When evaluating the design criteria for an electrical distribution system in a facility of significant magnitude, vast complexity, or of critical operations, such as a hospital, a centralized uninterruptible power supply (UPS) system backed up by the emergency standby power source should be considered. There are numerous benefits associated with utilizing a central UPS system such as improving electrical system reliability and efficiencies, simplifying building operations, and reducing maintenance costs and system downtime.
Hospitals, among other facilities with complex infrastructure, contain a large variety of operational systems and special equipment that require a reliable power source. No matter how many utility sources supply a typical facility or campus with an emergency standby power system, there is a variable amount of time, ranging anywhere from a few seconds to a minute, that these critical systems and equipment will be de-energized and completely shut down before they are transferred onto emergency generator power upon loss of the utility service. In a hospital, momentary power loss to certain loads can be problematic, and in some cases compromise individual departmental operations, patient safety and negatively impact revenue. In lieu of multiple localized battery backup units, a centralized UPS and distribution system can provide the necessary power simultaneously to a large number of desired loads during this momentary outage. When the UPS is backed up by a reliable emergency standby power source, the associated battery or flywheel capacity can be minimized as all the runtime that is required is for the duration between losing normal power and transferring to emergency power.
The primary hospital loads to consider for a centralized UPS include items typically found on the Life Safety and Critical branches of the emergency power supply system, including, but not limited to, egress lighting and exit signs, fire alarm, security, nurse call, patient monitoring and other communications systems, building automation systems, telecommunications rooms, patient critical care area lighting and power, as well as medical imaging equipment. A majority of these loads are often provided with, or powered by, a means of localized battery backup, which can be difficult to manage and costly to maintain. Multiple localized UPS units can also end up occupying valuable program space in patient care or staff support areas that could otherwise be utilized more effectively. With strategic design, the necessary emergency branch automatic transfer switch (ATS) units can be integrated into the centralized UPS distribution system in order to comply with all applicable codes, and maintain all of the system benefits.
There is an upfront premium cost associated with the purchase and installation of central UPS systems, but the costs can often be justified by factoring in all of the additional localized backup systems that would no longer be required in addition to the increased reliability of critical patient care systems. Central UPS systems can also prove to be financially advantageous to facility owners over time as there can be reduced cost in operations and maintenance of a centralized system when compared to multiple smaller systems in a large facility or campus.