Two ways to help keep health care facilities online are UPS backup and additional automatic transfer switches.
6. UPS Backup for IT and Imaging Equipment. Every time there is a transfer from the utility to the emergency power source due to a normal power failure, there is a power blackout of up to 10 seconds. This 10-second power outage means up to 15 minutes of shutdown and restart for computer-based equipment. Equipment on a digital platform is more susceptible to power interruptions than analog models.
While the previous design may have been to provide a power conditioner for sensitive imaging equipment to ensure it's not susceptible to power source voltage or current fluctuation, this won't work today, unless UPS equipment (not the power conditioner) is provided to ride through the 10-second blackout during the transfer of power from a normal to emergency source. Similarly, in most hospitals today, the UPS will be required to support the IT and data network and equipment. Each hospital and its consulting engineers should evaluate the feasibility of providing central versus local UPS systems, depending on equipment locations, space conditions, special requirements, economics, etc.
7. Additional Automatic Transfer Switches. The National Electrical Code requires emergency power to be separated into three branches: life/safety (egress lighting, alarms, etc.), critical (patient area lighting/outlets) and equipment (AHUs, elevators, etc.), mandating stand-alone power feeders and dedicated transfer switches for each. This means that when going above the code to add additional equipment onto a hospital's emergency power system, additional automatic transfer switches may be required.
When making any of these additions to an existing hospital's emergency power system, it's crucial to evaluate the entire emergency distribution system to ensure that the emergency power supply, fuel oil storage, paralleling gear, feeders, and distribution equipment are all of adequate size and that electrical equipment is of adequate short circuit rating, especially if a generator plant capacity increase is warranted. When these systems fall short, a comprehensive plan to upgrade the generator plant and existing emergency distribution system must be developed.
In the very near future, many of these technologies and precautions will become commonplace when addressing emergency preparedness, including wider use of computer-based technologies in healthcare facilities. Some emergency power practices will likely be standardized sooner rather than later. For example, emergency standby power plants will soon have a minimum of two paralleled generators (N+1 preferred, where "N" can carry 100 percent of the emergency load), always located above flood level. All electrical service and critical plumbing, medical gas, and mechanical service equipment will be located above the 500-year flood level. Permanent provisions will be made for temporary street connections to rolled in services, such as chiller, boiler, generator, or water truck.
Other changes that may come in the near future include providing central or local UPS for computer-based imaging equipment and all hospital IT equipment, perhaps also for ORs. And emergency power will be used to provide comfort cooling in critical areas.
Marina Dishel , PE, LEED AP, is a vice president at Syska Hennessy Group's New York office and can be reached at mdishel@syska.com. Syska Hennessy Group worked with many New York City health care institutions to implement major emergency power infrastructure upgrades that went beyond code requirements. The best practices and recommendations described in this article are based on Syska's work with those and other hospitals.
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