A Specialized Discipline

Under the direction of John D. Frank, P.E., vice president of Van Boerum & Frank Associates Inc. (VBFA), Salt Lake City, Jeff Watkins, P.E., served as project engineer. Watkins, a principal of the firm, explained that designing an HVAC system for a health care facility is a very specialized discipline with its own set of guidelines and code requirements.

"Following AIA guidelines for health care design, we must take into consideration patient comfort, the need for a sterile environment in the operating rooms, medical gas needs, and proper humidification," he said.

Since the climate in St. George is semi-arid, with summer temperatures averaging between 95Þ to101Þ F, HVAC systems must be designed to maintain a minimum of 30 percent humidification. With the humidification equipment constantly introducing moisture into the airstream through the air handlers, Dixie Regional Medical Center needed a duct liner that is moisture-repellent, according to Watkins.

"We specified a duct liner that has moisture-repellency characteristics because of the need to maintain our humidity requirements," he said.

The duct liner chosen was ToughGardâ„¢ R Duct Liner with Enhanced Surface, by CertainTeed Corp. The mechanical contractor, Western Sheet Metal, Salt Lake City, installed 300,000 square feet of the rotary-based fiberglass duct liner, designed to provide acoustical and thermal performance. According to the manufacturer, its recently introduced Enhanced Surface on the fiberglass duct liner "is more moisture-resistant than other fiberglass duct liners and has proven in tests to be approximately 40 percent more moisture resistant than the previous generation of ToughGard liners."

The new surface is designed to help alleviate some specifiers' concerns about moisture that may enter a duct system due to improperly sealed duct joints or poorly installed and maintained duct systems. The airsteam surface contains an EPA-registered antimicrobial agent, designed to reduce the potential of microbial growth that may affect this product.

At the peak of the project, Western Sheet Metal devoted 40 people to the fabrication of 600,000 pounds of sheet metal ductwork for the medical center. According to Western executive Bruce Montrone, the company completed work on an 18-month schedule. Like VBFA, Western is also a veteran of many health care facility projects, including McKay Dee Hospital, the state's largest hospital. Its HVAC supplier on this project is Hercules Industries.

Historic Project

Dixie Regional Medical Center traces its roots to the early Mormon settlers who came to St. George in the 1850s. Built in 1913, the original Washington County Hospital was replaced by the Pioneer Memorial Hospital. Then in 1975, the Dixie Regional Medical Center was built and purchased one year later to become part of Intermountain Health Care, a nonprofit corporation.

Construction of the new hospital campus, which began in early 2001, is estimated to cost more than $100 million. It will feature 108 patient rooms, a 24-bed intensive care unit, a 30-bed emergency department, and eight operating rooms.

Okland Construction Company, with offices in Salt Lake City and Tempe, Ariz., serves as general contractor on the project.

Another participant with extensive experience in the construction of medical centers, Okland has built the Magic Valley Regional Medical Center in Twin Falls, Idaho, the Colorado Springs Memorial Hospital, and the Salt Lake Regional Medical Center. The architectural firm for this project is Ashen + Allen, headquartered in San Francisco. Western Sheet Metal is subcontractor to J & S Mechanical Contractors, Draper, Utah.

VBFA is responsible for the design and specification of not only the HVAC system, but also plumbing, fire protection, and medical gases systems. The new mechanical system comprises three chillers in the central plant, with environmentally friendly R-134A, and total tonnage of chilled water at 1,930 tons. One chiller is on emergency power in order to provide cooling in emergency situations. Two steam boilers provide all heating, domestic hot water, and humidification and sterilization for the facility. Nine air handlers range in size from 55,000 cfm of air to 85,000 cfm.

The VAV reheat system consists of medium-pressure ductwork, with air passing through the VAV boxes, and then dropping to low pressure, all designed to provide optimum comfort control in all spaces. Individual control is provided throughout the facility. All medium-pressure ductwork is wrapped with insulation, while all low-pressure supply and return ductwork in lined, except for invasive procedure rooms, as indicated by code requirements.

Dixie Regional Medical Center administrator Steve Wilson is proud of this project.

"We are excited to benefit from the expertise of our design and construction firms," he said. "This is a once-in-a-lifetime project and we are committed to constructing the most beautiful, efficient hospital possible to serve the people of Utah's Dixie region."

Publication date: 12/29/2003