During the past few years, the effects of catastrophic weather events have compromised the operation of many commercial buildings, data centers, educational complexes, and government and healthcare facilities. In many cases, the facilities were unable to maintain uninterrupted power to operate “business as usual” or to serve the essential needs of a community because of the failure of emergency backup power due to wind or flooding.   

The occurrences of so-called “100-year storms” seem to be a lot more frequently than once a century. According to the National Hurricane Center, seven of the eight most costly U.S. hurricanes occurred in the last decade (with number adjusted for inflation):

  1. Katrina, 2005, $105.8 billion in damages
  2. Sandy, 2012, $60 billion
  3. Andrew, 1992, $45 billion
  4. Ike, 2008, $20+ billion
  5. Wilma, 2005 $20+ billion
  6. Ivan, 2004, $19.8 billion
  7. Charley, 2004, $15.8  billion
  8. Irene, 2001, $15.8 billion

In many cases, following existing codes regarding where to place electrical equipment such as generators, fuel tanks and other critical electrical system components were not enough. Extensive as they may be, prevailing codes cannot and do not cover every eventuality. Evaluation of the lay of the land, the local weather history and proximity to rivers, streams, and coastlines should be part of the design and installation process.

While electrical codes and the standards are slowly adapting to accommodate the new weather realities, details on how to avoid placing components in vulnerable areas are lacking. When codes do address such issues, it may just be a suggestion rather than a mandate. To maximize reliability and resiliency of emergency power operating as intended, decision-makers should pay attention to the realities of the placements with respect to local conditions.

The National Fire Protection Association (NFPA) and the National Electrical Code (NEC) both do address placements that would enhance chances of reliability of backup power when called upon. The NFPA 110: Standard for Emergency and Standby Power Systems, 2013 edition, Annex A, states: “EPSS [emergency power supply system] equipment should be located above known previous flooding elevations where possible. The document continues to say: “For natural conditions, EPSS design should consider the ‘100-year storm’ flooding level or the flooding level predicted by the Sea, Lake, and Overland Surges from Hurricanes (SLOSH) models for a Class 4 hurricane.

In Chapter 7, the body of NFPA 110 uses less precise language in relation to locating equipment with respect to flooding: “The rooms, enclosures, or separate buildings housing Level 1 or Level 2 EPSS equipment shall be designed and located to minimize damage from flooding” caused by sewer water backup, firefighting efforts or other disasters.

These references to flooding appear in the section titled Outdoor EPS Installations, but are not referred to at all in the preceding section titled Indoor EPS Installations; unless someone is checking Outdoor EPS, the guidelines would be missed altogether.

NFPA 99: Health Care Facilities Code, 2012 edition, replicates wording in NFPA 110, but is more specific in Annex B: “Flooding into a facility’s lower levels where utilities are often housed results in a disruption of these services….Power is lost typically as a result of high winds and flooding. Generators and transfer switches have been lost due to their location below the high water mark.”

NEC Article 517.35 (C) states “Careful consideration shall be given to the location of the spaces housing the components of the essential electrical system to minimize interruptions caused by natural forces common to the area (e.g., storms, floods, earthquakes, or hazards created by adjoining structures or activities),” but does not require any specific placement.

Decisions about where to place generators, switchgear, breaker boxes, building connections, other critical electrical equipment and, if possible, fuel sources, for the operation of emergency backup power should go beyond what code states or implies and should take into consideration:

  • prevailing code;
  • geography of the location (e.g., proximity to a river, stream or shoreline);
  • previous known high water marks and flooding elevations; and
  • solid, common sense, overall evaluation of the site.

Bhavesh S. Patel is director of marketing and customer support at ASCO, Florham Park, N.J. For more information, call (800) 800-2726, email bhavesh.patel@emerson.com or visit www.emersonnetworkpower.com/asco.