July-August 2009

Medical Power Practices

Case studies in standby emergency power

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Photo: @iStockphoto.com/Maksymka

By Lori Lovely

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Undergoing continued growth in 2006, it was clear that additional future growth was on the horizon for the Vanderbilt University Medical Center (VUMC). VUMC is a comprehensive healthcare facility in Nashville, TN, dedicated to research, biomedical education, and patient care. Its campus includes The Vanderbilt Clinic, which has space for more than 100 ambulatory specialty practices of the Vanderbilt Medical Group. Because together they provide around-the-clock acute care to over a million patients annually, an uninterruptible power supply is crucial.

More than that, it’s required by The Joint Commission on the Accreditation of Healthcare Organizations. According to that accreditation body, each healthcare facility must have an emergency power testing program that includes generator load testing and Emergency Power Supply System (EPSS) maintenance. Standby power generation systems must be tested monthly at 30% load for 30 minutes.

Per code, power systems must operate around the clock with full redundancy, providing switchover of power within 10 seconds, in the event of power interruption. A combination of utility and generator backup power is required for compliance in achieving proper redundancy, with multiple generators feeding loads versus loads dedicated to a single generator.

Plan in Place
Jon Ross, project engineer for Smith, Seckman & Reid Inc., was designing the new tower addition at VUMC at the same time that the new medical research building was beginning construction. The research building required new emergency generators that were to be located on the roof of the building for lack of other options. The new hospital tower project, which was in the early design stage, would also require more capacity than the existing hospital emergency generators had available. Ross says that the early design plan was to add another generator plant to serve the hospital tower.

Photos: John Ross
Because Vanderbilt's other equipment was already Cat, there was strong desire to go with Cat Gensets.

A sixth unit is expected in 2009, in addition to replacement of two aging gensets.

Realizing that both the research building and the new tower required more generators, Ross presented an idea to then-head of space and facilities at Vanderbilt, Fred DeWeese, initiating a collaboration to consolidate power across the medical campus. “We looked at the whole campus for ways to consolidate,” explains Ross. In drafting his plan, he considered the load requirements across campus. “There were 18 generators across campus, some of which were paralleled.”

In the past, Vanderbilt had added generators as needed for projects without a comprehensive plan for serving the entire medical campus. Ross says it’s not an uncommon approach. “Some take a longer look at infrastructure and spend money to consolidate. Others use the money given for a project and make do. Vanderbilt is kind of like that.”

Compounding the problem is the fact that Vanderbilt has an urban campus, with buildings spread out over a large area, making consolidation difficult. “Obviously, our preference was to put everything in one area, but we couldn’t,” adds Ross. He thought that with the large facilities being constructed and the requirement for significant added generation, it was time to “step back” and look at a campus solution, not just a project solution. 

In determining a plan, Ross says many considerations were taken into account. “We tried to decide where power comes from for new projects. How much equipment could we get in? What else could happen? Should we put in more than we need now—for future growth? Since we know growth will continue, we needed to think long-range and set up a plan to accommodate growth.”

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A new generator facility couldn’t be built within existing buildings because of spatial limitations, but needed to be near the existing electrical infrastructure. There were other constraints: noise, exhaust fumes, and fuel storage. In addition, Ross thought ahead to maintenance, particularly for emergency equipment.

The resulting plan that was proposed included building a new emergency power plant big enough to serve not only the new hospital tower, but also the entire existing hospital and clinic. That made the three existing 1,200-kW emergency generators that originally served the hospital, available to use at the research building. Since the existing generators were actually located between the hospital and the research building, the cost of redirecting the generator capacity to the new building would be more than offset by not having to buy generators for the research building. Next Page >

What Do You Think?

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jobigger

July 2nd, 2009 7:47 AM PT

I have been a reader/subscriber of Distributed Energy since Issue No. 1 and look forward to each issue. That said, I found the author's descriptions in "Medical Power Practices" of the equipment and systems for Vanderbilt University's Medical Center emergency power system to be very confusing. A large portion of the word descriptions in the article could have been replaced by simplified one-line diagrams of the hospital campus systems, for instance. And what cost and performance information that was provided was sprinkled throughout the article; a concise summary is much more valuable to the reader (see, for example, Table 1 on page 20 of this issue). The Caterpiller units are impressive but one or two of the photos could have been replaced with other graphics that would increase the reader's understanding of the overall system's operation and benefits. Connecting together various emergency and alternative electric generating systems to create high-efficiency, -reliability, or -security networks on a university campus, medical complex, or industry development is being recognized as an opportunity for significant savings of energy and funds. Clarity is critical to describing these projects. For a comparison, an article appeared in the April 2009, issue of POWER magazine (page 22) describing a similar project to increase reliability of the Illinois Institute of Technology campus in Chicago, Illinois.

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