NC-2009 IEQc8.1: Daylight and Views—Daylight

  • NC&CS EQ8.1 Type3 Daylighting Diagram
  • Use a collaborative design process

    Access to daylight inside buildings makes for healthier and more comfortable occupants—and is also linked with greater productivity. When designed with proper glare control and minimized solar heat gain, daylighting provides high-quality light while reducing energy use for lighting and for cooling. Increased daylight through increased vision glazing can help projects earn IEQc8.2 for access to views. Realizing the benefits of daylighting requires a collaborative design process.

    Balance other design goals

    Keep in mind that daylighting strategies must balance with other design goals. For example, you will want to provide enough glazing area for lighting, and plan for open spaces that allow for light transfer, but not at the expense of too much heat gain, glare, or loss of privacy. Incorporating daylighting goals into the early planning stages will help project teams avoid design conflicts at more advanced stages. Daylighting goals should be laid out explicitly in the Owners Project Requirements document required for EAp1: Fundamental Commissioning.

    Documentation can be cumbersome

    This credit is easy to achieve for projects with large windows, open floor plates, and most occupied areas near the perimeter, but the documentation may be cumbersome for some large projects, depending on the chosen compliance path.

  • Changes in LEED-NC v2009 versus v2.2

    Compliance paths for IEQc8.1 have some key differences between v2.2 and v2009. In LEED-NC v2.2, Option 1: Calcualation allows you to show compliance with EQc8.1 by demonstrating over 75% of the regularly occupied areas have a glazing factorThe ratio of interior illuminance at a given point on a given plane (usually the work plane) to the exterior illuminance under known overcast sky conditions. LEED uses a simplified approach for its credit compliance calculations. The variables used to determine the daylight factor include the floor area, window area, window geometry, visible transmittance (Tvis) and window height. of at least 2%. These glazing factor calculations consider window, wall, ceiling and floor areas, glazing type and VLT values.

    In LEED-NC v2009, the glazing factor calculations option has been removed. In v2009, however, the Option 2: Prescriptive method provides a new approach to demonstrate achievement of the credit that considers many of the same factors as the glazing factor calculations from v2.2.

    Another significant difference between v2009 and v2.2 is that v2009 allows for a combination of compliance path options to achieve the credit, via  Option 4.

  • FAQs for IEQc8.1

    What spaces are considered regularly occupied and must be included in the calculations?

    The USGBC's IEQ Space Matrix has detailed guidance that is helpful for any spaces you aren't sure about.

    When should daylight measurements be taken?

    LEED does not prescribe the date or time, but it is recommended that they be taken close to noon under clear sky conditions, and, if possible, on or near one of the two equinoxes.

    Do I need to have glare control devices?

    Yes.

    Where can I find the Supplemental Views and Daylight Calculator?

    On LEED Online, in the credit, under credit resources.

    Do I need to submit the Supplemental Views and Daylight Calculator?

    You must submit a spreadsheet which contains all the information required on the calculator, and submitting the LEED Online calculator is recommended, but some teams have preferred to create their own, and have had them accepted.

    Can I average the compliant square footage between 9 a.m. and 3 p.m. for a space and use the average as the compliant square footage?

    No, the compliant square footage would be the worst-case scenario between the two times. For example, a 900 ft2 space located on the western side of a building is 100% compliant at 9 a.m. but only 50% compliant at 3 p.m. The compliant square footage in this case is 450 ft2.

    What daylight simulation software can I use for LEED compliance?

    LEED doesn’t require certain software to run the compliance calculation. However, the simulation should be able to run under “clear sky” conditions and calculate illuminance levels at 2’-6” above finished floor (AFF).

    Can I use Option 2: Prescriptive method if I have:

    • Windows with different Tvis values within the same wall width?

    • Windows with different head heights within the same wall width?

    • Windows with different sill heights (and above 30”) within the same wall width?

    • Windows with permanent shading devices?

    • Skylights with different Tvis values within the same ceiling area?

    • Clear skylights?

    • Light that is transferred between one room to the next through an interior wall opening—glazed or unglazed?

    • A Tvis/WFR value above 0.180?

    • Rooms that borrow light from an atrium?

    • Roof monitors?

    • Tubular daylighting devices such as Solatube?

    • Roof overhangs?

    • Shared daylighting scenarios?

    No. The only option in any of these cases will be the simulation or the measurement methods.

Legend

  • Best Practices
  • Gotcha
  • Action Steps
  • Cost Tip

Pre-Design

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  • Focus on optimizing building orientation. Look for opportunities to optimize the glazing on each orientation to account for varying heat gain and lighting angles. When selecting a site, look for potential obstacles to daylight such as neighboring buildings, vegetation, and topography.


  • To reduce heating loads, use daylighting strategies in tandem with passive solar heating strategies, such as using materials with greater thermal mass and orienting the building for maximum solar gain.


  • To reduce cooling loads, use overhangs, lightshelves or fins, courtyards, and lightwells to block high-angle summer sun and low-angle morning and afternoon sun. These strategies also reduce glare and can improve daylighting by reflecting it deeper into the building.


  • Glare can become a problem if you have too much glass, or east- and west-facing glass. Using shading devices can allow projects to combat glare and still have large expanses of glazing. Daylighting from the north is consistent and high quality, while daylighting from the south is abundant and comparatively easy to control.


  • Large areas of glazing may cause unwanted heat gain and compromise energy efficiency. However, daylighting may require less glazing than you think—about 40% window-to-wall ratio may be more than you need. Glazing closer to the ceiling will have a greater daylight benefit than glazing near the floor—anything below 30 inches is considered to have no daylight benefit.


  • When programming, identify occupant lighting needs that could be met with daylight. The Illuminating Engineering Society of North America (IES) has prescribed footcandle levels for project types, occupant types, and tasks.


  • Set daylighting goals at the initial goal-setting workshop and incorporate them into the Owners Project Requirements document required for EAc1: Fundamental Commissioning.


  • Having two different sources of daylight in a space will help minimize contrast and shadows.

Schematic Design

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  • Identify regularly occupied spaces that need to be included in the LEED daylight calculation. Locate these spaces near perimeter glazing, courtyards, or other daylight sources.


  • Your project's regularly occupied spaces should be defined consistently across other LEED credits, especially IEQc8.2: Daylight and Views—Views.


  • Some applicable spaces may be exempt from the daylighting calculation if their uses are daylight-sensitive. Examples include museum or gallery spaces, auditoriums and high-security areas. If you have daylight-sensitive spaces in your project that you would like to exempt from the calculation, you must provide a detailed narrative explanation and exemption request along with the credit documentation. This requests are scrutinized carefully, however, and may not be successful.


  • Find out the Visual Light Transmittance (VLT) value of the glazing and enter it on the LEED credit form for each occupied space. The VLT is usually included with the glazing specifications.


  • Take the VLT of the whole window, not just the glazing, to account for shading from mullions.


  • More natural light is transmitted through glazing with higher VLT values, but higher VLT values tend to correlate with higher solar heat gain coefficients (SHGC). Assess the optimal balance of these values, along with U-value, based on the project’s climate and heating and cooling needs. These values are available on manufacturers’ specifications.


  • Hold an integrated design meeting with the architect, interior designers, mechanical engineer, lighting designer and the end users to discuss daylighting-related tradeoffs.   Optimize glazing area while preventing excessive heat gain and glare; and use open space planning that allows for greater light transfer while preserving privacy.


  • Consider designing spaces with narrow floor plates so that most spaces are near windows and have access to daylight.


  • Prescriptive compliance paths for EAc1 (other than energy modeling) do not allow window-to-wall ratios greater than the relevant reference standard. Projects using these compliance paths are limited in the amount of allowable glazing area.


  • Designing for daylighting will allow you to reduce the number of ambient light fixtures and their frequency of use, reducing the cost of electric lighting both upfront and in operations.


  • Retailers may see increased sales linked with daylighting, according to studies showing a correlation between sales and natural lighting. Additional savings may be seen by employers through increased employee retention/satisfaction as well as productivity and reduced absenteeism.


  • Choose a LEED compliance path to verify that the daylighting meets the footcandle requirements of 25–500 footcandles for 75%–90% of regularly occupied spaces.

    • Option 1:  Computer daylight simulations can be the most effective design tool, but hiring a modeler will be an upfront cost.
    • Option 2: Prescriptive LEED calculations can help inform design, but not as accurately as a daylight simulation. The calculations can be time-consuming for large buildings, but do not require expert help.  The prescriptive calculations will only take window, wall, ceiling and floor areas, and glazing type into account, so other methods that help daylighting such as lightshelves and light-colored finishes won’t be factored in.
    • Option 3: Daylight metering can be an inexpensive way to measure actual footcandles, but won’t be accurate until construction is complete, when the results cannot help to inform design.

Design Development

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  • Explore a combination of daylight strategies such as space planning techniques, glazing selection, lightshelves and more.


  • Interior finishes can enhance or hinder daylight levels. Specify light-colored ceiling and wall paint to bounce light further into the room.


  • A common misconception is that a design needs to have more glass for effective daylighting. But effective daylighting can also be achieved with smaller apertures and glazing designed for specific indirect light, located high in a space to bounce light on to a ceiling.


  • Daylight sensors that adjust lamp brightness based on the presence of natural light can greatly reduce lighting energy loads. On average, commercial buildings use 25% of their energy for lighting. Dimming ballasts are more expensive and complicated to specify than stepped ballasts. Stepped lighting is considered less attractive because the dimming is not gradual  but can do an excellent job reducing energy use.


  • Daylight controls, sensors, integrated blinds, and lighting controls come with moderate first costs but will bring energy savings over the long run.


  • Integrate glare control into the design.


  • Identify designs that combine glazing and building elements for optimum daylighting, such as window frames with integrated overhangs or light shelves. However, make sure that there is a thermal break (insulation) between the interior and the lightshelves, or these could become large-scale radiators of interior heat.


  • Glare can hinder the use of a space and be unpleasant for occupants. Daylight modeling can help project teams anticipate problem areas due to sun angles as they interact with the architecture. Exterior and interior shading along with associated controls can greatly reduce the effects of glare.


  • Fill out the LEED credit form with the names of the regularly occupied spaces and their square footage.


  • Simulation is the only way to account during the design phase for daylight designs that have many variables such as the use of lightshelves and light-colored interior finishes. The Glazing Factor Calculation path (Option 1) takes into account only walls, windows, floor and ceiling areas, and the measurement path (Option 3) will not help inform design as much.


  • Option 1:  Computer Simulation


  • Use daylight simulation software to adjust daylight design as needed before it is finalized.


  • Coupling daylight modeling with energy modeling can help project teams make effective decisions about daylighting as it relates to other strategies like thermal massing, window area, window efficiency, and shading.


  • Simulation makes documentation easy by clearly indicating compliant areas.


  • Simulation is the only way to account during the design phase for daylight designs that have many variables such as the use of lightshelves and light-colored interior finishes. The prescriptive  compliance path (Option 2) takes into account only walls, windows, floor and ceiling areas, and the measurement path (Option 3) will not help inform design


  • Daylight simulations may add an upfront cost but they offer fast payback in the form of effective daylighting strategy selection resulting in reduced energy costs.


  • Option 2:  Prescriptive Design


  • Run prescriptive design calculations to verify that the required percentage of floor area meets the required levels.


  • This compliance path does not require modeling and can still help inform decisions during the design phase. However, the documentation and calculations can be complicated and time-consuming.


  • Option 3:  Measurement


  • Measuring daylighting with handheld light meters can be time-consuming for large areas. Also, you are likely to need to defer this credit to the construction phase LEED submittal so that accurate light readings can be taken with interior walls in place.


  • Measurement can account for complex daylight designs but does not help inform the design process. It can only confirm compliance once the space has already been constructed.  At that late phase, it may be too costly to make design changes to bring more floor area into compliance.


  • Measurement is a low-cost compliance method but may not help to optimize daylight during the design phase. An optimized daylight design can cut down substantially on lighting costs over the long run.


  • Option 4: Combination


  • A hybrid compliance path may be the best solution for some projects. For example, if most of the regularly occupied spaces pass the calculation criteria in the prescriptive path, and a portion of the spaces fall short very narrowly or use strategies like lightshelves not accounted for by the prescriptive path, measurement of those spaces after finishes are complete could demonstrate that they are sufficiently daylit after finishes are complete.

Construction Documents

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  • For Options 1 and 2, enter square footage for the portions of the regularly occupied areas that meet the daylight requirements in the LEED credit form and upload all required documents to LEED Online.


  • Incorporate daylight-related items such as lightshelves, daylight sensors, and light-colored paint into specifications.


  • During the value engineering process, ensure that components critical to the daylight design, such as high-performance glazing and internal shading devices, are not removed from the project.

Construction

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  • For Option 3, take daylight measurements with a hand-held light meter and record the values on a 10x10 grid plan. Enter square footage for the portions of the regularly occupied areas that meet the daylight requirement in the LEED credit form and upload all required documents to LEED Online.


  • Measuring daylight levels can be a time-consuming process in large buildings. Measurements are taken on a 10-foot by 10-foot grid, with four measurement points for each 10 ft2 section. Taking and recording each measurement takes about 30 seconds—not including setting up the grid—for a total of about two minutes per grid section.


  • Daylight sensors and other daylight controls should be added to commissioned systems for lighting for EAp1: Fundamental Commissioning.

Operations & Maintenance

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  • Cleaning plans need to integrate the maintenance of interior and exterior shading and control dust so that reflectivity is not compromised.


  • Daylighting controls can be set and tailored for each space. The facility manager or another designated person should be in charge of adjusting the settings to meet the needs of occupants.


  •  Educate staff and occupants on daylight-related and glare-control technologies. Some daylighting controls such as shades or blinds may require occupant operation, and without instruction, may not be used properly, resulting in the building not operating as designed.

  • USGBC

    Excerpted from LEED 2009 for New Construction and Major Renovations

    IEQ Credit 8.1: Daylight and views - daylight

    1 Point

    Intent

    To provide building occupants with a connection between indoor spaces and the outdoors through the introduction of daylight and views into the regularly occupied areas of the building.

    Requirements

    Through 1 of the 4 options, achieve daylighting in at least the following spaces1:

    Regularly Occupied SpacesRegularly occupied spaces are areas 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. Points
    75% 1



    Option 1. Simulation

    Demonstrate through computer simulation that the applicable spaces achieve daylight illuminance levels of a minimum of 10 footcandles (fc1. A footcandle (fc) is a measure of light falling on a given surface. One footcandle is defined as the quantity of light falling on a 1-square-foot area from a 1 candela light source at a distance of 1 foot (which equals 1 lumen per square foot). Footcandles can be measured both horizontally and vertically by a footcandle meter or light meter. 2. The non-metric measurement of lumens per square foot, one footcandle is the amount of light that is received one foot from a light source called a candela, which is based on the light output of a standardized candle. A common range for interior lighting is 10 to 100 footcandles, while exterior daytime levels can range from 100 to over 10,000 footcandles. Footcandles decrease with distance from the light source. The metric equivalent of a foot candle is 10.76 lux, or lumens per square meter.) (108 luxMeasurement of lumens per square meter.) and a maximum of 500 fc (5,400 lux) in a clear sky condition on September 21 at 9 a.m. and 3 p.m.

    Provide glare control devices to avoid high-contrast situations that could impede visual tasks. However, designs that incorporate view-preserving automated shades for glare control may demonstrate compliance for only the minimum 10 fc (108 lux) illuminance level.

    OPTION 2. Prescriptive

    Use a combination of sidelighting and/or toplighting to achieve a total daylighting zone (the floor area meeting

    the following requirements) that is at least 75% of all the regularly occupied spaces.

    For sidelighting zones:

    • Achieve a value, calculated as the product of the visible light transmittance (VLT) and window-to-floor area

      ratio (WFRWindow-to-floor ratio (WFR) is the total area of the window (measured vertically from 30 inches above the finished floor to the top of the glass, multiplied by the width of the glass) divided by the floor area.) of daylight zone between 0.150 and 0.180.

    • 0.150 < VLT x WFR < 0.180



    • The window area included in the calculation must be at least 30 inches (0.8 meters) above the floor.
    • In section, the ceiling must not obstruct a line that extends from the window-head to a point on the floor that is located twice the height of the window-head from the exterior wall as measured perpendicular to the glass (see diagram on the next page).




    • Provide glare control devices to avoid high-contrast situations that could impede visual tasks. However, designs that incorporate view-preserving automated shades for glare control may demonstrate compliance for only the minimum 0.150 value.

    For toplighting zones:

    • The toplighting zone under a skylight is the outline of the opening beneath the skylight, plus in each direction

      the lesser of (see diagram below):

      • 70% of the ceiling height,
      • 1/2 the distance to the edge of the nearest skylight
      • The distance to any permanent partition that is closer than 70% of the distance between the top of the partition and the ceiling.




    • Achieve skylight coverage for the applicable space (containing the toplighting zone) between 3% and 6% of the total floor area.
    • The skylight must have a minimum 0.5 VLT.
    • A skylight diffuser, if used, must have a measured haze value of greater than 90% when tested according to ASTMVoluntary standards development organization which creates source technical standards for materials, products, systems, and services D1003.
    Option 3. Measurement

    Demonstrate through records of indoor light measurements that a minimum daylight illumination level of 10 fc (108 lux) and a maximum of 500 fc (5,400 lux) has been achieved in the applicable spaces. Measurements must be taken on a 10-foot (3-meter) grid and shall be recorded on building floor plans.

    Provide glare control devices to avoid high-contrast situations that could impede visual tasks. However, designs that incorporate view-preserving automated shades for glare control may demonstrate compliance for only the minimum 10 fc (108 lux) illuminance level.

    Option 4. Combination

    Any of the above calculation methods may be combined to document the minimum daylight illumination in the applicable spaces.

    Potential Technologies & Strategies

    Design the building to maximize interior daylighting. Strategies to consider include building orientation, shallow floor plates, increased building perimeter, exterior and interior permanent shading devices, high-performance glazing, and high-ceiling reflectance values; ly, additionally, automatic photocell-based controls can help to reduce energy use. Predict daylight factors via manual calculations or model daylighting strategies with a physical or computer model to assess footcandle levels and daylight factors achieved.

Technical Guides

IEQ Space Matrix - 2nd Edition

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.


IESNA Recommended Practice of Daylighting—Daylight Design Guidance

This is the American industry authority on lighting levels and energy use.  The Illumination Engineering Society of North America (IESNA) publishes several design guides for recommended lighting levels, daylighting and much more.


Window 5.2 computer program—The Lawrence Berkeley National Laboratory

This is a database of window brands, VLT and U-values for different glazing manufacturers.  The program provides a versatile heat transfer analysis method.     


Whole Building Design Guide—Guidance for Daylight Design

This is an excellent resource for researching how to apply different daylight strategies and the implications the design strategies may have.  Includes information on materials and methods of construction as well as calculation tools and software resources.


IEQ Space Matrix - 1st Ed.

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.

Software Tools

Building Lighting System Software Tools Directory

This is a comprehensive list of modeling tools compiled by the U.S. Department of Energy.


Radiance—Lighting Design Software

This daylight modeling tool is widely accepted in the lighting industry.


Virtual Environment Apache Thermal Analysis Software

A simple modeling tool for preliminary light and energy analysis.  Virtual Environment software, or VE-Ware, gives you instant feedback on a building's energy consumption and carbon emissions, as well as benchmarking it against the Architecture 2030 Challenge if it is located in the US.  You can access the carbon and energy calculator through the Revit and SketchUp plug-ins.  


AGi32—Lighting Design Software

This is one of the most frequently used daylight modeling computer simulation programs.  AGi32 offers lighting analysis software for calculations and renderings of electric lighting and daylighting systems.


SketchUp

SketchUp is used to create 3-D graphic models that can help in your daylighting analysis and documentation.

Organizations

Heschong-Mahone Group

This is a lighting group that has published research on the effects of daylighting.


IES—Illumination Engineering Society of North America

This is the organization that sets lighting standards.  The IES also works directly with ASHRAE to develop energy standards.

Publications

Daylighting in Schools: Reanalysis Report

This is a case study for the effects of daylighting on productivity in schools.  Prepared by Heschong Mahone Group for the California Energy Commission.


Psychosocial Value of Space—Whole Building Design Guide

This is a study exploring the relationship of daylighting and other design features on human psychological well being.  By Judith Heerwagen -
J.H. Heerwagen & Associates, Inc.


Windows and Classrooms: A Study of Student Performance and the Indoor Environment

This is a case study for the effects of daylighting on productivity in schools.  Prepared by Heschong Mahone Group.

Prescriptive Compliance

Option 2

To use the prescriptive compliance path, follow a process like the one in this example, which achieves the credit using a combination of side and top lighting.

Daylight Measurement

Option 3

Take daylight measurements with a handheld light meter and record the values on a 10x10 grid. Enter square footage for the portions of the regularly occupied areas that meet the daylight requirement in LEED Online.

LEED Online Forms: NC-2009 IEQ

The following links take you to the public, informational versions of the dynamic LEED Online forms for each NC-2009 IEQ credit. You'll need to fill out the live versions of these forms on LEED Online for each credit you hope to earn.

Version 4 forms (newest):

Version 3 forms:

These links are posted by LEEDuser with USGBC's permission. USGBC has certain usage restrictions for these forms; for more information, visit LEED Online and click "Sample Forms Download."

Design Submittal

PencilDocumentation for this credit can be part of a Design Phase submittal.

667 Comments

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Marisa Picard
Apr 16 2015
LEEDuser Member
5 Thumbs Up

Open Floor Plan with different Tvis Values

Project Location: United States

Can I do prescriptive method of calculation for an open floor plan if the N+W glazing walls of the building have a TvisVisible light transmittance (VLT) (Tvis) is the ratio of total transmitted light to total incident light (i.e., the amount of visible spectrum, 380–780 nanometers of light passing through a glazing surface divided by the amount of light striking the glazing surface). The higher the Tvis value, the more incident light passes through the glazing. of 38% and the South + East glazing walls have a Tvis of 56%?

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Todd Reed Daylight Designer, 7group Apr 16 2015 LEEDuser Expert 11541 Thumbs Up

Yes.
Each façade will have its own daylight zone, so for that floor you will have N,S,E,W with their own determined daylight zone and you will use the corresponding VLT. Each façade gets it own line in the calculations. I would divide the floor area appropriately for each façade.

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Marisa Picard Apr 16 2015 LEEDuser Member 5 Thumbs Up

Thanks Todd.
I'll give that a go.

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MM K
Apr 13 2015
Guest
1748 Thumbs Up

Option 3

For option 3, do measurements have to be taken more than once?

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Todd Reed Daylight Designer, 7group Apr 13 2015 LEEDuser Expert 11541 Thumbs Up

No.

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MM K Apr 13 2015 Guest 1748 Thumbs Up

And the measurements can be taken any day of the year? Is there a specific methodology to follow apart from the height and distance requirements?

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Todd Reed Daylight Designer, 7group Apr 13 2015 LEEDuser Expert 11541 Thumbs Up

There is no specific methodology to taking measurements. They do not have to be taken at a certain time, on a certain day, or under any specific weather condition. Just make sure you have a measurement every 10 SF.

I would suggest that you take them at noon or close to it under sunny skies.

If you are taking measurements to be used to guide future design decisions or make changes, I would say you take a series of measurements under different sky conditions and at different times.

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Cindy Estrada LEED AP BD&C SDS Architects, Inc.
Apr 02 2015
LEEDuser Member
675 Thumbs Up

Regularly Occupied or Not?

Project Location: United States

Hello-
I don't know if anyone has asked this question or not, it is a rather unique situation. Our project is a technical college and this particular building's academic programs revolve around teaching energy efficiency. Our mechanical room is designed such that students will not only have access, but will monitor the buildings systems and record changes. So in essence this room is both mechanical ( which usually not counted as regularly occupied) and laboratory (which would be considered regularly occupied). As with most mechanical rooms it has no day lighting. Wondering if this room would still be exempt or I should count 1/2 with a narrative?
Any thoughts on this?

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Todd Reed Daylight Designer, 7group Apr 03 2015 LEEDuser Expert 11541 Thumbs Up

I would say that it could still be exempt as long as the students just go in there, take the readings, and leave. Even if they go in there on a daily basis, they are only going in there for readings, so if that's the case, I would not worry about it. If you have the space laid out in a way that you are holding classes on a regular basis, then you are on a fine line. Now if the students go in there for say maybe one or two classes a semester, I would not worry about it.

I'm assuming with this type of project you will be going for green building education or the school as tool credit. So you will be discussing how the school is used to teach. As long you clarify in that documentation how they monitor the systems, you should be ok.

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Lisa Fabula Sustainable Project Manager KEMA Services
Mar 26 2015
LEEDuser Expert
699 Thumbs Up

Areas passing at one time but not another

Project Location: United States

If part of the building area passes at 9am but does not pass at 3pm does that mean we cant use that 9am area for that time. Basically what I am getting at is that if at 9am 80 percent of the building is withing the 10-500 fc1. A footcandle (fc) is a measure of light falling on a given surface. One footcandle is defined as the quantity of light falling on a 1-square-foot area from a 1 candela light source at a distance of 1 foot (which equals 1 lumen per square foot). Footcandles can be measured both horizontally and vertically by a footcandle meter or light meter. 2. The non-metric measurement of lumens per square foot, one footcandle is the amount of light that is received one foot from a light source called a candela, which is based on the light output of a standardized candle. A common range for interior lighting is 10 to 100 footcandles, while exterior daytime levels can range from 100 to over 10,000 footcandles. Footcandles decrease with distance from the light source. The metric equivalent of a foot candle is 10.76 lux, or lumens per square meter. range and at 3pm the building is also at 80% but some of the areas are in different locations. Meaning that they dont share all the same area. Would this still work. Or is the area that does not pass at 3pm disqualify an area that would have passed at 9am?
Thanks in advance

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Todd Reed Daylight Designer, 7group Mar 27 2015 LEEDuser Expert 11541 Thumbs Up

Lets look at this by a room to room basis and not as a whole building. You will be completing the calculator by listing individual spaces, so this is the best way to think about it. So if a room is 90% compliant at 9am but only 80% compliant at 3pm, then the room is 80% compliant.

The lowest percentage at either time is the compliant square footage that is used in the calculator. So if a space is not compliant at 9am, but is at 3pm, its not compliant at all.

Hope that helps!

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Lisa Fabula Sustainable Project Manager, KEMA Services Mar 27 2015 LEEDuser Expert 699 Thumbs Up

Yes it does very much. Thank you so much!

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shane lucero rsp architects
Mar 23 2015
LEEDuser Member
2 Thumbs Up

Supplemental Calculation Spreadsheet

Hello,

Where would I find the Supplemental Daylight and Views Calculation Spreadsheet for v2009 (LEED Online states it's "found under 'Credit Resources'")?

Thank you.

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Todd Reed Daylight Designer, 7group Mar 24 2015 LEEDuser Expert 11541 Thumbs Up

Under the old platform, credit resoources was located right on the credit page. Under the new platform, click on credit library, then scroll down to the daylight credit and click on that. In the credit, click on resources and that is where you will find the views and daylight calculator for download.

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Todd Reed Daylight Designer, 7group Mar 24 2015 LEEDuser Expert 11541 Thumbs Up

Let me expand that a little more. In the new platform, in the project, click on the credit, underneath the credit you get 5 options, form, upload, resources, credit library. That is where you click on the credit library.

You could also such go to the credit library through USGBC's website and download it.

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ben chouinard
Mar 13 2015
Guest
2 Thumbs Up

Does Revit daylight analysis satisfy CaGBC for IEQc8.1

Project Location: Canada

Can anyone confirm if the in-house plugin for Revit 2015 will be accepted for IEQc8.1 simulation?

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Todd Reed Daylight Designer, 7group Mar 24 2015 LEEDuser Expert 11541 Thumbs Up

I do not see any issues that would not keep the results from being accepted. There is no specifc guidance in v3 as to which simulation program is required or what the simulation program must do. With the Revit daylight analysis, you will get the time in point calculations,it will provide the floor plan showing the daylight sim results, and it will provide a spreadsheet showing the actual fc reading per room.

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Paul Rogers Architect BAU Architects
Mar 02 2015
LEEDuser Member
112 Thumbs Up

Acceptable methods of Glare Control

I know that glare control is a requirement for each window. The reference manual gives a list of these to be: fixed exteror shading devices, light shelves, interior blinds and louvres, fritted glazing and electronic black out glazing.

Has anyone ever heard of an instance where glazing with a lower LT could be considered as glare control?

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Todd Reed Daylight Designer, 7group Mar 02 2015 LEEDuser Expert 11541 Thumbs Up

I personally have not seen anyone make a successful argument for LEED. Now we can discsuss how low VLTs do help reduce or eliminate some forms of glare in the interior and how that effects daylight and what not, but unless you get a LI (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) passed through the TAGLEED Technical Advisory Group (TAG): Subcommittees that consist of industry experts who assist in developing credit interpretations and technical improvements to the LEED system., you are going to need something else.

Personally I believe that only form of glare control device that should be accepted is some form of movable blinds or shades. Exterior shading devices or lightshelves will only block the sun for certain times and angles. The only way to cover all possible forms of glare and possible occurrences is with movable blinds. The other reason is for if and when the space becomes over illuminated with to much daylight, it is possible in spaces that are not designed with daylight in mind. Then what are the occupants left with?

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Weidong Luo Ecotech International
Jan 28 2015
Guest
75 Thumbs Up

where to download?

Project Location: China

When working on leedonline for this credit, we are told to Download, complete and upload the Supplemental Daylight and
Views Calculation Spreadsheet (found under "Credit Resources").
The problem is, we cannot locate where the Credir Resource is or where to download the spreadsheet. Anybody can help?
Thanks,
David

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Weidong Luo Ecotech International Jan 28 2015 Guest 75 Thumbs Up

We found it already, thanks.

David

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Caroline Hedin Architect, studio point253 Feb 13 2015 LEEDuser Member 1215 Thumbs Up

I abhor this new layout. I could not find it either and after hours, discovered it here: http://www.usgbc.org/node/2614118?view=resources

I realize you have already found it but others may be struggling with the same issue so I thought we could help them.

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Michael Russo Architect in Training / Sustainability Specialist Weddle Gilmore Black Rock Studio
Jan 07 2015
Guest
4 Thumbs Up

Hello, I am documenting this

Project Location: United States

Hello,

I am documenting this credit using the simulation method. For many of the regularly occupied spacesRegularly occupied spaces are areas 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 rooms are above the 10fc requirement except for a small corner of the room. Based on reading this thread, my understanding is that the % of the room that is daylit can be counted towards the total required daylit SF. Is that correct?

Or if a room has an area that is below 10fc, then is that entire room disqualified? Thanks for your help!

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Todd Reed Daylight Designer, 7group Jan 09 2015 LEEDuser Expert 11541 Thumbs Up

Michael,

With the simulation method, what ever area in a room that is above 10fc and below 500 fc at both 9am and 3pm, that is your compliant square footage.

For example, a 200 sq ft room has 190 sq ft within the range at 9am and 180 sq ft within the range at 3pm, then your compliant square footage for the space to be entered into the calculator would be 180 sq.

If some of the area of a room is below or above any limit, it does not disqualify the entire space, only the sq footage.

Hope that clarifies your issue.

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Michael Russo Architect in Training / Sustainability Specialist, Weddle Gilmore Black Rock Studio Jan 09 2015 Guest 4 Thumbs Up

Thanks for your fast response!

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Lisa Fabula Sustainable Project Manager, KEMA Services Mar 26 2015 LEEDuser Expert 699 Thumbs Up

Michael Question.

If part of the building area passes at 9am but does not pass at 3pm does that mean we cant use that 9am area for that time. Basically what I am getting at is that if at 9am 80 percent of the building is withing the 10-500 fc1. A footcandle (fc) is a measure of light falling on a given surface. One footcandle is defined as the quantity of light falling on a 1-square-foot area from a 1 candela light source at a distance of 1 foot (which equals 1 lumen per square foot). Footcandles can be measured both horizontally and vertically by a footcandle meter or light meter. 2. The non-metric measurement of lumens per square foot, one footcandle is the amount of light that is received one foot from a light source called a candela, which is based on the light output of a standardized candle. A common range for interior lighting is 10 to 100 footcandles, while exterior daytime levels can range from 100 to over 10,000 footcandles. Footcandles decrease with distance from the light source. The metric equivalent of a foot candle is 10.76 lux, or lumens per square meter. range and at 3pm the building is also at 80% but some of the areas are in different locations. Meaning that they dont share all the same area. Would this still work. Or is the area that does not pass at 3pm disqualify an area that would have passed at 9am?
Thanks in advance

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Ema S
Nov 12 2014
Guest
478 Thumbs Up

Rolling Shades

Are rolling shades mandatory when doing the prescriptive method?

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Jill Dalglish, PE Senior Engineer, Dalglish Daylighting Nov 13 2014 LEEDuser Expert 5745 Thumbs Up

Some type of glare control is required for all methods. Rolling shades are one type.

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Sara Zoumbaris Sustainable Design Consulting
Oct 23 2014
LEEDuser Member
263 Thumbs Up

Medical Center MRI, CT Scan Rooms

Project Location: United States

Although the October 2013 Matrix, does not allow any patient rooms to be without daylighting/ views, I believe these rooms could be eliminated due to the nature of their process. Has anyone dealt with these rooms before in a medical center setting?

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Todd Reed Daylight Designer, 7group Oct 23 2014 LEEDuser Expert 11541 Thumbs Up

Because of the required shieldingShielding is a nontechnical term that describes devices or techniques that are used as part of a luminaire or lamp to limit glare, light trespass, or sky glow. for a MRI room and what occurs during the scanning, of both MRI and CT, you can exclude these rooms from the calculations.

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Chris DeGroot Mr, Neumann Monson PC Jan 07 2015 LEEDuser Member 60 Thumbs Up

We have incorporated daylighting into CT rooms in the past. Check on the distance/elevation of required shieldingShielding is a nontechnical term that describes devices or techniques that are used as part of a luminaire or lamp to limit glare, light trespass, or sky glow.. You could potentially just use top lighting or if adequate distance is provided, side lighting. Daylight in these rooms is highly desirable for the staff and patients.

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Paul Rogers Architect BAU Architects
Oct 20 2014
LEEDuser Member
112 Thumbs Up

Hot desks as regularly occupied space?

Project Location: Sweden

Should an area designated for hot desking be included as a regularly occupied area? No single user will spend more than one hour per day at these workstations.

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Todd Reed Daylight Designer, 7group Oct 20 2014 LEEDuser Expert 11541 Thumbs Up

Yes, its still considered a workstation, and why wouldn't you want these spaces to have daylight.

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Jill Dalglish, PE Senior Engineer, Dalglish Daylighting Oct 20 2014 LEEDuser Expert 5745 Thumbs Up

Todd, it is a workstation, but why would it be considered regularly occupied if it doesn't fulfill the one hour requirement?

I agree that I personally would want these spaces to have daylight.

Paul, these are very hot hot stations!

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Todd Reed Daylight Designer, 7group Oct 20 2014 LEEDuser Expert 11541 Thumbs Up

Jill, there are numerous spaces listed in the regularly occupied space matrix that you could easily say, will be occupied for less than one hour and therefore are not considered regularly occupied. But to avoid the continuous argument as to what is and is not regularly occupied, they listed a bunch of spaces. Well, they haven't listed every single type of space out there. So you take these spaces that are not specifically listed in the matrix and then group them with what type of activity occurs in this space. Hot desk, people getting together to discuss items, review documents etc. etc. You could say the same for a conference room. You could argue they are different and that a hot desk is only meant for "quick" get togethers, where as conference rooms are not. But I could argue that you could meet at a Hot desk for more than an hour. Where are hot desks typically located? Within an open office plan off to one side where teams can gather. How can you not list that as regularly occupied, its not circulation.

So it is best to place the space based on activity rather than argue that it is "meant" to be used for less than one hour, even though it could be used for more than hour.

You can make

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Jill Dalglish, PE Senior Engineer, Dalglish Daylighting Oct 20 2014 LEEDuser Expert 5745 Thumbs Up

Thanks. Also, it was good to remind myself that the one hour per person isn't a requirement as much as a guideline.

Paull, I think Todd is right and if you're going to try to exclude these spaces you're going to have to provide a very strong case as to why no one would want to use them for more than an hour. When I think of non-regularly occupied spacesRegularly occupied spaces are areas 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. based on the time guideline, I think of a corridor, as he mentions, or a small copier station for example.

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Paul Rogers Architect, BAU Architects Oct 21 2014 LEEDuser Member 112 Thumbs Up

Great. Thanks so much for your help.

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Eddy Santosa Lead Building Performance Analyst Callison
Sep 26 2014
LEEDuser Expert
3476 Thumbs Up

DIVA day conference in Seattle - October 2nd 2014

DIVA Day is a full-day event focused on the use of DIVA and associated simulation tools to improve and enhance design through performance-based, especially daylight, workflows including presentations by practitioners and researchers at leading architectural, consulting, and engineering firms and universities.

http://diva4rhino.com/diva-day-2014

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Christine Spendiff
Sep 08 2014
Guest
88 Thumbs Up

Conference Rooms with folding partitions

I have a large conference room with a folding partition to create two smaller conference rooms. Do I run the simulation with the partition open (one large room) or closed (two small rooms)?

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Todd Reed Daylight Designer, 7group Sep 09 2014 LEEDuser Expert 11541 Thumbs Up

Run without the partition. Movable partitions are not to be considered.

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Stella Stella
Sep 01 2014
Guest
237 Thumbs Up

Option 3 daylight measurement

Hi,
We are proposing to carry out the Option-3 daylight measurement in our project to demonstrate compliance. I would like to know if the measurements could be taken before the furniture have been installed or should it be done after the complete fit out with the furnitures installed ?Please advice.

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Todd Reed Daylight Designer, 7group Sep 02 2014 LEEDuser Expert 11541 Thumbs Up

The measurements can be taken prior to the furniture being installed to document the credit.

I would also say that you take measurements after the furniture is installed. It can show you the effect furniture has on the daylight conditions of the space. Spaces are designed to provide the best daylight, then ignore the furniture layout and color. This can result in the wrong color of furniture or layout negating on the daylight design put into the space.

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Stella Stella Sep 03 2014 Guest 237 Thumbs Up

Thank you Todd.

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MM K Apr 13 2015 Guest 1748 Thumbs Up

For this option, is there a specific methodology and conditions that must be followed or just a simple measurement?
Thanks

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Terry Squyres Principal GWWO Inc./Architects
Aug 21 2014
Guest
901 Thumbs Up

Museum/Visitor Center Exhibit rooms

We are documenting this credit and ran up against an issue. While we have exhibit spaces currently listed under regularly occupied spacesRegularly occupied spaces are areas 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. under Plf2. We are attempting to exclude them for IEQc8.1 and 8.2 calculations as they are spaces that we typically like to control the lighting. Have others tried this in a narrative approach and been denied the point? Is this another futile argument like auditorium spaces?

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Todd Reed Daylight Designer, 7group Aug 21 2014 LEEDuser Expert 11541 Thumbs Up

Even though general gallery spaces are considered regularly occupied as noted in the space matrix, you can provide a narrative to exclude them. An exhibit, such as art, which cannot have direct sun could be excluded. A natural or living exhibit which requires certain types of daylight could be excluded.
But this exclusion is based on how well your narrative is written for the exclusion. A narrative that says, "some exhibits can't have daylight" and that's it, will be challenged. Be specific and use real examples and state how daylight is a detrement to the exhibit. If it's nothing more than you want to control the lighting levels, that will not be accepted either.

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Lilian Martins Sustainability Consultant, BArch, MSc MLM Consulting Engineers
Jul 22 2014
LEEDuser Member
26 Thumbs Up

Radiance and Ecotect

Is it mandatory to run the model on Radiance when the model has been built up on Ecotect?
I have been facing issues on installing Radiance because of my computer windowns version.

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Eddy Santosa Lead Building Performance Analyst, Callison Jul 22 2014 LEEDuser Expert 3476 Thumbs Up

The reason is that Ecotect only can run under uniform or overcast sky. You can install desktop radiance version.

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Todd Reed Daylight Designer, 7group Jul 22 2014 LEEDuser Expert 11541 Thumbs Up

Whats your issue with Radiance, can you not get installed or can;t you get it to run with Ecotect? If you could expand your issue i may be able to help. I'm running the latest of everything and have had no issue with installing Radaince. Linking them all together was tricky.

http://web.mit.edu/SustainableDesignLab/projects/TeachingResources/Getti...

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Lilian Martins Sustainability Consultant, BArch, MSc, MLM Consulting Engineers Jul 22 2014 LEEDuser Member 26 Thumbs Up

Thanks for your responses.
Radiance is not installed properly for an unknow reason. Radiance doesnt find rview and falsecolour.exe files. When I run the simulation and try to import the results, it says: invalid file format - no data found.

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Todd Reed Daylight Designer, 7group Jul 22 2014 LEEDuser Expert 11541 Thumbs Up

Ahh yes, i had that problem. You need to install desktop radiance and link those files. When you setting up the simulation in Ecotect, do you get all green checks on your links?If so, where are you saving the sim file. It should have a very short path name. I save it to my C drive to get results then move it to the server.

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Lilian Martins Sustainability Consultant, BArch, MSc, MLM Consulting Engineers Jul 22 2014 LEEDuser Member 26 Thumbs Up

Todd, the link you sent below is of help! Thanks very much for this! Now the green checks are all OK and the simulation is running properly!

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Eddy Santosa Lead Building Performance Analyst, Callison Jul 22 2014 LEEDuser Expert 3476 Thumbs Up

If the software can't find the file, it is usually caused by newer version radiance that you installed. You can try older version of radiance. I believe the newer one is no longer use falsecolor.exe, but,as i remember, it uses falsecolor2. Check your radiance folder whether you have the file that the error mentioned.

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John Covello LEED AP BD+C, EBOM, LEED and Sustainability Manager Development Management Group
Jul 17 2014
LEEDuser Member
512 Thumbs Up

Method 3 Measurement for Hotel Guest Villas

I have a couple of questions:
We have a hotel project with 80 villas that are grouped into building blocks of 4 and 6. Would we have to take measurements for each individual villa or could we use the measurements for one villa and duplicate it over the other ones in it's block?
Would a butler pantry count as a regularly occupied space? The butler would be in there only part of the time for housecleaning and to prepare simple meals.

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Todd Reed Daylight Designer, 7group Jul 18 2014 LEEDuser Expert 11541 Thumbs Up

The only way i see being able to measure one and use it for all others is if they are all orientated the same way and there is nothing surrounding them such as trees or buildings. You would have to have a clear narrative on using this method and clearly demonstrate that there is nothing effecting the daylight distribution of any of the villas.

If it were just a pantry, just storage, then it could be excluded. However, you state that the preparation of meals will occur in the pantry. As noted in the regularly occupied space matrix dated October 2013, residential kitchens must be included as regularly occupied. Hotel guest rooms fall under the residential category. I'm not exactly clear as to what is in this pantry. If there is a stove and refrigerator then there is no getting around this. However, if the preparation of meals in this space is just the butler making a sandwich on a counter and there are no food preparation appliances in the space. Then you could argue that it is not a true kitchen and could be excluded.

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ÅF Lighting ÅF Infrastructure
Jul 03 2014
Guest
16 Thumbs Up

Automatic shading to control glare

To whom it may concern,
We are involving a project going to be built in Uppsala, Sweden. Its aim is to get the LEED 2009 certification for this building.
So to get a point of IEQ Credit 8.1 (Daylight), we saw that if in its manual, page 549, says that “However, designs that incorporate view-preserving automated shades for glare control may demonstrate compliance for the minimum 25 fc1. A footcandle (fc) is a measure of light falling on a given surface. One footcandle is defined as the quantity of light falling on a 1-square-foot area from a 1 candela light source at a distance of 1 foot (which equals 1 lumen per square foot). Footcandles can be measured both horizontally and vertically by a footcandle meter or light meter. 2. The non-metric measurement of lumens per square foot, one footcandle is the amount of light that is received one foot from a light source called a candela, which is based on the light output of a standardized candle. A common range for interior lighting is 10 to 100 footcandles, while exterior daytime levels can range from 100 to over 10,000 footcandles. Footcandles decrease with distance from the light source. The metric equivalent of a foot candle is 10.76 lux, or lumens per square meter. illuminance level). Moreover, in page 554, it says that:
“To control glare, use any of the following common strategies:
• Fixed exterior shading devices,
• Exterior light shelves,
• Interior light shelves,
• Interior blinds and louvers,
• Operable draperies and blinds
• Fritted glazing
• Electric blackout glazing”
Now the question is if we used one of the above systems to control glare, can we skip to exclude all values above 500 fc? And also, is it possible to use a screen printed glass to prevent glare and then again skip to exclude all luxMeasurement of lumens per square meter. level above 500 fc?

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Jill Dalglish, PE Senior Engineer, Dalglish Daylighting Jul 03 2014 LEEDuser Expert 5745 Thumbs Up

Screen printed glazing is equal to fritted glazing, so it can be used to control glare.

The only thing that allows you to take the exemption on page 549 is view-preserving automated shades that are controlled with a photocell. They want to make sure that the shades are opened when the glare condition is not present.

If you are running into a lot of cases with values above 500 fc1. A footcandle (fc) is a measure of light falling on a given surface. One footcandle is defined as the quantity of light falling on a 1-square-foot area from a 1 candela light source at a distance of 1 foot (which equals 1 lumen per square foot). Footcandles can be measured both horizontally and vertically by a footcandle meter or light meter. 2. The non-metric measurement of lumens per square foot, one footcandle is the amount of light that is received one foot from a light source called a candela, which is based on the light output of a standardized candle. A common range for interior lighting is 10 to 100 footcandles, while exterior daytime levels can range from 100 to over 10,000 footcandles. Footcandles decrease with distance from the light source. The metric equivalent of a foot candle is 10.76 lux, or lumens per square meter., you have a lot of glare. Glare is the biggest design concern with daylighting. In reality, you don't need a high quantity of daylight in the interior of a building because eyes will adjust to the level available (to a point.) Even, high quality illumination is better.

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FABIO VIERO Head of Sustainability Manens-Tifs s.p.a.
Jun 30 2014
LEEDuser Member
875 Thumbs Up

Forniture in IEQc8.1 option 1

Dear all,
I'm now working on a project (office building, new construction) under LEED NC v2009 Certification.
Can you confirm that the non-permanent forniture (not used as functional distribution, e.g. internal walls) is excluded from the model (e.g. cabinets, desks,..)?
I've not found any specific note about that into the reference guide.
Thank you so much.

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Jill Dalglish, PE Senior Engineer, Dalglish Daylighting Jun 30 2014 LEEDuser Expert 5745 Thumbs Up

There are no specific mentions of furniture in the credit. It is generally agreed that it is optional. However, you might be surprised at the difference it makes in your calculations and should include it for a more complete analysis. At the very least, you need to know what the typical desk height is in order to set the vertical level of your calculation plane. If it is a child's classroom or a maintenance shop, adjust accordingly.

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Paul Rogers Architect BAU Architects
May 09 2014
LEEDuser Member
112 Thumbs Up

Benifit of view-preserving automated shades?

I understand that if view–preserving automated shades are incorporated, that the project need not comply with the 500fc requirement. Can someone please help clarify for me the logic that for exemption from this threshold that the shades must be automated?

For energy calculations, I understand the logic behind the practice having solar shading automated for their effect to be included. A building user when thermally uncomfortable is likely to adjust the thermostat before the solar shading. However, I do not think that this is not the case for daylight/glare. A building user who is subject to glare is very likely to make adjustments to the curtains, drapes or blinds on an as needed basis. Whereas with, an automated system, the shades are often triggered regardless of whether or not a building user is subject to glare.

Do other group members agree with the above or is it do they feel that it is an advantage to have automated shades for glare?

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Jean Marais b.i.g. Bechtold DesignBuilder Expert May 09 2014 LEEDuser Member 9718 Thumbs Up

The problem is that if you have a bad design with constant glare problems, the user will endup just leaving the shading in place with the lights on...even if the conditions improve and the shading is no longer required, he won't make the adjustment to open the shading because he does not experience discomfort in his current state. However, he is (perhaps subconciously) robbed of his views and no daylighting happens and the lights don't turn off. This defeats the intent of the credit.

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Todd Reed Daylight Designer, 7group May 09 2014 LEEDuser Expert 11541 Thumbs Up

Not only what Jean said, but also with automated shades, they will come down at a certain level, so its assumed that the space will never reach an illuminance level that will be uncomfortable. Although, people are more acceptable to high daylight levels, including levels well over 500 fc1. A footcandle (fc) is a measure of light falling on a given surface. One footcandle is defined as the quantity of light falling on a 1-square-foot area from a 1 candela light source at a distance of 1 foot (which equals 1 lumen per square foot). Footcandles can be measured both horizontally and vertically by a footcandle meter or light meter. 2. The non-metric measurement of lumens per square foot, one footcandle is the amount of light that is received one foot from a light source called a candela, which is based on the light output of a standardized candle. A common range for interior lighting is 10 to 100 footcandles, while exterior daytime levels can range from 100 to over 10,000 footcandles. Footcandles decrease with distance from the light source. The metric equivalent of a foot candle is 10.76 lux, or lumens per square meter.. Without automated shades, it is not known whether someone would actually get up and pull the shades, therefore the daylight scenario must be designed to not exceed that level.

I have no problem with this option in LEED. The hardest element to design for in a building is the occupant. However, i believe that with proper occupant education, we don;t need all these automated controls. All to often we design these high tech automated controls and never tell the occupants anything. Then facilities is doing nothing but answering questions as to why this is doing this or that. One thing we neglect is to educate those who will use these spaces. I see way too much during an occupancy walk through of project where teachers have never been told anything about the lighting controls, thermostats, or why there are these "thingys" hanging from the outside of the buildings. To me it means failure and thats why you see sensors taped and all kinds of methods to override or disconnect those expensive control systems. I could go on about this topic but i believe there is word limit in posts.

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Librarian Librarian Librarian Lord, Aeck & Sargent
May 08 2014
LEEDuser Member
110 Thumbs Up

Include or Exclude a classroom auditorium

We are doing an addition to a classroom building on a college campus. A ~100 seat auditorium style classroom makes up about 25% of the regularly occupied space of the building. Has there been any precedent for auditoriums and/or classrooms being allowed to be excluded from calculations? The space will be used heavily for AV and distance learning presentations which will require specific lighting conditions.

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Todd Reed Daylight Designer, 7group May 08 2014 LEEDuser Expert 11541 Thumbs Up

Since its a classroom, it cannot be excluded. Also, even if it were an Auditorium by use, the Regularly Occupied Space Matrix dated October 2013 states that they must be considered regularly occupied.

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Kristina Abrams AIA, LEED AP BD&C Ayers Saint Gross, Inc.
Apr 24 2014
LEEDuser Member
77 Thumbs Up

Daylight Simulation Modeling Topography

Our current daylight simulation shows hotspots along a window wall that is shaded by existing trees and topography. We did not model the topography as part of the simulation. How can we account for trees and topography in the simulation

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Jill Dalglish, PE Senior Engineer, Dalglish Daylighting Apr 24 2014 LEEDuser Expert 5745 Thumbs Up

I guess I don't understand why you can't include the trees and topography in the simulation?

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Todd Reed Daylight Designer, 7group Apr 24 2014 LEEDuser Expert 11541 Thumbs Up

As Jill stated, why can;t you?

You can definitely include topography into your simulation and it should be to determine actual levels. How its modeled depends on your program. Use simple geometries for items in the near vicinity. I have modeled a mountain, (what we call mountains in PA) for a project that was located on the north slope of the mountain and for one located in the valley in the Pittsburgh. Morning and evening low sun angles were non- existent because of the terrain.

Vegetation can be tricky,especially if its deciduous trees, and what values of transparency do you use based on tree type and depth of the woodline. Vegetation is a great element to use to help with direct solar issues.

I use simple planes for trees and make my best judgement on transparency of the canopy. You can sometimes get this information about the canopy density from arborist books to help determine the transparency.

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Ahmet D
Apr 23 2014
Guest
144 Thumbs Up

Who does it ?

Isn't it usually calculated & completed by electrical engineer ?

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Jill Dalglish, PE Senior Engineer, Dalglish Daylighting Apr 25 2014 LEEDuser Expert 5745 Thumbs Up

Hello Ahmet,

Are you asking who fills out the daylighting LEED form? I would say that most of the time the architect fills out the form.

If a firm is contracted to perform daylighting simulations, it can be a wide variety of disciplines such as a lighting designer, daylighting designer, LEED specialist, or electrical engineer. In this case, it is usually the person who does the simulation who fills out the LEED form.

If the credit is achieved by the measurement option, it can be anyone who knows how to use a light meter. I guess in this case it is most likely the electrical engineer or architect, but could also be the building engineerA qualified engineering professional with relevant and sufficient expertise who oversees and is responsible for the operation and maintenance of mechanical, electrical and plumbing systems in the project building., facilities manager, LEED specialist, or the lighting or daylighting designer.

Jill

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Sara Zoumbaris Sustainable Design Consulting
Apr 22 2014
LEEDuser Member
263 Thumbs Up

Daylight Option 2- Borrowing Light

Hello All,

We have a project that is relying on quite a bit of borrowed light for their interior spaces. I was told by a colleague that in NCv2.2, borrowed light was allowed but we cannot find any information saying it is or is not allowed with version 2009 (aside from LEED user's exclamation above.) Are we sure as a community this is not an acceptable route and can someone prove it to me via a comment by a reviewer etc?

Thanks!

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