sustainable stories : THE WALTON CENTER FOR PLANETARY HEALTH

TEMPE, ARIZONA

The following stories and diagrams were developed in partnership with Arizona State University, GRIMSHAW Architects, Buro Happold Engineers, Thornton Tomassetti, Sherwood Engineers, TenEyck Landscape Architects, RFD, Salt River Project, and McCarthy Building Companies. Thank you to each of them for contributing to the success of each story below and playing an integral role in making each a reality.

CELEBRATING HISTORICAL SITE FEATURES

HONORING HISTORICAL NETWORKS

The Walton Center is transected by a functioning waterway that has brought water to this site and surrounding areas for more than 2,000 years.

This open ditch provided water power for the Hayden Flour Mill and follows the path of ancient canals that came before it. The Salt & Verde rivers provide water to the Valley and starting in 1903 the Bureau of Reclamation built dams to provide water storage and reliable irrigation water supplies to the Salt River Valley canal systems. Salt River Project has operated and maintained the canal systems, dams, and reservoirs on behalf of the Bureau since 1917. Historically the ditches not only provided reliable water for a robust agricultural community, but also offered relief from the summer heat for early residents.

*This map is an abstraction of an original map drawn by Dr. Omar Asa Turney in 1929 that shows the prehistoric and then-present irrigation canals running across the Salt River Valley.*

*In Harmony with History*
The building was designed in harmony with the historic site features of the rail spur and canal. The base of the building appears to “straddle” these features while giving ample room for the rail spur and canal to be enjoyed by visitors.

SITE HISTORY

East of this bridge you will find a remnant of the first paved Coast-to-Coast highway and a rail spur line that linked the Creamery (now Four Peaks Brewing) in Tempe to the greater Union Pacific network and markets in downtown Phoenix.

*Above photo (courtesy of the Tempe History Museum) shows all three elements of the ditch, the Creamery and the highway in one historic photo from 1915.*

NATIVE HERITAGE

Long before ASU and Tempe occupied this place, this land was home to ancient peoples, including the ancestors of the Akimel O’odham River People who still live in the Salt and Gila River valleys today, as well as ancestors of the Hopi people who today inhabit portions of northeastern Arizona. The inhabitants of this place brought irrigation water from the Salt River and cultivated farm fields. The footprints of the ancestors – the archaeological evidence of farming and habitation – are deeply important to present-day Native people.

The artifact above is a Sacaton flare rim bowl (circa A.D. 950-1150) excavated from the building site. It measures 5.5 cm tall with a diameter of 10.5 cm. The open-quartered layout and design execution style are attributed to Sacaton Red-on buff bowls.

SITE ARCHAEOLOGY

Approximately 4' of dirt was removed from the NE corner of the site revealing ancient irrigation canals dating between A.D. 950 and 1450. Archaeologists recovered evidence that maize (corn), cotton, and squash were cultivated here, and agave hearts and cholla buds gathered from surrounding desert areas were processed food and trade. Combined with the other historic features found on the site it demonstrates history of human occupation of Tempe since time immemorial - from ancestral farmlands to a place dedicated to industrial, commercial, education, and scientific growth with a prominent role in local, national, and international markets.

A HISTORY OF CONVERGENCE

This site has a unique history of being connected to larger networks that, over time, transported resources and people. Originally, the first inhabitants built an extensive system of canals to convey water to crops in the Salt River Valley. Later, the Maricopa and Phoenix Railroad company built rail lines through Phoenix and Tempe to transport goods to the region. The first coast-to-coast all-weather highway ran parallel to the canal and linked San Diego, CA with Savannah, GA. It was later designated as US 80 or the Bankhead Highway. Finally, the Valley Metro Rail built the light rail to rapidly connect the greater Phoenix metro area. All of these networks can be seen and experienced on site today.

Renowned for their work ethic and skills, Yaqui workers served as the primary labor force for the construction and maintenance of almost 1,300 miles of SRP canals during the first half of the twentieth century. Yaqui men built, cleaned, repaired, and managed vegetation in the canals throughout the eastern Salt River Valley, including this one. Shown here, from left to right, are SRP Yaqui workers Joe Gerry, Francisco Estrada, and Loreto Flores. Image courtesy of SRP Archives

1. This picture shows what the canal that crosses this site looked like in 1962, but the ditch’s roots are far older. The first inhabitants of this place engineered and constructed the first canals by hand. Later settlers refurbished some of the older canals in the late 19th century. These same canals continue to provide water to Tempe today. Image courtesy of SRP Archives.
2. Rail car of the Maricopa & Phoenix Railroad seen stopped at Tempe Depot located at 5th Street and Willow (now College Ave). Portions of the Mesa Branch, also known as Creamery Branch, can be seen on site today.
3. Bankhead Highway was a cross-country automobile route started in the early 1900’s. It spanned from Savannah, GA to San Diego, CA. Eighth Street in Tempe is among the last original paths of the highway in Tempe.
*4. Today the site is bounded by a multi-modal Valley Metro station on the south and linked via a new pedestrian bridge to the Novus Innovation corridor and the ASU athletic venues to the north.*

ENERGY & ATMOSPHERE

EXTERIOR SHADING

Using Glass Fiber Reinforced Concrete (GFRC) as the primary skin reduces thermal banking and exposure to solar heat gain in spaces that are most impacted by direct sun. Shading the exterior is essential to cooling in the hot Arizona climate. Computer analysis helped the team understand the impact on reducing solar heat gain from the GFRC shade. The results show the variation in solar radiation on the glazing and the benefit of the shade with a small sliver of the glass seeing an average of full sun.

These diagrams show the solar affects on the building’s exterior shell skin. Image 1 diagrams solar energy collection through photo-voltaics which are used to provide electricity for the building. While the exterior shell in image 2 and 3 reflects and blocks thermal heat to create a center courtyard oasis.

*Bridge Solar Analysis*
*The shading panels on the bridge were designed specifically for solar shading and wind flow to allow for pedestrian comfort and campus identity.*

EXTENDING THE SHADOW NETWORK

The bridge encourages the use of mass transit by making the direct link from the Valley Metro Light Rail Station to the Novus Innovation District without crossing any roads. The user experience is enhanced by providing shade and landscape along the path including on the bridge where there is a substantial shade structure, parametrically designed to provide optimal shade and maximum visibility, and planters which are also irrigated using the SRP canal water.

OPTIMIZED ENERGY PERFORMANCE

One of the major goals for the building was to achieve increased levels of energy performance beyond code and the LEED prerequisite standards to reduce environmental and economic impacts associated with excessive energy use. The current building design has an EUI of 104 kbtu/sf, a 20% reduction from an ASHRAE baseline. Incorporating on and off-site photo voltaic electric generation achieves a reduction of 50% in energy consumption. Initial goals set a stretch goal of 120 kbtu/sf, which was surpassed with modeled energy performance.

*The diagrams to the right show the impact of sunlight hours per day on the building to compare the effects of providing a shade canopy.*

A SUSTAINABLE SITE

HEAT ISLAND MITIGATION

*These axonometric studies compare the solar effect on a solid mass, a courtyard design oriented South, envelope openings for airflow, and elevating the walkways to mitigate heat island effect.*

Heat island effect is mitigated by lifting the building to create areas of shade for use by students, faculty, and visitors. The exterior envelope material, Glass Fiber Reinforced Concrete (GFRC), was selected because the density of the material is relatively lower than other options, so it reduces the thermal banking of the building skin. The biomimic GFRC panels were inspired by the self-shading ribs of the saguaro cactus. The panels on each facade provide maximum shading of the windows while protecting the interior daylighting and views.

BIOPHILIC COURTYARD DESIGN

The building design focuses on aspects of the natural world and brings planting and shade trees into the heart of the building at the ELAB. By creating green view corridors it links the interior to the exterior. The plant palette includes native plant species, pollinators, and habitat for indigenous and migratory wildlife throughout the site. The canopy over the ELAB was designed to balance the need for daylight for the plants and shade for comfort.

Augmenting the Harvest Program

*Locations of food-bearing plants on site.*

The site enriches the ASU Campus Harvest program by providing food-bearing plants, such as pomegranate and Arizona black walnut, within the site design. Additionally, in keeping with the historic and educational aspirations for the project, the site pays homage to the first inhabitants of the land with the ancient food crops of Agave plants and Mesquite trees.

THE STORY OF WATER

WATER PATHWAYS

The path of water is celebrated and traced by capturing rainfall in landscape planters and conveying surface drainage from the ELAB through the breezeway into vegetated retention basins. Additionally, all but one of the air handler units on the roof level are plumbed so that the mechanical condensate, or the water produced by the process of cooling air, is conveyed to ground and used by the ELAB plants.

*Water Drainage*
*Rainfall collected on the roof and on site drains to the northeast corner of the site, where water is conveyed to bioswales that recharge the aquifer.*

*This diagram shows the flow and circulation of water throughout the site that helps utilize canal water and water the landscaping.*

A MODERN IRRIGATION SYSTEM

To conserve resources, the site makes use of raw water from the Salt & Verde Rivers for 100% of the site landscape needs. Water-saving drip irrigation and “smart” irrigation controls are used instead of the traditional water intensive flood irrigation. This approach not only conserves canal water but also reduces dependence on city-supplied potable water. The hardscape is designed so that all rainfall conveys to planting areas, and the site is planted with native and adapted species that have low irrigation demands.

CARING FOR THE CANAL

Making use of on-site resources, the canal water supply is diverted to a wet well where it is cleaned through multiple filter technologies and then pumped through a state-of-the-art drip irrigation system to water all of the plants on the site, reducing potable water demands on the City water system. When water is not flowing to serve downstream SRP customers, two weirs hold water in the canal to serve as the storage tank for the on-site landscape irrigation system. A recirculation pump creates a constant flow of water which helps to reduce bacteria build up in the storage tank and provide vector control to prevent insect growth. Another pump circulates the stored water through a bio filtration system on the north side of the canal that reduces sediment and bacteria in the stored water.

The use of passive and natural filtration processes minimize maintenance needs while also showcasing the beauty and practicality of a traditional source of water in our Valley.

*Bio-Filtration*
Weirs at both ends of the canal trap water to store it for use on this site when the canal is not actively flowing to provide water for downstream users. To help clean the stored water, it is pumped through a bio-filtration planter. Another recirculating pump keeps the water between the two weirs moving for vector control.

MATERIALS & RESOURCES

Understanding Life Cycle

Assessing the life cycle of the whole building compares the calculated performance of the building design as compared to a typical baseline building. The intent was to optimize the environmental performance of products and materials. The building design calculations show a 21% or greater reduction in all 6 impact categories. The LEED requirement is a minimum of 10% in at least 3 categories:

• Global Warming Potential: 26% reduction

• Ozone Depletion: 21% reduction

• Acidification: 26% reduction

• Eutrophication: 26% reduction

• Formation of tropospheric ozone: 28% reduction

• Depletion of nonrenewable energy: 35% reduction

*Material Life Cycle Costs*
The life cycle of a standard building material starts as a raw material to be extracted which then goes through multiple processes before being integrated into the building. Recycling options were analyzed to reuse as much material as possible.

MATERIAL TRANSPARENCY

The design team gave priority to materials from manufacturers that publish data on product ingredients and the life-cycle impacts of their products. These materials disclosures allowed the project team to make informed decisions that reduce negative environmental and human health impacts associated with building materials. Selecting products that offer disclosures supports positive market transformation by encouraging more businesses to adopt these practices. In addition, the project carefully vetted interior finishes such as paints, ceilings, flooring, and wall panels for low emissions or low VOCs (volatile organic compounds), which creates a healthier indoor environment by minimizing airborne pollutants.

These graphs show the pollution and depletion affects of main building materials such as concrete, steel, wood, insulation, waterproofing, windows, doors, ductwork, and plumbing. This type of analysis helped the team pick materials with minimal environmental impacts.

CONSTRUCTION WASTE DIVERSION

As part of the demolition and construction process, waste is produced that typically is sent to a landfill. The design and construction team for this building created a sustainable and environmentally conscious waste management and demolition plan resulting in 80% diversion of waste from landfill in the construction process, 5% higher than the required minimum. This calculation includes the demolition of the existing building and site improvements where resulting waste products, such as wood, metal, cardboard, concrete, and plastics, were diverted into a recycling facility rather than a landfill.

This chart analyzes the amount of material (in tons) compared to time for materials that were diverted and recycled: Paper/Plastics (orange), Concrete (purple), Metal (green), Wood (blue), and Total (black).

HEALTH & WELLNESS

a selection protocol

The design team developed a Material Selection Protocol that prioritized human health, climate and ecology. This approach explored health and happiness, collaboration, inclusion, equity and fair trade to develop integrated design solutions aimed at reducing the embodied greenhouse gas emissions of the project. The protocol also aimed to intersect with local, regional, and global ecological health, while recognizing regeneration and diversity as a critical component of this health. Through the process, the team identified redundancies in the design and simplified the materials palette to increase the “power of the purse”.

*This diagram links the impact of each building material category to occupant health and environmental impact.*

ACTIVE DESIGN

The ELAB was designed to encourage casual meetings, provide a place for informative displays about the research on all of the ASU campuses, and create connections to other parts of the community. It includes Design for Active Occupants by pulling the stairs into the ELAB to encourage occupants to use the stairs instead of the elevators.

This diagram highlights the flow from public to private as users move up in the building. Each level has different circulation patterns for different users. For example, the general public on level one, visiting faculty through level 2, and researchers through level 3.

URBAN FLOW

Located on a highly visible and congested corner of the campus, the project design encourages walkability with deliberate connections for people that want to move diagonally across the site in two different directions on grade or by using the pedestrian bridge that links a busy light rail stop with the north side of the campus on the second level. All the pedestrian paths offer the option of shade and include interesting landscape, science-on-display, and historical features along the way.

*In addition to the main circulation along University Ave. and Rural Rd., diagonal circulation paths were cut through the ELAB courtyard for pedestrian access to the light rail and building elements.*

ENERGY REDUCTION

EMBODIED CARBON REDUCTION

The project employs several strategies for reducing the carbon footprint of the building’s material. Void form (bubble deck) not only reduced the quantity of concrete, but it was also less expensive. The spheres made of recycled plastic are cast into the concrete deck replacing concrete that was not needed to provide the required structural support. The team also developed procedures to use concrete made with 40% fly Ash in all areas of the project. The fly ash replaces the cement, the component in concrete with the largest carbon footprint. Fly ash typically makes finishing concrete difficult, but by working with the builder, the team was able to develop strategies to reduce the impact and lower the overall carbon footprint of the project.

A void-form deck construction was used to minimize the use of concrete and carbon production by casting hallow plastic balls held in place by steel reinforcement. This also reduces dead building loads, allowing for less structural steel requirements on lower levels.

a systems approach

The building relies on radiant cooling with chilled ceilings, active chilled beams, and chilled sails. The building is significantly more efficient by almost completely eliminating the fan load associated with forced air systems. These systems optimize airflow and temperature delivery to efficiently meet thermal comfort. Smart controls and CO2 sensors allow the building to efficiently meet ventilation requirements to promote the health and well-being of the occupants.

The use of an air displacement cooling system in the auditorium tells the story of both energy efficiency and health and wellness. The displacement system optimizes delivery of air to cool people from vents under their seats and effectively deliver cool air where it is needed. From a health and wellness perspective, the displacement system allows for contaminated air to move upwards into stratified areas and away from the occupants.

ENERGY MODELING

Enhanced energy modeling from the beginning of the project helped the design team make informed decisions during design instead of testing locked in decisions at the end of the process. Results included locating high energy uses on the north side of building and placing the lower energy use office spaces as a buffer to southern elevations. In addition, several energy conservation measures were analyzed to understand where the project could target reductions in energy consumption for both passive and active systems.