|
|
CATEGORY: Topics » Bilevel Switching
By Craig DiLouie, on April 9, 2009
While the basic ON/OFF switch is not considered an energy-saving lighting control, it can be if at least two switches are used to control lighting in a space that is configured on two lighting circuits, giving the user a choice of two levels of light output.
Alternate rows, fixtures or lamps can be switched, offering a choice of 50% and 100% light output. Or the center lamps can be switched separately from the outer lamps in three-lamp fixtures, offering a choice of 33%, 66% and 100% light output. In one study by ADM Associates, the latter option was demonstrated to produce 22% energy savings in private offices.
At least one-half of the energy codes in the United States are based on the International Energy Conservation Code (IECC), which requires light level reduction controls such as multilevel switching or dimming in enclosed spaces such as private offices.
Occupancy sensors are just as simple—a switch married with a sensor to enable automatic switching based on whether the sensor detects the presence or absence of people. Occupancy sensing is a reliable method for generating energy savings: According to the Advanced Lighting Guidelines, occupancy sensors in private offices can produce up to 45% energy savings.
All energy codes require that general lighting be automatically turned OFF when it’s not used. Further, IECC says that if an occupancy sensor is used in an enclosed space such as a private office, light level reduction controls are not needed, suggesting an either/or choice.
What if bilevel switching was combined with occupancy sensor functionality? Would this produce higher energy savings in a private office than bilevel switching or occupancy sensing alone. And: What combination of manual initiative and automation would produce the highest energy savings while also satisfying workers?
 Typical office used in the study. The California Lighting Technology Center (CLTC) organized a study in eight private offices at the University of California – Davis in 2008 to attempt to generate useful data related to these questions. Each office, between 90 and 140 sq.ft. with a ceiling height of 9 ft., is lighted by a combination of indirect/direct pendant fixtures and daylight entering through a window with manually adjustable vertical blinds. The study was sponsored by Watt Stopper/Legrand.
“The baseline comparison,” researchers Theresa Pistochini, Judy Xu and Rahul Shira wrote in a report on the study, “is made to a theoretical case where the occupant has no control over their lighting and it is switched ON and OFF by an occupancy sensor.”
In the test offices, the pendants are configured with dual circuiting, with a ballast driving two lamps (48W) placed on each circuit. This enabled the researchers to set up three test conditions and record data on occupancy.
 Office at 50% light level. • Auto-ON to 100%: When the office became occupied, an occupancy sensor signaled both relays to automatically turn the lights ON to 100% light level. If the occupant wanted a lower light level, they can flick a switch to 50% or manual-OFF. When the occupant left the office, the sensor then automatically swept the lights OFF.
• Auto-ON to 50%: When the office became occupied, the sensor signaled one relay to automatically turn one-half of the lamps ON to achieve 50% light level. The user could flick a switch to increase light level to 100% or turn the lights OFF. When the occupant left the office, the sensor then automatically swept the lights OFF.
• Manual-ON to 50% or 100%: When the office became occupied, the sensor did not turn the lights ON. Instead, the user could turn the lights ON to 50% or 100% light level, or leave them OFF. When the occupant left the office, the sensor then automatically swept the lights OFF.
 The bilevel switching occupancy sensor. “Occupants were informed about the manner in which the electric lights would behave and also that they were participating in a lighting controls study,” the study’s authors write. “However, the occupants were specifically not told that the purpose of the study was to measure the impact of their behavior on energy consumption.”
All three scenarios saved energy compared to the baseline scenario, suggesting that combining bilevel switching and occupancy sensing saves more energy than using an occupancy sensor alone. Specifically:
• The auto-ON to 100% bilevel occupancy sensor saved 34% compared to the baseline.
• The auto-ON to 50% bilevel occupancy sensor saved 52% compared to the baseline.
• The manual-ON bilevel occupancy sensor saved 46% compared to the baseline.
“This is quite impressive given that the designed lighting power density in the offices was already quite low at 0.7 to 0.9W/sq.ft., says Pistochini, development engineer for CLTC. “Giving individuals control of their lighting is important for achieving both user satisfaction and efficient use of energy.”
“The results showed that if we look beyond technology and include human factors and common sense, we can still find simple solutions that can be easily applied to save more than 50% lighting energy in existing commercial buildings,” says Pete Horton, VP market development for Watt Stopper/Legrand.
An advantage of bilevel switching is that users have a choice of light levels, enabling them to adjust light levels based on preference for different tasks or lighting conditions, such as the variable availability of daylight.
Pistochini says about half the study participants preferred the auto-ON to 50% scenario, while the other half preferred complete control and therefore preferred to the manual ON scenario. “The hypothesis with automatic-ON to 50% is that the occupant, when presented with manual-ON switches, will not give much thought to the amount of light needed and turn ON both of them. With the automatic-ON to 50%, the occupancy often enters the office, finds the light level acceptable, and continues working. Occasionally, they desire more light and turn ON the other switch.”
“This study indicates that there is still a lot of room for lighting energy savings in new and existing buildings,” says Horton. “If you are looking for energy savings and a good return on investment, combining bilevel switching and occupancy sensing appears to offer one of the highest values a building owner can achieve.”
He believes this research will be influential, pointing out that because 46-52% energy savings higher energy savings can be demonstrated with bilevel occupancy sensing compared to standard occupancy sensing, energy codes are likely to address this approach in the future.
By Craig DiLouie, on November 12, 2008
The Energy Policy Act (EPAct) of 2005 created the Commercial Buildings Deduction (CBD), which established an accelerated tax deduction rewarding investment in energy-efficient interior lighting, HVAC/hot water systems and building envelope.
Initially set to expire December 31, 2007 and then December 31, 2008, the CBD was recently extended by Congress to expire in five years: December 31, 2013.
The Deduction
A tax deduction is a cost subtracted from adjusted gross income when calculating taxable income; tax liability is not reduced dollar for dollar, as is the case with a tax credit, but instead in proportion to the taxpayer’s tax bracket.
Deducting the cost of a capital investment such as new lighting is not special. What is special about the CBD is the owner can potentially write off the entire cost of the new lighting in the tax year in which it is placed in service, instead of capitalized and depreciated or amortized over time. So it’s an accelerated tax deduction: If a cost item associated with installing new lighting is normally depreciated and claimed over a period of years, it can now be claimed in a single tax year.
The CBD essentially has two levels depending on whether one wants to achieve savings targets for the entire building—interior lighting, HVAC/hot water and building envelope—or each of these systems individually. And the Interim Lighting Rule, which was supposed to be in effect only until the partial deduction rules were written, is still in effect.
The Interim Lighting Rule does not require special software or building energy modeling and is therefore relatively simple to implement, so we will focus on this part of the CBD in this article.
Click here to learn more about the complete deduction and the partial deduction rules.
The Interim Lighting Rule
The Interim Lighting Rule enables commercial building owners to deduct the full cost of new interior lighting, capped at $0.30-$0.60/sq.ft. on the sliding scale in Table 1, if the new lighting achieves a lighting power density (W/sq.ft.) that is 25-40% lower than the maximum values published in Standard 90.1-2001’s Table 9.3.1.1 or Table 9.3.1.2 (not including additional power allowances).
The exception is warehouses: The lighting system must reduce power density by at least 50% to earn a deduction of up to $0.60/sq.ft.
Both retrofit and new construction projects qualify, as long as the project is located in the United States or its territories.
Qualifying building types are listed in Table 9.3.1.1, although IRS Notice 2008-40 adds nonresidential unconditioned garage spaces to building types covered by the CBD. Houses of worship, meanwhile, do not qualify because religious organizations are tax-exempt and their buildings are not owned by the public.
So if a retrofit project in a 100,000-sq.ft. commercial office building costs $100,000 and the cost is $0.60/sq.ft., then $60,000 could be written off in the tax year the new lighting is placed in service, and the remaining $40,000 would be written off normally.
Besides reaching a reduction in power density, three other conditions must be met to qualify for the CBD under the Interim Lighting Rule:
• Install all mandatory controls and circuiting provisions in Standard 90.1-2001 (but only if a new construction or qualifying lighting alteration project, as retrofits—projects in which only lamps, ballasts and/or controls are replaced—are not covered by 90.1).
• Install bi-level switching in all occupancies except hotel and motel guest rooms, store rooms, restrooms, public lobbies and parking garages.
• Achieve the minimum recommended calculated light levels as established in the 9th Edition of the IES Lighting Handbook.
What is “bi-level switching”? Generally, bi-level switching is manual or automatic control (or a combination of the two) that provides at least two levels of lighting power in a space (not including OFF). NEMA has stated that bi-level switching typically produces 10-15% energy savings.
Multi-level switching scheme enabling 0%, 33%, 66% and 100% light and power levels. Graphic courtesy of DOE.
Dimming or switching can be used. It can be as simple as a split-ballasting system with the lighting assigned to two circuits, each controllable from a separate wall switch that is accessible to occupants (unless remote access is required for safety or security). The A/B switching can be based on alternate ballasts switching or alternate fixtures. From this basic scheme, other options become available. For example, the control can be a photosensor, occupancy sensor or input from a schedule instead of a wall switch, or alternatively dimming ballasts can be used that respond to a range of control inputs.
Also note that Standard 90.1-2001 only recognizes permanently installed lighting, so upgrading portable task lighting does not qualify as a contribution to the CBD. Similarly, the Standard exempts exit signs from interior lighting power calculations, and therefore exit sign upgrades do not qualify as a contribution toward earning the CBD.
Project Certification
For a building owner to claim the CBD, the project must be certified by a qualified individual—a contractor or engineer properly licensed as such in the jurisdiction where the building is located. The individual, who cannot be an employee of the building owner, must demonstrate in writing to the owner that he or she has the qualifications to do the certification.
According to IRS Notice 2008-40, the qualified individual must document the reduction in lighting power density in a thorough and consistent manner, with the certification including:
• Contact information for the qualified individual performing the certification.
• Address of the building to which the certification applies.
• Statement by the qualified individual that the interior lighting systems have been, or are planned to be, incorporated into the building that meet all of the requirements of the Interim Lighting Rule (suitable reduction in lighting power density, controls and circuiting in compliance with Standard 90.1-2001, etc.).
The certification must also include a statement by the qualified individual that:
• Field inspections were performed by a qualified individual after the lighting was placed in service;
• That these inspections were performed in accordance with testing procedures prescribed in the National Renewable Energy Laboratory (NREL) as Energy Savings Modeling and Inspection Guidelines for Commercial Building Federal Tax Deduction (PDF) (see pages 1-2) and currently in effect; and
• These inspections confirmed the building is meeting the specified reduction in lighting power density.
The qualified individual must also provide:
• A list showing the energy-efficient lighting components and features of the building and projected power density;
• Statement that the building owner has received an explanation of the energy efficiency features of the building and projected power density; and
• A declaration: “Under penalties of perjury, I declare that I have examined this certification, including accompanying documents, and to the best of my knowledge and belief, the facts presented in support of this certification are true, correct and complete.”
The building owner should keep a copy of the certification in their tax records.
Click here (PDF) to see NEMA guidance on certification letters.
Software
Note that although IRS Notice 2006-52 (PDF) says the certification must include a statement that qualified computer software was used to calculate energy and power consumption and costs, this is not needed to demonstrate compliance with the Interim Lighting Rule. Instead, a spreadsheet or similar software can be used.
Public Buildings
If the building is government-owned (doesn’t pay taxes), the designer (“person that creates the technical specifications for installation of energy-efficient commercial building property”) can claim the CBD, according to IRS Notice 2008-40. If more than one designer is involved, the owner may allocate the CBD to the designer who was primarily responsible for the design or, at the owner’s discretion, among the designers.
More Info
NEMA created an excellent website at www.lightingtaxdeduction.org that explains the CBD.
By Craig DiLouie, on April 12, 2008
Education has become a major construction market in recent years. In 2005, about $80 billion in spending made the K-12 and higher education markets the largest nonresidential segment, which held in 2006 ($85 billion) and 2007 ($100 billion) and will likely hold in 2008-09.
And it’s a good thing, too. Each year, more and more students are using facilities that are getting older and older, and using them differently than previous generations.
 Figure 1. Lighting typically represents 30-40% of school utility costs. Consider that in the fall of 2006, nearly 50 million students began using more than 385,000 school buildings; the number attending public elementary and secondary schools had risen 24 percent since 1985. According to the U.S. Department of Energy, just a few years before—in 2003—more than 60% of all school floorspace had been built before 1980, and 40% of that space had never been renovated. And students are increasingly using whiteboards, computers, Internet and multimedia, making classroom design as sophisticated as hi-tech corporate board rooms and conference spaces. To top it off, energy codes are becoming more and more restrictive on schools: A maximum power density of 1.6W/sq.ft. for classroom is prescribed by ASHRAE Standard 90.1-1999/2001, 1.4W/sq.ft. by ASHRAE 90.1-2004/2007, and 1.2W/sq.ft. by California’s Title 24-2005.
So the public and private sectors are spending record funds on school construction, renovation and modernization. Demand for lighting quality and flexibility is increasing to keep up with new visual needs, and the amount of power available for lighting is decreasing. This implies that tough design choices must be made; as the average school building built today will last the next 40-50 years, these choices are critical.
The high-performance schools movement, promoted by organizations such as the Collaborative for High Performance Schools, provides guidance on how to achieve schools that have good lighting, indoor air quality, temperature and humidity and acoustics, and minimized energy consumption, resource allocation and costs. Reducing energy costs is welcome to most schools; lighting alone typically devours 30-40% of school utility expenditures. But is lighting up to the task? Can today’s lighting technology provide a quality visual environment with the kind of flexibility required in high-end conference rooms, while minimizing energy costs and meeting tough energy codes?
The New York State Energy Research and Development Authority (NYSERDA) took this one step further by basically asking what’s the best value in school lighting, with value being defined as the most appropriate lighting for the lowest energy cost?
NYSERDA sponsored a demonstration project featuring a new Integrated Classroom Lighting System (ICLS) created by Finelite, Inc., a fixture manufacturer, installed as a retrofit into 28 existing classrooms at seven schools and universities. The Lighting Research Center (LRC) assessed teacher and student satisfaction.
The result is a design template demonstrated to satisfy audio-visual needs and improve teacher and student satisfaction while reducing lighting power density to an average 0.73W/sq.ft., nearly 50% less than ASHRAE 90.1-2004/2007. Although Finelite optimized the design into an engineered system integrating the company’s light fixtures with state-of-the-art lighting control strategies, the template, if properly designed, can be treated as open source with suitable products from a wide range of manufacturers.
The design typically is composed of two rows of direct/indirect pendants with a wallwasher whiteboard fixture mounted on the main teacher board. The fixtures are placed parallel to the window, with the rows spaced 14-15 ft. apart.
 Figure 2. The ICLS template. Legend:
1) Two rows of two-scene indirect/direct luminaires mounted perpendicular to the main teaching wall (parallel to window wall) and spaced 14-15’ apart.
2) A dedicated luminaire is used to illuminate the whiteboard on the main teaching wall.
3) Teacher control is placed at the front of the classroom. For easy teacher access place controls within 6 inches of the whiteboard.
4) Sensors are placed in the center of the classroom. Sensors always include occupancy and daylight harvesting is added where appropriate.
5) A master ON/OFF switch is by every door to the classroom.
Each fixture uses three high-performance (3100-lumen) T8 lamps—with one inboard lamp providing the downlight component and two outboard lamps providing both uplight and downlight. The inboard lamp and outboard lamps are electrically separate so that they can be separately controlled.
The fixtures are integrated into a lighting and control system featuring a ceiling-mounted dual-technology occupancy sensor placed between the rows of pendants, a master switch at the door and a “teacher control center” located near the main teaching board, which features:
- A “Whiteboard” switch that turns the wallwashing fixture mounted on the main teaching board ON and OFF;
- A “General/AV Mode” enabling the teacher to switch between General mode (downlight OFF, uplight/downlight ON) and A/V (and reading) Mode (downlight ON, uplight/downlight OFF; and
- A “Quiet Time” switch that overrides the occupancy sensor for one hour, keeping the light on during long periods of occupied non-movement such as standardized testing.
 Figure 3. The “Teacher Control Center,” which was mounted 6 inches from the main teaching board. Teachers were also able to access another option, A/V Dimming Mode, which allowed them to turn on and then dim the inboard lamp providing the downlight component. This required a dimmable ballast. All controls were connected via a CAT-5 plenum-rated low-voltage line with plug-and-play connections.
Optionally, a photosensor can be added, adjusting light output based on daylight availability.
 Figure 4. Hunter High classroom with the lights on General Mode.  Figure 5. Hunter High classroom with the lights on A/V Mode. Watt Stopper/Legrand provided off-the-shelf power and auxiliary relay packs to accomplish the fixture switching, the occupancy sensors with the customized Quiet Time feature, and switches for the teacher control station (through its sister company Pass & Seymour Legrand). Click here to see an interview with Jon Null, Director of Marketing for Watt Stopper/Legrand, about this project, or scroll down.
Results:
- Because all three lamps cannot be ON at the same time, the maximum lighting power density is capped at about 0.8W/sq.ft.
- The switching controls reduced average lighting power density to 0.73W/sq.ft., about half of ASHRAE 2004/2007 and about 40% less than Title 24.
- The LRC found that teachers generally preferred ICLS to the previous lighting system and that students also rated it favorably.
- The system was installed for $1.83-$2.29/sq.ft.; options such as daylight switching and a third fixture row to increase uniformity, add to the cost).
- The LRC found that installers generally characterized the system as “easy to install.”
- The design is suitable for both new construction and retrofit.
 Figure 6. The combination of energy-efficient lighting and integrated controls reduce average lighting power density to an average 0.73W/sq.ft. Click on the image to see it enlargened in a new window. Direct/indirect lighting and separately controlled fixtures for general and main teaching board lighting are considered best practices by the Collaborative for High Performance Schools. Optimizing this approach as a system with integrated controls maximizes its utility for A/V functions while minimizing energy consumption. Many of the research findings of this study are being incorporated into best practice developed by the Collaborative as well as the U.S. Green Building Council’s LEED for Schools green building rating system, according to LRC.
For more information about ICLS, including the complete reports on the California Energy Commission and NYSERDA demonstration projects, click here.
By Craig DiLouie, on June 13, 2007
While automatic shutoff of general lighting, required by prevailing energy codes, has received a significant amount of attention by the lighting specification community, bi-level switching is another frequent code requirement that can play an important role in energy conservation.
While energy savings with bi-level switching can be less than automated control strategies due to reliance on human initiative, it is a simple, durable switching strategy, with no special user training or maintenance to maintain its functionality.
In this special report by the Lighting Controls Association, we will describe bi-level switching code requirements, its role in the Commercial Buildings Deduction, methods and equipment, and the results of a study of typical energy savings achievable with bi-level switching in popular applications.
Bi-Level Switching and IECC
While ASHRAE/IESNA 90.1 is the national energy standard, many states have adopted an alternative—the International Energy Conservation Code (IECC) developed by the International Code Council (ICC), a membership association dedicated to building safety and fire prevention. The IECC is a model energy code that covers lighting in addition to other energy-using building systems. States have adopted various versions of the IECC, including the 2000 version (with 2001 supplement), 2003 version (with 2004 supplement), and 2006 version (with 2007 supplement), with the 2003 version being the most prevalent. The 2003 and 2006 versions of the IECC, covered in this report, require bi-level switching in interior spaces.
A number of states have developed state-specific codes that may or may not also require bi-level switching. For example, California’s Title 24 energy code requires bi-level switching in interior spaces.
Below is a table that reflects state-by-state adoption of IECC as of April 8, 2007. Confirm your state’s status by clicking here and scrolling down to the commercial code section of the page. Note that the 2003 and 2006 versions of IECC reference ASHRAE 90.1 as an alternative standard. ASHRAE 90.1 versions up to 2004 do not require bi-level switching in interior spaces.
IECC requires at least one manual control for lighting in all interior spaces enclosed by ceiling-height partitions, with few exceptions. If the space …
* has more than one light fixture
* is not controlled by an occupancy sensor
* is not a corridor, storeroom, restroom or public lobby
* has a lighting power density (lighting W/sq.ft.) >0.6W/sq.ft.
* is not a guestroom/sleeping unit
… then it must have bi-level switching. IECC defines bi-level switching as providing occupants the ability to reduce lighting load in a reasonably uniform pattern by at least 50%, and recognizes four methods (see “Methods of Bi-Level Switching” below).
Bi-level Switching and the Commercial Buildings Deduction
The Commercial Buildings Deduction created by the Energy Policy Act of 2005 established the Interim Lighting Rule, which enables an accelerated tax deduction of $0.30-$0.60/sq.ft. proportional to lighting power density savings of 25-40% below ASHRAE 90.1-2001.
There are several other requirements, one of which is bi-level switching must be installed in all occupancies except hotel and motel guest rooms, store rooms, restrooms and public lobbies.
Methods of Bi-level Switching
IECC recognizes four methods of light level reduction control:
* Controlling all lamps or fixtures (e.g., dimming or light level switching)
* Dual switching alternate rows, fixtures or lamps
* Switching middle lamp independent of outer lamps (3-lamp fixtures)
* Switching each fixture or each lamp
Suitable solutions include dimming controls, manual switches and daylighting controls. Other methods are acceptable if approved by the authority having jurisdiction.
Below is an example of the dimmer control option:
Another option for controlling all lamps and fixtures is to use step-dimming or light level switching ballasts, which provide a uniform change in illumination in the space. For example, a light level switching ballast incorporates two hot power leads for control with two standard switches or relays; switching one lead on provides 50% power while having both switches on provides 100% power. Alternatively, if only one switch is available or desired, the light level switching ballast can provide 100% power when the switch is first turned on and 50% after toggling down and back up.
Below is an example of bi-level switching based on separately circuiting and switching alternate fixtures:
Below is an example of bi-level switching based on separately circuiting and switching alternate lamps (a/b).
Another approach based on lamps would be multi-level switching, which enables three levels of light output and power input using three-lamp fixtures: all lamps OFF (0% light output), one lamp on in each fixture (33%), two lamps on in each fixture (66%), and all lamps ON (100%). Multi-level switching provides greater flexibility than bi-level switching and poses a less abrupt change in light level when automatic control is used. Greater granularity is possible depending on the lighting equipment and need.
Note that the term “bi-level switching” often refers to both bi-level and multi-level switching strategies.
Study of Bi-Level Switching Use and Energy Savings
In May 2002, “Lighting Controls Effectiveness Assessment: Final Report on Bi-Level Lighting Study” was published by the California Public Utilities Commission (CPUC), prepared by ADM Associates for Heschong Mahone Group, project managers for the Southern California Edison Company on behalf of the CPUC.
This is one of only a few field studies that have actually examined the use and utility of bi-level switching as a means to reduce energy costs. Two specific goals of the study were:
* Study how occupants used manual bi-level switching controls, including behaviors that reduced savings potential; and
* Estimate energy and demand savings.
The researchers measured data for bi-level switching applications in 256 open and private office, retail and classroom spaces in 79 buildings. The fixtures contained three lamps that were switched in a multi-level switching scheme, providing four lighting states: all lamps OFF, 1/3 lamps operating, 2/3 lamps operating and all lamps ON.
Table 2 below shows the breakdown of use of different bi-level switching conditions (high-wattage or 2/3 lamps switch only ON, low-wattage or 1/3 lamps switch only ON, or both switches ON or OFF).
 Table 2. Use of bi-level switching conditions at 3PM on weekdays by space type. Source: ADM Associates ADM Associates discovered that private offices demonstrated the highest level of energy savings derived from using bi-level switching at 21.6% (with bi-level energy savings defined as occurring at 1/3 or 2/3 power). Open offices came in second at 16.0%, followed by retail at 14.8% and classrooms at 8.3%.
One of the factors of bi-level switching use that was studied was daylight contribution. Use of bi-level switching and subsequent energy savings in open offices and retail spaces showed a positive correlation with daylight availability. Private offices did not show a positive correlation. Classrooms did, but demonstrated the opposite of researcher expectations: Classrooms with the lowest amount of daylight also had the lowest level of use of lighting.
In the end, the study demonstrated that manual bi-level switching results in energy savings, which could be increased with occupant education, and with the limitations on the use of only one switch offset by the simplicity and economy of the approach.
By Lighting Controls Association, on April 18, 2004
Prepared by the Lighting Design Lab
article reprinted courtesy of Architectural Lighting Magazine
 Pier 69 on Seattle’s historic waterfront was built in 1931 to warehouse rolls of metal for the production of canned salmon containers. The only concrete pier on the waterfront, Pier 69 stretches over 750 feet long and 135 feet wide. Hewitt Isley tackled this stolid building to create a new home for the Port of Seattle’s administrative headquarters. Their dynamic reno-vation created what the Seattle Weekly named “one of the grandest indoor spaces in the Northwest.”
The breadth of the building called for a dual focus. For the perimeter offices, Puget Sound and Seattle’s waterfront are the primary attraction; for the interior spaces, Hewitt Isley created two atrium areas filled with daylight and the rippling music of a 400 foot stream. Both the perimeter offices and the atria share their abundant daylight with the open office space between.
Lighting Features:
- Two large atria with photocell controls
- Perimeter offices share daylight with the interior
- Daylight/occupancy sensors control lighting in perimeter zones
- Partition mounted indirect fluorescent lighting saves energy in open plan work spaces
TWO ATRIA : Traveling Between Different Light, Different Moods
Hewitt Isley’s design approach of respecting the original structure while contrasting it with the new influenced the design of the two atrium spaces. The pier’s original structure was three stories high at the east end but only two stories at the west. The design team wanted to create two atrium spaces along the length of the building. But the existing sawtooth roof at the east end was higher than allowed by current building codes; so it couldn’t be replicated on the west. In addition, the sawtooth form couldn’t easily accommodate a penthouse for the new mechanical equipment.
Thus Hewitt Isley chose to change the roof form at the west end atrium, creating two delightfully different interior environments. The new west atrium has both north and south facing glazing at the atrium edges with the needed mechanical penthouse sandwiched in between. The bold shafts of sunlight here (which would be problematic in a more formal work space) are a warm contrast to the more subdued, even daylighting from the north facing clerestory windows of the east atrium. A 400′ granite embanked stream runs the length of the building uniting the two atria and recreating that northwest experience of wandering along a stream moving from quiet, forested light to dancing sunlight.
Photocell controls regulate indirect metal halide lights in the atrium, turning them off when sufficient daylight is present. This saves energy and money and lengthens the life of these hard to reach lamps.
PERIMETER OFFICES : Sight-seeing Along the Way
The perimeter offices have a rich “layered” approach to sunlight control. Large aluminum shading devices on the south elevation block direct sun penetration during the summer while letting in lower angle winter sun. The north elevation on the other hand, has a sleek, flat facade to maximize penetration of diffuse northern light throughout the year.
The next layer of control is the window glazing itself. The architects selected Azurelite glass from PPG, one of a new family of high performance glazings. Azurelite’s special blue-green tint reinforces the Port’s aquatic setting and selectively admits the visible portion of the solar spectrum (high visible transmission) while blocking the infrared, heat containing portion (low shading coefficient). The double glazed window units also incorporate a low-e film to reduce winter heat loss.
Interior perforated metal mini-blinds are the final defense against direct sun penetration. These redirect sunlight onto the ceiling of the space in their open position, while preserving a view out through their perforated surface, even in their fully closed position.
All perimeter offices and conference rooms have fully glazed interior walls to share daylight and the magnificent waterfront views with interior corridors and adjacent open plan work spaces.
CONTROLS : Taking the Shortcut to Energy Savings
In perimeter offices, electric lighting works with daylight to balance light levels and save energy. Each 12′x12′ perimeter office has two 2′x4′ recessed troffers with parabolic louvers. These 3-lamp luminaires are equipped with energy efficient T-8 fluorescent lamps and electronic ballasts. Inner and outer lamps are separately switched, allowing dual level control for varying daylight levels and occupant needs. The outer two lamps are activated by a switch-mounted occupancy/daylight sensor. When someone enters the space, the occupancy sensor turns on the outer two lamps only if the daylight level is below a predetermined minimum level. If higher light levels are required, the occupant can manually activate a separate wall switch to turn on the inner lamps. This three step approach ensures that lights are off when the space is unoccupied and only the minimum number of lights are on when it is occupied. Energy savings from a system like this can top 30-50%!
Pier 69′s renovation stands as a strong example of coupling dramatic design with lighting energy savings. In work areas, daylight is tightly controlled and integrated with the electric lighting scheme to maximize lighting quality and energy savings. In the more social atrium areas daylight breaks free of its tight controls and splashes out in dazzling sunlit displays – so welcome in our gray Northwest.
Project: Port of Seattle Headquarters
Location: Seattle, Washington
Owner: Port of Seattle
Architect: Hewitt Isley
Interiors: Gensler Associates (San Francisco)
Lighting Designers: S. Leonard Auerbach & Assoc.
Controls: Esmond Petska & Assoc.
Photography: Patrick Barta Photography
|
|
