Consulting-Specifying Engineer - June 2008 - (Page 36)

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// that an increasing amount of equipment is required to be on emergency power, especially during a disaster and its aftermath. Queen’s wasn’t the only hospital affected by the earthquake; indeed, for those 12 hours, no hospital in Hawaii had enough emergency power to maintain 100% operation. At the time of the earthquake, Queen’s had approximately 1.25 MW of emergency power, while the facility peak demand is slightly more than 6 MW. Coupled with the fact that Hawaii’s electric company, HECO, isn’t on a grid that stretches from other states and cooperates with other utilities, hospital administrators could see the writing on the wall. Queen’s needed to upgrade its emergency power system. The Aloha State is beautiful, but during a single one-week period in August 2007, Hawaii experienced a hurricane warning, an earthquake, a tsunami warning spurred by the earthquake, and flash fires on one or more of the islands. Disaster preparedness in Hawaii is a must, so the hospital’s electrical system had to be redesigned to withstand most any disaster. The medical center needed only an additional 5 MW of power to supplement its existing power, but the age of the existing generators—and the benefits of the redundancy—made it clear that the redesign should include extra capacity. The emergency power system also should be above flood level. Based on space constraints and emergency planning, the hospital building was designed in four levels (see Figure 2). Each level was designed to withstand up to a Category 5 hurricane, with the building overall capable of withstanding the seismic activity in Honolulu. As a result of the power system redesign, Level One includes a new utility service entrance 11.5-kV switchgear, upgrading the existing service from two feeds from the same substation to three feeds from two different substations. The emergency system was designed to include 8 MW of power at 11.5 kV, the current distribution voltage throughout Hawaii and on the Queen’s Medical Center campus. The parallel switchgear was designed In October 2006, an earthquake knocked out utility power at Queen’s Medical Center in Honolulu for 12 hours. Photo: TLC Engineering to accommodate four 2-MW generators, without future generator space for expansion, and is located on Level Two. The addition of these generators provides Queen’s with sufficient capacity to handle the current load with any single generator in the system down. Even with two 2-MW generators down, the system can handle the majority of the load with the existing generator system and the new system online. The switchgear provides power throughout the campus through a dual-radial system, which serves most of the buildings via a belowgrade tunnel. Queen’s is evaluating the potential to modify the system to a loop configuration to further enhance reliability. The generators, which have direct-mounted radiators, are on Levels Three and Four. Providing the radiator as a directly coupled unit was a design challenge based on the space available—but worth the effort. If remote radiators were located on the roof, they would need to be protected from flying debris in a hurricane, and because the radiators were required to operate when the generator operates, significant safeguards would have been ROOF LEVEL FOUR – GENERATOR B-1 AND B-2 LEVEL THREE – GENERATOR A-1 AND A-2 LEVEL TWO – PARALLEL SWITCHGEAR LEVEL ONE – NORMAL SWITCHGEAR UTILITY TUNNEL BELOW CRAWL SPACE SERVICE ROAD Figure 2: The hospital building at Queen’s Medical Center in Honolulu is designed in four levels, each able to withstand a Category 5 hurricane and seismic activity. 36 Consulting-Specifying Engineer • JUNE 2008

Table of Contents Feed for the Digital Edition of Consulting-Specifying Engineer - June 2008

Consulting-Specifying Engineer - June 2008 Contents Viewpoint Letters News M/E Roundtable No Gambling Allowed on Smoke Control in Las Vegas Be Prepared: Hospital Protections for Catastrophic Events Ready for Retail Commissioning Documents: Necessary Evil Codes & Standards Codes & Standards Case Study Equipment Lifecycles New Products Advertiser Index Green Space

Consulting-Specifying Engineer - June 2008

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