Jumbo Project: Cherry City Electric and Elephant Lands at the Oregon Zoo

Electrical contractors have their share of unusual customers, but few demand as much respect—and attention—as an elephant.

Cherry City Electric crews may be the few in their trade who can say they’ve worked closely with the world’s largest land animals. The Salem, Ore., electrical contractor dedicated more than three years to the installation of a state-of-the-art system to manage lighting, electrified barriers, water filters and the delivery of food for the Oregon Zoo elephant habitat.

Elephant Lands comes with all the amenities today’s technology and a team of zoo experts, engineers and contractors could offer. It was part of a full zoo expansion and renovation overseen by general contractor Lease Crutcher Lewis, Portland, Ore.

The project was a design/assist that required more than the usual design efforts, said Mike Sager, Lease Crutcher Lewis project manager. For the general contractor, the installation consisted of seven smaller projects, one of which was Elephant Lands.

Portland’s Oregon Zoo is a 64-acre site with 1,800 individual animals, representing 232 species or subspecies and more than 1,000 species of exotic plants in its botanical gardens. It is also active in survival plans for 63 animal species, including elephants. The zoo has a 60-year history with the large mammals, during which it not only put the elephants on display but also studied their behavior and health and provided creative care to help the families grow within the familiar matriarchal tradition.

In 2013, the zoo received funding to build a new habitat, which features about eight acres of indoor and outdoor grounds for the elephants, including Forest Hall—one of the largest indoor elephant habitats in the world.

Keeper Gilbert Gomez checks out the exterior of Forest Hall from the Elephant Lands access road.
Keeper Gilbert Gomez checks out the exterior of Forest Hall from the Elephant Lands access road. Credit: Oregon Zoo / Michael Durham

Elephant Lands boasts two water pools, time-release feeders and a viewing area for human visitors to watch elephant activities in Forest Hall. They all helped meet the zoo’s overarching goal to build a habitat that was comfortable for the elephants, allowed them more freedom of movement, while also bringing visitors closer than ever. Forest Hall was designed in a fan shape to provide the best viewing for visitors, with special glass that is impervious to elephants. The habitat comes with hilly corridors and open grazing areas.

The goal also was to gain energy efficiency, so the system included photovoltaics on the roof.

Cherry City Electric’s project encompassed five separate indoor and outdoor locations, each with electrical equipment: the Life Safety Services Building, the Elephant Barn, Forest Hall, the zoo’s East Hub and the zoo train.

The EC was responsible for all power and grounding needs for the new elephant facility, including three rooftop air handling units and a 30-kilowatt (kW) solar power system. In addition, 86,000 feet of conduit and 418,000 feet of 600-volt wiring were installed, said Kurt Hamilton, Cherry City Electric estimating and preconstruction director. The company also ran 64,000 feet of low-voltage cabling.

A unique customer

One of the initial challenges for all crews involved was just how the completed facility would be used.

“This is one of the few cases where the end-users are animals,” Sager said. “And the design required not only talented designers but also a load of research and also reiterative design workflow to arrive at the finish line.”

The team visited other zoo facilities before developing the final plan. The result was a habitat the zoo said is guided and inspired by the natural structure of matriarchal elephant society.

Solar panels were mounted on the Forest Hall roof.
Solar panels were mounted on the Forest Hall roof. Credit: Oregon Zoo / Michael Durham

The project was phased in such a way that areas for separation of the herd could be maintained, and parts of the herd could be moved as elephant handlers needed. The zoo used temporary barriers that could be relocated to accommodate the staff and elephant needs. Most important during construction, the zoo and contractors had to protect the safety of elephants, work crews and visitors.

“We scheduled the project in phases to accommodate the elephants on-site with the animals always maintaining an equal or greater amount of habitat square footage,” said Jim Mitchell, Oregon Zoo construction manager.

The phasing approach gave the elephants a chance to test pieces of the design as it was being built.

“As a result of the testing, we were able to modify design aspects prior to all of it being built,” he said. “One elephant liked his hay moistened so he stuffed the drinker with hay, which caused the mechanism to fail. We added some screening to the design, which prevented the unit from clogging with hay.”

Even though elephants were removed from the immediate area and held behind the temporary barriers each day, they were close enough to watch the workers, and the electricians soon got to know each of the elephants. In fact, the giant inhabitants would come running to investigate whenever they heard activity or an unusual sound.

The animals don’t touch the direct-current electrified fencing or grass, but they sense it when they approach and stay away. In fact, their trunks are so sensitive that they can tell if the barrier is working or not without making contact. The keepers pay close attention to their response. The current system controls have built-in alarms and indicator lights for ground faults and power loss to prevent any problems from arising.

Forest Hall just months from completion at the Oregon Zoo’s Elephant Lands habitat
Forest Hall just months from completion at the Oregon Zoo’s Elephant Lands habitat. Credit: Oregon Zoo / Michael Durham

Throughout, the elephants were curious about the workers in their area and liked to watch and listen to the work underway, said Daryl Glover, Cherry City Electric general foreman.

Despite human efforts, the elephants kept electricians and other crews on their toes. Since the elephants were entertained by the work they observed, the animals got to know the electricians, sometimes on an individual basis.

Occasionally, the elephants got into mischief, Sager said. In one instance, they knocked a tree limb over a hot wire the crews had run to protect some of their work. By clearing the hot wire out of the area, the herd was able to then access the work that crews had left behind.

Glover also recalled this destruction.

“Whether [it was] intentional, I’m not sure, but yes, the elephants put a log against the cables and grounded out the system,” he said. “It was actually hilarious. We were constantly entertaining for them. We all developed strong personal relationships with the elephants.”

If elephants were uncooperative and wouldn’t leave the work area when zoo keepers wanted them to, work had to be modified or rescheduled.
“For everybody, it was a little unpredictable,” Sager said.

Another challenge was ensuring the elephants couldn’t damage the completed work. An elephant standing on its rear legs can reach its trunk up to 21 feet high, so anything overhead had to be 22 feet up or more.

Permanent equipment was mounted so that it would remain inaccessible after the crew finished the job. All wiring was routed through concrete or steel covers to protect it from the elephants.

A 22-foot-high electric trolley system transports cranes that carry bags of straw overhead for elephants when zoo keepers are unable to walk through Forest Hall. The cranes are lifted and lowered on winches and can deposit bags of straw, treats or toys (such as beach balls) for elephants in the barn. The two overhead trolleys—one traveling 50 feet and the other on 100 feet of track—can safely supply goods to elephants without being disturbed.
In addition, “hot grass” was installed to control the elephants’ movement. This amounted to bundles of electrified wire extending from the ground that looked like tufts of grass.

A child is dwarfed by a photo  of Packy in Forest Hall.
A child is dwarfed by a photo of Packy in Forest Hall. Credit: Oregon Zoo / Michael Durham

Keeping cool

Elephants need water access, so the zoo installed two pools: one could accommodate several animals swimming at a time with 160,000 gallons of water, and the other is a much smaller wading pool. Both pools have a water-filtration system that includes sand-filter pumps, transfer pumps, chlorine and ozone treatment and control equipment such as level and flow sensors.

The elephants also have two jet water cannons that handlers can use to provide cooling in the viewing areas. Cherry City Electric also installed pool grounding wire according to National Electrical Code requirements.

Other zoo needs

The low-voltage system consists of data, audio/video systems, a programmable fire alarm system, the PA and keeper-talk interior sound system in Forest Hall for keeper demonstrations, announcements and music. There is also a small audio system in the Elephant Barn for the pleasure of the elephants, which have demonstrated an affinity for music. Cherry City Electric also installed security, CCTV and 85 hydraulic gate controls with complex controls. Additionally, the company ran power for the direct digital controls and low-voltage lighting.

Outside Elephant Lands, Cherry City Electric provided power for an extension to the zoo train. This consisted of a new subpanel and transformer for the train power, Glover said. The company also installed inductance loops for controls to work with the train crossing arms and lights. Powered controllers for gates were installed along the train route.

The project was completed in December 2015.

Bull Asian elephant Tusko visits Forest Hall for the first time.
Bull Asian elephant Tusko visits Forest Hall for the first time. Credit: Oregon Zoo / Michael Durham

In total, Cherry City Electric installed 493 lighting fixtures—407 were indoors and 86 outdoor fixtures were installed to illuminate the pathways, bridge and one site pole light. The company also installed a 300-kW Caterpillar generator.

“Being able to say we completed this project is always nice to tell other peers and family or friends,” Glover said. “The pride we take in our work as well as the great relationships formed with the Oregon Zoo and Lease Crutcher Lewis were also gratifying.”

The project was finished and completed within budget, and it included owner “wish list” items added during the course of the project, Sager said.

“Having a new building with the latest in lighting, controls and mechanical systems has made the keepers and elephants very happy,” Mitchell said.
Bob Lee, who oversees the Oregon Zoo elephant program, said the zoo has been thrilled with the habitat so far.

“We’ve seen the herd moving around just the way we hoped, with elephants determining their own social structures, breaking off from the main herd and returning later—making their own choices about where they want to be and who they want to be with,” he said.

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