.
The owner must provide the flexibility of a demand-controlled system that provides control capability for 50% of the building occupants. Common compliant systems would include under-floor air displacement, variable refrigerant flow, or sufficient operable windows.
Early during pre-design the owner identifies occupant comfort and control goals in the Owner's Project Requirements for commissioning in EAp1 and EAc3.
Assess your climate and your ability to provide occupant-controlled interventions for different comfort criteria. These may include:
Desk fans are not considered an acceptable strategy according to LEED Interpretation #1722, although USGBC has not officailly applied that Interpretation to LEED-2009 rating systems.
For commercial buildings, systems like fan coils paired with dedicated outdoor air systems can help provide local control to occupants, while reducing first-cost expenses like duct-work.
Including operable windows in the building can reduce dependence on specific mechanical system designs. Positioning as many occupant spaces near operable windows as possible can make this credit easier to achieve.
Some conventional systems typically rely on central control, and multiple controls may be difficult to incorporate. Underfloor air distribution, on the other hand, is designed for flexibility and individual control in a way that naturally supports this credit.
The required comfort control has to address only one of the four primary comfort criteria identified by ASHRAE 55-2004: air temperature, radiant temperature, humidity or air speed. You may address multiple criteria, but aren’t required to do so.
The comfort system does not have to be especially expensive or complex. It may simply be, for example, localized air conditioning with occupant controls.
Providing occupant comfort controls can add some costs, but they can also save money and improve occupant comfort and productivity. Occupant comfort controls allow for the mechanical system to respond to conditions specific to different parts of the building, improving overall comfort while saving energy. Typically, a system under central control is sized and calibrated for the least comfortable space. For example, in cooling season overhead air conditioning is provided for the warmest space, while everyone else under the same AHU feels uncomfortably cold. By providing individual controls, everyone can adjust the cooling or air speed to their comfort needs. This control often directly translates to lower energy costs.
Individual thermal comfort plug-in devices are allowed under IEQc6.2, as long as they are included in the design but not the baseline energy model.
Develop a list and number of all occupied spaces in the building, noting multi-occupant spaces. The number of individual occupant spaces and multi-occupant spaces should be the same between IEQc6.1 and IEQc6.2.
A multi-occupant space is space for group interactions, like classrooms, conference rooms, cafeterias, lobbies, warehouse loading areas, theaters, break rooms, commercial kitchens, retail stores, and exhibit spaces that expect large number of people to gather.
Each multi-occupant space should have at least one comfort control that regulates air temperature, radiant temperature, humidity, or air speed in that room.
For individually occupied spaces, identify the total number of workstations anticipated to be in each space per the project FTE count or based on the estimates listed in the Reference Guide Appendix 1. "Workstations" are referred here as places where full-time occupants spend majority of their time.
How many people per operable window? If using operable windows, locate as many people as possible close to them. Although strictly speaking it may make sense to count one person as needing one operable window, the experience of the LEEDuser team is that the credit has been approved by counting multiple people sitting close to a window as long as a person is within a 20-foot depth and a 10-foot length from one. The operable portion of the window must also be at least 4% of the size of the floor area of the space accessible to a given window, per ASHRAE 62.1-2007. For example, for a 5-foot-long window plus 10 feet on either side the total qualifying floor area would be 25 (5 + 10 + 10) multiplied by 20, or 500 ft2. At 4% of the floor area, the operable window area must be at least 20 ft2. Refer to the Documentation Toolkit for a diagrammatic representation of the window-area-to-floor-area relationship.
How many people per control? Even though the credit calls for individual comfort controls, projects often earn this credit by grouping occupants around a single operable window. Similarly, a single mechanical system control can serve up to two occupants, contributing to the 50% credit threshold.
If less than 50% of occupants have access to operable windows, add more operable windows, adjust the layout, or add ducts, baseboards or diffusers with controls to add individual comfort controls. Run calculations again and redesign till 50% of people have access to the controls.
Core and Shell projects must demonstrate that their base building provides all the potential and flexibility for a fit-out of multiple comfort controls that regulate at least one of the four comfort factors. For example, a system without the potential for a lot of individual controls may not work for an open office but may work for a convention center.
An open office space is individually occupied where each person has an individual desk and defined space.
Individually occupied spaces are defined as the place where an occupant spends most of their time, such as a private office, reception desk, workstations or cubicles in open-plan offices.
A control can be as simple as a switch to turn air conditioning on or off, changing temperature in a small permitted range using a thermostat, or closing a diffuser to reduce air flow.
Providing comfort controls that allow an occupant to turn a system on only when using the space, and turn it off at other times, supports energy efficiency goals. Whether or not it can contributes to demonstrable energy reductions for EAc1: Optimize Energy Performance is another question. Except for operable windows, this would be difficult to demonstrate.
Note the credit requirement is based on number of occupants for individually occupied and number of spaces for multi-occupants. Only half of the total building occupants must have controls in individually occupied spaces. However, each of the multi-occupant spaces must have independent controls.
For example, an open plan office has 100 desks and 10 private offices, for a total of 110 individually occupied spaces. At least 55 of the people occupying those spaces must have access to comfort controls. The same office also has two conference rooms. Both conference rooms need their own controls.
Facilities managers may have reservations about providing controls to users. The range of control can be limited to a certain range, however, and should be programmed to be reset at least at the end of the day with the building’s typical temperature setback. Be sure that occupants will be educated on how to use controls.
Additional controls imply higher construction costs, with additional wiring, and maintenance for uninterrupted operations. There are low-cost options, such as baseboard heating radiators and heat pumps that are easy to operate and provide good local comfort. Compare the upfront costs of better controls to the long-term benefits of higher productivity, better test scores or hotel occupancy, plus savings in energy usage.
Underfloor air or ceiling-air plenum are common systems for allowing occupant comfort control. In addition, they can:
In the absence of operable windows, it is difficult to meet the 50% credit requirement unless the mechanical system is designed with zones to provide multiple comfort controls.
Operable windows, although offering some energy and comfort benefits, have some drawbacks. They allow in outside air, which may not be of the highest quality, and also allow in outside noise. The unconditioned air they allow in can affect the operation of mechanical systems.
Operable windows are generally higher in cost than fixed windows.
A mechanical system with more individual controls may cost more than a conventional system. This cost can be offset, though, by lower operating costs, a more flexible layout, and improved occupant productivity.
If using a mechanical system, confirm that the project design is progressing with a system that allows for multiple controls.
Update the count of total individual workstations and those with controls. If the controls do not add to be 50% of total workstations then investigate the potential to add more controls or change the layout to make them more accessible to windows.
Configure the mechanical system so that when windows are open, cooling is turned off to avoid wasting energy. You can accomplish this by hooking operable windows up to wireless sensors that communicate with the cooling system.
Install a building management system that communicates with occupants to open operable windows when outside temperature and humidity are within comfort range as defined by ASHRAE 55-2004.
If using operable windows, make sure the window schedule and all construction drawings include relevant details. Specify windows and window locations that make them easy to operate.
Provide for the commissioning of control and response systems in the commissioning scope for EAp1.
During the construction bidding phase, discuss the schedule to make sure correct control equipment is purchased and installed on time. The controls are only as good as the feedback and response system they are connected to. Explain the control sequence to the subcontractors to minimize confusion.
If value engineering threatens comfort controls, remember their benefits—including energy savings and higher productivity.
Ensure correct installation of all mechanical systems.
Complete LEED Online documentation. Include mechanical system layouts of base building systems and an estimated design of tenant layout with proposed controls schedule and cut sheets.
List all spaces and occupancy types for the project on LEED Online. Mark the kind and number of controls available in each of those spaces. Select “None” if any of those occupants do not have individual controls. The online submittal form will automatically advise on number of required occupants with controls and those that are available.
The commissioning agent should check and verify operation and setpoints of the controls. (See EAp1.)
Educate occupants about the range of control adjustments available. Many air diffusers can open or close the air vent and change the temperature only within a limited range, typically within 5ºF–10ºF of acceptable comfort levels. For example, a heating system may allow a range from 68ºF–74ºF. Comfort controls may not allow larger changes or switching to air conditioning during the heating season, and it is helpful for occupants to understand this. Encourage occupants not to leave windows open when heating or cooling is on.
Train operations and maintenance staff to troubleshoot any problems, particularly if there is a BMS system that responds to user controls, with overrides for end-of-day setbacks.
Incorporate controls into the operations manual and training so that facility staff are aware of the controls mechanism and response system.
Excerpted from LEED 2009 for Core and Shell Development
To provide a high level of thermal comfort system control1 by individual occupants or groups in multi-occupant spacesMulti-occupant spaces are places of egress, congregation, or where occupants pursue overlapping or collaborative tasks. Multi occupant spaces may be regularly or non-regularly occupied spaces. (e.g., classrooms or conference areas) and promote their productivity, comfort and well-being.
Provide individual comfort controls for 50% (minimum) of the building occupants to enable adjustments to meet individual needs and preferences. Operable windows may be used in lieu of controls for occupants located 20 feet inside and 10 feet to either side of the operable part of a window. The areas of operable window must meet the requirements of ASHRAE Standard 62.1-2007 paragraph 5.1 Natural Ventilation (with errata but without addenda2).
Conditions for thermal comfort are described in IEQ credit 7: Thermal Comfort—Design and include the primary factors of air temperature, radiant temperature, air speed and humidity.
Provide comfort system controls for all shared multi-occupant spacesMulti-occupant spaces are places of egress, congregation, or where occupants pursue overlapping or collaborative tasks. Multi occupant spaces may be regularly or non-regularly occupied spaces. to enable adjustments that meet group needs and preferences.
Core and shell projects that do not purchase and/or install the mechanical system or operable windows (or a combination of both) have not met the intent of this credit.
See Appendix 1 — Default Occupancy Counts for occupancy count requirements and guidance.
Design the building and systems with comfort controls to allow adjustments to suit individual needs or those of groups in shared spaces. ASHRAE Standard 55-2004 (with errata but without addenda) identifies the factors of thermal comfort and a process for developing 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) for building spaces that suit the needs of the occupants involved in their daily activities. Control strategies can be developed to expand on the comfort criteria, and enable individuals to make adjustments to suit their individual needs and preferences. These strategies may involve system designs incorporating operable windows, hybrid systems integrating operable windows and mechanical systems, or mechanical systems alone. Individual adjustments may involve individual thermostat controls, local 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 floor, desk or overhead levels, control of individual radiant panels or other means integrated into the overall building, thermal comfort systems and energy systems design. In addition, designers should evaluate the closely tied interactions between thermal comfort as required by ASHRAE Standard 55-2004 (with errata but without addenda) and acceptable indoor air quality as required by ASHRAE Standard 62.1-2007 (with errata but without addenda), whether natural or mechanical ventilation.
1. For the purposes of this credit, comfort system control is defined as control over at least 1 of the following primary factors in the occupant’s vicinity: air temperature, radiant temperature, air speed and humidity.
2. Project teams wishing to use ASHRAE approved addenda for the purposes of this credit may do so at their discretion. Addenda must be applied consistently across all LEED credits
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.
This ASHRAE standard stipulates minimum outdoor air requirement and minimum window opening for naturally ventilated space. This formula is referenced in this credit where windows are used as control mechanism.
This seminal report documents the financial costs and benefits of green schools compared to conventional schools, specifically with reference to Massachusetts. Page six describes the benefits of ventilation controls on occupant productivity.
Taylor Engineering lays out design guidance for integrating operable windows into an HVAC system, while also reducing energy consumption.
In this article from ASHRAE Journal, the authors outline the benefits of an integrated designAn integrated design process (also called "integrative" design by some proponents) relies on a multidisciplinary and collaborative team approach in which members make decisions together based on a shared vision and holistic understanding of the project. Rather than a conventional linear design process in which a design is passed from one professional to another, an integrated process has all key team members talking together through out the design and construction process as they share ideas and use feedback across disciplines to iteratively move toward a high-performing design. approach for underfloor-air distribution, and explain how UFAD can contribute to LEED credits including IEQc6.2. (Subscription Required)
Documenting this credit in LEED Online includes completing the table shown here (as samples), with occupancy types and thermal comfort control types indicated.
Operable windows are an appropriate way to meet the requirements for this credit in many building types. A single operable window can serve multiple occupants, as shown here.
A variety of sample narratives and floorplans from real projects show how different projects have achieved this credit.
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.
It is a mechanical ventilated office building. To achieve this credit:
1. (For VAVVariable Air Volume (VAV) is an HVAC conservation feature that supplies varying quantities of conditioned (heated or cooled) air to different parts of a building according to the heating and cooling needs of those specific areas. system serving space without operable window) Dose is mean that: If there is a conference room with 50 people, 25 thermal control panels are needed. If there is a dining room with 200 people, 100 thermal control panels are needed. This is very strange. Too many thermal control panels have to be installed to meet the credit requirement.
2. (For a few places has operable window)
2-1. Does it has influence on the way the building is ventilated which need to be selected in IEQp1? Once the building has a few operable window, it is a natural and mechanical mixed ventilated building instead of a mechanical ventilated only building?
2-2. Dose is mean that: each operable window which is 4% or more of space floor area is one control which can serve 2 people? OR once the window is 4% or more of space floor area, it can be taken as thermal control, all occupants who is 20 feet from the window can be taken as has people have thermal control?
A conference room would be a "shared multi-occupant space" so would only need enough controls to meet the needs of the space. Please take a look above on the requirements for "shared multi-occupant spacesMulti-occupant spaces are places of egress, congregation, or where occupants pursue overlapping or collaborative tasks. Multi occupant spaces may be regularly or non-regularly occupied spaces.".
"The overall intent of this credit is that all multi-occupant spaces (like meeting spaces) must have at least one occupant comfort control. For individual spaces or open-plan offices, at least 50% of occupants must be able to control their individual comfort conditions."
I am working on a C&S project in which most of the tenants are retail stores. To achieve this credit I am under the impression that complying spaces will be limited to office and administrative areas since retail space is not a shared multi-occupant space nor included in the IEQ Space matrix for EQc6. Therefore, 50% of only office spaces (tenant and CS) must comply with the requirements of the credit. Can anyone verify, and will a representative tenant floor plan be necessary? For example, If a retail tenant builds an office as a part of their fit-out does that need to comply with the requirement and/or be included in the lease agreement? The owner is providing mechanical equipment but not the ductwork. Thanks in advance.
Hi London - have you seen LEED for Retail? It might be helpful to reference, even if you're using LEED C&S.
We have a mall seeking LEED C&S 2009. Most of the spaces will be tenanted. The owner will be installing the main HVAC system (Chillers & Boilers), whereas the tenants will fit out their HVAC system later.
I am trying to assess the difficulty in achieving this credit. The mall will contain retail shops, restaurants, and movie theaters (all are tenanted). The C&S areas fitted by the owner are basically the underground parking levels and the mall circulation areas (mall concourse).
My queries below:
1) Generally speaking, is it too difficult to achieve this credit?
2) The mall concourse circulation is occupied by transient occupants. It would not make sense to provide these transients with thermal comfort controls. However, the circulation area has a thermostat which is controlled by the Mall's facility managers if need be. Is this sufficient for complying with this credit?
3) Restaurants & Retail shops will have FTEFull-time equivalent (FTE) represents a regular building occupant who spends 8 hours a day (40 hours a week) in the project building. Part-time or overtime occupants have FTE values based on their hours per day divided by 8 (or hours per week divided by 40). Transient Occupants can be reported as either daily totals or as part of the FTE. Residential occupancy should be estimated based on the number and size of units. Core and Shell projects should refer to the default occupancy table in the Reference Guide appendix. All occupant assumptions must be consistent across all credits in all categories. employees and transient visitors. Is it sufficient to have 1 thermostat control for each restaurant / retail, and this thermostat operated by the shop's employees (not transients)? If a retail shop has 3 employees, it doesn't make sense to provide 3 controls, as the employees will be constantly moving in the shop (unlike a shared office space whereby each person works on 1 fixed desk).
I would check out LEED for Retail as general guidance, around your questions, even if you are pursuing under LEED C&S.
Our project is installing the fan coil units and each will be individually controllable. Its quite typical in the UK to have an open plan office with a mix of permanent workstations, "hot desks" and partly enclosed (high partitions ~6-7ft high or very open plan meeting areas, in addition to cellularised meeting rooms. For the more open areas hot desks / open plan meeting tables what is the best way to demonstrate compliance for these areas, how much local control would these areas need ? would one control in an area of 180-200sf suffice and then more control (50%) for the permanent workstations? any thoughts on how best to approach this credit would be appreciated. regards
For the most part - even open office workstations need to be treated and counted as a series of individual workstations and therefore need their own controls to meet the credit. If you have desks that are very rarely occupied, using the definition of LEED: "Non-regularly occupied spacesEnclosed space intended for human activities, excluding those spaces that are intended primarily for other purposes, such as storage rooms and equipment rooms, and that are only occupied occasionally and for short periods of time. Occupied spaces are further classified as regularly occupied or nonregularly occupied spaces based on the duration of the occupancy, individual or multioccupant based on the quantity of occupants, and densely or nondensely occupied spaces based on the concentration of occupants in the space. are spaces that occupants pass through, or spaces used in pursuit of focused activities for less than one hour per person per day (on average)" then you could probably get away with not providing controls for these spaces. Otherwise, you need to count each desk as a work station and then provide the required percentage of controls for those workstations.
Would a mechanically ventilated building be able to rely on 2 methods for documenting compliance: T-stats and windows? Some occupants will use one, while the others will rely on another. Would it be Ok in this case to say in the ventilation IEQp1 form that this project is only mechanically ventilated?
If windows are used for compliance, does it have to be 1 window per 2 people? Or could 10 people use 1 window?
Thanks a lot for your input!
Yes, you can use both t-stats and windows in combination to meet the credit requirements.
In terms of a window - one window would count as counting toward one control and for one workstation and not for multiple people. It would be treated in the same way as you would for the T-stat controls. For a window to count toward a control for any workstation I would review the ASHRAE 62 requirements " the openable area has to be a minimum of 4% of the net occupiable floor area. Where openings are covered with louvers or otherwise obstructed, openable area shall be based on the free unobstructed area through the opening..." Note that this requirement is slightly more stringent for projects in CA; T-24 calls for a minimum of 5%, window to floor area ratio.
Thank you, Lauren. It is very helpful.
My CS project is an office building. I'm wondering if it's enough if the project has individual radiant control but that there is a max limit of temperature and that the tenant can only decide to have that radiant temperature or turn it off. I read that if a project have radiators where the tenants can adjust the temperature within a certain temperature range that can comply with the credit, but we are having all or nothing. Either you choose to have the radiator on and then you'll be given a temperature or you choose to have the radiator off and then you'll get nothing. This is a kind of individual control since you can decide that you don't want any warmth at your work station from the radiators, but I don't know if this is enough. Any thoughts?
Many thanks in advance!
This is an interesting one, Mathilda. I have seen it asked before but I haven't seen an official answer to it. I apologize for the late response to this question. I am going to try to get you an answer now from 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)..
Yes, as described, this is an acceptable individual thermal comfort control.
Thank you for your responses. While I was looking at LEED Online form I realized you had to sign a box insuring that: "Comfort controls offer a range of options to the user and do not function as simple on/off switches". I guess that my projects solution described above falls under "simple on/off switches" since we only have a preset temmperature or nothing, so I'm not sure we can earn this credit. But I still want to hear what 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). have to say, Lauren.
Larissa's response was my reference to 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).. She actually is with the USGBC so I apologize for the confusion. I agree that there is confusion around this issue. The Reference Guide does not seem to require more than "simple on/off switches" and that this guidance is really coming from the Template itself.
Ok, so we will meet the credit with this solution? That´s great!
I'm working on a core and shell shopping mall project and tenants will be responsable for HVAC equipment and thermostates installation in their spaces.
First of all I would like to ask how do we define "occupants" for controllability of systems calculations. Is it only the number of shopping mall employees or does it include both employees and transients?
Second, since we don't know future layout of tenant spaces should we creat a potential layout, is that enough? Should we require future tenants to install specific number of controls (as specified by our calculations)?
In the calculations I'll be including only building employees. But could somebody confirm that stores and supermarkets in a shopping mall are considered shared multioccupant spaces for which at lest one means of control is required and people working at the cash desks (50%) don't need individual thermal comfort controls?
Adam, unfortunately this is an area with unclear requirements. See this excellent discussion thread for some background on similar issues, but no clear resolution.
We are working in a naturally ventilated LEED CS project. Every office and regularly occupied spaceAn area where one or more individuals normally spend time (more than one hour per person per day on average) seated or standing as they work, study, or perform other focused activities inside a building. The one-hour timeframe is continuous and should be based on the time a typical occupant uses the space. For spaces that are not used daily, the one-hour timeframe should be based on the time a typical occupant spends in the space when it is in use. will have natural ventilation, but Restrooms will have mechanical ventilation by air extraction. These will be the only mechanically ventilated spaces in the building.
I have two questions regarding this credit:
1. Is a tentative tenant layout completely necessary? Or could we show that more than 50% of the project's area is within 20 ft of windows?
2. In the LEED Online form, one should select if the project is mechanically or naturally ventilated. Ia a project like this, we selected both. A "mechanical ventilation" section appears, and asks for signature from the mechanical designer stating that comfort controls provide a range of options, and are operable by the ocuppants. The mechanical ventilation system installed won't comply with this since its intended to just extract foul air from the restroom, not to provide thermal comfort.
We are kind of confused how to treat this signature spaces and if our "uncomfotable"mechanical ventilation will prevent us from achieving this credit.
I would highly suggest doing a sample tenant layout to help achieve the credit. Otherwise, it's very difficult to prove that you're meeting compliance with natural ventilation.
If I understand correctly, it sounds like you're mostly meeting the credit through your natural ventilation system, rather than you mechanical system. The credit requires you to meet it through mechanical or natural or both. In this case, I'd prove your compliance through the natural ventilation requirements (restrooms would be excluded because they aren't regularly occupied) and then just provide a narrative on the LEED Online form for the mechanical system that clarifies that your system's mechanical ventilation system is just extracting air and is not contributing toward your credit compliance.
Hope that helps.
Just to clarify: Each operable window counts as one control. Therefore if I have an open office space with 50 people within 20' of the exterior wall, then I need at least 24 windows and one thermostat. Correct?
I agree with you except I don't think you need one thermostat unless you only had 24 windows (wasn't sure if the example was just a hypothetical example). If you already have one thermostat and want to include it then that would be fine but you can comply with one or the other (windows or mechanical controls).
What if I had 10 work stations, all within 20' of the same single window? Would I only be able to count 2 occupants as having controls, or would I get to count 5 occupants as having controls?
My project team is trying to determine the cost and feasability of going for this credit. We're working on a new office tower and we'll have some operable windows, but they're expensive, so we're trying to work out how many we need.
The description up above on LEEDuser suggests that occupants need only be within 20' of a window, and that many occupants can share one window. To be honest, this doesn't make sense to me. It seems like max 2 people should be sharing a window, or else they'll all be disagreeing on whether to close or open it.
What's your experience?
Our project is a C&S office and the furniture layout is not yet known. The cooling and heating system will consist of a VRV. Thermostats and other controls will be installed by the tenant.
LEED User says: "For Core and Shell projects to meet the credit requirements, the owner must provide the flexibility of a demand-controlled system
that provides control capability for 50% of the building occupants, so that the tenant can meet the intent of the credit".
It will always be possible for tenants to install thermostat for every 2 workstations. In addition, depending on the furniture layout, some of the workstations will probably be 20 feet from openable windows.
As such it is in our view that tenant could meet the credit. Is there any other documentation we should provide in order to get this credit ?
You are correct in noticing that this credit is fairly easy to achieve in a LEED-CS applciation as it is fairly easy to design the space to ensure compliance. I know you mentioned that you don't have a furniture layout yet but I believe that you'll need to put together a sample layout for at least part of your space to aide in outlining how you'll comply. LEEDv2009 requires you to upload a representative drawing/floorplan(s) that identifies thermal comfort controls declared in the Credit Form's table. LEEDv2 does not require a floorplan upload.
Make sure to note the possible locations of individual workstations as well as the possible locations of multi-occupant spacesMulti-occupant spaces are places of egress, congregation, or where occupants pursue overlapping or collaborative tasks. Multi occupant spaces may be regularly or non-regularly occupied spaces. in conjunction with noting their controls.
It sounds like you're on track with your explanation provided.
many thanks for your reply.
Assuming the Core and Shell is a shopping mall with retail stores (as future tenants). None of the retail stores have access to openable windows.
Can we still get this credit is we prove that the HVAC system currently designed, allows tenants to install a thermostat in their respective retail store ?
Just to confirm: is your project registered under LEEDv3? If so, I am terribly sorry but I stand corrected. This morning I found specific language in the LEEDv3 Reference Guide (page 527) which states that "Core and Shell projects that do not purchase and or/install the mechanical system or operable windows (or a combination of both) have not met the intent of this credit."
To me, this indicates that it will be a stretch to achieve this credit in your case by stating that the system is designed to allow for the installation of thermostats.
In LEEDv2 it was possible to take this approach but not in LEEDv3. I am curious if others have experienced an approach that was acceptable.
I'm sorry to lead you astray originally.
We have a similar situation, we have a C&S office project. The HVAC system provided at the project will only reach the core and not any further, this means only cold water will be provided at each office level so the tenant will connect to it with whatever system he desires too.
It does allow the tenant to use a system that will fulfill the requirements for LEED-CI but we are not 100% sure the tenant will implement such.
I just want to double check if we are not achieving this credit by the way we are designing the HVAC system.
We have done several LEED CS V3 projects and achieve this credit in different ways. First of you will always have to provide a potential tenant layout, which is consistent throughout the credits. Keep that in mind especially if you also attempted daylight and views. You have to figure out the FTEFull-time equivalent (FTE) represents a regular building occupant who spends 8 hours a day (40 hours a week) in the project building. Part-time or overtime occupants have FTE values based on their hours per day divided by 8 (or hours per week divided by 40). Transient Occupants can be reported as either daily totals or as part of the FTE. Residential occupancy should be estimated based on the number and size of units. Core and Shell projects should refer to the default occupancy table in the Reference Guide appendix. All occupant assumptions must be consistent across all credits in all categories. per your space then. Keep in mind, that you will also have to account for supporting spaces like storage in the basement, which belong to the space, but usually don't have any occupied spacesEnclosed space intended for human activities, excluding those spaces that are intended primarily for other purposes, such as storage rooms and equipment rooms, and that are only occupied occasionally and for short periods of time. Occupied spaces are further classified as regularly occupied or nonregularly occupied spaces based on the duration of the occupancy, individual or multioccupant based on the quantity of occupants, and densely or nondensely occupied spaces based on the concentration of occupants in the space. there. So that increases your number of FTE.
One of the projects had operable windows and radiators with thermostats all along the perimeter spaces. So we layed out the space so that as many FTE's as possible have a thermostat. In another project we have radiant slabs, which are design to allow for private offices every 2 axis along the windows. So 2 windows equal one zone. Even thought the tenants didn't always design that way, they have the possibility to do so and install the thermostats for each room. It's my understanding, that you have to have a system installed in the tenant spaceTenant space is the area within the LEED project boundary. For more information on what can and must be in the LEED project boundary see the Minimum Program Requirements (MPRs) and LEED 2009 MPR Supplemental Guidance. Note: tenant space is the same as project space., which allows the tenant to have the thermal comfort control. But you don't have to have the actual thermostat in place. So David my guess would be a NO, or you have to have a lease agreement requiring that.
Also for retail, please keep in mind that there are separate guidelines for retail spaces in regards to this credit. So even thought this is a Core & Shell project I would apply the specifics of the retail certification for those areas. I actually just did for one of my LEED CS projects and it was excepted, but we also had 75%. So no need for the reviewer to get down to the details.
Thank you Sussan, it was really helpful. I will get back in case I have more questions.
We have a c&s industrial project, 1/F-21/F are warehouse area, only 23/F-25/F are office area. I
We have a c&s industrial project, 1/F-21/F are warehouse area, only 23/F-25/F are office area. Ventilation system in warehouse area is divided into 3 typies:FCU will be provided in 1&2/F, 3-15/F will be nature ventilation, and mechanical ventilation in 17-21/F to be installed by tenant. FCU will be installed in 23-25/F. And thermosate will be provided for at least 50% of occupant for the area with FCU(1-2/F AND 23-25/F). However, for 3-21/F, do i need to demonstrate the compliance? and how, if yes.
Thanks for any advice!
We have a c&s mixed use building with a small restaurant and retail spaces on the first floor. Mechanical system is installed under c&s for all tenant spaces (LEEDv2009).
Can doors to outside be counted instead of operable windows for providing thermal comfort?
Or can one thermostat control the temperature in the sales/ dining area for both customers and employees?
Appreciate any advice.
Lauren and Susann, please clarify... it sounds like you do NOT need to provide ("purchase and install") the mech system for the tenant spaces, but DO need to provide the whole building mech system capable of serving those spaces per the intent and requirements of this credit. Susann suggests demonstrating this with a hypothetical tenant layout. Even if this approach is acceptable, it is unclear how to complete the online form (still in beta), which offers two options for tenant spaces: "In Scope" or via "Tenant Sales or Lease."
The "In Scope" option specifically says that "Data shall be based entirely on design and construction elements that are included in the LEED Core & Shell project scope." So I'm guessing the hypothetical tenant plans would be submitted under the "Tenant Sales or Lease" option?
Example: I have a 4 story core and shell building with two stories occupied by the owner, and two stories occupied by tenants. There was no provision written in our client's tenant lease agreement for thermal comfort, so the "tenant lease" option is out. We did, however, also design the tenant spaces (under a separate contract / not in the CS project scope). So we do know what their thermal comfort controls are, and there's a chance these controls will also meet IEQc6.
My question is: Can we include the tenant spaces as "In Scope" for IEQc6, or will the reviewers expect to see tenant spaces handled consistently across all other credits (such as WEp1)?
Any thoughts on this are greatly appreciated!
I received some clarification from 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). on the matter. Please see their response below and let me know if you have any additional questions.
"Per the LEED v2009 RG, Core and Shell projects that do not purchase and/or install the mechanical system or operable windows (or a combination of both) have not met the intent of this credit. If the mechanical system is installed but not completely fit-out for the tenant spaceTenant space is the area within the LEED project boundary. For more information on what can and must be in the LEED project boundary see the Minimum Program Requirements (MPRs) and LEED 2009 MPR Supplemental Guidance. Note: tenant space is the same as project space., the project can still attempt this credit and it would be 'in-scope'. The building HVAC system must be capable of being expanded to allow for a high degree of occupant control. Buildings that use an overhead VAVVariable Air Volume (VAV) is an HVAC conservation feature that supplies varying quantities of conditioned (heated or cooled) air to different parts of a building according to the heating and cooling needs of those specific areas. system will have to demonstrate that it is possible for the system to provide enough control points for 50% of the occupants. However, the VAV boxes do not have to actually be installed as part of the C&S scope.
The requirements of WEp1 and IEQc6 are vastly different in regard to in-scope or TSLA, therefore consistency due to this issue would not be required between these two credits.
If the project team is using a beta form, it is strongly recommended they upgrade to the new version of the form, which is v4.0."
Thanks Lauren! That helps.
I'm wondering if the comment "to demonstrate that it is possible for the system to provide enough control points for 50% of the occupants." requires a representative floor plan. Or can we demonstrate this with a narrative about the system capacity and controls adaptability?
If we have to provide a representative tenant floor plan, what would that look like? Do we just mark up a plan with a hypothetical office layout, showing T-stat locations and VAVVariable Air Volume (VAV) is an HVAC conservation feature that supplies varying quantities of conditioned (heated or cooled) air to different parts of a building according to the heating and cooling needs of those specific areas. boxes? Is there any further complexity to this that I'm missing?
I would encourage your team to create a representative floor plan. And the ones I have created are just as you have described.
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