In the final paragraph, replace: "Conditions for thermal comfort are described in ASHRAE Standard 55-2004 (with errata but without addenda) and include the primary factors of air temperature, radiant temperature, air speed and humidity." With: "Conditions for thermal comfort are described in IEQ credit 7.1: Thermal Comfort-Design and include the primary factors of air temperature, radiant temperature, air speed and humidity."
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Credit language
© Copyright U.S. Green Building Council, Inc. All rights reserved.
Intent
To provide a high level of thermal comfort system control1 by individual occupants or specific groups in multi-occupant spaces and promote their productivity, comfort and well-being.
Requirements
Provide individual thermal comfort controls for every single occupant patient room.
AND
Provide individual thermal comfort controls for 50% (minimum) of the remaining 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 (6 meters) inside and 10 feet (3 meters) 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).AND
Provide comfort system controls for all shared multi-occupant spaces to enable adjustments that meet group needs and preferences. Conditions for thermal comfort are described in IEQ credit 7: Thermal Comfort—Design and Verification, and include the primary factors of air temperature, radiant temperature, air speed and humidity. Comfort system control for the purposes of this credit is defined as the provision of control over at least one of these primary factors in the occupant’s local environment. See all forum discussions about this credit »What does it cost?
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See all forum discussions about this credit »Addenda
10/1/2012 – Updated: 2/14/2015
Global ACP
Description of change:
Campus Applicable
No
Internationally Applicable:
Yes
11/1/2011 – Updated: 2/14/2015
Reference Guide Correction
Description of change:
Revise the definition for individual occupant spaces to be, "In individual occupant spaces, occupants perform distinct tasks from one another. Such spaces may be contained within multi-occupant spaces and should be treated separately where possible. Individual occupant spaces may be regularly or non-regularly occupied spaces."
Campus Applicable
No
Internationally Applicable:
No
11/1/2011 – Updated: 2/14/2015
Reference Guide Correction
Description of change:
Replace the definition for group multioccupant spaces with the following definition for multi-occupant space, "Multi 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."
Campus Applicable
No
Internationally Applicable:
No
11/1/2011 – Updated: 2/14/2015
Reference Guide Correction
Description of change:
In alphabetical order, add the following definition for multi-occupant spaces, "Multi-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."
Campus Applicable
No
Internationally Applicable:
No
11/1/2011 – Updated: 2/14/2015
Reference Guide Correction
Description of change:
Replace the definition for group multioccupant spaces with the following definition for multi-occupant space, "Multi 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."
Campus Applicable
No
Internationally Applicable:
No
4/2/2014 – Updated: 2/14/2015
Reference Guide Correction
Description of change:
Under Indoor Environmental Quality, remove IEQ Credit 6.2 Controllability of Systems--Thermal Comfort. An exemplary performance point is not available for this credit in LEED for Healthcare.
Campus Applicable
No
Internationally Applicable:
Yes
5/7/2007
LEED Interpretation
Inquiry:
The project team is providing individual floor air valves each with variable duration (open / close) primary air dampers and multi-position diffusers for occupant comfort conditioning as part of an under floor air distribution system. Individual floor air valves will be provided for a minimum of 50% of the building occupants. The variable duration (open/close) primary air dampers in the floor air valves will be controlled using thermostats. Multiple air valves will be connected to one thermostat, such that there will not be one thermostat for 50% of the occupants. However, all of the local floor air valves include multi-position adjustable floor diffusers which are integral to each floor air valve. At a minimum, 50% of the occupants will have control over the primary air flow direction out of the local floor air valve in their space (comfort zone) by adjusting the multi-position local floor diffuser air outlet. Changing the direction of the air flow inherently changes the speed of the airflow in a given direction. LEED NC v.2.2, First Edition, Reference Guide, p361, indicates: Conditions for Thermal Comfort per ASHRAE Standard 55-2004 include the following as primary factors: air temperature, radiant temperature, air speed, and humidity. The Reference guide also states that, "Comfort System control, for the purposes of this credit, is defined as the provision of control over at least one of these primary factors in the occupant\'s local environment" and that "Individual adjustments may involve individual thermostat controls, local diffusers at floor, desk or overhead levels, or control of individual radiant panels, and energy system design." This CIR is to confirm that providing air valves, with multi position diffusers, that allow more than 50% of the occupants to change the direction of airflow out of their floor diffuser (which changes the speed in that direction) will satisfy the LEED credit requirement for thermal comfort.
Ruling:
The applicant is asking whether multi position diffusers that allow changes in direction of airflow satisfy the requirements for individual comfort control for EQc6.2. The applicant is suggesting that changing the direction of airflow inherently changes the speed of the airflow in a given direction, meeting credit compliance by providing control of air speed. Simply changing the direction of airflow in one\'s workspace does not adequately meet the credit intent to provide individual comfort controls. Individual diffusers must have the ability to regulate the speed of the air leaving the diffuser, not simply the direction of airflow. Applicable Internationally.
Campus Applicable
No
Internationally Applicable:
Yes
11/1/2011
LEED Interpretation
Inquiry:
The project is an 80,000 sf K-12 school located in the pacific northwest. A majority of the building is being conditioned by "standard" mechanical means and can demonstrate compliance according to ASHRAE 55-2004 Figure 5.2.1.1., however there are portions of the building that will be thermally regulated by natural ventilation and with extensive radiant systems.The purpose of this request is to determine whether the more passive, naturally ventilated portion of the building may be considered "naturally conditioned" with their thermal comfort criteria evaluated according to ASHRAE 55-2004 Figure 5.3 rather than being evaluated according to Figure 5.2.1.1.The northwest climate is considered heating dominated with narrow diurnal temperature variations and as a consequence has limited cooling needs, especially during the school year. The need for cooling is isolated to only brief time periods at the beginning and end of the 9-month school year when potential thermal comfort concerns would arise. To mitigate thermal comfort concerns during these isolated times, the design incorporates occupant-controlled operable windows and ceiling fans to allow comfort control within the classrooms. In addition to the operable windows, the design also includes utilizing the thermal massing properties of the concrete floors to better modulate the release of cooling within the space(s). The cooling will be supplied by evaporatively-cooled water via hydronic loops in the floors during the nighttime periods when the building is unoccupied. The intent is pre-charge the thermal mass of the floors with enough cooling to offset the effects of internal heat gains and eliminate the need for active mechanical cooling during the day. Since the charging is taking place during the evenings, there will not be any ability for the occupants to directly call for additional cooling to be added to floor or space and the mass will in essence be allowed to release it cooling naturally trough out the day. Lastly, we are interpreting that this approach of pre-cooling the mass without the need of compressor-based mechanical cooling could be construed as a assisted passive approach, however it is unclear whether the USGBC will recognize these spaces as "naturally conditioned" for the purposes of IEQc7.1. ASHRAE 55-2004, Section 5.3, states that "occupant-controlled naturally conditioned spaces are those spaces where the thermal conditions of the space are regulated primarily by the occupants through opening and closing of windows". We believe that the definition is still being satisfied with the mass pre-charging strategy described previously, since the regulation of the thermal conditions will still be controlled by the occupants through the opening and closing of windows.Can the thermal comfort criteria in these rooms be evaluated according to "naturally conditioned" rather than "typical" criteria and if so, is modeling an acceptable means of documenting compliance?
Ruling:
The applicant is asking whether a space that meets the ASHRAE Standard 55-2004 definition of "naturally conditioned spaces, occupant controlled," but is also served by an in-floor radiant cooling system that is in turn served by an evaporatively-cooled water tower that will be utilized at night to pre-charge the high thermal mass concrete floors, may be evaluated according to ASHRAE Standard 55-2004 Section 5.3 - Optional Method for Determining Acceptable Thermal Conditions in Naturally Conditioned Spaces in lieu of the requirements of Section 5.2 Method for Determining Acceptable Thermal Conditions in Occupied Spaces.Section 5.3 of Standard 55-2004 states, "there must be no mechanical cooling system for the space (e.g. refrigerated air cooling, radiant cooling, or desiccant cooling.)" in order to use the Optional Method for Determining Acceptable Thermal Conditions in Naturally Conditioned Spaces. If the radiant cooling system is operated during the day, the project would be considered mechanically cooled and not eligible to use the Section 5.3 method. However, if the system is operated as described in the Interpretation Request and the radiant cooling system is only used at night as a pre-cooling strategy then the intent and spirit of the conditions for using Section 5.3 are met. Note that:1. For times when active mechanical cooling OR heating is used during occupied hours, Section 5.3 does not apply and Section 5.2 Method for Determining Acceptable Thermal Conditions in Occupied Spaces shall be used.2. In the Cooling season when the night-time pre-cooling strategy is used, the minimum design operative temperatures in the morning shall be evaluated compared to the allowable minimum operative temperature based on Section 5.3 to ensure comfortable conditions throughout the day. Applicable internationally.
Campus Applicable
No
Internationally Applicable:
Yes
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© Copyright U.S. Green Building Council, Inc. All rights reserved.
Intent
To provide a high level of thermal comfort system control1 by individual occupants or specific groups in multi-occupant spaces and promote their productivity, comfort and well-being.
Requirements
Provide individual thermal comfort controls for every single occupant patient room.
AND
Provide individual thermal comfort controls for 50% (minimum) of the remaining 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 (6 meters) inside and 10 feet (3 meters) 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).AND
Provide comfort system controls for all shared multi-occupant spaces to enable adjustments that meet group needs and preferences. Conditions for thermal comfort are described in IEQ credit 7: Thermal Comfort—Design and Verification, and include the primary factors of air temperature, radiant temperature, air speed and humidity. Comfort system control for the purposes of this credit is defined as the provision of control over at least one of these primary factors in the occupant’s local environment.