Entry Type ID Date Applicable Rating System Primary Credit Inquiry (LIs) Ruling (LIs) Related Addenda/LIs Related Resources Campus Applicable Internationally Applicable Country Applicability Reference Guide (Addenda) Page (Addenda) Location (Addenda) Description of Change (Addenda) "LEED Interpretation" "1579" "2006-10-03" "New Construction, Existing Buildings, Commercial Interiors, Core and Shell, Schools - New Construction" "IEQc8.1/8.2: Daylight and Views-Daylight" "For an elementary school project registered under NC 2.1, we are targeting EQ 8.1 and can demonstrate that some regularly occupied spaces meet the daylighting requirement using the calculator/formula in the reference guide, but some do not. The spaces that don\'t comply test well using a light meter. My questions are: 1.) Is it permissable to demonstrate credit compliance using a hybrid approach: The calculation/formula in spaces where that demonstrates compliance and actual measurements where it does not? 2.) What is the correct and prescribed procedure for taking measurements? The reference guide does not provide one. I\'m assuming clear sky conditions and measuring with a light meter on the same size grid required for daylight modeling are part of the protocol - what else? Is the procedure described anywhere? Can you provide the referenced standard for testing or a description of the procedure?" "Yes, it is permissible to use both calculations and actual measurements in order to demonstrate compliance with EQc8.1 requirements. The protocol for taking measurements is outlined in the LEED-NC v2.2 Reference Guide which states that measurements must be taken on a 10-foot floor grid for all occupied spaces and must be recorded on building floor plans. Per the daylight modeling protocol, measurements should be taken 30"" off the floor, under clear sky conditions at noon. Please document the time of year the measurements were taken. Calculations should be taken at solar noon. This is the time of day that divides the daylight hours in half (between sunrise and sunset). Using this definition, daylight savings does not need to be taken into account. Since all measurements can\'t possibly be made all at once right at noon, take them within a reasonable timeframe before and after noon (i.e. between one hour before noon and one hour after noon) and do not take measurements in direct sunlight. Records of indoor light measurement must demonstrate a minimum daylight illumination level of 25 footcandles. Applicable Internationally." "None" "None" "X" "LEED Interpretation" "1727" "2007-04-10" "New Construction, Existing Buildings, Commercial Interiors, Core and Shell, Schools - New Construction" "IEQc8.1/8.2: Daylight and Views-Daylight" "One wall of our building is a curtain wall. This curtain wall contains 4 different types of glazing, each with a different visible transmittance value, all within one room. We propose using the average visible transmittance value of the four types of glazing to do daylighting calculations for areas adjacent to the curtain wall. Please advise whether this approach is acceptable." "No, the method described of taking the overall average visible transmittance value of all four types of glazing within the curtain wall and using it for all areas adjacent to the curtain wall is not an acceptable means of calculating the daylight factor of the areas in question. However, doing a weighted average of the visible transmittance value (Tvis) of all the glazing classified as daylight glazing and a weighted average of the visible transmittance values of all the glazing classified as vision glazing on a room by room basis would be acceptable. This methodology would effectively take into account the window geometry and associated minimum visible transmittance values. Alternatively, the project team may elect to perform a daylight simulation model to demonstrate credit compliance. See the LEED NC v2.1 EQc8.1 ruling dated 6/21/2004 for guidance on pursuing this approach. Applicable Internationally." "None" "None" "X" "LEED Interpretation" "5517" "2003-02-04" "New Construction" "IEQc8.1/8.2: Daylight and Views-Daylight" "Credit IEQ 8.1 requires a minimum Daylight Factor of 2% in 75% of all spaces occupied for critical visual tasks, with the exception of low occupancy areas and spaces where programmed tasks would be hindered by daylight. We are proposing that all non-perimeter laboratory spaces are exempted because daylight would interfere with the research. The CIEMAS facility will provide interdisciplinary research space for Photonics, Bio-Medical Engineering, and Medical Applied Sciences. Laboratories that will be used for light-sensitive Photonics research would be hindered by the presence of daylight. Also, the university anticipates interdisciplinary research between the Photonics and Bio-Medical Engineering departments, and requires the laboratories to accommodate this flexibility. Therefore, these research spaces are located within the building interior. Laboratory spaces that would not be hindered by daylight, such as for Medical Applied Sciences and teaching labs, are located along the building perimeter. " "This credit is addressable by the project if the project can clearly document why the spaces in question are exempted from daylight requirements, AND show that a significant portion of the project is still daylit after the affected spaces are exempted. Applicable Internationally. " "None" "None" "X" "LEED Interpretation" "5563" "2005-02-24" "New Construction" "IEQc8.1/8.2: Daylight and Views-Daylight" "For LEED Credit EQ 8.1, we are attempting to demonstrate that we achieve daylighting for 75% of the occupied spaces in a school. The classrooms are simple, rectangular shapes, with windows on one wall and tubular skylights toward the interior of the room. Using the method outlined in the Reference Guide, we can achieve the 2% daylight factor if our skylight openings equal 12 square feet. Because tubular skylights are more efficient at bringing in light, the actual opening is smaller and thus the calculation does not yield the 2% daylight factor. We used Lumen Micro to simulate the daylighting and can demonstrate that the distribution of light is more even, with the tubular skylights, to that with the larger conventional skylights. Our question has to do with the calculation of the daylight factor. As stated in the Reference Guide, the daylight factor is the ratio of exterior illumination to interior illumination. 1. The exterior illuminance for our site on a clear day is 4,736 footcandles. A 2% daylight factor would require 95 footcandles across the interior grid. 2. The tubular skylights have similar light levels and more evenly distributed light than larger conventional skylights that qualify using the method outlined in the Reference Guide. Nonetheless, they do not meet the 2% daylight factor due to the high exterior illuminance. 3. Using a lighting simulation program, the rooms with north windows yield lower light levels than the rooms with south windows, as would be expected. This difference is not considered using the Reference Guide method. Again, the grid points do not come close to 95 footcandles, however over 90% of the room has light levels of 25 footcandles or higher, the proposed level in LEED NC 2.2. As per the CIR of 4/19/2004, we would only count the portion of the room that achieves 25 footcandles or more. Would these calculations successfully demonstrate meeting the requirements for the daylighting credit? " "Yes, the compliance path referencing 25 footcandles has been identified as providing equivalent performance to the v2.1 credit requirements. Model daylighting strategies with a physical or computer model to assess footcandle levels and daylight factors achieved. Modeling must demonstrate 25 horizontal footcandles under clear sky conditions, at noon, on the equinox, at 30 inches above the floor. Any portions of a room achieving the requirements can qualify for this credit. Alternately, it may be possible to adhere to the standard compliance path. See EQ 8.1 CIR Ruling 2/1/2002 for information on the use of solar tubes in 3D daylight simulations. Applicable Internationally. " "None" "None" "X" "LEED Interpretation" "5671" "2004-06-21" "New Construction" "IEQc8.1/8.2: Daylight and Views-Daylight" "On this project, the space geometries are rather complex to allow a fair use of the calculation method using the geometry and height factors in Table 1 and Equation 1 described in the Reference Guide. Hence, we are using a daylighting simulation program (Radiance) to calculate the daylight factors for this project. The requirement for this credit states, ""Achieve a minimum Daylight Factor of 2% (excluding all direct sunlight penetration) in 75% of all space occupied for critical visual tasks."" To be able to assess the daylighting potential correctly as and as intended we would like to clarify the following: For any given space, should we calculate the daylight factors for points on a grid in the space and make sure that each and every point has at least a 2% daylight factor? OR For any given space, should we calculate the daylight factors for points on a grid in the space and make sure that the average of all the points is at least a 2% daylight factor? Which of the above calculation methods meets the intent of the credit? When we compared the daylight factors of a simple classroom design as calculated by the method outlined in the Reference Guide using Equation 1 and Table 1, with a simulation model of the space, we found that the results of Equation 1 are closer to the average daylight factor in the simulation as opposed to the minimum daylight factor in the simulation. When doing a simulation model to calculate the daylight factors: Do we lay out a grid of points across the entire space at the task height? OR Do we lay out the grid to reasonably exclude parts of the room that will not have tasks? For example in a classroom, the perimeter 2\' adjacent to the walls will never have a desk surface, so can we lay out the grid leaving out the 2\' perimeter of that room? " "To answer your first question, please see the EQc8.1 Ruling dated 4/19/2004, which outlines a method for using daylight simulation data to demonstrate achievement of the credit requirements. Consistent with that ruling, your simulation should lay out a grid of points across the entire space at task height. Points on the grid must achieve a 2% daylight factor in order to be included as part of the 75% qualifying area. The required threshold of 75% of the occupied space accounts for the fact that small fractions of each room may not meet the minimum requirement. Applicable internationally." "None" "None" "X" "LEED Interpretation" "5715" "2004-04-19" "New Construction" "IEQc8.1/8.2: Daylight and Views-Daylight" "Our project involves the renovation of 5 existing historic, residence halls. We were somewhat surprised to find out that student rooms with large existing windows (4\'x6\')with 8\'6"" head height, were coming up short of the 2% daylight level using the LEED calculator. So, we composed a daylighting computer model to study the rooms. In the model, there are small areas of each room that do not meet the 2% requirement. In most cases, this area is the doorway entry area adjacent to a closet. Our question is: In modeling this, does 100% of each student room need to meet the 2% factor? (Realizing that the doorway will not be used for critical tasks such as reading or studying.) In other words, can a small percentage of each room fall below the 2% factor as long as the total 2% daylight area totals more than 75% of the total occupied spaces? " "The LEED v2.0 Calculator (also usable for v2.1) is designed for simple geometries and provides default data to support a simplified analysis. For a more detailed analysis, a daylight simulation such as the one undertaken is an appropriate means to demonstrate meeting the credit\'s requirements. This credit can be approached so that 100% of each room does not have to meet the 2% daylight factor. In order to do so, the portion of the room with a 2% (or higher) daylight factor would count towards the 75% of all space occupied for critical visual tasks. The portion of the room not meeting the 2% daylight factor would not count towards the 75%. In using the LEED v2.0 Calculator, the two portions of the room (the one meeting the 2% daylight factor and the one not meeting the 2% daylight factor) would be counted as separate spaces. The square footage of all compliant spaces is tallied and then divided over the total square footage of all regularly occupied spaces. If the percentage is greater than 75%, then the building qualifies for this credit. Applicable internationally." "None" "None" "X" "LEED Interpretation" "5749" "2004-05-24" "New Construction" "IEQc8.1/8.2: Daylight and Views-Daylight" "Our project is an humane society building, which includes animal adoption, and medical facilities. As a result much of the square footage of the project is for animal holding. Please clarify if the animal holding areas need to be included in the daylight and view calculations. We understand from the guideline that food prep, laundry areas, copy and restrooms are exempt from the calculations. Thank you for your response." "The animal holding areas are not exempt from the requirements for this credit. In this case the occupants include animals, who\'s well-being is also enhanced by daylight. In addition, it is likely that some critical visual tasks will be performed by the human occupants in these spaces. " "None" "None" "LEED Interpretation" "5778" "2003-09-24" "New Construction" "IEQc8.1/8.2: Daylight and Views-Daylight" "Ours is an industrial building with 6 overhead doors ranging in size from 16\'x16\' to 20\'W x 25\'H, every elevation has at least one overhead door. It is an operation requirement that while the building is occupied, the overhead doors are open - there would be NO time at which these doors would be closed with staff and/or public in the building. Given this requirement, can we use the door openings in the daylight and views credits 8.1 & 8.2, using a transmittance of 1.0? Thanks." "It is possible that the overhead doors can be used towards the achievement of EQ credits 8.1 and 8.2, though more information is required to positively determine compliance, including: 1. Where is the building located (city and state) and what is the program? 2. In what official policy and/or document is this operational requirement described? 3. Is the building (and space in question) occupied year-round? 4. Are there adjacent offices and work areas that also benefit from the doors? 5. Calculations and vehicle adjacencies as defined in this ruling. By themselves, the doors may or may not achieve the required quantity of daylight factor and views. Calculations demonstrating achievement of the credit are required. Include typical operational factors in these calculations, i.e., if large vehicles, equipment or freight block much of the aperture during the day, these obstructions must be accounted for in daylight and view calculations. The appropriate geometry factors must be included in calculations for both light and views. Please include a letter certifying that the overhead doors are to be open when the building is occupied. Applicable internationally." "None" "None" "X" "LEED Interpretation" "5907" "2004-09-08" "New Construction" "IEQc8.1/8.2: Daylight and Views-Daylight" "The requirement for this credit states, ""Achieve a minimum Daylight Factor of 2% (excluding all direct sunlight penetration) in 75% of all space occupied for critical visual tasks"" with the exception of low occupancy areas and spaces where programmed tasks would be hindered by the use of daylight. For an elementary school project, we would like to clarify the following to be able to fully assess our daylighting potential: [1] We are proposing that activities undertaken in both the Gymnasium and the Computer Lab in our elementary school project would be hindered by the use of daylight. Both spaces are used periodically throughout the day. Natural light in the computer lab would compromise overhead lesson presentations and glare on the screens would be distracting to students. It is the opinion of some that daylight would also create a distraction in some of the sports activities to occur in the gymnasium. Can we omit these spaces from our calculations? [2] A Credit Ruling for EQc8.2 dated 10/16/01 stated "". . . the book stack area is exempt from the calculation for views required by EQ Credit 8.2."" For Credit 8.1 we would also like to be able to define the critical visual task zone in our Instructional Media Center to not include the stacks area as we feel that this is essentially a support space to the reading and storytelling areas of the library. Please advise if this assumption is acceptable for EQc8.1. [3] The kitchen in our project is to be operated as a ""finishing kitchen"" with a serving area. Since this area is designed to act as a support space to the Multi-Purpose Room/Cafeteria, are we right to assume that not daylighting this space is acceptable?" "The credit requirements for EQc8.1 specifically exclude spaces where tasks would be hindered by the use of daylight. For all questionable spaces to be excluded, please clearly delineate the areas of the project being excluded from the calculations and provide a brief narrative describing the rationale and assumptions made for each excluded area in the certification documentation for this credit. 1. It is a common practice to minimize daylight in computer labs, and so with a proper narrative this space can be excluded from the calculations. Regarding the gym space, many projects have utilized daylight strategies which can limit glare problems in gyms. For instance, diffuse skylights and diffuse windows are often used to mitigate the negative effects of direct sunlight. However it is possible that some gym activities could be hindered by daylighting. Therefore, to exclude the gym space from the calculations, please provide a narrative describing gym activities and how daylighting will hinder these activities. 2. The credit requirements for EQc8.1 specifically exclude support spaces for storage. Therefore, the stacks area of the Instructional Media Center can be excluded if a narrative is provided that describes the primary function of the stacks area as storage. 3. Finishing kitchens are considered a support area and therefore can be excluded from the EQc8.1 calculations. Applicable internationally." "None" "None" "X" "LEED Interpretation" "5937" "2003-08-27" "New Construction" "IEQc8.1/8.2: Daylight and Views-Daylight" "This Credit Interpretation is in reference to an international airline terminal project. In the initial programming and planning meetings for this project, it was determined that for reasons of occupant comfort, safety, and security, some ground-level regularly occupied office space needed to avoid any type of vision glazing. Noise was the principal reason for this decision. The concern was that glazing is not sufficient to insulate these spaces from the very loud and omni-present noise emanating from jet engines. Issues of contaminated outside air entrainment and of security/safety related to glazed areas at ground level also contributed to the decision. While LEED V2.1 asserts that ""exceptions for spaces where tasks would be hindered by the use of daylight will be considered on their merits"", this CIR is being submitted to determine if the USGBC will also consider the exemption of spaces for airline terminals where tasks will be hindered by noise and other factors besides daylight on their merits. It\'s important to note that this condition is only present in the back-of-house spaces. It should be noted that front-of-house spaces are located on upper levels where noise is less of a factor, and that there is a deliberate and extensive use of vision glazing in these areas. " "The office space affected by airplane noise cannot be exempted from the credit calculations. Limited exceptions are solely based on visual considerations. If the project is in a phase where the floor plan can no longer be reconsidered, look further into design solutions such as multi-pane glazing, high sound transmission coefficient (STC) assemblies, noise breaks, smaller oblique apertures, toplighting, etc. Incorporating even a limited amount of glazing will likely enhance occupant well-being. However, LEED requirements still need to be met in order to achieve the daylight and views credits. Contaminated outside air entrainment, security and safety issues are not related to EQ Credit 8 and can be mitigated. Applicable internationally." "None" "None" "X" "LEED Interpretation" "6063" "2004-08-23" "New Construction" "IEQc8.1/8.2: Daylight and Views-Daylight" "We request a credit interpretation for EQ Credit 8.1 and 8.2 Daylight and Views. The project is a 25,361 sf addition to an existing 29,284 sf religious facility. Part of the addition is a multi-purpose center. This area is to be used for four general purposes" "The area in question is designed for multiple use and variable occupancy scenarios. While daylight may not be desirable for some of the stated uses, there are other uses that would benefit from having daylight and access to views. It may be possible to include daylight controls in the design of the space to allow daylight when desired while providing control when the daylight hinders operations. There are many excellent examples of daylit worship centers, and the narrative provided in the CIR request does not provide a compelling argument to justify the exclusion of this space from the daylight and views calculations. Applicable internationally." "None" "None" "X" "LEED Interpretation" "752" "2004-04-19" "New Construction, Existing Buildings, Commercial Interiors, Core and Shell, Schools - New Construction" "IEQc8.1/8.2: Daylight and Views-Daylight" "In regards to LEED Credit 8.1 we would like a definition of regularly occupied spaces and critical visual task areas. Our building is an Institutional Building and therfore contains several spaces that are periodically occupied throughout the day such as, waiting rooms, training rooms, dinning rooms, reading rooms and family research area and a yoga room. We would like to know if these areas fall under the definiton of regularly occupied and critical visual task areas." "The issue of ""regularly occupied spaces"" has been previously addressed in EQ Credit 6.1 ruling dated 11/9/2001. In summary, it is difficult to have a finite definition of ""regularly occupied spaces"" as the programmatic needs for each building will vary, even for common types of spaces. For example, for one project, a waiting room may be considered a transition space only, akin to a lobby, but for another, it may accommodate a workspace and would therefore be classified as ""regularly occupied space"". If various occupants of the building use a space on a regular basis and daylight would not interfere with the tasks performed there, it would meet the criteria for spaces needed to be considered for this credit. Spaces such as training rooms, dining rooms, reading rooms and research areas appear to meet the criteria as they are regularly occupied and would typically benefit from the introduction of daylight. If any space is to be excluded from the calculations, provide a brief narrative to explain rationale and assumptions. Applicable Internationally. " "None" "None" "X"