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" "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" "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" "752" "2004-04-19" "New Construction, Existing Buildings, Commercial Interiors, Core and Shell, Schools - New Construction" "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"