NC-v2.2 EQc8.1: Daylight and Views—Daylight 75% of Spaces

  • NC22_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 significantly reducing energy use for lighting and for cooling. Increased daylight through increased vision glazing can help projects earn EQc8.2 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 daylighting, 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 CommissioningThe process of verifying and documenting that a building and all of its systems and assemblies are planned, designed, installed, tested, operated, and maintained to meet the owner's project requirements..

    Documentation can be cumbersome

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

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 while accounting for varying heat gain and lighting angles. When selecting a site, look for potential obstacles to daylight such as shading from 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 instead with daylight. The Illuminating Engineering Society of North America (IES) has prescribed foot-candle 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 that can cause eye strain.

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 EQc8.2: Daylight and Views—Views. Note that aisles between open plan workstations are considered part of that occupied space and if not included skew the results of the calculation.


  • Some “regularly occupied” 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.

 Previous CIRs offer some guidance for this. Note that this path is approved on a case-by-case basis and may not succeed.


  • 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 and satisfaction as well as productivity and reduced absenteeism.


  • Choose a LEED compliance path to verify that the daylighting meets a minimum glazing factor of 2% for at least 75% of all regularly occupied spaces or a minimum of 25 footcandles for at least 75%of regularly occupied spaces. If 95% of regularly occupied spaces meet the credit requirements, a project can earn an point via IDc1 for Exemplary Performance.

    • Option 1: Glazing factor 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.  These calculations will only take window, wall, ceiling and floor areas, glazing type and VLT values into account, so other methods that help daylighting such as lightshelves and light-colored finishes won’t be factored in. Glazing Factor is the ratio of interior illuminance at a given point on a given plane (usually the work plane) to the exterior illuminance under known overcast conditions.
    • Option 2: Computer daylight simulations can be the most effective design tool, but hiring a modeler will be an upfront cost.
    • 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 open 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 glazing for effective daylighting. 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 bringing light deeper into a space.


  • 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 up front and complicated to specify than stepped ballasts. However, stepped lighting is considered less attractive because the dimming is not gradual and can be distracting to occupants 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.


  • 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.


  • Identify the regularly occupied spaces and their square footage.


  • Option 1:  Glazing Factor Calculation


  • Run prescriptive design calculations to verify that the required percentage of regularly occupied areas meets the required levels for credit compliance. Use the LEED EQc8.1–8.2 Glazing Factor and Access to Views Calculation to enter the names of the regularly occupied spaces, their square footage, and the corresponding VLT value of the glazing.


  • Identify the glazing type within each regularly occupied space. The LEED Reference Guide includes a helpful figure (p. 374) and chart of daylighting design criteria (p. 375) to help determine glazing type. The possible glazing types identified by LEED include the following:

    • Vision Glazing – Sidelighting (window areas between 2’6” – 7’6”)
    • Daylight Glazing – Sidelighting (window areas above 7’6”)
    • Vertical Monitor – Toplighting
    • Sawtooth Monitor – Toplighting
    • Horizontal Skylight – Toplighting


  • For Option 1, find out the Visual Light Transmittance (VLT) value of the glazing and enter it on the LEED EQc8.1–8.2 Glazing Factor and Views Calculator 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 a higher VLT value tends to correlate with a higher solar heat gain coefficient (SHGC). Assess the optimal balance of these values, along with U-value, based on the project’s climate and heating and cooling needs, as well as the orientation of each elevation. These values are available on manufacturers’ specifications.


  • Confirm glare control exists for each window.


  • 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 2:  Daylight Simulation Model


  • 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 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.


  • 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 3:  Daylight 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.

Construction Documents

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  • For Option 1, use the LEED EQc8.1–8.2 Glazing Factor and Views Calculator to confirm compliance of regularly occupied spaces.  Enter total square footage of regularly occupied areas, and total area of regularly occupied space that meet the daylight requirements in the LEED Submittal Template. In addition, upload all required supporting documents to LEED Online.


  • For Option 2, enter square footage of regularly occupied areas, and total area of regularly occupied space that meets the daylight requirements in the LEED Submittal Template. In addition, upload all required supporting 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 10 foot x10 foot grid plan. Enter square footage of regularly occupied areas, and total area of regularly occupied space that meet the daylight requirements in the LEED Submittal Template. Upload all required supporting 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 for New Construction and Major Renovations Version 2.2

    EQ Credit 8.1: Daylight and views - daylight 75% of spaces

    1 Point

    Intent

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

    Requirements

    Option 1 — Calculation

    Achieve a minimum 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 2% in a minimum of 75% of all regularly occupied areas. The glazing factor is calculated as follows:

    [INSERT FIGURE HERE]

    OR

    Option 2 — Simulation

    Demonstrate, through computer simulation, that a minimum daylight illumination level of 25 footcandles has been achieved in a minimum of 75% of all regularly occupied areas. Modeling must demonstrate 25 horizontal footcandlesHorizontal footcandles occur on a horizontal surface. They can be added together arithmetically when more than 1 source provides light to the same surface. under clear sky conditions, at noon, on the equinox, at 30 inches above the floor.

    OR

    Option 3 — Measurement

    Demonstrate, through records of indoor light measurements, that a minimum daylight illumination level of 25 footcandles has been achieved in at least 75% of all regularly occupied areas. Measurements must be taken on a 10-foot grid for all occupied spacesEnclosed space intended for human activities, excluding those spaces that are intended primarily for other purposes, such as storage rooms and equipment rooms, and that are only occupied occasionally and for short periods of time. Occupied spaces are further classified as regularly occupied or nonregularly occupied spaces based on the duration of the occupancy, individual or multioccupant based on the quantity of occupants, and densely or nondensely occupied spaces based on the concentration of occupants in the space. and must be recorded on building floor plans.

    In all cases, only the square footage associated with the portions of rooms or spaces meeting the minimum illumination requirements can be applied towards the 75% of total area calculation required to qualify for this credit.

    In all cases, provide daylight redirection and/or glare control devices to avoid high-contrast situations that could impede visual tasks. Exceptions for areas where tasks would be hindered by the use of daylight will be considered on their merits.

    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 automatic photocell-based controls. Predict daylight factors via manual calculations or model day- lighting 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.


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.

LEED Online Sample Template – EQc8.1

This template is the flattened, public version of the dynamic template for this credit that is used within LEED-Online v2 by registered project teams. This and other public versions of LEED credit templates come from the USGBC website, and are posted on LEEDuser with USGBC's permission. You'll need to fill out the live version of this template on LEED Online to document this credit.

LEED Online Supporting Calculator – EQc8

 

This "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. and Access to Views Calculator" can be used in support of EQc8.1 and EQc8.2 documentation. This calculator is a flattened, public version of a dynamic template for EQc8 that is used within LEED-Online v2 by registered project teams. This and other public versions of LEED credit templates come from the USGBC website, and are posted on LEEDuser with USGBC's permission.

 

Design Submittal

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

169 Comments

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LEED Pro Consultant Bioconstruccion & Energia Alternativa
Mar 27 2014
LEEDuser Member
2729 Thumbs Up

Working hours and daylight

Hi,
My project is not achieving the required 75% but it is close to. The main factor is that at 3 pm the spaces are not getting to the 10 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.. The working hours for that particular building (as it is part of a campus) does not go til 3 pm when the simulation is performed. In the other hand during the morning when they will actually be using the space achieves a great porcentage of daylight. Will it be possible to achieve the credit explaining this? Any advice of how should I submit the documentation to prove it?

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Todd Reed Daylight Designer, 7group Mar 27 2014 LEEDuser Expert 15253 Thumbs Up

Rosamaria,

Your not going to earn the credit. Eventhough the current schedule of the building does not go past 3pm, it does not mean that in the future that it would not.

If not already built, redesign the space to meet the illuminance levels or change the VLT of the glazing.

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Veronica Reed Founder SDSARCH CIA. LTDA.
Jan 14 2014
LEEDuser Member
489 Thumbs Up

percentage of daylight compliant spaces

On our project we are achieving 94.98% of compliance for the daylight credit, does anyone know if LEED will allow for us to round up the numbers to 95%? or will they only take into account the 94%?

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Todd Reed Daylight Designer, 7group Jan 14 2014 LEEDuser Expert 15253 Thumbs Up

If the credit form shows 94.98%, then it's not 95%.

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Brandon Dean DBP
Sep 25 2013
Guest
262 Thumbs Up

Glare Control Requirements

The credit language states, "In all cases, provide daylight redirection and/or glare control devices to avoid high-contrast situations that could impede visual tasks." However, nothing is stipulated in the template regarding supporting documentation.
Can you please help clarify if glare controls need to be specified/submitted?

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Todd Reed Daylight Designer, 7group Sep 25 2013 LEEDuser Expert 15253 Thumbs Up

Brandon, in v2009 they are a requirement, but you are posting in v2.2 in which they are suggested but not specifically required. So your question may be better posted in v20009.

To answer it in regards to v2009. In regards to documentation on this issue, you need to check the box on the credit form indicating that they are installed or being used. In the calculator, you choose the type of glare control device installed. Nothing else is required. However, if the reviewer sees something that would lead them to question whether they are really installed, then you will probably be asked for specs and or images to confirm they actually have been installed.

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Anne Harney Senior Associate Ayers Saint Gross Architects + Planners
Jul 23 2013
LEEDuser Member
645 Thumbs Up

Daylighting in Open Cafeteria - occupiable space definition

We have a large open plan cafeteria with three different ceiling heights that define 3 daylit zones. Each zone is divided into occupiable areas by furniture and millwork however the "rooms" defined are not enclosed and are equally impacted by the daylight provided by the envelope glazing. Instead of inputting square footage of each occupiable area, I am defining the occupiable areas within this open plan by zone, so there are 3 occupiable areas total within the open plan.

Each of these three areas meet the requirements for daylighting. Surrounding the perimeter of the open plan are fast food portals. The service area where a customer orders is open to the daylit open plan, however, the kitchens behind each portal are not open to the daylight. If I break the open plan into 3 zones, that only looks like 3 rooms on the calculator, but it is the majority of the building (and is the space occupied by the majority of the building occupants). Adding the kitchens (which may each have 1 person working full-time), which are small support type spaces that do not meet the daylighting requirements, will make the 75% of occupiable spaces requirement inachievable - even though the majority of the building is daylit. Do the kitchens needs to be counted? Is there a way to address this in the credit?

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Todd Reed Daylight Designer, 7group Jul 23 2013 LEEDuser Expert 15253 Thumbs Up

Kitchens need to be included. When determining the occupied area of a kitchen, you can exclude the area of where the kitchen equipment will be instead of just taking the gross floor areaGross floor area (based on ASHRAE definition) is the sum of the floor areas of the spaces within the building, including basements, mezzanine and intermediate‐floored tiers, and penthouses wi th headroom height of 7.5 ft (2.2 meters) or greater. Measurements m ust be taken from the exterior 39 faces of exterior walls OR from the centerline of walls separating buildings, OR (for LEED CI certifying spaces) from the centerline of walls separating spaces. Excludes non‐en closed (or non‐enclosable) roofed‐over areas such as exterior covered walkways, porches, terraces or steps, roof overhangs, and similar features. Excludes air shafts, pipe trenches, and chimneys. Excludes floor area dedicated to the parking and circulation of motor vehicles. ( Note that while excluded features may not be part of the gross floor area, and therefore technically not a part of the LEED project building, they may still be required to be a part of the overall LEED project and subject to MPRs, prerequisites, and credits.). This may or may not help you. Not sure which option you are using to calculate daylight, either the 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., simulation, or measurement.

How do you address the daylight credit? Answer, when designing a building and all the occupied spacesEnclosed space intended for human activities, excluding those spaces that are intended primarily for other purposes, such as storage rooms and equipment rooms, and that are only occupied occasionally and for short periods of time. Occupied spaces are further classified as regularly occupied or nonregularly occupied spaces based on the duration of the occupancy, individual or multioccupant based on the quantity of occupants, and densely or nondensely occupied spaces based on the concentration of occupants in the space., your set your performance goals. If a space is deemed to have daylighting, then you determine the quantity and quality of the daylight that each space shall receive and then design the space so that it achieves the goals. If you are just now looking at daylighting and the credit requirements now, then you will need to address the design to achieve the credit. You have what you have now.

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Todd Reed Daylight Designer, 7group Jul 23 2013 LEEDuser Expert 15253 Thumbs Up

Anne, is this a v2.2 or a v3 project? Sounds like you are doing the prescriptive path which is v3, so this should be posted in the v2009 forum instead of here.

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Anne Harney Senior Associate, Ayers Saint Gross Architects + Planners Jul 23 2013 LEEDuser Member 645 Thumbs Up

Will post in 2009, thanks. If the kitchen is as commercial kitchen requiring complete fire separation, does it still need to be included?

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Todd Reed Daylight Designer, 7group Jul 23 2013 LEEDuser Expert 15253 Thumbs Up

For v3 projects, refer to the regularly occupied spaceAn area where one or more individuals normally spend time (more than one hour per person per day on average) seated or standing as they work, study, or perform other focused activities inside a building. The one-hour timeframe is continuous and should be based on the time a typical occupant uses the space. For spaces that are not used daily, the one-hour timeframe should be based on the time a typical occupant spends in the space when it is in use. matrix dated April 2013, kitchens are considered regularly occupied.

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Shristi Bajracharya architect technical interface
Jul 15 2013
Guest
547 Thumbs Up

output summary??

In the leedonline form, it says provide an output summary from the daylight computer simulations. Does this mean that we need to show them the report of the simulation done in ecotect?? what does it really mean? please can some one clarify this in detail?

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Todd Reed Daylight Designer, 7group Jul 15 2013 LEEDuser Expert 15253 Thumbs Up

What you need to submit is simulation results. So in Ecotect, once your sims are complete and the results are shown in the analysis grid, you can submit an image of the results. So in plan view, zoom in so the illuminance levels are legible, then save image as jpeg. Ensure you clearly label the image and provide a narrative explaining to the reviewer what you are providing if you have multiple sim results.

What i do is create my own spreadhseet. Each image of sim is labeled and then the compliant square footage is entered into the spreadsheet. This way the reviewer sees my results and the calcs are clearly available. Its not extra work for since i use a similar format in my daylighting report for our clients.

Technically you could submit the sim report that Ecotect generates. But this only shows the results of the points, not where the points are. Its hard to verify if the sim results are realistic when just submitting a spreadsheet of numbers. You could also take the results and make graphs, but in regards to documenting the credit, this requires more work than what is actually needed. The image of the results is the best option and not hard to do.

Good Luck

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Shristi Bajracharya architect, technical interface Jul 22 2013 Guest 547 Thumbs Up

thank you for the reply...I have already prepared the required documents showing the simulation results from ecotect. According to LEEDonline, it says
"Provide an output summary from the daylight computer
simulations. Note: Must be consistent with Upload L-8. Supplemental Daylight and Views Calculation Spreadsheet."
So I thought it must be talking about the output summary from Ecotect which I couldn't get from the result section for some reasons. Although all the simulation data has been acquired from the software and i have merged them with the plans showing the daylit zones.What you have said is what I have exactly done. I was only wondering if they were talking about something extra than this. Tell me if there is anything that i am doing wrong?

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Todd Reed Daylight Designer, 7group Jul 22 2013 LEEDuser Expert 15253 Thumbs Up

You are not doing anything wrong. There is no need to print out the simulation summary from Ecotect. I would also include a narrative that includes your input parameters. Reflectances, VLTS, Sim Times, and climate file used. Some programs in there simulation summary report has the input parameters included in them, but a narrative works just as good.

What you have done and what you are providing should be fine. Remember, a reviewer is looking at your project for the first time and is not familiar with it as you are. They also don;t have an endless amount of time to figure out what you have submitted. When you put together your documentation, you should take the mind set that the person looking at it has one hour to figure it and things need to be clear, concise, complete, and correct. Otherwise, if a reviewer can;t figure out what you have done, you end up with a review comment asking for clarification, which could have been avoided in the first place.

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Eileen Keenan Sustainability Coordinator Bing Thom Architects
Jul 04 2013
Guest
22 Thumbs Up

Can a REVIT model be used as a base for daylighting simulation?

Hi,
I've been asked to help a project team finish off an older LEED submission for a library under NCv2.2. The building geometry is complex and with hindsight a simulation should have been done but the simpler calculation path was attempted and has been (justifiably) questioned by the Reviewer. The project is now occupied 7 days a week/365 days a year and turning off the lighting for the time it would take to measure the daylight levels in the completed building is a challenge for the owner. The building was designed using REVIT and a full 3D model exists. Is there a means by which this model could be used or exported to generate the simulation now without expending too much additional time? It's fairly obvious to all that the building complies with the Credit, but difficult to demonstrate at this stage.
Thanks!

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Larry Sims Principal, Studio4, LLC Jul 08 2013 LEEDuser Expert 3553 Thumbs Up

although the entire video is interesting, @ the 6:55 mark shows daylighting analysis

http://www.youtube.com/watch?v=BKZ35xh4ofw&list=PL21FF9E4A228C297F&index=1

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Todd Reed Daylight Designer, 7group Jul 08 2013 LEEDuser Expert 15253 Thumbs Up

Yes, you can export your Revit model into 3D Studio Max to conduct single point in time calculations. The results of 3D Max are comparable to Radiance. Christoph wrote a paper on the comparison showing they results are valid. So that should keep the reviewer from questioning at least the program used.

You can also export your Revit model using the gbxml option into Ecotect and then into Radiance. Reduce the amount of info in the Revit model before exporting to reduce errors and run time.

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Todd Reed Daylight Designer, 7group Jul 08 2013 LEEDuser Expert 15253 Thumbs Up

If you are using the gbxml option, older versions of Revit, such as 2011 and older, had some issues with exportation into Ecotect via gbxml option. There was a work around posted on one of the Autodesk forums. The latest versions of the programs have resolved those issues.

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Suzanne Allerton Architect W2A Design Group
Jun 11 2013
Guest
1510 Thumbs Up

Using a Day sim simulation with Google sketch up model

Are there any objections to using a google sketch up model with
the Day sim program to acheive this credit... anything to
add would be helpful Thank you, Suzy

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Todd Reed Daylight Designer, 7group Jul 08 2013 LEEDuser Expert 15253 Thumbs Up

The issue with Daysim is the metric, DA-Daylight Autonomy, which in this version of LEED is not a valid metric to document the credit. You will need to provide single point in time simulations for 2.2 projects.

Your best option is to get your Sketchup model into Radiance via Ecotect. Depending on how the Sketchup model was built, you may have alot of geometry errors.

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Olivier Brouard Sustainable Energy Engineer
Mar 25 2013
Guest
489 Thumbs Up

Question about total area that qualifies for LEED IEQ 8.1

Hi everyone,

I am running two simulation at 9am and 3pm September 21 to determine the total qualified area percentage that apply for the credit or not. (Total regularly occupied spaceAn area where one or more individuals normally spend time (more than one hour per person per day on average) seated or standing as they work, study, or perform other focused activities inside a building. The one-hour timeframe is continuous and should be based on the time a typical occupant uses the space. For spaces that are not used daily, the one-hour timeframe should be based on the time a typical occupant spends in the space when it is in use.: 12170 ft²)

The results I have obtained from the 2 simulations are as follow:
- 9 am : 73.38% (8,930 ft²)of the area qualifies between 10fc and 500 fc
- 3 pm: 77.35% (9,413 ft²) of the area qualifies between 10fc and 500 fc.

Knowing that the daylighting zone percentage of regularly occupied spacesEnclosed space intended for human activities, excluding those spaces that are intended primarily for other purposes, such as storage rooms and equipment rooms, and that are only occupied occasionally and for short periods of time. Occupied spaces are further classified as regularly occupied or nonregularly occupied spaces based on the duration of the occupancy, individual or multioccupant based on the quantity of occupants, and densely or nondensely occupied spaces based on the concentration of occupants in the space. is given by the division of the total daylighted regularly occupied area by the total regularly occupied area, what is the final answer ?

Should both time simulation (9am and 3pm) be over 75% or does it work to make the average of the two; (73.38%+77.35%)/2=75.36 % ?

Thank you very much.

Best.

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Todd Reed Daylight Designer, 7group Mar 25 2013 LEEDuser Expert 15253 Thumbs Up

You cannot average the results of both times to get the compliant percentage. It will be your worst case scenario which will be the 73.38%.

The language clearly states 75% at both 9am and 3pm.

You may want to look at what spaces you have in the simulations and you may be including spaces that would not be considered regularly occupied or could be excluded. Also, double check your gross regularly occupied square footage.

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Olivier Brouard Sustainable Energy Engineer Mar 28 2013 Guest 489 Thumbs Up

Hi Todd,

Thank you for your expertise. Speaking of the gross square footageSum of the floor areas of the spaces within the building including basements, mezzanine and intermediate-floored tiers, and penthouses with headroom height of 7.5 ft or greater. It is measured from the exterior faces of exterior walls or from the centerline of walls separating buildings, but excluding covered walkways, open roofed-over areas, porches and similar spaces, pipe trenches, exterior terraces or steps, chimneys, roof overhangs, and similar features., it is not at the project advantage to include wall/shaft areas when defining the boundary areas.

Is it permitted to only calculate the Net usable space area ? (I would like eventually to increase the 73.38 to 75 using this method)

Thank you,

Best.

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Todd Reed Daylight Designer, 7group Mar 29 2013 LEEDuser Expert 15253 Thumbs Up

Oliver,
What i should have noted was to check your gross regularly occupied spaceAn area where one or more individuals normally spend time (more than one hour per person per day on average) seated or standing as they work, study, or perform other focused activities inside a building. The one-hour timeframe is continuous and should be based on the time a typical occupant uses the space. For spaces that are not used daily, the one-hour timeframe should be based on the time a typical occupant spends in the space when it is in use. instead of the gross area. Look at things like corridors and areas which would be considered circulation. Those areas would not be considered regularly occupied.

You are correct in that it only usable space can be considered. So wall shaft areas should not be included.

Some other items that you may want to look at is surrounding existing structures and other features. If you are not meeting compliance based on areas exceeding 500fc which is typically due to direct solar penetration. Surrounding buildings and other features would provide the shading needed to reduce the levels below the 500fc.

Other items would be your input parameters. Are your surfaces orientated the correct way? What about internal reflectances? Depending on the program, if your surfaces are not correctly orientated, then this would cause the amount of sunlight entering the space to be zero. If using a Radiance based engine, what are your bounces set at?

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Veronica Reed Founder SDSARCH CIA. LTDA.
Sep 05 2012
LEEDuser Member
489 Thumbs Up

Using Simulation results for EAp2 and EAc1 but not using it for

We are working on a new terminal building for an airport n a remote location. The weather is tropical humid climate so we had to include as many louvers and elements as possible to reduce heat gain and maintain comfort. However, we are getting bad results in the simulation for daylighting. Can we use the simulation results for Energy and Atmosphere but then disregard these results for daylight and do the calculation in the LEED calc sheets?, this is getting better results for daylight than the simulation. Is this possible?

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Todd Reed Daylight Designer, 7group Sep 05 2012 LEEDuser Expert 15253 Thumbs Up

You can use daylight sim results to help document your EA credits and then use the 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. calculations in EQc8.1.

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Veronica Reed Founder, SDSARCH CIA. LTDA. Sep 05 2012 LEEDuser Member 489 Thumbs Up

Thanks Todd. The building is also an un-sealed building, we do not have glazing in most areas, just a screen, in this case, can the calculation still be done?

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Todd Reed Daylight Designer, 7group Sep 05 2012 LEEDuser Expert 15253 Thumbs Up

Technically you could still use the 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. calculations. This is how i would do this to ensure the reviewer does not question the applicability of the glazing factor method with all those lourvers.

I would use a VLT of 92% or maybe even 90%, given that typical screen has a very large openess factor. The area of the glazing would be open area between the lourvers that has direct view. So lets say the lourvers are at a 30 degrees below nadir. The distance used would be the measurement from the exterior edge of one lourver to the interior edge of the lourver above or below that one. I would not perform this without consideration of the louvers if they are angled. If perpendicular from the glazing you could perform this without considering them.

I'd really have to see what your facade looks like to give you my best suggestion.

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Jill Dalglish, PE Senior Engineer, Dalglish Daylighting Sep 06 2012 LEEDuser Expert 6625 Thumbs Up

I wouldn't bank on getting this credit with the 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. calculations. There really isn't a window type that applies to multiple louvers. I'm not going to say that it's not possible though. There are just no guarantees when it comes to cases that are outside of the book case.

I think it's possible that you could be rejected for this case due to the lack of glazing as well. I say this because if is considered an exterior space, then it cannot be considered as regularly occupied spaceAn area where one or more individuals normally spend time (more than one hour per person per day on average) seated or standing as they work, study, or perform other focused activities inside a building. The one-hour timeframe is continuous and should be based on the time a typical occupant uses the space. For spaces that are not used daily, the one-hour timeframe should be based on the time a typical occupant spends in the space when it is in use.. Do you have any mechanical heating or cooling in these areas? If you do not, it might be considered exterior space.

I have never tried submitting a case like this. Please come back to the forum later to report how it goes.

I'm curious, how "bad" are the simulations?

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Veronica Reed Founder, SDSARCH CIA. LTDA. Feb 28 2013 LEEDuser Member 489 Thumbs Up

Hi Todd, Jill

Since we are not able to use the simulation results for daylighting which are not showing actual daylight levels we have inside the building, we are going to go for option 3, documenting and measuring actual daylight levels inside the building using a 10f x 10f grid. It says on the checklist here we should do 4 measurements on each point on the grid, so in this case I will assume the 4 measurements have to be taken in a time frame within the hours or operation of the building. The airport operating hours will be from 7am to 2pm only, since at that time operations are closed and the airport is closed. In this case I would do 4 measurements at 7am, 9am, 11am, 1pm. Is this what 4 measurements refer to?
Todd, I cannot find a way to upload the image of the airport but you can access the project's website and you can see the projects elevations and images there. Hope this helps in you providing further suggestions and comments that could help us best document this credit.
http://www.ecogal.com.ec/

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Todd Reed Daylight Designer, 7group Feb 28 2013 LEEDuser Expert 15253 Thumbs Up

Veronica, you do not need to take four different measurements at four different times. One measure at each point in the determined grid as close to noon as possible under clear sky conditions. I would use a 10'x10' gird for spaces that are more than 200 sq ft. Any space smaller than that i would used a 5'x 5' grid.

A very nice project by the way.Looking at the images and plans, and based on its location, i can see why maybe the simulations are not showing credit compliance. Noon at the equator, the sun is directly above you, and with all the overhangs i can see how it may not be getting the 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., but without any glazing I'm still not sure why. How is the daylight otherwise.

In reading the the brochure, which a person in the office translated, it states that the project is the first ecological airport in the world with certification. Can you expand on what certification that may be? Thanks.

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Jill Dalglish, PE Senior Engineer, Dalglish Daylighting Feb 28 2013 LEEDuser Expert 6625 Thumbs Up

Hello Veronica, I am curious what checklist you are looking at? There is nothing in the credit that mentions 4 measurements. There is also nothing that specifies time or date for measurement in this version of LEED for this method, so you may want to do a sampling at different times and dates to see what works best for you. I'm sorry, but the link to the project isn't working for me right now.

Also, please note that the minimum required footcandles was changed in an Addendum in Nov. '09 from 25fc to 10fc. So that should help some!

Using a 5' x 5' spacing in smaller spaces is recommended but not required. In the simulation option you cannot use less than 9 measuring points per room no matter what the spacing, so that is probably a good guideline too.

I also want to remind you that you have the option to combine methods, so if any of the spaces complies with simulation, you can submit the simulation for that space, submit the prescriptive method for spaces that comply that way and then use measurement for the rest of the spaces. Not sure if that makes it easier on you or not.

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Todd Reed Daylight Designer, 7group Feb 28 2013 LEEDuser Expert 15253 Thumbs Up

Jill, this is a 2.2 project, so the addenda changing the values to 10fc is only applicable to 2009 projects.

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Veronica Reed Founder, SDSARCH CIA. LTDA. Mar 22 2013 LEEDuser Member 489 Thumbs Up

Hi Tood, Jill,

thanks again for the comments, these are helpful. The four measurements we specified ourselves for the measurement and verification plan as a mean to verify if the daylighting sensorsA lighting feature that takes advantage of sunlight to cut the amount of electric lighting used in a building by varying output of the lighting system in response to variations in available daylight. They are sometimes referred to as "natural lighting control sensors " or "photocells."   are correctly calibrated and giving the energy savings expected.
The project is aiming for LEEd Gold, even though given the project's location and constraints have un looking at LEED silver, but this is the certification the brochure refers to, meaning that this is the first airport applying for a LEED certification, according to the developers, but I am not certain that this is the first one.

We are performing the lighting measurements this week, so I will let you know what results come up.

And one last question to both of you, so 75% of the spaces does this mean literally 75% of all spaces including restrooms? so for example 75 of 100 spaces regardless of the area?, or does it mean 75% of the area of the building? I have had conflicting views from others in our team.

Thanks for your help!

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Jill Dalglish, PE Senior Engineer, Dalglish Daylighting Mar 22 2013 LEEDuser Expert 6625 Thumbs Up

No, it means 75% of all Regularly Occupied SpacesEnclosed space intended for human activities, excluding those spaces that are intended primarily for other purposes, such as storage rooms and equipment rooms, and that are only occupied occasionally and for short periods of time. Occupied spaces are further classified as regularly occupied or nonregularly occupied spaces based on the duration of the occupancy, individual or multioccupant based on the quantity of occupants, and densely or nondensely occupied spaces based on the concentration of occupants in the space. (ROS). I capitalize because this is a LEED defined term. Restrooms are not ROS. The definition of this term has changed around a lot and I'm not sure which one now applies to LEED 2.2. For LEED 2009, there is a "Space type matrix" you can find here. http://new.usgbc.org/resources/eq-space-type-matrix.

For 2.2 it used to be based on "where workers stand or sit" to perform their duties and wasn't based on the amount of time spent in the space as "regularly occupied" seems to imply. For 2009, they list one hour as the minimum time before considering a space ROS. In general, I would say that storage rooms, restrooms, utility rooms and the like are not ROS.

If you have questionable spaces, you can post those here to get an opinion.

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Cristina Algaze Architect. LEED AP BD+C. Jul 23 2013 LEEDuser Member 194 Thumbs Up

Hello Veronica, Jill and Todd.

I am working on a NC v2.2 certification for an elementary school in Dorado, Puerto Rico. Puerto Rico is a climate similar to Veronica's project location, hot and humid. We also have non-conditioned spaces that are regularly occupied (as per LEED) that are naturally ventilated with operable opaque louvered (jalousie) windows. The windows are completely opened when the space is in use and it has a lot of daylight and views.

I have a few questions about spaces with these operable jalousie windows, because they are operable and opaque.

My strategy for documenting this credit is the following:
Spaces with normal glazing I am going with Option 1, with 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. calculations. Spaces as the one that I am describing above I am going with the actual measurements of Option 3.

Question #1: Can I combine methods as described above?

Q#2: How do you think that operable jalousie (opaque) windows should be addressed in this credit?

Thanks

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Todd Reed Daylight Designer, 7group Jul 23 2013 LEEDuser Expert 15253 Thumbs Up

Cristina,

#1. Yes, you can combine options. Ensure you provide a narrative which states this and note which spaces will be documented under which option.

#2.I agree that the measurement option is the best option to use. Being an international project in a tropical climate, i would provide a narrative explaining the situation, maybe an image if the space is completed, and document the credit. Technically a reviewer could make an argument that the louvers are opaque and are not automatically controlled, so occupants may be in a space which is dark unless the louvers are opened. But, these louvers are just like blinds installed in many buildings in which the occupants have to operate to let light in. The intent is there and being where the project is located, i believe there should not be any issues with it being accepted.

Good Luck

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Jill Dalglish, PE Senior Engineer, Dalglish Daylighting Jul 23 2013 LEEDuser Expert 6625 Thumbs Up

This is an excellent question and case example. If you remember, could you please report back on how this approach goes for you? Technically, regularly occupied spacesEnclosed space intended for human activities, excluding those spaces that are intended primarily for other purposes, such as storage rooms and equipment rooms, and that are only occupied occasionally and for short periods of time. Occupied spaces are further classified as regularly occupied or nonregularly occupied spaces based on the duration of the occupancy, individual or multioccupant based on the quantity of occupants, and densely or nondensely occupied spaces based on the concentration of occupants in the space. have to be "enclosed." Whether or not the unconditioned spaces with the opaque jalousie windows are considered enclosed would be good to know. I would think you would have the option of leaving these spaces out of the calculations altogether if you wanted to (which would probably depend on which way the calculations go).

I'm curious about why they are opaque.

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Todd Reed Daylight Designer, 7group Jul 24 2013 LEEDuser Expert 15253 Thumbs Up

Jill,

So i had a discussion with Marcus on this issue in regards as to how they handle the energy modeling side with spaces like the one that Cristina has. (A very brief discussion so i may be missing the nitty gritty) Since the space is a classroom, and there are other spaces with glazing, these spaces are still included in the model. But they are only modeled with interior lighting, and no HVAC. You still include them for energy savings from the lighting. So in regards to consistency, those classrooms are considered regularly occupied. This scenario could change and has to be addressed on a per project basis, especially with international projects. If all the spaces in Cristina's building were screened in and not considered regularly occupied, then there would be alot of credits which they could not attempt.

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Jill Dalglish, PE Senior Engineer, Dalglish Daylighting Jul 24 2013 LEEDuser Expert 6625 Thumbs Up

I would agreed with you about consistency before the Space Matrix came out, but now it is obvious that LEED is not concerned with consistency across the credits on how ROS is observed.

I didn't see where she stated that the spaces are classrooms. I don't see why that matters. I would include the spaces in an energy model either way and if they had HVAC or not. They will affect the building's energy use in all cases.

There are plenty of buildings that just can't get a LEED cert. because they don't have HVAC.

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Jill Dalglish, PE Senior Engineer, Dalglish Daylighting Jul 24 2013 LEEDuser Expert 6625 Thumbs Up

Also, energy models include all spaces whether they are regularly occupied or not.

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Cristina Algaze Architect. LEED AP BD+C. Jul 29 2013 LEEDuser Member 194 Thumbs Up

Hi Jill and Todd, thanks for your interest in my project. Yes, I am working on an 'out of the LEED Box' project, which is hard work and a bit stressing. You could say that some of our spaces, even if they are naturally ventilated they are certainly enclosed and therefore Regularly Occupied. We modeled the whole project in the energy model for the same reasons that you are explaining above. It looks like we are doing great in the EA credits!

Maybe the answer to your question is the following: the project is a public school in Puerto Rico. That means that we have to design for passive survivability – the ability of the building to operate under unusual circumstances like no electricity after a hurricane event or just the normal inefficiencies of the system that sometimes the lights just go out and the kids must stay at school. That’s why all spaces are oriented towards the natural ventilation and has operable windows. In addition, the school must have good durability for high energy occupants, that’s why we avoid glass windows in the high traffic high activity spaces such as classrooms and cafeteria at an accessible height. Nonetheless all window areas have glass clerestories and light shelves for maximizing daylighting.

In the last few days we finished analyzing the applicable spaces with the 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. calculations of EQ 8.1 and it looks like the formula is not being fair to the building’s actual performance. This is why I think that in the next couple of weeks I will do Option 3 measurement for all spaces to compare results. Again, thank you and I will keep you posted because it is an interesting case study and a really nice project!

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Todd Reed Daylight Designer, 7group Jul 29 2013 LEEDuser Expert 15253 Thumbs Up

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. is definitely not a metric which will define whether a space is well daylit in regards to both quantity and quality. It does reasonable well in determining whether or not simple geometry, side lit space will a decent amount of daylight. In your case, with clerestories, light shelves, etc., simulation would be the option to compare the actual measurements back to.

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Arlinda Lalaj Architectural Designer
Jun 14 2012
Guest
118 Thumbs Up

Daylight Factor Calculation (includes direct sunlight or not)

I am calculating the daylight factorThe ratio of exterior illumination to interior illumination, expressed as a percentage. The variables used to determine the daylight factor include the floor area, window area, window geometry, visible transmittance (Tvis), and window height. using a lighting simulation in Radiance for Ecotect. I usually run the simulation for overcast sky conditions becaouse I don't want to include direct sunlight. My question is weather LEED requirements for a minimum Daylight factor of 2% in
75% of all spaces, includes direct sunlight or not. Thank You

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Jill Dalglish, PE Senior Engineer, Dalglish Daylighting Jun 14 2012 LEEDuser Expert 6625 Thumbs Up

Please note that daylight factorThe ratio of exterior illumination to interior illumination, expressed as a percentage. The variables used to determine the daylight factor include the floor area, window area, window geometry, visible transmittance (Tvis), and window height. and 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. (the one in this version of LEED) are two different things. Glazing factor assumes an overcast sky and does not require simulation. Correct me if I'm wrong but isn't there a spreadsheet calculator that is provided by LEED to enter in all of the glazing factor information and then it calculates it for you? (I'm having an issue with getting into my account right now, or I'd go look myself.) So, I think doing a separate calculation in Radiance for Ecotect is unnecessary for the Option 1 - Glazing Factor. If you are using Radiance for Ecotect for Option 2-Simulation, then you need to use sunny skies.

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Arlinda Lalaj Architectural Designer Jun 15 2012 Guest 118 Thumbs Up

I am using Radiance to calculate Luminance levels for Option 2. On the LEED® Credit EQ-8.1 I read "Achieve a minimum Daylight FactorThe ratio of exterior illumination to interior illumination, expressed as a percentage. The variables used to determine the daylight factor include the floor area, window area, window geometry, visible transmittance (Tvis), and window height. of 2%(excluding all direct sunlight penetration) in 75% to achieve effective daylighting." so I was wondering weather the simulation counts for sunny skies. Also, the project is in California so most of the days are sunny. Thank You

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Jill Dalglish, PE Senior Engineer, Dalglish Daylighting Jun 18 2012 LEEDuser Expert 6625 Thumbs Up

Which version of 2.2 are you using? I can't seem to find the quote you're referring to. Can you include a link to the document you're referring to?

Make sure that you are using the most recent version. I see that there are errata up to 2008.

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Arlinda Lalaj Architectural Designer Jun 18 2012 Guest 118 Thumbs Up

I found the quote under this link: http://www.green.harvard.edu/sites/all/themes/green-ofs/theresource/leed...
Again, I am not sure if this is correct , but since we are still in schematic design these are early concept design simulations not related to the LEED requirement for now. Anyhow I would still like to know for the future.
Thank You

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Todd Reed Daylight Designer, 7group Jun 18 2012 LEEDuser Expert 15253 Thumbs Up

That is CI (Commercial Interior Template) with a date of 2008. That is why you are seeing daylight factorThe ratio of exterior illumination to interior illumination, expressed as a percentage. The variables used to determine the daylight factor include the floor area, window area, window geometry, visible transmittance (Tvis), and window height.. So is this a CI project or is this a NC v2.2 project? What version of LEED is the project registered under?

You need to ensure that you are using the correct rating system and most recent template or form. You should also review the most recent erratas for the version you are using along with reviewing any LEED Interpretations that may be relevant for your project.

As farFloor-area ratio is the density of nonresidential land use, exclusive of parking, measured as the total nonresidential building floor area divided by the total buildable land area available for nonresidential structures. For example, on a site with 10,000 square feet (930 square meters) of buildable land area, an FAR of 1.0 would be 10,000 square feet (930 square meters) of building floor area. On the same site, an FAR of 1.5 would be 15,000 square feet (1395 square meters), an FAR of 2.0 would be 20,000 square feet (1860 square meters), and an FAR of 0.5 would be 5,000 square feet (465 square meters). as daylight factor calculation, that is done under the CIE unifrom sky. So your clear sky assumption would not be valid.

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Jill Dalglish, PE Senior Engineer, Dalglish Daylighting Jun 18 2012 LEEDuser Expert 6625 Thumbs Up

Is your space CI or NC? Is the credit registered in v2.2 or 2009? This link refers to a CI document and you are posting in the v2.2 NC forum.

Daylight factorThe ratio of exterior illumination to interior illumination, expressed as a percentage. The variables used to determine the daylight factor include the floor area, window area, window geometry, visible transmittance (Tvis), and window height. has a broader meaning than the way it is used in this document, so I see now what your question is.

You would not use Radiance (simulation ) to achieve the credit using this option. This is option 1 and simulation is option 2. The question about including direct sun or not does not apply to option 1, it is irrelevant.

Make sure that you are using the LEED version and product that applies to your project. The daylighting credit for NC, CI and EB can be very different and the daylighting credit has changed a lot since 2.2.

In version 2.2, they don't take high illuminance values into consideration, but they do in 2009. Good luck!

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Karenda MacDonald Architect Borges Architectural Group
Jun 05 2012
Guest
105 Thumbs Up

Car Repair Area

I am working on a 40,000 square foot car dealership - approx 20,000 sf is a car service area with minimal windows, but skylights. Would car service space be considered an occupied space?

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Jill Dalglish, PE Senior Engineer, Dalglish Daylighting Jun 05 2012 LEEDuser Expert 6625 Thumbs Up

Yes.

Are you registered under v2.2? (This is the v2.2 forum. Just curious.)

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Karenda MacDonald Architect, Borges Architectural Group Jun 05 2012 Guest 105 Thumbs Up

The project actually is registered under V2.2 - the owner has redesigned 3 times and this is the 3rd set of construction documents we have worked on for the same project.

To figure the square footage of the service areas I have excluded the drive aisles as circulation. Can I exclude the areas where the cars actually sit while being repaired or is that also considered regularly occupied spaceAn area where one or more individuals normally spend time (more than one hour per person per day on average) seated or standing as they work, study, or perform other focused activities inside a building. The one-hour timeframe is continuous and should be based on the time a typical occupant uses the space. For spaces that are not used daily, the one-hour timeframe should be based on the time a typical occupant spends in the space when it is in use.?

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Jill Dalglish, PE Senior Engineer, Dalglish Daylighting Jun 05 2012 LEEDuser Expert 6625 Thumbs Up

Wow.

Since the occupants are working on the cars, they need to be included. I'm not sure that they will allow exclusion of the drive aisles but if it's the difference between being eligible for the credit or not, you might as well try to leave them out. Have a good written explanation ready for the reviewer in case they have comments.

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Todd Reed Daylight Designer, 7group Jun 06 2012 LEEDuser Expert 15253 Thumbs Up

I recommend that you submit a floor plan that clearly marks the areas you are not including along with, as previously recommended, a well written narrative.

Can ask how much skylight glazing you have and the height of the car service space? What VLT are using for these skylights? I ask, because if you have the freedom to use skylights, then its about the amount and spacing of them to achieve the desired daylight levels. I understand that its not always that simple, but with the option in this type of facility you can achieve the credit without playing the regularly occupied not regularly occupied game.

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Heather Holdridge Sustainability Coordinator Lake/Flato Architects
Mar 26 2012
LEEDuser Member
2131 Thumbs Up

Regularly Occupied Spaces - Lab Building

We are trying to determine the regularly occupied spacesEnclosed space intended for human activities, excluding those spaces that are intended primarily for other purposes, such as storage rooms and equipment rooms, and that are only occupied occasionally and for short periods of time. Occupied spaces are further classified as regularly occupied or nonregularly occupied spaces based on the duration of the occupancy, individual or multioccupant based on the quantity of occupants, and densely or nondensely occupied spaces based on the concentration of occupants in the space. for a lab facility. The layout of this facility includes both regular office space and lab space for each employee. The labs are broken down into main lab and prep lab. Additional support spaces include culture rooms and microscope rooms. As the scientistics will be "sitting or standing to work" in each of these spaces, are they all considered regularly occupied? I would assume the lab itself is regularly occupied but perhaps not the prep space (which could be comparable to the printer/copy station in an office). Does anyone have experience with this type of program and defining spaces?

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Todd Reed Daylight Designer, 7group Mar 26 2012 LEEDuser Expert 15253 Thumbs Up

According to the IEQ REgulary Occuppied matrix, lab spaces are considered regularly occuppied, but in health care facilities this can be reviewed under a space by space requirement.

Personally, if lab is conducting experiments by which daylight can effect the experiments or the materials, then it could be argued to be excluded. Usually prep labs are storage rooms in which experiments are prepped to be conducted in the lab, so these are regularly excluded.

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David Ng Mechanical Consultant The Aquila Group
Mar 07 2012
Guest
208 Thumbs Up

simulation to verify prescriptive method

I have a project in which I am applying the prescriptive method, however, I want to check my results doing simulation. There is no columns neither walls. It is just an open space for office. In the prescriptive method I am using .5 for my 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. and in my simulation I put 50% in the transmittance. The problem is that when I do the simulation (using SPOT) with that number (50%) the average in my area is 2475 luxMeasurement of lumens per square meter. and I think that the value should be around 500. Why is this happening?
What I am wondering is if my transmittance value is correct and if there is a factor of conversion from Tvis to transmittance.

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Todd Reed Daylight Designer, 7group Mar 07 2012 LEEDuser Expert 15253 Thumbs Up

Comparing values from the prescriptive path with simulations is like comparing apples to donuts. So i don;t know what you are trying to gain from this other than your project meets the credit requirements with both options.

Some more information would help to maybe help you. Orientation, glass to floor ratio, or wall, orientation, climate/location, ceiling height, and overall space dimensions.

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David Ng Mechanical Consultant, The Aquila Group Mar 07 2012 Guest 208 Thumbs Up

Thank you so much for your comment. i think i will just leave it and trust my prescriptive method.

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debra a. lombard sustainability specialist Sustainability Research & Consulting
Jan 10 2012
Guest
258 Thumbs Up

Anyone tried ID credit for dayligting > than 75% reg occ spaces?

Has anyone applied for and/or received ID credit for dayligting more than 75% of regularly occupied spacesEnclosed space intended for human activities, excluding those spaces that are intended primarily for other purposes, such as storage rooms and equipment rooms, and that are only occupied occasionally and for short periods of time. Occupied spaces are further classified as regularly occupied or nonregularly occupied spaces based on the duration of the occupancy, individual or multioccupant based on the quantity of occupants, and densely or nondensely occupied spaces based on the concentration of occupants in the space.? We have a building that provides daylight to 67% of all spaces including kitchen, bathroom, maint. workroom, offices and conference rooms. I'm just wondering if a project got denied such a credit what the GBCIThe Green Building Certification Institute (GBCI) manages Leadership in Energy and Environmental Design (LEED) building certification and professional accreditation processes. It was established in 2008 with support from the U.S. Green Building Council (USGBC).'s comments were denying such. OR if your project did get the ID credit we'd like to know your approach to documentation.

Thank you!
Debra Lombard, LEED AP, EMIT, EIT

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Todd Reed Daylight Designer, 7group Jan 24 2012 LEEDuser Expert 15253 Thumbs Up

Well 67% will not even meet the minimum level for one point. The 2.2 Reference Guide states that 95% is the minimum for any option used and must follow the requirements of the credit.

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Tyler Barter Architect Oak Point Associates
Dec 15 2011
LEEDuser Member
754 Thumbs Up

Simmulation help..

Hello,
We just recieved our reveiw comments back on one of the school projects that was done using Schools 2007. We did not get the daylight credit and got the suggestion to do simulation in addtion to clarifying the calculation method. We currently have the drawings in Autodesk Building Systems 2004, does anyone know of a program we might be able to make use of that will work with our current plans? Or has anyone had luck doing metering to off set the calculations method?

Thank you

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Todd Reed Daylight Designer, 7group Dec 15 2011 LEEDuser Expert 15253 Thumbs Up

Well you can use Ecotect which is an Autodesk product which you can import to radiance. Depending on the complexity of the design and the shape of the space, you could use SPOT. 3d Studio Max will also do simulations which is an autodesk product.

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Tyler Barter Architect, Oak Point Associates Dec 15 2011 LEEDuser Member 754 Thumbs Up

Todd, Thanks for your reply. I am looking to figure out some rooms that have borrowed lights. which seems to be a problem for this school. I will take a look at these programs though.

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Jill Dalglish, PE Senior Engineer, Dalglish Daylighting Dec 15 2011 LEEDuser Expert 6625 Thumbs Up

We have had luck with the measurement option. Not sure what you mean by offsetting the calculations. As you know, the 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. calculations cannot be used for borrowed light.

I will be curious to know what you decide on. Please post back when you do! Thanks

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Todd Reed Daylight Designer, 7group Dec 16 2011 LEEDuser Expert 15253 Thumbs Up

Tyler,
I see your issue now. So you attempted the credit using the 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. calculation, in which borrowed light scenarios can not be used. Depending on the number of spaces that have this scenario and if the project is already built, the measurement option might be more feasible. I'm assuming the learning curve on doing simulations and the time in which you need to re-submit.

Did you adjust your glazing factor calculations for compliant and no-compliant square footage to see if you earn the credit that way?

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Philip Smith TriSpective BIM Services Dec 19 2011 Guest 61 Thumbs Up

Tyler,
If the simulation you need is just a lighting simulation, I believe Autodesk Building Systems 2004 has a simple version of Autodesk VIZ that comes with the product. As long as your model is in 3D you should be able to do a daylight simulation and export it to an avi file.

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Tyler Barter Architect, Oak Point Associates Dec 19 2011 LEEDuser Member 754 Thumbs Up

Todd- Yes we did adjust the compliant and non compliant square footages and it still does not work. we are looking into some simulation programs but measurements seem a much easier way to go with the time we have. I will pass along the out come. Thank you for your information!

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