The emergency and critical circuits in many power systems, including emergency systems and fire pumps, are required to be designed and located to minimize hazards that could be caused by failures due to flooding, fire, icing, vandalism and other adverse conditions.

When hurricanes hit

Massive Category 4 Hurricane Helene devastated much of the southeastern part of the country in September 2024. The maximum sustained wind in Helene was 140 mph. Hospitals, fire and police facilities and other critical support structures were damaged by water surges, high wind and similar conditions. There was enough damage to these that people were evacuated from hospitals and other buildings and transferred to safer locations. This has happened before, with some storms wreaking enough havoc that hospitals could not function as emergency medical facilities.

Hurricane Katrina is one example of a Category 4 hurricane that caused total devastation in the New Orleans area, southern Mississippi and the Gulf Coast, with storm effects as far as northern Pennsylvania. The maximum sustained wind in Katrina was 175 mph. It is one of the five deadliest hurricanes to ever strike the United States.

There was so much structural damage in the worst-hit areas that there weren’t other hospitals to transfer critical patients to for necessary treatment. Critical power circuits and systems were so damaged as to be nonoperational. What can be done in the future to ensure that a similar storm won’t compromise critical systems and structures?

A new NEC article

Hurricane Katrina was so deadly and catastrophic that an entirely new article covering critical operations power systems (COPS), Article 708, was added to the 2008 NEC. The scope of Article 708 reads as follows: “This article applies to the installation, operation, monitoring, control, and maintenance of the portions of the premises wiring system intended to supply, distribute, and control electricity to designated critical operations areas (DCOA) in the event of disruption to elements of the normal system. Critical operations power systems are those systems so classed by municipal, state, federal, or other codes by any governmental agency having jurisdiction or by facility engineering documentation establishing the necessity for such a system. These systems include but are not limited to power systems, HVAC, fire alarm, security, communications, and signaling for designated critical operations areas.”

These are systems installed in vital infrastructures that, if destroyed or incapacitated, would disrupt national security, the economy or public health or safety. In addition, NFPA 1600-2019, Standard on Continuity, Emergency, and Crisis Management, was also adopted and is available for further information on disaster and emergency management. 

To the best of my knowledge, however, few installations have been installed as COPS. Every time I hear of these disasters, I wonder why we don’t have more COPS based on Article 708 installed in areas prone to hurricanes and similar natural disasters.

When Hurricane Harvey made landfall in Houston in August 2017, the storm dumped 48 inches of rain over four days, causing a major flood and $125 billion in damage. Many of the large high-rise buildings, hospitals and similar critical operations centers had flooding in the basements where emergency generators were located.

Even rooftop generators were affected, since high winds and heavy rains created horizontal rain that inundated the electrical switchgear and generator equipment with water.

Design with natural disasters in mind

Emergency system designers should be aware of these issues in areas where storms are common and take it into consideration. Building water-resistant enclosures should be high on the list of protective options for critical power systems. Once a hospital or other emergency facility has been designed to comply with Article 708, others should know this infrastructure is in place. 

Overhead power line failure during high winds is a fairly common occurrence in hurricanes and similar storms. Emergency systems, as covered by 700.10(D) in Article 700, and reinforced by 708.20 in Article 708, covering COPS, can ensure continuous emergency power for essential systems in hospitals and other critical infrastructures. Only when reinforcing these systems can we begin to ensure people will be safe in natural disasters.

stock.adobe.com / Riko