Note: This document contains addenda information that is supplemental to that found in the LEED Interpretations and Addenda database, found on http://www.usgbc.org
.
Addenda
Number Post Date
Rating
System Category Credit ID
Indoor
Environmental
Quality 100000922 5/9/2011
ISSUE: Replace the credit text with that provided below.
IEQc2.4:
Occupant
Comfort: Daylight and Views
Ref Guide Issue Type Page
Green
Building
Operations and
Maintenance,
2009 edition
Nongrammatical
411-
425
Location
All

credit points
EB: o&M iEQ credit 2.4
1 point
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.
Project teams must achieve the performance thresholds in either the daylight or views requirements below: option 1. Daylight
Through 1 of the 4 paths, achieve daylighting in at least 50% of all regularly occupied spaces 1 .
patH 1. simulation
Demonstrate through computer simulations that the applicable spaces achieve daylight illuminance levels of a minimum of 10 footcandles(fc) and a maximum of 500 fc 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 may demonstrate compliance for only the minimum 10 fc illuminance level.
oR patH 2. prescriptive
For sidelighting zones: n
Achieve a value, calculated as the product of the visible light transmittance (VLT) and window-to-floor area ratio (WFR) between 0.150 and 0.180.
0.150
<
VLt x
WfR
<
0.180
n
The window area included in the calculation must be at least 30 inches above the floor. n
In section, the ceiling must not obstruct a line in section 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 next page).
Exemplary performance option 2
1 Exceptions for areas where tasks would be hindered by the use of daylight will be considered on their merits.
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63°
H
Ceiling Above This Line
2H n
Provide or 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: n
The toplighting daylighted 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
• 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.
412
35° 35°
H
Permanent
Partition
Hx0.7
Toplighting Zone n
Achieve skylight coverage for the applicable space (containing the toplighting zone) between 3% and 6% of the total floor area. n
The skylight must have a minimum 0.5 VLT. n
A skylight diffuser, if used, must have a measured haze value of greater than 90% when tested according to ASTM D1003.
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oR patH 3. Measurement
Demonstrate, through records of indoor light measurements that a minimum daylight illumination level of 10 fc and a maximum of 500 fc has been achieved in the applicable spaces. Measurements must be taken on a 10-foot grid and 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 illuminance level. oR patH 4. combination
Any of the above calculation methods may be combined to document the minimum daylight illumination in the applicable spaces. option 2. for Views above the finished floor for building occupants in 45% of all regularly occupied areas.
Determine the area with direct line of sight by totaling the regularly occupied square footage that meets the following criteria: n
In plan view, the area is within sight lines drawn from perimeter vision glazing. n
In section view, a direct sight line can be drawn from the area to perimeter vision glazing.
The line of sight may be drawn through interior glazing. For private offices, the entire square footage of the office can be counted if 75% or more of the area has a direct line of sight to perimeter vision glazing. For multi-occupant spaces, the actual square footage with a direct line of sight to perimeter vision glazing is counted.
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Environmental issues
Daylighting and views improve the indoor quality of buildings by allowing occupants exposure to natural light and a visual connection to the surrounding outdoor environment. In addition, daylighting decreases energy costs for electric lighting and reduces space-cooling loads by avoiding heat generated by lights. A well-designed daylighted building is estimated to reduce energy use by 50% to 80%,27 thereby conserving natural resources and reducing air pollution impacts from energy production and consumption. Providing daylight and views in workspaces can also increase occupant productivity and reduce absenteeism and illness. However, adding daylight and views features to existing buildings may require renovation projects that have the potential to generate waste, cause indoor air quality contamination, and contribute to other environmental problems.
Despite the known benefits of daylighting in buildings, a downside is the increased likelihood that birds may fly into windows. It is estimated that as many as 1 billion birds perish each year from striking glass. The problem increases with greater percentages of unfragmented and untreated glazing because birds in flight fail to perceive glass as an obstacle. Treatment of facades to reduce collusions includes using exterior shading devices, introducing etched or fritt patterns, and/or creating appropriate visual markers – achieved by differentiating plane, material, texture, color, or opacity or using other features that help fragment glass reflections and reduce apparent overall transparency and reflectivity.
Economic issues
Adding daylighting and views to existing buildings will incur renovation and materials expenses and may lead to excessive heat gain and loss if not designed properly. However, these features are proven to increase workers’ performance and the resulting pleasant work environment can help recruit and retain employees. In most cases, employees’ salaries significantly outweigh the first costs of incorporating daylight and views into a building.
Daylighting can significantly reduce electric lighting requirements and energy costs in many commercial and industrial buildings, schools, libraries, and hospitals. Daylighting, combined with energy-efficient lighting and electronic ballasts, can reduce the lighting power density in some office building by up to 30%.28 When properly designed, daylighting not only reduces energy costs associated with the decreased demand for electric lighting but can also decrease the energy load for mechanical heating and cooling systems and save as much as 1/3 of total energy costs.29 Increased maintenance activities, such as regular window cleaning, should be taken into consideration when adding daylight and view features.
Purchase of new systems furniture that meets the requirements listed under this credit, as well as maintains a panel height below 42 inches, will assist in achieving access to views for building occupants. This credit relates to the following: n
MR Credit 2: Sustainable Purchasing—Durable Goods
In addition, the increased window to wall ratio in a design can affect the potential building energy performance and has a direct correlation to related lighting design energy conservation strategies, including lighting controls: n
EA Credit 1: Optimize Energy Efficiency Performance n
IEQ Credit 2.2: Controllability of Systems—Lighting
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ASTM D1003–07E1, Standard Test Method for Haze and Luminous Transmittance of
Transparent Plastics
American National Standards Institute (ANSI) www.ansi.org
This test method covers the evaluation of specific light-transmitting and wide-angle-light-scattering properties of planar sections of materials such as essentially transparent plastic.
EB: o&M
Access to daylight and outdoor views increases occupants’ comfort by providing interaction with the outdoor environment. Achieve this credit by giving occupants either daylight or outdoor views.
Determine which option is more feasible for the project building given existing conditions; consider opportunities for introducing additional daylight and views into the building through space reconfiguring or alterations and additions.
Daylight
Some buildings cannot use natural lighting because of site constraints or specialized building uses that prohibit sunlight penetration. For example, neighboring buildings or trees may reduce the potential for daylight, or daylight may be incompatible with the preservation of archival materials in a library. Existing buildings have limited opportunities to increase daylight, and views are generally limited in existing buildings without major alterations. For facility alterations and additions, incorporate designs that provide access to daylight and views in a glare-free way, using vision panels, low partitions, or exterior sun shading. Or reconfigure the spaces to optimize use of existing glazing, alter wall color and reflectivity, use interior light shelves, or change window treatments.
Effective strategies to achieve deep daylight penetration into buildings include higher ceiling heights, shallow floor plates, courtyards, atriums, clerestory windows, toplighting, interior light shelves, louvers, and view-preserving shades.. Glazing parameters directly affect the heat gain and loss of the building, which may result in increased energy use. It is important to address the glazing properly, not only for energy usage, but also for visual quality.
The desired amount of daylight depends on the tasks conducted in each space. Daylighted buildings often have several daylight zones with differing target light levels. In addition to light levels, daylighting strategies should address interior color schemes, direct beam penetration, and integration with the electric lighting system.
Glare control is perhaps the most common failure in daylight strategies. Existing buildings with sufficient daylight often suffer from glare issues that have never been addressed and should be examined to maintain occupant comfort throughout the workday. Large window areas provide generous amounts of daylight to the task area, but if not controlled properly, this daylight can produce unwanted glare and affect the lighting quality. Measures to control glare include light shelves, louvers, view-preserving blinds, fins, and shades. Typically, low luminance ratios and lighting of primary surfaces will enhance visual quality. Glare control should be designed for all glazing areas that affect tasks..
Daylighting design often uses computer modeling applications to simulate conditions; these applications produce continuous daylight contours to simulate the daylight conditions of interior spaces and account for the combined effects of multiple windows within a daylit space. Often there is no daylight model available for the interior spaces of an existing building, particularly for current conditions of multi-tenant spaces. ieQ credit 2.4
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Photoresponsive controls for dimming electric lighting can be incorporated into daylight strategies to maintain consistent light levels and smooth the transition from natural light to electric light.
These controls result in energy savings by reducing electric lighting in high daylight conditions while preserving lighting levels on the task surface. These types of automatic controls need commissioning, measurement, and verification.
Effectively managing glare in a space should not be perceived as requiring a trade-off with occupant views. Many manufacturers offer view-preserving shades and blinds that control glare while also allowing occupants to see directly to the outdoors. The preservation of both daylighting and views can significantly increase occupant comfort and productivity.
Despite the known benefits of views in buildings, a potential downside is the likelihood that birds may fly into the windows. Larger areas of unfragmented or untreated glazing increase the risk.
To reduce these collisions, consider treating the window glazing. Use exterior shading devices, introduce etched or fritt patterns, and/or create appropriate visual markers, such as differentiated planes, materials, textures, colors, opacity, or other features that help fragment glass reflections and reduce apparent overall transparency and reflectivity.
Common glare control devices are: n
Fixed exterior shading devices n
Exterior light shelves n
Interior light shelves preferably with some translucency (3 to 5%) to avoid dark shadows under the light shelves.
n
Interior view-preserving blinds with manual, motorized or automated controls n
Louvers n
Operable draperies
To optimize daylighting, select glazing with a appropriate visible transmittance (T vis
). See Figure 1 for glass characteristics.
Figure 1. Glazing characteristics
416
Absorbed
Reflected
Glass
Transmitted
(Tvis)
Solar Heat Gain
(g)
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Views
Access to outdoor views is defined as a direct line of sight to the outdoor environment via vision glazing between 30 inches and 90 inches above the floor. Glazing above or below these dimensions does not count. The line of sight used to determine horizontal views is assumed to be 42 inches to reflect the average eye level of a seated person (Figure 2).
Consider how existing interior walls and furnishings can be rearranged to maximize access to outdoor views from the occupants’ workspaces. The use of low partitions and vision panels can allow access to views for the building’s core spaces. A successful configuration strategy for office interiors places open-plan areas along the exterior walls and locates private offices or areas not regularly occupied, such as copy rooms, toward the core of the building. Maintaining the views for spaces near the core is a primary design objective. Consider utilizing opportunities created by churn to incorporate greater access to views. With an existing building, creating building management specifications for future space upgrades and systems furniture purchases that incorporate views will increase the likelihood of credit achievement in future certification
Figure 2. using Horizontal View at 42 inches to confirm access to Views
EB: o&M ieQ credit 2.4
Begin assessing the building’s access to daylight and views early on. If space reconfiguration, furniture purchases, or facility alterations and additions are necessary for credit achievement, include all plans in the overall certification timeline. If this credit is pursued, building occupants should have access to daylight or views before the performance period has concluded.
calculating Regularly occupied areas
The project team should first identify all regularly occupied spaces within the project and calculate their associated floor areas. The regularly occupied spaces and total area calculated for this credit should be consistent with the regularly occupied areas identified in other credits. Any spaces dedicated to tasks that would be compromised or hindered by the inclusion of daylighting should be identified and the reason for their exclusion should be explained for documentation purposes.
Any area exclusion must be based solely on the basis of the task performed in the space and not the length of time an occupant will spend there. In addition, exceptions to the requirement are solely based on visual considerations, not based on sound; office spaces affected by airplane noise cannot be exempted from the credit calculations.
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Multi-purpose rooms must be included in the credit calculations. Because some activities in these spaces may be hindered by daylight, effective shades, view preserving blinds, and lighting controls should be included in the design.
For veterinary, boarding, or animal shelter facilities, include the area regularly occupied by the animals.
option 1. for Daylight
The requirements for any option can be met even if 100% of each room does not meet the minimum requirements when using the daylight simulation, prescriptive, or measurement approaches. The portion of the room within the daylight zone or meeting the illumination level requirements counts toward the percentage of daylighted area, and the rest of the space is included in the calculation of total area. The floor area of all compliant spaces is tallied and then divided by the floor area of all applicable spaces.
patH 1. simulation n
Create a daylight simulation model for the building or for each applicable area. The model should include glazing properties as well as representative surface reflectance settings for interior finishes. n
For each applicable area, include a horizontal calculation grid at 30 inches above the floor, or measured at the appropriate desk or work height level for the intended use of the space.
This represents the typical work plane height. It is recommended that the calculation grid be set up with a regular size interval so that the grid has at least 9 measuring points in a room bu with a a maximum interval of 5 feet to provide a detailed illumination diagram for each room. n
Calculate the daylight illumination for each applicable space using the following daylight criterion: clear-sky conditions at both 9:00 a.m. and 3:00 p.m. September 21 for the project’s geographic location. Figure 14 illustrates a sample daylight analysis for an office space. n
Identify the area of the room that has daylight. n
Illumination between 10 footcandles and 500 footcandles for both times (9:00 am and
3:00 pm). Spaces that do not meet the daylight illumination levels at both times do not qualify. n
If the space uses automated view-preserving shades, the maximum footcandle requirement does not apply.
n
Sum the square footage of all daylighted rooms or areas and divide by the total square footage of all regularly occupied spaces. patH 2. prescriptive
To demonstrate compliance via Path 2, project floor plans should be evaluated to categorize internal areas as sidelighting or toplighting daylight zones. Per the methodologies below, daylighted areas adjacent side windows (i.e. vision and daylighting glazing) and below any skylights/toplights should be calculated. These two areas taken together represent the compliant area for the project and are divided by the total floor area to demonstrate credit compliance. Care should be taken not to double-count compliant areas that may fall under both categories.
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sidelighting
This option provides a relatively simple method of determining whether the daylighting requirements are met. It is applicable to many standard building designs, primarily rectangular floor plates with a central core. The project team needs the following basic information to determine compliance: n
Window head height n
Window sill height n
Window area n
Visible light transmittance (abbreviated as VLT or T vis
) n
Floor area
Perform the following calculation for the applicable space: n
Determine the eligible window area (WA) for the space.
• Determine whether a modified head height must be used. As shown in Figure 3, draw a 63-degree angle from the vertical, in section, from the window head to the floor. If the ceiling obstructs this line, a modified head height must be used.
• Draw a 63-degree angle from the vertical, in section, using the ceiling corner that obstructed the previous line as a starting point. The point at which this line intersects the window is the modified head height. If a modified head height is used, count only window area below the modified head height. See Figure 3. n
Determine the floor area (FA). n
Determine the ratio of the window area to the floor area (WFR) — that is, WA/FA. n
Determine the ratio of visible light transmittance to window to floor area — that is,
(T vis
) (WFR). n
If the result is between 0.150 and 0.180, the space counts as a daylight zone. If the result is between 0.000 and 0.150, a portion of the space is compliant. Calculate the compliant floor area as follows:
• Divide the calculated result by 0.150 and multiply by the floor area of the space.
This fractional result represents the floor area to be counted as qualifying daylit area.
• When using this method in conjunction with toplighting, the qualifying floor area from sidelighting is assumed to be the floor area immediately adjacent to the windows.
An example of the sidelighting calculation is shown in Table 1.
Figure 3. sample Modified Window Head Height
EB: o&M
Dropped
Ceiling
63° ieQ credit 2.4
Ceiling Above This Line
2009 EDition
2H
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toplighting
This method is applicable for many standard building designs and may be particularly useful for single-floor retail developments. The project team needs the following basic information to determine compliance: n
Area of skylights or toplighting (SA) n
Visual light transmittance (VLT or T vis
) of skylights or toplighting n
Floor area of the space (FA) n
Measured haze value of skylight or toplighting diffuser
Perform the following calculation for each space: n
Determine the skylight or toplighting coverage, which is the ratio of skylights or toplighting area to floor area—that is, (SA/FA) (100).
n
Determine the top-light daylight zone area, which is the outline of the opening beneath the skylight, plus in each direction the lesser of- 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 n
Confirm a minimum 0.5 VLT for skylights or toplight.
n
Confirm that the skylight or top-light diffuser has a measured haze value greater than 90% per the ASTM D1003 testing methodology.
n
The area of the toplighting zone complies if the skylight or toplight roof coverage is between 3% and 6%, the measured haze value is greater than 90%, and the minimum
0.5 VLT criteria is achieved.
An example of the toplighting calculation is shown in Table 1.
Figure 4. toplighting Daylight Zone
420
35° 35°
H
Permanent
Partition
Hx0.7
Toplighting Zone combined sidelighting and toplighting Daylight Zone
For buildings that have both sidelighting and toplighting conditions, a combination of the above 2 methodologies can be utilized to demonstrate compliance.
patH 3. Measurement n
Take field measurements of illuminance levels of all applicable areas at 30 inches above the floor, or measured at the appropriate desk or work height level for the intended use of the space.
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n
Record indoor light measurements of all regularly occupied spaces on a grid that has at least 4 points in a room and with a maximum grid interval of 5 feet. n
Enter the floor area with daylight illuminance levels of 10 footcandles or above into a summary table. See Table 2. n
For spaces where some of the measurements meet the minimum 10 footcandle requirement, only the floor area meeting the minimum criteria is counted as the daylight zone.
patH 4. combination
The above calculation methods may be combined to document the minimum daylight illumination in at least 50% of all regularly occupied spaces. To combine the methods, determine for each space which single method will be used to determine the daylight zone.
Once the daylight zone has been determined for each applicable space, sum the daylight zone areas, this sum is the total daylighted area.
Divide the total daylighted area by the total combined floor area for all applicable spaces to determine the qualifying floor area percentage.
EB: o&M option 2. for Views
Two calculations are required to determine compliance. One, using the direct line of sight to perimeter glazing, determines whether 45% of the regularly occupied area has the potential for views. It is based on vision glazing between 30 inches and 90 inches above the floor and the location of full-height interior partitions. Movable furniture and partitions are included in the scope of this credit calculation. See Figure 5. Movable furniture and partitions are those that can moved to provide access to the view by the user without the need for tools or assistance from special trades and facilities management. The other uses the horizontal view at a typical seated eye height to determine access to views.
Figure 5. Direct Line of sight to perimeter Vision Glazing ieQ credit 2.4
Direct Line of sight to perimeter Vision Glazing n
Create a spreadsheet and identify all regularly occupied areas. Determine the floor area
(square footage) of each applicable space using construction documents. n
Using a floor plan, determine the fraction of the regularly occupied area that has direct line of sight to the outdoors for each window. The line of sight can pass through 2 interior glazing surfaces but not through doorways with solid doors.
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n
For private offices, if the percentage of floor area with direct line of sight is 75% or more
(i.e., only the corners are noncompliant), enter the entire square footage of that room in the spreadsheet (see Table 3) as meeting the credit requirement. If less than 75% of the room has a direct line of sight, estimate the compliant floor area and enter that value. n
For multioccupant spaces, such as work areas, conference rooms, and classrooms, estimate the actual square footage with direct line of sight to perimeter vision glazing.
Determining Horizontal View at appropriate Eye Height (42 inches) n
Using representative building sections, draw a line at 42 inches (typical seated eye height) across the section to establish eye height and any obstruction to the perimeter glazing.
Draw 1 or more representative sight lines from a point at eye height in the regularly occupied space to the perimeter vision glazing (Figure 2). n
For each space with a horizontal view at seated eye height, enter yes in the spreadsheet
(Table 3). If a room has direct line of sight on the floor plan but does not have an unobstructed view at eye height, the floor area does not count toward the requirement; enter no.
n
Total the areas that meet all the above criteria and divide the sum by the total regularly occupied area to determine whether the building meets the 45% access to views requirement.
As a first step in preparing to complete the LEED Online documentation requirements, work through the following measures. Refer to LEED Online for the complete descriptions of all required documentation.
n
Maintain documentation, such as floor plans, sections, and elevations highlighting the location of regularly occupied spaces with a qualifying amount of daylight. n
Maintain documentation such as floor plans, sections and elevations highlighting the location of regularly occupied spaces with credit required views. n
If using daylight simulation, update the computer model as the design progresses.
figure 6 provides an example of a daylight simulation model.
Figure 6. sample Daylight simulation Model output
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Figure 7. sample prescriptive Diagram
EB: o&M ieQ credit 2.4
table 1. sample prescriptive calculation
Regularly
Occupied
Space ID
Space Type
Floor Area
(sf) Zone
Floor
Area (sf)
Prescriptive
Window
Area
(sf)
Sidelighting Daylight Zones
Window to Floor
Area
Ratio
(WFR)
VLT
(T vis
) of
Window
VLT x
WFR
Sidelighted
Area
Subtotal
(sf)
Zone
Floor
Area (sf)
Room 119
Room 123
Room 129 conference/
Meeting office: private office: private
Room 144 conference/
Meeting
Room 201 other
Room 206
Room 210 office: open office: open
1,090.00
1090.00
248.00
455.00
680.00
905.00
220.00
930.00
1,180.00
298.00
466.60
905.00
64.00
100.00
200.00
0.23
0.21
0.21
0.22
0.68 0.155
0.70 0.150
0.70 0.150
0.70 0.155
1090.00
298.00
466.60
905.00
0.00
0.00
0.00
0.00
0.00
150.00
0.00
220.00
870.00
1030.00
Toplighting Daylight Zones
Total
Area of
Skylight
Openings
(sf)
Skylight
Coverage
(T
VLT vis
) of
Skylight
Toplighted
Area
Subtotal
(sf)
Total
Daylighted
Area,
Prescriptive
(sf)
25.00
8.00
35.00
44.00
0.04
0.04
0.04
0.04
0.60
0.60
0.60
0.55
0.00
0.00
150.00
0.00
220.00
870.00
1030.00
1090.00
298.00
616.60
905.00
220.00
870.00
1030.00
picture Ex.
conference/
Meeting total regularly occupied area (sf)
560.00
210.00
45.00
0.21
6,020.00
total daylighted area, prescriptive (sf)
0.70 0.150
210.00
266.00
25.00
0.04
0.60
266.00
476.00
5505.60
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table 2. sample Daylighting Measurement
Regularly Occupied Space ID
Room 101
Room 102
Room 103
Room 104
Room 110
Room 112
Room 114
Room 115
Space Type office- private office- private other conference/Meeting office- open office- private conference/Meeting office- private
TOTAL
Floor Area (sf)
400
600
240
975
2420
330
720
604
6,289
Floor Area with Daylight
Illuminance Levels between
10 fc and 500 fc
400
500
0
975
2120
330
0
604
4,929
Exemplary performance is available to projects that achieve both 75% daylighting and 90% views.
The building site orientation and its specific regional location will directly influence the available daylight throughout the day and during the seasons. For instance, in northern latitudes, winter days are short, and occupants might spend the entire period of daylight inside. As such, seasonal variances in the daily sun path should be evaluated during the project design’s development to minimize the potential for glare inside the building while maximizing the use of functional daylighting. The consistent availability of adequate daylight at a particular project site will also affect the potential for reduction in lighting power demand through the use of various daylighting strategies, such as incorporation of photo-responsive controls for perimeter lighting zones. Likewise, consideration should be given when selecting glazing systems to balance the visible light transmittance with overall building energy performance goals so to minimize undesirable heat loss or gain. In addition, the visual appeal of the exterior environment greatly impacts the subjective quality of the views.
Please see USGBC’s LEED Resources & Tools (http://www.usgbc.org/projecttools) for additional resources and technical information.
Websites
Analysis of the Performance of Students in Daylighted Schools http://www.innovativedesign.net/studentperformance.htm
This website details Innovative Design researchers Michael Nicklas and Gary Bailey’s 1996 study of
3 daylighted schools in North Carolina.
The Art of Daylighting http://www.edcmag.com/Archives/10e5869a47697010VgnVCM100000f932a8c0
This Environmental Design + Construction article provides a solid introduction to daylighting.
California Energy Commission Public Interest Energy Research Program http://www.energy.ca.gov/research/
The Public Interest Energy Research (PIER) Program supports energy research, development, and demonstration projects, including those related to windows, daylighting, and productivity. Relevant
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studies available on the Integrate Energy Systems: Productivity and Building Science portion of the website include the following: n
Windows and Offices: A Study of Office Worker Performance and the Indoor Environment n
Windows and Classrooms: A Study of Student Performance and the Indoor Environment n
Daylight and Retail Sales
Efficient Windows Collaborative http://www.efficientwindows.org
This site, jointly developed by the University of Minnesota, Alliance to Save Energy, and Lawrence
Berkeley National Laboratory, provides information about the benefits of energy efficient windows, descriptions of how they work, and recommendations for their selection and use.
Radiance Software http://radsite.lbl.gov/radiance/
Free daylighting simulation software is available from the Lawrence Berkeley National Laboratory.
Tips for Daylighting with Windows http://windows.lbl.gov/daylighting/designguide/designguide.html
This comprehensive daylighting guide is from Lawrence Berkeley National Laboratory.
Windows and Daylighting Homepage http://windows.lbl.gov
This resource from the Lawrence Berkeley National Laboratory provides product research, software tools, and other daylighting-related information.
Whole Building Design Guide, Daylighting http://www.wbdg.org/resources/daylighting.php
Whole Building Design Guide, Electric Lighting Controls http://www.wbdg.org/resources/electriclighting.php?r=school_library
The Daylighting and Electric Lighting Controls sections provide a wealth of resources including definitions, fundamentals, materials, and tools.
EB: o&M print Media
Daylighting Performance and Design, by Gregg D. Ander (John Wiley & Sons, 2003).
This book contains information on daylighting strategies, materials, and construction methods.
Facility alterations and additions are discussed in the Introduction of the LEED for Green Building
Operations & Maintenance.
ieQ credit 2.4
2009 EDition LEED REfEREncE GuiDE foR GREEn BuiLDinG opERations & MaintEnancE 425