Hospitals are beginning to look past codes to set power reliability minimums. The devastation of extended blackouts and storms in the last decade has led some of this country's largest acute care institutions to re-think their emergency power plans, asking "What is needed to maintain power beyond the existing code-mandated minimum requirements?"
Currently, NFPA 70 (National Electrical Code), Article 517 — Health Care Facilities, and NFPA 99 (Health Care Facilities Code) address minimum emergency power requirements aimed at providing public safety and patient safety during a normal power outage. The code generally covers egress lighting; the fire alarm, medical gas alarm, and public address systems; floor power for critical areas; critical ventilation; critical mechanical and medical equipment; and the like.
But, in the face of an extended crisis, today's code minimums can leave a hospital in the dark and without the tools to properly diagnose and treat new and existing patients. Critical imaging suites for MRI and CAT scans, areas conducting non-invasive procedures, ventilation of non-critical areas, and comfort cooling, for example, are all crucial to a hospital's daily operations and its revenue generation, but beyond current code requirements for emergency power.
In response to extended large-scale blackouts in New York City in the last decade, several New York City health care institutions have implemented major emergency power infrastructure upgrades. These institutions took such steps as expanding existing power plants and providing new emergency power plants, providing new campus emergency distribution systems, installing supplemental critical and equipment risers, and providing emergency power to chiller plants, HVAC equipment, imaging suites, etc. Because some of these institutions were so proactive, they were able to maintain close to normal operation during and in the aftermath of Hurricane Sandy, including handling patient overflow from other hospitals that had to shut down.
How does a hospital know which additional systems to include in its emergency power provisions? Additionally, what measures must be taken to ensure the hospital's emergency power source is reliable? What follows is a list of recommendations when designing hospital emergency power systems — practices that travel beyond today's code requirements.
1. Two or More Generators. Code doesn't specify how many generators to provide — just that an emergency power source is required. It is recommended to provide a generator plant consisting of at least two (or more) generators with paralleling gear. Although the increased reliability is obvious, there are many hospitals that have either one generator or separate unsynchronized/unparalleled generators, in which case a single generator failure will lead to a blackout. The second, plus any additional generators represent pure spare capacity providing 100 percent replacement for the loss of one generator. This arrangement provides a redundant source and higher probability, with a lower failure rate to start the generator plant and can be further strengthened as desired by providing a true N+1 arrangement and increasing the size of the generators. As an example, if a 1500kW generator plant is required, it can consist of either one 1500kW generator (not recommended), two 750kW generators (no redundancy), two 1500kW generators (N+1) or three 750kW generators (N+1). (In an N+1 arrangement, the "+1" is the size of the unit needed in case one unit is out of commission.)
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