Going for Gold

Pacific Ridge School is a non-profit, independent school located in Carlsbad, Calif. In 2007, Pacific Ridge School opened with 108 middle school and high school students and four temporary modular buildings. With school enrollment now two years ahead of the original plan, Pacific Ridge School has accelerated its master campus building plans to break ground on the first phase of its expansion plan, which includes a new synthetic athletic field and an energy-efficient high school building to accommodate up to 360 ninth- through 12th-grade students.

Located on a previously graded 12.85-acre parcel, the campus master plan embraces the school’s mission to be “engaged in the classroom and engaged in the world.” The master plan outlines the high school building, middle school building, multi-purpose building, athletic center and a performing arts building for phased development, while respecting critical academic adjacencies, student access and security, site amenities and sustainability.

Pacific Ridge School High School is targeting a LEED for Schools Gold certification. Sponsored by the U.S. Green Building Council, LEED metrics were first introduced into the construction industry in 1998. LEED has become an industry standard for measuring “green buildings.” 

The total building project will cost $20 million, of which the school has already raised over half from trustees, foundations, parents and other school supporters. The school expansion is the result of the collaboration of architecture firm Carrier Johnson, land-use planning and environmental services firm Hofman Planning Associates, construction management firm Downey Group and general contractor Swinerton Builders. 

Building Plans: Ethics Meets Design
Building Design
The proposed 32,500-square-foot high school building will include 19 classrooms with oval seminar tables; four science laboratories; two student reading lounges; a college counseling area; and faculty, staff and administration offices. Linearly organized within two opposing wings, more than 99 percent of the learning and support spaces will have access to natural daylight and views. Central to each wing is a student reading lounge, hierarchically differentiated from the balance of the structure by higher volumes and expressive butterfly roofs for distributing daylight. The reading lounges reflect the team-oriented approach to Pacific Ridge School’s instructional methodology, providing a forum for informal gathering, individual study, group study and presentation.

Extending instruction to the outside, overhead operable doors in each Reading Lounge open to exterior learning courtyards protected by trellises and canopy trees for shading. Reflecting the region’s temperate climate and the school’s commitment to the global environment, the reading lounges and building lobby have been thermodynamically modeled for passive ventilation only. Classrooms, laboratories and office areas have passive ventilation backed by energy-efficient HVAC. The high school construction will be load-bearing tilt-up concrete exterior walls with interior insulation and structural steel internal framing. Specialized areas such as the reading lounges will have Douglas fir parallel laminated beams and wood detailing harvested from forest certified and managed woodlands.

Interior material selections were guided by longevity, durability and environmental impact. Materials that visually express their recycled and renewable content communicate the school’s educational commitment to the environment.

Mechanical and Electrical Design
The environmental building systems reinforce the school’s academic mission to foster global engagement and ethical responsibility. Solar modeling for daylight control and harvesting guided the placement of windows, light shelves, shading devices and solar tube skylights. Within the building, photo sensors and occupancy sensors work in tandem with user lighting control systems to automatically adjust lighting levels. More than 99 percent of instructional and regularly occupied non-instructional spaces achieve daylight and views.

Computational fluid dynamic thermal modeling and predicted mean vote thermal comfort analysis guided passive ventilation design for regularly occupied spaces. The reading lounges and building lobby have been modeled for passive ventilation with no thermal conditioning. Classrooms, laboratories and office areas located adjacent to double-loaded corridors have passive cross-ventilation afforded by operable windows and innovative relief air vents vented through the building roof. Classroom occupant comfort is predicted to be within the comfort zone without supplemental conditioning 49 percent of the year. When occupant comfort cannot be maintained by passive ventilation alone, an efficient variable refrigerant flow system utilizing outdoor condensing units and in-room fan coil units monitored by occupancy sensors, and operable window interrupts will be on stand-by.

Domestic hot water will be provided at the source of use by efficient instant gas water heaters, and water use will be reduced by low-flow fixtures and waterless urinals. Automatic fixture sensors at toilet room lavatories and an ENERGY STAR dishwasher within the staff lounge will conserve additional water. The project targets a 30 percent reduction in potable water over a conventional code-compliant building.

Green power utility purchase agreements combined with the installation of an SDG&E sponsored 1,500-square-foot (15 kW) rooftop photovoltaic array will offset the school’s energy use by approximately 2.5 percent — a relatively small contribution to renewable energy, but a significant statement to the school’s commitment to a sustainable future.

The building energy management system will be monitored and interfaced with a future educational interactive flat screen display in the school’s lobby. The interactive display will graphically track current and historic energy consumption, allowing students to better understand the impact of their decisions on the global environment.

Thanks primarily to passive ventilation and effective energy efficient daylighting, the high school building’s overall energy performance is projected to be approximately 40 percent less than a building designed to California Energy Code. See relatively flat energy projected monthly energy curve in Table 1 as compared to a standard energy compliant building.

Landscape and Athletic Field
Both California natives and plants that have successfully adapted to the Southern California climate are being selected for their ability to thrive without significant supplemental watering. Proposed trees along the southern edge of the building will provide solar relief and possibly reduce cooling costs. Landscape plantings on steeply sloped hillsides will control erosion and mitigate fossil fuel consumption associated with routine maintenance, as will synthetic turf at the athletic field. Recycled content within the synthetic turf will divert used tires and sneakers from landfills.

An automated irrigation system, incorporating the city’s reclaimed water with rain shutoff, will reduce unnecessary watering during times of heavy precipitation. Existing irrigation systems in areas not receiving new planting (or otherwise impacted by construction activity) will be maintained in place to reduce resource use. Valves for shrub and ground cover areas shall be separated and irrigation “zones” shall be grouped together based on water use and solar exposure. This effort reduces unnecessary watering based on water needs of plants.

The irrigation system will be designed to provide uniform coverage and will be hand-adjusted in the field to eliminate overspray onto sidewalks, buildings, etc. This effort reduces unnecessary watering due to uneven precipitation rates and overspray. Low-volume spray heads will be utilized to irrigate planted areas. This effort reduces unnecessary watering from run-off. Overall irrigation conservation is estimated to reduce irrigation water by 50 percent over conventional irrigation measures.

Site Drainage Design
Storm water that comes in contact with the building (roof, decks and walkways) will be directed through internal mechanical piping onto grade. The replacement of existing concrete v-ditch drainage swales with riparian bio-swales will help percolate draining storm water, improving storm water quality and reducing site runoff.

Results: Meeting LEED Standards
Environmental sustainability is the cornerstone of Pacific Ridge School’s expansion plans. Pacific Ridge is committed to becoming one of the few schools across the country to receive gold accreditation from LEED. Highlights of Pacific Ridge meeting LEED standards include: onsite solar power, recycled construction materials, natural lighting for 99 percent of classroom space, passive ventilation for nearly 50 percent of classroom space and a reduction of landscape irrigation by 50 percent. Overall, Pacific Ridge School will realize a 40 percent reduction in energy consumption compared to traditional school buildings. Seeking LEED certification parallels the values of Pacific Ridge School and its students, who are conscientious local community members, and responsible global citizens.

Article complied by Carrier Johnson, a San Diego-based architecture and interior design firm, and Pacific Ridge School. For more information about Pacific Ridge School, call 760/448-9820, e-mail [email protected] or visit www.pacificridge.org. For more information about Carrier Johnson, call 619/239-2353 or visit www.carrierjohnson.com.