H I G H P E R F O R M I N G B U I L D I N G S Fa l l 20096

C A S E S T U D Y

Elevating Performance

B U I L D I N G AT A G L A N C E

B U I L D I N G T E A M

Owner Kitsap County, Wash.

Architect The Miller|Hull Partnership

Civil Engineer SvR Design Company

MEP Engineer Abacus Engineered Systems

Landscape Architect Site Workshop

Structural Engineer AHBL

Commissioning Engineering Economics

Daylighting Analysis Seattle Daylighting Lab

General Contractor Swinerton Builders

Name Kitsap County Administration Building

Location Port Orchard, Wash.

Owner Kitsap County

Principal Use Administrative office

Includes Offices, underground garage (nat-urally ventilated), cistern irrigation system

Employees/Occupants Approximately 210

Gross Square Footage 67,850 ft2

Total Cost $18.2 million

Cost Per Square Foot $268

Substantial Completion/Occupancy 2006

Occupancy 100%

Distinctions/Awards 2009 Beyond Green Award by the Sustainable Buildings Industry Council; 2008 AIA Honor Award, AIA Northwest & Pacific Region; 2008 AIA Merit Award, AIA Seattle Chapter; 2007 AIA Merit Award, AIA Washington Civic Design Awards

“The care, concern and environmental

sensitivity that went into the construction

of this new structure set it apart from nearly

any other government building in the

region, and it expresses its own statement

about the people of this community.”

— U.S. Rep. Norman D. Dicks, D-Washington, From speech at building grand opening

K I T S A P C O U N T Y A D M I N I S T R A T I O N B U I L D I N G

B Y R O B E R T M I S E L , A I A

Extensive glazing on the building’s north elevation provides an abundance of natural light to the open office spaces. The lobby ceiling displays can-vas oil paintings by local artist Frank Samuelson. The series depict salmon migration from ocean to stream.

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This article was published in High Performing Buildings, Fall 2009. Copyright 2009 American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. Posted at www.hpbmagazine.org. This article may not be copied and/or distributed electronically or in paper form without permission of ASHRAE. For more information about High Performing Buildings, visit www.hpbmagazine.org.

H I G H P E R F O R M I N G B U I L D I N G S Fa l l 20098 Fa l l 2009 H I G H P E R F O R M I N G B U I L D I N G S 9

larger design process. As a result, the building team was able to push the boundaries of conventional HVAC systems and construction methodologies, reduce energy con-sumption, save water and create a building that contributes posi-tively to employee performance and comfort.

Design ProcessThe design process began with an eco-charette where primary stake-holders met for a brainstorming ses-sion to set environmental goals for the building. These goals were tracked and evaluated throughout the project.

Managing and conserving site water became a primary goal. Miller|Hull collaborated with the landscape architect and civil engi-neer to develop a system for the capture and reuse of rainwater. By studying the weather and rainfall patterns in the area, and compar-ing them with the detention requirements

and likely site irrigation needs, the building team developed a rainwa-ter collection and detention system designed to provide 100% of the required site irrigation.

Terracing the building into the hillside allows for multiple, smaller floor plates with an open office seat-ing plan. Operable windows provide access to fresh air.

Even Daylight DistributionThe building is oriented along an east-west axis. Limited use of hot, south-facing windows helps reduce the energy required to cool the building. Increased use of north-facing windows provides indirect natural light. Where windows were desired in spaces that faced the sun, extensive overhangs were installed to reduce glare and solar heat loads in summer.

Daylighting studies of the office spaces were performed to ensure all occupants had access to an immediate source of natural light. Narrow floor

A steep hillside turned out to be an impor-tant part of achieving sustainable goals for

a project in Kitsap County, Wash. The 54 ft change in elevation could have eliminated the site for con-sideration. However, the building team took advantage of the natural features of the site for the county’s administration building.

The team recognized that the steep site provides not only an inherent opportunity for earth sheltering, but also for rainwater harvesting, daylighting of interior spaces and natural ventilation. The building is designed as a series of stepped terraces arranged around a central vertical circula-tion core. Designers incorporated a water conservation system that collects rainwater from the vege-tated roofs and stores it to provide site irrigation.

The Kitsap County Administration Building creates a pedestrian link between the adjacent courthouse and public works buildings. The terraced floor plates reduce the scale of the building toward the sur-rounding neighborhood while main-taining a civic presence towards the county campus.

Kitsap County pursued an integrated design that incorporates sustainability into the

plates combined with interior sky-lights guarantee the presence of natu-ral light even into the earth sheltered portions of the building and reduce the need for artificial lighting.

Open office lighting is designed with linear fluorescent T5HO indirect pendants with 0 – 10 V dimming ballasts. Daylight zones are created near glazing walls and skylights. Each fixture length in the daylight zone uses integral daylight sensors to control the light levels.

This sensor integration eliminates the need for additional ceiling drops for separate sensors in the space, allowing for a cleaner installation. It also provides tighter control of each fixture length in the zone. Occupancy sensors are integrated into the control system and are cost effective since they eliminate wasted energy by turning lights off when room occupants forget.

E N E R G Y AT A G L A N C E

B U I L D I N G E N V E L O P E

Energy Use Intensity (Site) 71.1 kBtu/ft2

Natural Gas 31.9 kBtu/ft2

Electricity 39.2 kBtu/ft2

Annual Source Energy 164 kBtu/ft2

Annual Energy Cost Index (ECI) $1.40/ft2 · yr

ENERGY STAR Rating 77

Roof

Type Modified Bitumen

Overall R-value R-21

Reflectivity 0.27

Type Vegetated (Green)/Precast Concrete Plank

Overall R-value R-23, plus thermal mass of soil/concrete

Reflectivity 0.12

Walls

Type Limestone Clad/Concrete Masonry Unit (CMU)/Metal Stud

Overall R-value R-11

Type Concrete/Metal Stud

Overall R-value R-15

Type Cement Board/Metal Stud

Overall R-value R-21

Building Glazing Percentage 40% (including skylights)

Basement/Foundation

Basement Wall Insulation R-value R-11

Basement Floor or Under Slab Insulation R-value R-10

Windows

U-value 0.48

Solar Heat Gain Coefficient (SHGC) 0.37

Visual Transmittance 61%

Location

Latitude 47.54°N (122.65°W)

Orientation Building axis generally east-west

KEY SUSTAINABLE FEATURES

Rainwater collection and vegetated roof system

Recycled Content Materials: fly ash cast-in-place and precast concrete, carpet, gypsum wall board, synthetic flooring and acoustic ceiling tile; construction debris and waste was recycled

Limited use of hot, south-facing win-dows, and increased use of north-facing windows; extensive overhangs where windows face the sun; light sensors at window areas

Individual Controls: operable windows, task lights at office desks, and individual airflow control in cubicles

Terracing of floor plates and thermal mass

Indoor air quality sensors in conference rooms; low- and no-VOC materials used in construction

Natural Ventilation: fan-assisted natural ventilation; light illuminates in the office and an e-mail is sent asking occupants to open the office windows

Underfloor air distribution

The main lobby space connects all five county departments and provides an overflow area for the commissioner’s chamber.

Internal skylights provide natural lighting into deep floor plate loca-tions and correspond to circulation pathways within the building.

The terraced building form allows for operable windows at every level, which provide fresh air for the office areas. Heated and cooled air is fed from the raised floor. Collected air is returned high along the enclosed offices at the linear skylights.

The scale of the Kitsap County Administration Building steps down with the site’s steep grade, allowing for earth sheltering. The design also gives the building an appropriate two-story scale that blends with the surrounding neighborhood houses.

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Thermal MassThe concrete structure provides tremendous thermal mass, which minimizes temperature fluctua-tions throughout the daily cycle. Cast-in-place architectural concrete walls are exposed at the building core, and the precast floor planks are exposed at the perimeter of the office spaces, minimizing the amount of finish materials used.

The thermal mass terraced floor plates and earth sheltering design help maintain a consistent tem-perature throughout the building. The earth cools the adjacent office space, creating an environment sim-ilar to a basement on a hot day. The consistent thermal mass contributes to the building’s energy perfor-mance; only one of the two boilers was activated during the first winter of operation.

Indoor Air Quality and Natural VentilationTo take advantage of the mild Puget Sound climate, fan-assisted natural ventilation is incorporated into the design. The building includes four large open office areas that have a long north wall with operable windows.

manager, Kitsap County Department of Administrative Services.

The project’s commitment to sustainability continues outdoors. Photo sensors, in conjunction with a time clock, allow outdoor lighting to operate only when daylight is not available.

“One consistent theme in my dis-cussions with occupants was the amount of available natural light, which they consider to be an attitude booster. I rarely turn on my office light due to the amount of natural light available in my office,” said Brian Lyman, AIA, capital projects

From top: south elevation, west elevation and east elevation.

The north side entry features an extension of the main lobby stair, which continues through three lev-els inside the building.

The south-facing main entry is protected by a deep overhang. The cov-ered area provides a public gathering space for the county campus.

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face of the building. Air enters through the windows and is relieved through internal louvers located near the skylights, above the interior offices at the back of the floor plate.

Natural ventilation modes are initiated by an e-mail to occupants notifying them that they may open their windows. Also, a red/green light signals appropriate conditions. Space temperature and carbon dioxide levels are monitored at all times, and natural ventilation mode is supplemented or terminated by forced air as ventilation is required.

Indoor air quality sensors in con-ference rooms determine the neces-sary quantity of outside air delivered by the HVAC system based on the number of room occupants. Significant energy savings result from reducing the amount of outside

are based on a combination of the outdoor air temperature and solar/internal building loads.

In natural ventilation modes of operation, building occupants manu-ally open the windows on the north

During appropriate outdoor condi-tions, natural ventilation is used in these sections of the building to eliminate the use of air-handling and refrigeration equipment. Appropriate outdoor air conditions

The south-facing Auditor’s Department receives ample daylight. An overhang helps reduce summer heat loads.

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each open office cubicle. The UFAD approach relies on introducing slightly pressurized air in the space beneath a raised floor, instead of moderately pressurized air in an extensive ductwork system located in the ceiling space.

in the design process the building team decided to pursue an under-floor air-distribution system (UFAD).

In early schematic design the energy life-cycle cost analysis (ELCCA) established a baseline UFAD and compared it to more traditional overhead variable-air-volume (VAV) and water-source heat pump systems. This analysis ensured that the building mechani-cal systems selected during design have the lowest costs over the expected life of the building. Several alternatives to the selected HVAC system design were analyzed to determine the estimated initial cost, energy consumption and main-tenance costs.

The UFAD allows for fine-tuned control by all building occupants via operable diffusers located in

air (which often must be heated or cooled) delivered to the spaces.

Forced air ventilation is similar to the economizer operation, but uses less energy. During normal econo-mizer operation, air is delivered to the space by the AHUs. In the forced air mode, the operable win-dows throughout the building are opened and the return air fan pulls air across the space and exhausts it through relief louvers in the upper floor mechanical rooms. Fan energy is greatly reduced compared to tra-ditional 100% economizer operation due to the much lower static pres-sure requirements.

Underfloor Air DistributionThe county did not pursue LEED certification, but was committed to a sustainable design approach. Early

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Operable windows provide natural ventilation, while the north-facing windows and a skylight provide day-light and views of the vegetated roof.

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Water harvesting is a fundamental feature of the administration building. Almost a full acre of vegetated roofs manage site water and drainage by collecting, detain-ing and redirecting storm water runoff to a series of five cisterns located around the perimeter of the building.

The cisterns retain the collected rainwater for site irrigation during dry months. During the rainy season, the vegetated roofs and cisterns serve as a detention system, slowly releasing the collected runoff to the city’s storm system. Costs of the cistern collection system were offset by omitting the detention facility from the project.

The vegetated roofs can be seen from every floor in the building. They help reduce storm water runoff, building mechanical costs and solar reflection.

The green roofs consist of a 6 in. soil profile atop a series of collection mats, fabric and rigid insulation. Both the vege-tated roof system and on-grade site plant-ings are irrigated with a high-efficiency drip irrigation system, which helped establish the plants during the first year.

The irrigation system features water-efficient irrigation fixtures and a rain sensor. It schedules watering in the evening and early in the morning to prevent unnecessary evaporation. The plants only require water in the driest of times.

In the first year of occupancy, the captured water provided 54% of the required site irri-gation water per growing season. Now that the green roof plantings are established,

the drought tolerant plant species allow the rainwater harvesting system to meet a minimum of 67% of the site irrigation needs. The design team anticipates that number could approach 100% as the plants continue to establish themselves.

The cisterns, which are capable of stor-ing more than 110,000 gallons, only draw upon city makeup water when irrigation demand exceeds the cistern capacity in summer months. The design team placed a seasonal stream, or dry creek bed, along Cline Avenue to collect water from the over-flowing cisterns in the winter months. The surface stream transports the water to a collection area at the foot of the slope.

The design team recognized an oppor-tunity to tell a story about rainwater collection. Descriptive signage was placed along the seasonal stream, at the cisterns and at an open stone-lined basin where the overflow water collects. A seasonal rain garden in the basin is surrounded by a demonstration garden, which consists of native, drought tolerant and low maintenance plant species on the north side of the property.

W AT E R H A R V E S T I N G , V E G E TAT E D R O O F S

A rainwater garden collects overflow runoff from the five cisterns that store water from the building’s roof areas. The cisterns fill up and overflow during the winter months when the irrigation system is not in use. The water spills into a seasonal streambed, which parallels the Cline Avenue pedestrian stairs. The water flows to the rain garden and then into the city’s storm water system.

The vegetated roofs consist of drought tol-erant plants, a 6 in. soil profile, 4 in. of rigid insulation and a precast concrete plank structure. Rainwater collected in cisterns irrigates the plants during dry months.

During the rainy season and signifi-cant rainfall, the cisterns overflow into a seasonal stream.

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Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep

Sup

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ater

0

5,000

-5,000

10,000

15,000

20,000

Rainfall Available

Cistern 1 Storage

Cistern 2 Storage

Cistern 3 Storage

Irrigation Demand Met by Supply

Irrigation Demand Met by Domestic Water

Rainwater HarvestingCisterns 1, 2 and 3 for Year 1

Note: Data estimated.

January 7.5

February 7.1

March 5.8

April 3.5

May 2.3

June 1.6

July 1.0

August 1.1

September 1.9

October 4.5

November 8.8

December 9.1

Mean Annual Rainfall 54.0

Mon

th

Mea

n R

ainf

all (

in.)

R A I N W AT E R H A R V E S T I N G CISTERNS 1 , 2 AND 3 FOR YEAR 1

K I T S A P C O U N T Y

A V E R A G E R A I N FA L L

Five cisterns collect rainwater from the roofs. The water is used for irrigation during the drier months. The cisterns can store more than 110,000 gallons. City water is only used when irrigation demand exceeds the cistern capac-ity in summer.

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terminal units with hydronic heating coils. Alternative 2 would replace the underfloor system with water source heat pumps. The chiller is replaced with a cooling tower. The hydronic heating and chilled-water loops are replaced with a condenser water loop. Outside air units replace the main air handlers.

The ELCCA results indicated that the selected UFAD system would have an estimated life-cycle cost savings of $175,000 to $330,000 versus the traditional alternatives that were considered.

Alternative 1 would replace the underfloor system with conventional series overhead ducted fan-powered

Additional caulking and seals help reduce the amount of air that leaks from the UFAD system and bypasses the intended occupied space.

UFAD Leakage Testing the UFAD to deter-mine the specified pressure requirements proved to be a difficult endeavor due to unanticipated leakage from within the floor plenum. The mechanical engineers’ specifi-cations required a 25% maximum leakage at 0.1 in. w.g. positive plenum pressure. Original pressure tests yielded leakage rates in a range of 55% to 65%.

Follow-up smoke testing revealed that air was leaking through walls with studs passing through the raised floor. This was a significant problem since this air bypassed the occupied spaces. Following a consulta-tion from an outside mechanical engineer, the contractor sealed those wall openings, provided additional caulking at wall and slab joints, and duct taped perimeter radia-tor plenums and other miscellaneous loca-tions. Subsequently, the contractor reduced the leakage to 35% to 45%.

At that time, we concluded the system was performing as was intended, despite the fact that the leakage percentage

exceeded the original maximum leakage requirement outlined in the project docu-ments. We recognized that generally some leakage will always occur in raised floor plenum distributions systems (as is true in all ducted systems).

The objective is to avoid “bad” leakage. Bad leakage is defined as air that leaks out of the raised floor plenum and bypasses the intended occupied space. The plenum must be properly sealed to prevent this occurrence.

“Good” leakage is classified as air that does not go through the floor diffusers into the room, but passes through electrical boxes in the raised floor, the seams in the floor tiles, etc. This leakage is considered good since it still enters the occupied space at a low level helping condition and ventilate the occupied areas. However, most of the supply air should come up through the supply diffusers as designed. It became clear that everyone owned responsibility for maintaining the integrity of the underfloor plenum.

Adjustments The first year of utility bills identified an unexpected significant increase in energy use above the antici-pated baseline. Since the baseline model was not a code baseline, it’s possible the model may not have considered things such as exterior site/garage lighting and cistern irrigation pumps. The energy use may be also be related to a learning curve for occupants and users of the building.

For example, facilities managers originally programmed the DDC so the HVAC system shut down in the evenings and started up again in the morning before employees

began arriving. Due to the thermal mass of the building, they soon discovered that the building maintained a more consistent overall temperature on its own, and that allowing the HVAC system to run 24 hours a day at variable rates was more efficient.

“It takes a while to change the tempera-ture of the concrete, which affects the sup-ply air going to the spaces. It’s not impossi-ble, just slow to react,” said Jim Stoll, Kitsap County facilities mechanical supervisor.

Setting the HVAC system for a 12-hour workday gave it the additional time needed to adjust temperatures in the building. An original estimate for temperature change was 1 degree in 20 minutes; actually, it was 1 degree in 45 minutes. Comparing the July to December period before and after the changes showed $12,000 in utilities sav-ings, according to Stoll.

Adjustments to the DDC system beyond the first year of occupancy contributed to the building working closer to the antici-pated level of efficiency. According to the facilities staff, the interior light timing sys-tem is instrumental in energy/utility savings. The use of daylight by skylights and windows also offered significant energy savings.

After the first year in the building, the facility managers recognized that employees were overriding the system in several areas. Adjustments to the DDC system — mostly in scheduling lighting, boil-ers and HVAC — and employee education enabled the building to conserve energy as it was designed. The staff has accepted and understands function of the red/green light system in assisting the HVAC system and assisting better CO² levels, according to Stoll.

L E S S O N S L E A R N E D

The building offers views of its veg-etated roofs and the Sinclair Inlet.

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Making these goals a priority early in the design process made them achievable. Had these goals not been established early, they would have been too expensive to implement later because they would have required wholesale changes to the design.

The measures taken to ensure a healthy and productive work-ing environment for Kitsap County employees has resulted in better indoor air quality and an opportunity to enjoy natural light and ventila-tion. Employees work in a building that is flexible and functional and uses resources wisely. They can take pride in the building, which con-tributes to the quality of service that county citizens receive. •

fire damper when it showed a problem with the cfm rate in a series of rooms. Stoll uses the data logging part of the system for maintenance issues and to analyze energy use trends.

Since the delivered air flows gen-tly upward from the floor surface instead of being forced downward at high velocity from the ceiling, many advantages result. These include:

• Improved thermal comfort and indoor air quality. Occupants deter-mine how much air is appropriate in their local environment by use of floor-mounted diffusers with individual air flow control. Stale air is pushed up above occupant head height and returned at the ceiling;

• Reduced energy consumption. Smaller fan motors, more efficient movement of room air and fewer days per year when mechanical cooling is required contribute to energy savings; and

• Increased flexibility and reduced costs during future office layout reconfigurations, and ease of maintenance access to equipment beneath the raised floor. Changes to office configurations, including dif-fusers and data/electrical, now take hours, instead of days to complete.

Commitment to SustainabilityKitsap County was interested in demonstrating its sustainability com-mitment to the community, so it was a willing client. The design team took a more integrated approach to building design for this project, and sought the opportunity to collaborate on larger interests such as water harvesting, sustainable mechanical systems and other energy reduction strategies.

The life-cycle, maintenance/replace- ment and capital cost(s) were:

Baseline SystemVariable volume system with displacement ventilationELCCA Cost: $3,608,352

Alternative 1Variable volume system with fan-powered terminal unitsELCCA Cost: $3,938,676

Alternative 2Water source heat pumpsELCCA Cost: $3,784,040

Overall, this mechanical system will save the county about 10% annually over an overhead ducted system and more than 40% annually over a heat pump system.

In the UFAD baseline system, air handlers are variable speed and have hydronic heating and chilled-water coils. Heating water is provided by two gas-fired condensing boil-ers. Chilled water is supplied by an air-cooled chiller. Air is supplied to spaces either directly from the air handlers or through underfloor termi-nal units with hydronic heating coils.

The DDC system is the most com-prehensive of all county buildings.

“Having the capability to manipu-late the individual components has been critical in extreme conditions when the computer-driven system could not keep up with the changes. The system also is invaluable in diagnosing problems within the total systems that normally would not be noticed until they reach a critical state,” said Jim Stoll, Kitsap County facilities mechanical supervisor.

For example, the DDC system assisted in locating an unconnected

Robert Misel, AIA, LEED AP, is an associate at The Miller|Hull Partnership in Seattle.

A B O U T T H E A U T H O R

E N E R G Y U S E

M A R C H 2 0 0 7 – F E B . 2 0 0 8

Peak Electricity Electricity Gas (kWh) (kW) (therms)

Mar 65,520 218.4 2,030

Apr 59,640 215.04 1,684

May 72,840 254.4 1,136

Jun 72,000 261.6 489

Jul 73,800 284.64 264

Aug 66,360 259.2 343

Sep 65,040 241.92 876

Oct 62,280 213.12 1,728

Nov 58,920 154.56 2,938

Dec 65,160 154 3,750

Jan 58,560 154 3,805

Feb 62,040 156 2,570

Annual 782,160 21,613

Max. Peak 284.64