Tag Archives: daylighting

Should Daylight Admissions be Mandated Through Building Codes?

CSU_SageGlass

Photo courtesy SAGE Electrochromics

by Helen Sanders, PhD, and Pekka Hakkarainen, PhD
The conversation about the health benefits of daylighting in the United States has truly reached the forefront. Articles detailing research, data, and discussions about the ramifications of lack of sunlight from the built environment are now appearing in mainstream press and dominate educational seminar schedules at major industry conferences.

By contrast, in some European countries, commercial building construction more or less requires all occupants to have access to daylight, even if the scientific data to support it has not been readily available. For example, in Germany, the building code mandates occupants be within a certain distance of a window.

A large amount of data has accumulated over recent years demonstrating the harmful effects on human health due to lack of daylight and exterior views. The human body’s circadian rhythms not only manage sleep-wake cycles, but also many other important biological functions of the body such as hormone production, weight management, and immune systems. The production and suppression of melatonin is key to the regulation of these functions, and this is triggered by the light-dark cycles of daylight.

Lack of sunlight during the day and too much artificial illumination from screens or electric lighting at night can cause circadian rhythm disruption that, in addition to causing poor sleep, can alter moods and cause depression or long-term health problems, such as increased risk of diabetes, obesity, and cancer.

Debra Burnet, a daylighting designer and specialist on the impact of daylight on human health and well-being suggests, “Daylight is a drug and nature is the dispensing physician.” This sums up the role daylighting plays in human health and underscores the importance of the building environment’s quality and its ability to deliver appropriately high doses of daylight at the right times of the day.

The public health issue related to lack of access to daylight is only a relatively recent phenomenon. This is because daylight and open flames (e.g. candles, oil lamps, or kerosene lamps) were historically the only form of lighting for buildings and designers had to be creative about maximizing the use of daylight.

For example, older buildings tend to have narrower floor plates and courtyards. With the advent of affordable electric light, designers had the freedom to ignore daylight admission because they had another affordable light source. As a result, with the constraint on daylight admission relieved, floor plates in the latter half of the 20th century deepened significantly. This is especially true for tall towers where larger floor plates were needed for structural requirements, and whose construction coincidentally became possible with advances in structural engineering occurring at the same time.

From these designs, the well-known ‘cube farms’ were created in offices where workers were housed in high-walled work stations a long way away from the nearest window without access to view or daylight for the entire working day. Only higher-level management was allowed the privilege of a perimeter private office with windows.

Since the U.S. Environmental Protection Agency (EPA) reported people spend 90 percent of their time indoors, it would seem to be a 21st century imperative to ensure buildings are designed to provide occupants with sufficient daylight to keep them healthy and productive.

Daylight and building codes
Having established the importance of daylight to human health and well-being, the question arises as to whether the quality and quantity of daylight admitted into buildings should be mandated through building codes.

Both International Green Construction Code (IgCC), and American Society of Heating, Refrigerating, and Air-conditioning Engineers (ASHRAE) 189.1, Standard for the Design of High-performance Green Buildings Except Low-rise Residential Buildings—have some level of provision for the quantity of daylight admission. However, only the building rating program of Leadership in Energy and Environmental Design (LEED) begins to deal with the quality (e.g. glare control or thermal comfort control) in its prescriptive paths.

Other than a requirement to have 25 percent of the floor area in a daylight zone in the 2015 International Energy Conservation Code (IECC), the baseline codes are pretty much silent on the quantity and quality of daylight admission, merely requiring lighting controls in spaces of a certain size and setting the maximum allowed window area (primarily for heat gain and heat loss reasons).

The reason why daylight-responsive controls (i.e. dimmable electric lighting) are required by energy codes in an increased number of smaller spaces is not about the impact on human health, but because of energy performance. Daylight harvesting has one of the largest impacts on reducing building energy consumption and is relatively easy to implement. The more daylight brought in, the more electric lighting energy and cooling load that is offset.

According to the Department of Energy (DOE), integrated façades, which include using a good daylighting design to bring in large amounts of daylight deep into the building, dimmable lighting controls to harvest that daylight, and high-performance fenestration with dynamic solar control and low U-factor, have the ability to save up to 2.6 Quads (or 2.6 x 1015 Btus) of energy per year if installed in the entire U.S. building stock (Figure 1).

Figure 1

Figure 1_Helen_Pekka_ConstructionSpecifierDecember2014

The graph above depicts annual energy usage across U.S. building stock predicted by Lawrence Berkeley National Laboratory (LBNL) based on the implementation of key facade system of insulating fenestration with dynamic solar control and dimmable lighting controls can deliver up to 2.6 Quads annually.   Data courtesy of LBNL report number 60049

To put this into perspective, the United States consumes approximately 100 Quads annually—from buildings to transportation and manufacturing processes. A total of 40 percent is consumed by buildings, and about half of that by commercial buildings. Therefore, just by improving the façade and implementing good daylighting controls in commercial building design, a significant amount of the nation’s energy usage can be saved. For commercial buildings, this represents about 13 percent overall savings—a significant step toward net-zero building design.

The Commercial Building Energy Consumption Surveys (CBECS) DOE administers suggests the existing commercial buildings consume, on average, approximately 90 kBtu/sf/annually. All energy uses, including plug loads, are taken into account in this measurement.

Figure 2 shows the energy consumption of the current U.S. building stock and the performance of successive revisions of ASHRAE 90.1, Energy Standard for Buildings Except Low-rise Residential Buildings, which is evaluated through energy modeling simulations by Pacific Northwest National Laboratory (PNNL). For the 2004 standard, PNNL determined the energy consumption for buildings built to that standard was just under 60 kBtu/sf/annually. By 2013, that number had improved to below 40 kBtu/sf.

Figure 2

Figure 2_Helen_Pekka_ConstructionSpecifierDecember2014

The average energy use of the current building stock, along with those built to ASHRAE1 90.1, Energy Standard for Buildings Except Low-rise Residential Buildings 2004 and 2013 standards and the energy use estimated for achieving net-zero energy buildings. Data courtesy of ASHRAE 90.1

Figure 3

Figure 3_Helen_Pekka_ConstructionSpecifierDecember2014

The graph shows modeled annual energy use for the standard Pacific Northwest National Laboratory (PNNL) medium office building in Phoenix for the code-compliant building without shades, assuming manual shade use (moved once a day at noon or at the end of the day), assuming better shade movement (not as optimized as automated shading, but closer), and with electrochromic glazing that provides automated glare and solar control. Data courtesy of PNNL

According to some, a net-zero energy building would have to operate at 20 kBtu/sf/annually to allow currently available onsite power technology (mostly wind and solar generation) to provide, on average, the energy those buildings consume over the course of a year.

The Lawrence Berkeley National Laboratory (LBNL)/DOE study summarized in Figure 1 determined integrated façades would improve the energy consumption of the current building by 2.6 Quads (2.6 x 1015 BTU). Since commercial buildings consume about 20 Quads, this represents about 13 percent energy savings relative to the current building stock. Figure 1 shows the improvement over the most recent codes that would be needed to reach net-zero design is in the neighborhood of 17 kBTU/sf/annually, or about 20 percent relative to the current building stock. ASHRAE 90.1-2013 does not require the use of dynamic façades, so if effectively used in commercial buildings, such systems have the potential to contribute to about two thirds of the improvement towards that goal on average. This is a huge contribution for a single design element.

Managing glare is critical
Delivering the promised energy performance of dimmable lighting controls relies on first ensuring there is enough daylight admitted deep into the building, and secondly there is a dynamic response for glare.

The way in which glare or visual discomfort is managed can be the difference between achieving the energy potential of daylighting control systems and not achieving it. If glare is present, occupants will pull manual shades or blinds and then, more often than not, leave them down long after the glare condition has passed. This blocks admission of light and negates the energy benefit of the lighting controls.

Studies have shown most occupants do not actively manage manual blinds. As a result, the expected energy savings by the daylighting system are unlikely to be realized unless glare is actively managed. To illustrate this point, a Swiss study gathered data on the operation of manual blinds in a set of façades—east, south, and west—and found only 19 percent of office spaces had their blinds pulled up, and 26 percent of the rooms had electric lights on when the blinds were down or partially down. When the occupant’s behavior was studied, it was found blinds were moved an average of only 1.7 times per week and 41 percent of occupants moved their shading devices less than once a week. As a result, the average area of the window that was operative (i.e. allowing one to see through it) was more than halved from the actual opening size.

Figure 4

Figure 5_Helen_Pekka_ConstructionSpecifierDecember2014

This is an example of using automatically controlled electrochromic glazing to dynamically control the glare and also control the incident solar radiation to reduce the loads on the HVAC system. With lighting controls, this provides an integrated facade solution offering a path to net-zero building envelopes. Photo courtesy of Sage Electrochromics

A significant amount of the energy savings in recent versions of ASHRAE 90.1 has relied on the implementation of lighting controls in more (and smaller) spaces. Recent modeling work by Rick Mistrick at Pennsylvania State University has demonstrated across all climate zones, manual blind use increases the electric lighting energy use in the ASHRAE 90.1 prototypical medium-sized office building compared to the energy performance that was originally predicted.

Compared to the result of modeling with no blind use, when manual blind use was assumed, the total interior electric lighting energy increased between 2.5 and six percent. On the west perimeter zone alone, the increase in lighting energy usage was up to 25 percent compared to the expected lighting energy for an optimally oriented building with long sides facing south and north, and a large core. For non-optimally oriented buildings, the impact will be even greater.

Figure 3 shows the impact of manual blind use on total building energy, and the impact of automating the glare control. Automated glare control systems can bring the ‘as-occupied’ energy performance closer to the original target performance. Using lighting controls with both an automatic response for glare and dynamic solar control—such as electrochromic glazing—can deliver even better performance than the code-compliant target. Whichever solution is chosen, it is clear automation is required to provide the optimal balance of building energy performance and occupant comfort.

One can see how a building that has been, at least in principle, well-designed for daylight admission and energy performance, can be turned into a poor performer quite quickly by occupant behavior if a manual response to glare, such as manually controlled blinds, is used. For optimizing occupant comfort and energy performance, an automatically controlled response for glare, such as automated shades
or blinds, or automatically controlled dynamic glazing is recommended. In this way, the glare can be controlled when present, and the glare control mechanism removed as soon as the glare condition is passed. (Figure 4 shows an example of this type of solution.)

Implications for building codes
Given the impact of well-managed daylight admission on reducing the energy impact of the nation’s building stock and on the health of the population, should design professionals be looking at how to encourage bringing a greater quantity and quality of daylight into buildings through building codes? If implemented well, such strategies could save energy, as well as make buildings more comfortable and healthy places in which to live and work.

Questions to consider regarding this strategy include the following:

  • Should baseline energy codes begin to require
    a minimum quantity of daylight admission in building projects?
  • Should automatic glare control be a requirement for all buildings where daylighting controls are also required? (Or at least require an analysis to ensure there are minimal glare conditions associated with the building design/use?)
  • Should daylight admission requirements exist for just green buildings rather than the code minimum?
  • Should the ‘quantity’ be a requirement, but the ‘quality’ of daylight left up to the designer?

On paper, concepts relating to specifying the quantity and quality of daylight seem quite simple, but, the devil is in the details. First, the question of quantity should be considered. How is the quantity of daylight in a space defined and are there metrics available?

Currently, the most advanced above baseline codes, such as LEED, use the concept of spatial daylight autonomy (sDA) to characterize if there is sufficient amount of daylight in a design floor plan. sDA indicates the percentage of the building that achieves the minimum specified illuminance level (e.g. 300 lux for LEED rating) for more than the specified percentage of time in the year (e.g. 50 percent for LEED rating). This metric is often represented as sDA (lux, percent per year), where the lux level and percentage of the year can be set. Even though it has taken numerous years to develop sDA as a daylight metric, there still remains controversy over how effective it is for determining daylight sufficiency.

In terms of mandating daylight quality, it is clear the energy-saving potential of lighting controls and the human health impact of daylight admission depend on effective glare management. Glare metrics are in development, but not yet fully validated, so it may be difficult to use specific metrics in code language without running into problems. The simplest approach, which does not require metrics, could be to require a dynamic response for glare for all buildings in spaces where lighting controls are mandated.

Figure 5

Figure 6_Helen_Pekka_ConstructionSpecifierDecember2014

The results of a survey of an audience of 150 architects at a presentation on integrated window and lighting systems at the 2014 American Institute of Architects (AIA) Convention in Chicago. Image courtesy of SAGE Electrochromics and Lutron Electronics

Of course, the argument could be made all buildings are different and glare control should really be left to the designer because in some cases there may not be a glare issue as the elevation is already shaded, or the design and/or the use case is such that glare does not create a problem. However, it is clear from the number of buildings seen across the United States where manual blinds are used that glare is not being sufficiently addressed across the board by designers (Figure 3). If there is potential for sun glare, it will become a problem unless dynamic glare control is planned in advance. If not done, the occupants will install permanent shading in one form or another, which negates the energy savings attributed to daylight. As a result, when the energy savings expected as a result of requiring daylight responsive lighting controls are desired, the responsibility usually cannot be delegated to the designer without at least some guidance and/or basic requirements.

One approach suggested by Jack Bailey of lighting design firm One Lux Studio (New York City) in the development of a recent proposal for the International Green Construction Code to address such arguments is to require automatic glare control in spaces where daylighting controls are required, but with the following constraints:

  • on the east and west orientations only, where horizontal shading is not sufficient to control low angle sun;
  • for buildings on ‘greenfield’ sites, where it would be less likely to have shading from nearby structures and where the designer is encouraged to do appropriate massing and orientation to minimize east- and west-facing façades; and
  • only in classrooms and office spaces where the presence of glare is most likely to cause blind use (other areas such as atria and similar transitional spaces may not need the same level of glare control).

One potential unintended consequence could be requiring an automatic response for glare would result in increasing the cost of the fenestration system, causing designers to use fewer or smaller windows. It is hard to imagine this could reduce the benefit of daylighting and views given how much designers like designing with glass, however, it may result in the desired consequence of encouraging better positioning of windows on the façade (more on the north and south and fewer on the east and west).

During a presentation these authors gave at the 2014 American Institute of Architects (AIA) Convention on integrated lighting and window systems, the roughly 150 architects in the audience were surveyed about what kind of daylighting requirements they thought should be included in the prescriptive energy codes. Seven different options were provided and attendees could vote multiple times. The results are shown in Figure 5. The top answer given by 80 percent of the audience was energy codes should require dimmable lighting controls everywhere, such as the requirements in Title 24 of the California Energy Code. The second most popular answer with 70 percent was to require a dynamic response for glare. Interestingly, few audience members were keen on mandating the position of windows or interior design requirements such as perimeter-open offices or glass-walled private offices, or including interior design into the scope of the codes—all of which could encourage increased daylight admission. Though not a scientifically developed poll, this suggests the conversation should continue.

Conclusion
The question of mandating daylight quality has sparked a debate that is causing interesting options to surface. From this and other discussions during the code development processes, hopefully some kind of code language can be developed to require not just a minimum quantity of daylight to be brought into buildings, but also address the quality of daylight so as to ensure the energy savings initially anticipated are actually delivered.

 

Helen Sanders, PhD, has 20 years of experience in the glass industry, with 15 years focused on dynamic glass technology and manufacturing. She is responsible for technical business development at SAGE Electrochromics Inc., a developer and manufacturer of electronically tintable glass. Sanders is a board member of the Insulating Glass Manufacturers Alliance (IGMA) and Glass Association of North America (GANA). She can be contacted by e-mail at helen.sanders@sageglass.com.

Pekka Hakkarainen, PhD, is vice-president of government and industry relations at Lutron Electronics. He has held several technical, market development, and business development positions since joining Lutron in 1990. Hakkarainen has been active with the National Electrical Manufacturers’ Association (NEMA) for 20 years, and is the immediate past-chair of the Lighting Systems Division. Currently, he chairs the High-performance Building Council and the Daylight Management Council. Hakkarainen can be contacted at phakkarainen@lutron.com.

 

Walking the Walk

Energy distributor makes efficiency top priority

A clear-span steel structural system was chosen to accommodate heavy equipment at the Washington Electric Cooperative project in Marietta, Ohio. A standing-steam metal roof system was specified to provide relief from the leaks of the former facilities. Photos © D.A. Fleischer Photography

A clear-span steel structural system was chosen to accommodate heavy equipment at the Washington Electric Cooperative project in Marietta, Ohio. A standing-steam metal roof system was specified to provide relief from the leaks of the former facilities.
Photos © D.A. Fleischer Photography

By Kevin Hutchings

Maximizing energy efficiency is a key concern on virtually every new commercial construction project. When the construction happens to be for the electric provider itself, it is easy to understand how the priority takes on even greater importance. This was the case for Washington Electric Cooperative, an energy distributor located in Marietta, Ohio.

The company had been operating for years out of three separate facilities, serving nearly 10,500 customers in six counties. After five years of site planning and land acquisition, it was ready to consolidate under one roof, adding both operational and administrative efficiencies in the process.

Chief among Washington Electric’s goals with its new facility was the desire to build to Leadership in Energy and Environmental Design (LEED) certification, underscoring its commitment to energy efficiency. Additionally, the company had a vested interest in using a local company for construction.

Persistence pays off
Washington Electric approached a local builder for a design-build solution. However, since the project was receiving financial assistance from the local Rural Utility Service (RUS), a government agency, the project was required to go through a bid process. After nine bidders and 90 days, local company Mondo Building & Excavating was chosen for the project.

The building was originally designed to pursue entry-level LEED certification. Striving for a higher goal of Silver would have required enhancements specific to such areas as water runoff and recycling—issues not germane to Washington Electric’s core business.

“We really wanted to do it right when it came to the energy side,” says the company’s CEO Ken Schilling. “We wanted to walk the walk with everything from solar panels to high-efficiency water heating, geothermal heating and cooling, and high-efficiency windows.”

In an effort to decrease the amount of artificial light needed and control heating costs, all offices were located on the outer perimeter, and a clerestory runs the entire length of the facility.

In an effort to decrease the amount of artificial light needed and control heating costs, all offices were located on the outer perimeter, and a clerestory runs the entire length of the facility.

Bringing more natural light inside the building also played a key role in LEED certification. For instance, all of the offices were located on

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the outer perimeter, enabling inclusion of windows. This allows the building to gain more heat from the sun during the winter, as well as reduce the energy required for electrical lighting.

Kevin Guiler, project manager, explains how another design element provided a flood of natural light.

“We added a clerestory that runs the entire 61-m (200-ft) length of the facility. It has 762-mm (30-in.) windows that add daylight and help conserve energy by reducing daily lighting needs,” he said.

The clerestory also features a gable-type window on the front facing to give it an attractive, finished look.

The new facility is 2787 m2 (30,000 sf)—including 1003 m2 (10,800 sf) of office space and 1783 m2 (19,200 sf) of space for operational support. At any given time, bills are being processed in the front area, while bucket trucks and track diggers are maneuvering in the building’s back area.

With such a broad range of activities happening inside, it was critical to find a cost-effective building design that could also be versatile.

A clear-span steel structural system was used to construct the facility, with 7.6-m (25-ft) bays in the back to accommodate the heavy equipment frequently moving in and out of the building. While the company’s needs did not call for a clear-span frame, the structural system did provide the flexibility necessary to optimize all work processes inside the facility.

The building’s roof features a standing-seam metal roof system. This was a change from the existing buildings the company was operating from—all three were experiencing leak issues. Schilling recalls the issues of the old administration building in particular.

“It was a brick building built around 1963, and it had a flat roof,” he says. “It leaked around the rooftop heat pumps and was giving us fits.”

The roof system provided a proven weathertight solution. The assembly’s efficiency, long life cycle, and recyclability attributes helped contribute to the sustainability of the new facility as well.

Smooth construction
Despite running into a few unforeseen challenges, including some tricky excavation work around a high-pressure gas line outside the building, the overall construction process itself went smoothly.

“Our concept was we wanted a simple building, but one that was very energy efficient and functional,” says Shillilng. “We were determined to get a lot of bang for our buck and have a building that will be useful for the next 50 years. “

CROPKevin Hutchings has been the training manager for Butler Manufacturing for 15 years. He is responsible for product, builder management, and sales training. Hutchings joined Butler as an order technician for the buildings division and in the retrofit roof group, where he gained substantial experience in metal roof design and detailing. He has also served as project services manager for the roof division of Butler, managing a number of large and complex retrofit roof projects. Hutchings can be contacted by e-mail at jkhutchings@butlermfg.com.

Getting it Right the First Time: Addressing heat and light problems with glazing

Photo courtesy Sage Electrochromics. Photo © Jeffrey Totaro Photography

Photo courtesy Sage Electrochromics. Photo © Jeffrey Totaro Photography

by Helen Sanders, PhD

Design teams and glazing contractors are often called in to help solve problems when building owners find there is too much light and/or heat coming in, making interior spaces practically unusable. This author has encountered examples where the sun’s glare is so unbearable in an office building employees were issued sunglasses, and have even covered windows with cardboard.

Electronically tintable, or electrochromic (EC) glass, is a category of dynamic glazing that allows occupants to control the indoor environment by changing the visible light transmission (VLT) and solar heat gain properties of the glass. EC glass can be controlled automatically in response to an external environmental signal (i.e. light, heat, or occupancy) or through integration into a building management system all with manual override capability. Electronically tintable glass has been increasingly adopted as an efficient all-in-one sun management system that provides a view to the outside.1

Dynamic glass modulates its solar heat gain coefficient (SHGC) and visible light transmission over a wide range, stopping at points in between to provide optimal solar and glare control. Photo courtesy Sage Electrochromics

Dynamic glass modulates its solar heat gain coefficient (SHGC) and visible light transmission over a wide range, stopping at points in between to provide optimal solar and glare control. Photo courtesy Sage Electrochromics

Many of the commercial projects where dynamic glass is incorporated are ‘fix-its,’ where the existing glass has been replaced with dynamic glazing to make the space work for its intended use. It is not that the existing glass had poor performance—quite the contrary: in some cases, the glass replaced had excellent solar control coatings. Rather, the issue is really the original design concept did not combine the glazing with other elements to adequately address the sun management challenge the exterior environment presents. Perhaps there was too much glass on east and west orientations that caused over-heating, or insufficient consideration of glare control.

For many applications, dynamic methods for solar control and glare control are needed for optimal energy performance and occupant comfort. Dynamic solar control can be achieved conventionally with mechanical movable louver systems or Venetian blinds integrated into double-skin walls. These systems are commonly used in Europe.

Alternatively, electronically tintable glass (i.e. electrochromic) can be used to provide both automatic glare and variable solar control. EC glass can, at the touch of a button or command from an automated system, modulate its solar heat gain coefficient (SHGC) from 0.41 to 0.09 and visible light transmission (VLT) from 60 to one percent2 over a wide range and stopping at points in between (Figure 1).

By achieving a visible light transmission as low as one percent in the tinted state, EC glass provides the ability to block uncomfortable glare while maintaining the view to the outside, unlike the mechanical alternatives which block or obstruct the view. By dynamically controlling the light and heat flow into the building, significantly more energy savings can be captured than when using a static glazed façade solution. Further, occupant comfort is enhanced while maintaining exterior views.

Kimmel Center for the Performing Arts
The renowned Kimmel Center for the Performing Arts in Philadelphia was designed in 2001 by Raphael Viñoly. It is an architectural icon with a vast barrel-vaulted, fully glazed roof housing multiple concert halls, theatres, and large public spaces. However, the Dorrance H. Hamilton rooftop garden—originally designed as a rentable space for private functions with panoramic views of the arts center and the surrounding city—was almost uninhabitable from May to September with temperatures reaching 48 C (120 F). The center’s management had to turn away over a thousand inquiries annually for renting the space.

In a renovation designed by BLT Architects completed in 2012, the rooftop garden has been enclosed in a glass box structure. The design employs dynamic glass in the roof to maintain the views of the center’s vaulted dome, the city, and public spaces, while maintaining a comfortable year-round temperature (Figure 2).3

The renovation of the Dorrance H Hamilton Roof Garden at Philadelphia’s Kimmel Center for the Performing Arts used electronically tintable dynamic glazing to provide temperature control, while maintaining full views to the barrel vaulted glass roof. [CREDIT] Photo courtesy Sage Electrochromics. Photo © Jeffrey Totaro Photography

The renovation of the Dorrance H Hamilton Roof Garden at Philadelphia’s Kimmel Center for the Performing Arts used electronically tintable dynamic glazing to provide temperature control, while maintaining full views to the barrel vaulted glass roof. Photo courtesy Sage Electrochromics. Photo © Jeffrey Totaro Photography

Dehority Hall at Ball State University in Muncie, Indiana, features electronically tintable dynamic glazing, which solved a heat and glare control problem in an existing skylight to deliver the original design intent of a comfortable, well-lit, multi-purpose space. [CREDIT] Photo courtesy Sage Electrochromics. Photo © Susan Fleck Photography

Dehority Hall at Ball State University in Muncie, Indiana, features electronically tintable dynamic glazing, which solved a heat and glare control problem in an existing skylight to deliver the original design intent of a comfortable, well-lit, multi-purpose space. Photo courtesy Sage Electrochromics. Photo © Susan Fleck Photography

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Ball State University
Ball State University in Indiana (Figure 3) encountered a similar issue with a skylight. A three-sided courtyard in an honors dormitory had been enclosed to create a multi-purpose interior space. To maintain the open feel of the original courtyard, a fully glazed roof was designed. Even though a high-performance, low-emissivity (low-e) coated glass with a 50 percent frit pattern was used, the university realized within three months of the December installation the space was not working. It was too hot and there was too much glare, even during the winter.

Figuring out how to shade a skylight using mechanical shade or blind systems can be challenging and expensive. In fact, the mechanical solutions investigated were more costly than the automated dynamic glass solution which the university implemented only a year after the initial installation. The result was a comfortable space that was open, yet versatile, allowing movies and presentations to be viewed during daylight hours.

Sun management
Generally, if the original design has not been well planned in terms of addressing the sun management issue, it is hard to come back retrospectively to ‘fix it’ in an elegant way using mechanical solutions that complement the original design intent. Adding sunshades to an existing fenestration system can be challenging, especially when the existing structure is not specified for the additional load.

Sunshades can be effective if included in the design of a new building when used on the south elevation and of an appropriate depth. Often, sunshades can be cut as part of a value engineering exercise and end up being two shallow, causing little or no shade on the window, or removed completely. Also, it is important to appreciate because of the low-angle sun incident on east and west elevations, sunshades are less effective at providing solar control from shading on those orientations.

The compromise solution is frequently to add interior shades or blinds, but this can be a difficult proposition for overhead or sloped glazing where gravity is working against the designer and can cause ongoing maintenance headaches. While this solution can reduce the glare issues, it may not solve the overall heat gain problem, since the heat is already in the building, and the view to the outside is obscured.

STEM Hall at Grove City College installed electronically tintable dynamic glass into the building’s east-facing, two-story atrium to preserve the view of the campus grounds and let in natural light, while minimizing the glare and heat of the morning sun. [CREDIT] Photo courtesy Sage Electrochromics. Photo ©Montana Pritchard Photography

STEM Hall at Grove City College installed electronically tintable dynamic glass into the building’s east-facing, two-story atrium to preserve the view of the campus grounds and let in natural light, while minimizing the glare and heat of the morning sun. Photo courtesy Sage Electrochromics. Photo ©Montana Pritchard Photography

Dynamic glazing can also provide the glazing contractor with a retrofit solution to simply solve their customers’ heat and light control problems in any climate. If strict privacy is a concern then additional opaque blinds or shades are commended as dynamic glass, while providing some level of privacy to occupants during the day does not offer strict privacy, especially at night.

Buildings with access to natural daylight and views to the outside are desirable because of the positive impact on the health and well-being of occupants, as well as the ability to save energy by turning off electric lights. The access to natural daylight entrains the body’s circadian rhythms, which are critical for the regulating health, attention, and mood—many studies have shown the link between lack of daylight and illhealth.4 Deborah Burnett, a presenter at a daylight symposium last year stated, “daylight is a drug and nature is the prescribing physician.”5 Sustainable design standards and programs—such as Leadership in Energy and Environmental Design (LEED), International Green Construction Code (IgCC), and American Society of Heating, Refrigerating, and Air-conditioning Engineers (ASHRAE) 189.1, Standard for the Design of High-performance Green Buildings Except Low-rise Residential Buildings—all appreciate both high-energy performance and providing a well-lit space with views to the outside.

However, designing with glass and not considering the negative effects of the sun can result in sub-optimal building environments that cause occupants to be uncomfortable and less productive. Moreover, such buildings can give use of glass in buildings a bad name and perpetuate the view that reducing glass in buildings is an appropriate solution and one to be encouraged in building codes.

This has been illustrated most recently when an addendum that would have reduced the allowable window-to-wall ratio in the prescriptive path from 40 to 30 percent was considered for ASHRAE 189.1. Due to numerous comments from many industry sectors, including the daylighting design community and academia, the proposal was withdrawn. However, the discussion is not yet put to bed. The optimization of energy performance, daylight and view, and providing occupant thermal and visual comfort is one of the most significant challenges for high-performance sustainable buildings. Determining how to codify such solutions in building codes and standards is also a challenge. A focus on addressing the three-way optimization may really only begin once as-built performance of buildings is measured not just for energy consumption, but also occupant comfort.

A new wellness facility at Butler County Health Care Center in David City, New England, incorporated electronically tintable dynamic glazing in a curved, 278-m2 (3000-sf) curtain wall providing patients, members, and staff with a comfortable healing environment and an unobstructed view to the outdoors. [CREDIT] Photo courtesy Sage Electrochromics. Photo ©Phil Daubman Photography

A new wellness facility at Butler County Health Care Center in David City, New England, incorporated electronically tintable dynamic glazing in a curved, 278-m2 (3000-sf) curtain wall providing patients, members, and staff with a comfortable healing environment and an unobstructed view to the outdoors. Photo courtesy Sage Electrochromics. Photo ©Phil Daubman Photography

Planning ahead
Glass can be a significant contribution in buildings from both an energy and occupant perspective; however, buildings need to be designed well the first time. From a national perspective, it is strategically important to improve the built environment’s quality.

Part of ‘getting it right the first time’ involves understanding how the envelope will interact with the exterior environment throughout the day and from season to season, along with having the tools and products for use in the façade to deal with the dynamic nature of the environment. Some design strategies work well for more southern climates (such as static overhangs) where the sun is intense and the angle does not change as much during the year. However, these strategies may not work as well in northern climates where access to light in the winter is desired, yet the sun angles are sufficiently low to cause glare issues.

There are design tools available that can help determine if perimeter spaces will work prior to building them. For example, the free software tool, DAYSIM, is a daylight simulation tool designed to model the amount of daylight coming into a perimeter space as a function of time of day over the course of a year. It is based on the Radiance software developed by Lawrence Berkeley National Laboratory (LBNL).

By using this tool, designers can easily see if there will be too much glare in a space and experiment with methods of eliminating the problem before the building is constructed. The software can handle both mechanical shades and blinds as well as dynamic glazing and can be helpful in determining if designs have a light control problem before construction.

Integrated design for daylighting
Another important part of a successful initial design is using an integrated approach wherein the daylighting, lighting, and interior design are done in conjunction with envelope design. This provides a holistic approach to optimizing use of daylight, offsetting electric lighting to save energy, and controlling for glare and unwanted heat gain. It also prevents the common occurrence of the envelope being specified and built before the daylighting designer is brought in, by which time he or she has lost most degrees of freedom. Further, because the interior and daylighting designers are involved early, it prevents opaque private offices or 1.8-m (6-ft) cube heights being specified around the perimeter—these negate the benefits of an otherwise good perimeter daylighting design.

The renovation of the General Services Administration (GSA) headquarters included a seven-story atrium built atop a formerly open-air courtyard. Electronically tintable dynamic glass was chosen for the atrium’s skylight to provide a comfortable environment for occupants, reduce energy usage, and demonstrate how green technologies are being incorporated into renovated buildings. [CREDIT] Photo courtesy Sage Electrochromics. Photo ©Montana Pritchard Photography

The renovation of the General Services Administration (GSA) headquarters included a seven-story atrium built atop a formerly open-air courtyard. Electronically tintable dynamic glass was chosen for the atrium’s skylight to provide a comfortable environment for occupants, reduce energy usage, and demonstrate how green technologies are being incorporated into renovated buildings.
Photo courtesy Sage Electrochromics. Photo ©Montana Pritchard Photography

The integrated design approach, in which climate-based daylight modeling tools have also been used, is great for glass because it directs the designer to use appropriate amounts of fenestration in the right locations. By proactively implementing solutions that deal with the negative effects of the sun, such as dynamic methods for glare and solar control, designs can be created that both work for occupants and are energy efficient. By coupling the façade design with dimmable lighting controls, daylight is effectively harvested to offset electrical lighting. This has a significant impact on the energy performance of a building, especially one with a good daylighting design in which sunlight penetration to the interior is maximized.

Electric lighting accounts for approximately 38 percent of total building electricity use. Up to 80 percent of this electrical energy ends up as heat generated by lights, which then has to be removed by the air-conditioning system.6 In fact, the impact of reducing electrical lighting consumption by using daylight in commercial buildings is far bigger than the energy impact of changing the solar heat gain coefficient and U-factor of the fenestration by a few points.

Conclusion
Contrary to popular belief, a building with no windows is actually not the most energy-efficient structure. Glazed buildings employing high-performance fenestration, with appropriate considerations for solar control, good daylighting designs with a dynamic response for glare, and automated dimmable lighting systems can be more energy-efficient because of the saving in electrical lighting energy.7

The benefits to occupants in buildings with natural daylight and views to the outside should not be overlooked. After all, this is the reason windows are installed in the first place. An integrated design approach, employing daylight modeling and high-performance façade solutions can play an important part in ‘getting it right the first time,’ making even highly glazed buildings both energy-efficient and comfortable for occupants. By demonstrating mastery of the high-performance building challenge, the continued use of glass in buildings can be promoted. It helps make the case for not reducing the maximum allowable amount of glazing in the energy codes.

Notes
1 For more, see the white paper by D. Malmquist and N. Sbar’s, The Benefits of Dynamic Glazing. Visit sageglass.com/wp-content/uploads/2013/08/SAGE-benefits_of_dynamic_glazing.pdf. (back to top)
2 Visit sageglass.com/sageglass/sageglass-product. (back to top)
3 Visit pennsylvania.broadwayworld.com/article/Kimmel-Center-Completes-Dorrance-H-Hamilton-Rooftop-Garden-Renovation-20120831. (back to top)
4 For more, see Kathy Velikov and Julie Janiski’s “The Benefits of Glass: A Literature Review on the Qualitative Benefits of Glass on Building Occupants” at na.en.sunguardglass.com/cs/groups/sunguard/documents/native/pro_045179.pdf. (back to top)
5 See Deborah Burnett’s presentation, “Knowledge to practice—Epigenetics design and the built environment,”from the May 2013 Velux Daylighting Symposium in Copenhagen. (back to top)
6 See the 2003 U.S. Department of Energy (DOE), Energy Information Administration’s (EIA’s) “Commercial Building Energy Consumption Survey.” (back to top)
7 See D. Arasteh, S. Selkowitz, J. Apte, and M. LaFrance’s Zero Energy Windows, Proceedings of the 2006 ACEEE Summer Study on Energy Efficiency in Buildings, August 13 to 18, 2006. LBNL report number 60049. (back to top)

Helen Sanders, PhD, is the vice president of technical business development at Sage Electrochromics. She has 17 years of experience in the glass industry, and more than a decade in dynamic glass technology and manufacturing. She is an active member of ASTM, Insulating Glass Manufacturers Association (IGMA), and Glass Association of North America (GANA). Sanders earned her master’s degree in natural sciences and a PhD in surface science from the University of Cambridge. She can be contacted by e-mail at helen.sanders@sageglass.com.

Industrial Daylighting

Increasing light quality and reducing energy load

All images courtesy Acuity Brands

By Brian Grohe

For an electrical conduit design and manufacturing company in Roselle, Illinois, a new plant would represent as much as a 60 percent increase in company production and 25 new jobs in the community. However, before expanding manufacturing operations to a 4923-m2 (53,000-sf) space, there needed to be major changes to the 14-year-old building.

The building would be reclassified from industrial to heavy manufacturing, and it would be made as environmentally sound as possible. This meant improved energy efficiency where it was most achievable—in the building’s thermal properties and lighting system. Specifically, the company wanted vegetated roofing assemblies, lowered indoor temperatures, and improved energy efficiency, as well as daylighting solutions.

Two years ago in another project, 15 skylights were retrofitted with new ones from a California-based manufacturer specializing in high-performance prismatic skylights for the commercial market. Having seen the enhanced performance of those skylights, project manager Ed Berbeka opted for them again.

This photo shows the 55 to 62 footcandle (fc) readings inside the facility after the installation of prismatic skylights.

This photo shows the 55 to 62 footcandle (fc) readings inside the facility after the installation of prismatic skylights.

A total of 56 skylights were installed in the Roselle facility last October, at the same time the insulation and new roofing was installed. For the insulation upgrade, R-25 insulation would meet the latest international standards for long-term, thermal-resistance values. For the roofing upgrade, the existing ethylene propylene diene monomer (EPDM) black membrane was replaced with more reflective white—and more energy-efficient—thermoplastic polyolefin (TPO) material. The TPO assembly, lightweight and time-tested since the mid-1970s, reflects the sun’s rays to reduce incoming heat, and does not require rock ballast.

New electrical and energy-efficient lighting was also part of the upgrade to the building. After the roof renovation, the building’s interior temperature decreased by an estimated 17 C (30 F)—a measure taken during the month of August, just before the entire project was completed.

Lighting also significantly improved. The new skylights cover three percent of the roof area, which is relatively standard for industrial buildings. Thanks to their prismatic properties, however, the lighting inside the building, which has a ceiling height of about 12.19 m (40 ft), is anything but standard.

Generally speaking, warehouse lighting varies from as few as 5- to 10-fc (footcandles) in inactive storage areas, to as much as 30- to 40-fc output in more active spaces such as loading docks or receiving areas. After the installation of the skylights, light-level readings in the building reached from 55 to as much as 62 fc—without any use of electrical lighting.

A new roofing membrane and insulation to reduce the HVAC load were installed.

A new roofing membrane and insulation to reduce the HVAC load were installed.

The electrician took note of the lack of ‘hot spots’ created by typical bubble-dome skylights, which can allow heat to build in the space below. The specified skylights, however, diffuse the incoming light through its prismatic lenses, eliminating hot spots, glare, or haze, as well as dissipating any heat. All that remains in the space is fully captured, evenly distributed and ultraviolet (UV)-stable daylighting coverage.

In addition to increasing the interior light source and providing increased energy savings, the building owner says the daylighting solution also boosted employee morale in the manufacturing plant.

Brian Grohe, LEED AP, is the corporate accounts manager–industrial for Acuity Brands. He holds a bachelor’s degree from Columbia College in Chicago. With more than nine years in the daylighting industry, Grohe has held roles in regional sales and business development. He can be contacted by e-mail at brian.grohe@acuitybrands.com.

National Wildlife Refuge maximizes on outdoor views and daylighting

The San Diego National Wildlife Refuge Visitor and Administrative Complex employed ceiling-mounted glass-panel doors throughout its design to provide a connection between the outside saltwater marsh landscape and its interior.

The San Diego National Wildlife Refuge Visitor and Administrative Complex employed ceiling-mounted glass-panel doors throughout its design to provide a connection between the outside saltwater marsh landscape and its interior.
Photos © Mike Torrey. Photos courtesy Klein.

The facility maximizes on daylighting in its administrative offices, multi-purpose room, and visitors center.

The facility maximizes on daylighting in its administrative offices, multi-purpose room, and visitors center.

 

Opening in August of 2011, the San Diego National Wildlife Refuge Visitor and Administrative Complex (Chula Vista, California) specified frameless, interior sliding glass door assemblies to maximize on interior space and daylighting.

The $6-million, one-story administrative headquarters project for the U.S. Fish and Wildlife Service is 743-m2 (8000-sf) and contains administrative offices, visitors’ center, multi-purpose room, maintenance facility, and laboratory. Designed by Line and Space LLC, the use of interior glass allowed the team to maintain a connection between the surrounding landscape and the facility’s interior.

Separating the multi-purpose conference room and offices from the main hallway is a system of moveable and non-moveable glass-panel doors from floor to ceiling. These are installed using ceiling-mounted tracks to move, increasing the facility’s clean look.

The extensive use of daylighting will not only offer occupants continuous views, it will also attribute to energy savings. The structure achieved the U.S. Green Building Council’s (USGBC’s) Leadership in Energy and Environmental Design (LEED) Gold certification for New Construction.

Located on the site of the only remaining saltwater marsh habitat in southern California, Sweetwater Marsh, the structure is situated on land previously disturbed, to not further disrupt the site. The building’s exterior was designed with glass panes angled downwards, reflecting ground and not sky, to limit the number of birds colliding with it.

The facility consolidated operations previously being conducted amongst four off-site facilities. The new structure’s addition allows the U.S. Fish and Wildlife Service to provide increased services including:

  • managing migratory birds;
  • protecting endangered or threatened species;
  • conserving and restoring terrestrial and aquatic habitats; and
  • protecting a biologically diverse habitat.

Other sustainable features incorporated into the design include:

  • use of a 30-kw photovoltaic systems converting sunlight into electricity with solar panels;
  • natural daylighting;
  • use of low volatile organic compounds (VOC) materials;
  • active and passive heating and cooling techniques; and
  • waterharvesting.