Hospital includes sophisticated electrical system

Meeting the demands of a growing population, Florida Hospital Memorial Medical Center in Daytona Beach, Fla., embarked on 12-story, 245-bed replacement hospital in 2004.

Gerald Versluys, PE, LEED AP, TLC Engineering for Architecture, Jacksonville, FL

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To meet the demands of a growing population, Florida Hospital Memorial Medical Center in Daytona Beach, Fla., embarked on a new 12-story, 245-bed replacement hospital in 2004.

The need for adequate space was a primary concern when master-planning the new facilities. All of the patient rooms are private and sized to comfortably accommodate patients, visitors, and equipment. The Birthcare Center includes a Level 1 nursery, labor, delivery, recovery, postpartum, and two Caesarean-section operating rooms. The 52-bay emergency department includes a fast-track area, and the heart center includes five catheterization labs, four cardiovascular operating rooms, a 14-bed cardiovascular care unit, and a 36-bed coronary critical care unit. The surgical suite includes 11 state-of-the-art operating rooms and four endoscopy rooms. The hospital includes a 3,500-sq-ft Tier 3 data center powered by an independent 100 kW UPS.

When the project was completed in 2009, the $151 million facility was an impressive 603,000 sq ft with a detached 17,400-sq-ft central energy plant. The central energy plant housed dual 4,000-amp electrical services; three parallel 2 MW generators; and four 900-ton water-cooled chillers, four cooling towers, three 3,600-hp hot water boilers, and a 50-hp steam boiler.

The dual-fed electrical service with ground fault protection and the parallel generators presented a grounding fault path sensing challenge. A differential ground fault sensing system was incorporated into the switchboards circuit protection to provide accurate sensing of ground currents in multiple locations within the system. This circuit protection system measures and sums the disparately sensed currents to ensure that ground fault current levels are accurately reported, regardless of power source. The code does not permit ground fault tripping of emergency feeders, so ground fault current monitoring and alarms were incorporated into all emergency feeders.

Each operating room within the facility is equipped with dual isolation power systems that are housed in a single enclosure. Each isolation power system is supplied by two critical branch feeders from separate transfer switches (see exception No. 2 in NEC 517.19) to assure the highest level of electrical service integrity.

In general, the facility required static trip circuit breakers on every feeder breaker 400 amps and larger to assure selective overcurrent device coordination. The bid documents included 119 time-current curve coordination studies, which demonstrated selective coordination of all specified circuit protection.