Located on Temple Square, the Salt Lake Tabernacle of the Church of Jesus Christ of Latter-day Saints (LDS) was built between 1864 and 1875. The aluminum-covered roof was constructed in an Ithiel Town lattice-truss arch system held together by dowels and wedges, as nails were scarce in Utah at the time. The building has a sandstone foundation, and 44 sandstone piers support the dome. The overall seating capacity of the building is 8,000, including the choir area and gallery.

In 2005, the LDS church decided to make seismic upgrades and structural re-enforcement of its historic tabernacle, and invited FFKR Architects, Salt Lake City, to design the improvements and Jacobsen Construction Co. to be the general contractor and construction manager. The project quickly evolved into a complete renovation, including replacing the aluminum roof panels, updating all the electrical and mechanical systems, and providing state-of-the-art sound and visual production and theatrical systems to support the church’s numerous recording and broadcasting activities.

At the time, Cache Valley Electric Co. (CVE), which has supported the electrical needs of the LDS church for years, was upgrading the utility tunnels in Temple Square. The tunnels were designed to partially support new utility services for the tabernacle. In addition, CVE’s voice and data division has had a relatively constant presence working with the LDS church on structured and broadcast cabling projects at the site.

“Our history with the owner made our participation in this project a natural fit. The church needed an electrical contractor who could begin the project in a design/assist role and transition into construction with a full understanding of design, building constraints, schedule, and budget dynamics,” said Jim Overright, CVE’s manager of special projects and project executive for the renovation.

CVE also has long-standing relationships with the project’s general contractor, architect, electrical engineer and mechanical contractor.

“It is safe to say that, in this area of the country, and in the construction market in particular, relationships seem to be a significantly more important factor even in the most contractually rigid scenarios than in other parts of the country. On this specific project, that team culture easily flourished,” Overright said.

Design/assist

Demolition and structural upgrades began substantially ahead of the mechanical and electrical design. CVE was brought into the process at the earliest stages to determine constructability of the design, review schematics and to begin estimating. When the design was 60 percent developed, the company began the field design, including initial shop drawings for the power distribution, lighting, fire alarm and detection, and theatrical and audiovisual systems.

“Because design inputs were coming from several different teams, we were responsible for providing the basic coordination to guide the installation,” Overright said.

When construction drawings were 100 percent completed, CVE began full coordination, constructability reviews, shop drawing design and submittals.

“This stage of the project allowed us to develop a budget proposal for execution into a contract for the balance of the construction,” he said.

In addition, CVE identified and facilitated schedule-critical submittal and procurement issues, selected manufacturers and suppliers for designed equipment and materials, evaluated and commented on integration and software development issues, and helped develop raceway paths for the sound and video broadcast systems.

For the actual construction, CVE electricians worked on upgrading the power distribution; stage and production lighting; heating, ventilating and air conditioning (HVAC) control; voice and data; and sound and video broadcast systems. The power system upgrade included rebuilding a new main electrical room in the tabernacle basement. Then the main service was brought in at 7,200 volts (V) from a custom-designed 2,500-kVA transformer and stepped down to 4,000 amps (A), 480/277V for distribution. To upgrade backup power, the team removed and refurbished an existing 1,250-kilowatt generator, located nearly 1,000 feet from the electrical room, to 5,000V.

“We then ran the distribution wiring through a tunnel system to an area immediately adjacent to the tabernacle and stepped down the voltage to 480,” said Jason Jensen, superintendent.

Transfer switches for both emergency and standby electrical power were installed inside the tabernacle. During previous upgrades, CVE had installed 7,200V service and a 750-kVA station-type transformer in an underground annex. For this project, that service was reconfigured into a second service for the south annex, which houses broadcast production equipment, a Dolby 5.1 room, a recording studio and dressing facilities. Dimming capabilities required for production-quality lighting meant installing an additional 750-kVA K-factor transformer to supply 10 800A dimming racks. Finally, the uninterruptible power supply was provided by a 300-kVA rotary Caterpillar 480V system.

Upgraded lighting

Historic fixtures in the tabernacle performance hall include 11 large chandeliers and numerous small pendant fixtures. CVE removed all the fixtures and sent them for repair and refurbishment then reinstalled and field-fitted with production-level lighting circuits. The remainder of the facility’s house lighting was upgraded with state-of-the-art fixtures and controls using digital multiplex protocol (DMX) relays and breaker panels. In addition, fluorescent fixtures and low-voltage track lighting were installed throughout the facility with low-noise ballasts and transformers.

The performing hall also is outfitted with a substantial production lighting system. The upgraded production lighting circuit design required the installation of 550,000 linear feet of wire to connect the lighting control to the production and house lighting fixtures. CVE accomplished lighting control through a combination of dimmer racks and relay panels connected on a common DMX architecture.

More than 90 years ago, Henry F. Laub founded Cache Valley Electric Co. in Logan, Utah, as a small electrical contracting firm. The company, which has always been led by a member of the Laub family, has grown into a $220 million firm with about 1,100 electricians in the field and four branch offices. With a reputation for delivering the necessary personnel, skills, equipment and professionalism to every electrical project, CVE has expanded to work in more than 30 states and operates tele-data, design/build, service, technology, signal and utility, controls, audio/video, and security divisions to serve the industrial, government, traditional high-voltage electric, and commercial markets. CVE’s philosophy is to provide the client with the very best value in the industry and to strive to exceed every expectation and requirement of the project, regardless of the contractual arrangement.

HVAC, data and sound

CVE also provided complete shop design and installation of the Honeywell HVAC control system, which included control valves, actuators, control panels, sensors, instruments, cabling and tubing.

“The controls and A/V group also provided design details, quality assurance and control, and installation support for other miscellaneous systems, such as the master antenna television, closed-circuit television, security, house clock, and the fire alarm systems,” Overright said.

CVE’s voice/data division provided the fiber and copper backbone for the tabernacle’s communications system with Category 6 horizontal cabling and equipment at four intermediate distribution-frame locations.

“We also installed approximately 300,000 lineal feet of sound and voice broadcast cabling for the entire facility,” said Brady Clark, voice/data project manager.

The raceway for the broadcast system consisted of a combination of conduit, under-floor raceway, tray systems and custom wireways.

“All systems and equipment installed were required to adhere to strict specifications intended to mitigate or eliminate vibration and sound transmission as well as protect the integrity of the cabling systems,” said Terry Smith, project manager.

Measures used to isolate vibration included dry-type transformers, special mounting, physical isolation of raceways connected to vibration-generating equipment, and acoustical separation and sealing of all electrical and technical equipment rooms, recording studios and broadcast spaces.

A job well done

The age of the tabernacle building presented CVE with numerous complications, which were aggravated by the installation of the seismic upgrades required to stabilize the original hand-placed stone column and timber beam construction.

“Without exception,” Overright said, “every single raceway, equipment placement or other aspect of the work required some sort of coordination and planning.”

In its theatrical and broadcast scope of work, CVE had to install raceway and design equipment spaces even before many of the theatrical contracts were awarded.

And the edict from the LDS leadership was that the tabernacle had to stay true to its origins.

“In other words, we had to make all the necessary upgrades without leaving any evidence for the visitor to see,” he said.

Regardless of the pitfalls and challenges presented by a massive renovation of such a complicated structure, many involved feel the project has been the most rewarding.

“We have worked on 4,000-megawatt power stations and on one of the highest security, high-tech space launch facilities I could have ever imagined, but the tabernacle will be the project of my lifetime,” said Overright, who credits the entire team for the project’s success. And the feeling of respect is mutual.

“CVE was responsive to our needs and able to quickly adjust to changing circumstances as the complicated project evolved,” said Roger Sears, the LDS project construction division’s senior project manager.

BREMER, a freelance writer based in Solomons, Md., contributes frequently to ELECTRICAL CONTRACTOR. She can be reached at 410.394.6966 and [email protected].