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Codes and standards governing installations of emergency backup power do not and probably cannot cover every eventuality.

Posted by Charles Hoeffler on

The high winds, heavy rain, rising sea level, flooding, and other consequences of Hurricane Sandy, circa October 26-29, 2012, affected 24 states, with particularly extreme damage occurring in New York and New Jersey. Overall, 8+ million utility customers lost electrical power. Damage exceeded $71 billion (based on the value of the dollar in 2013) and wreaked havoc on energy infrastructure at many facilities and in numerous communities. At several facilities, there was total loss of electrical power.

So what did we learn and how much have codes changed to minimize repercussions from a future “storm of the century” so that power – for essential services or even all services – continues to flow?

Codes and standards governing installations of emergency backup power do not and probably cannot cover every eventuality. However, updates and changes should reflect common sense considerations gained from Hurricane Sandy and other recent major storms.

For example, the NFPA 110: Standard for Emergency and Standby Power Systems, 2013 edition, Annex A, paragraph A.7.2.4 states, “EPSS (emergency power supply system) equipment should be located above known previous flooding elevations where possible.” And paragraph A7.2.5 goes on to say, “For natural conditions, EPSS design should consider the ‘100-year storm’ flooding level predicted by the Sea, Lake, and Overland Surges from Hurricanes (SLOSH) models for a Class A hurricane.

The qualifiers in the two paragraphs – “where possible” and “should consider” – can weaken the effect of the code if the specifiers are not stringent and forceful in determining what “possible” really can entail. “Where possible” and “should consider” are in no way the same as “must” and don’t command the same attention.

Another example: NEC articles 700 and 701 speak to the capacity for emergency systems and legally required standby systems, respectively. They note that emergency generators have to handle all the loads but do not apply to hospital generator sets, which might have to run for extended periods. So sizing them according to historical data and other demand factors may not be sufficient in dire times of need.

A major aim of code changes should, and increasingly, does include the goal of minimizing vulnerability of energy systems to disruption.

FEMA’s Hurricane Sandy Recovery Fact Sheet #3 (November 19, 2014), notes that FEMA’s Hurricane Sandy Mitigation Assessment Team (MAT) identified 47 recommended actions related to building codes and standards, more than half of which, thus far, have been partially or fully enacted.

For example, in New York City, the MAT recommended numerous improvements to the NYC Building Code for consistency with the National Flood Insurance Program (NFIP). These included:

  • adding a “flood zone compliance special inspection” of work related to raising, lifting, elevating, or moving buildings and specifying requirements for construction documents needed for such special inspections (done).
  • an amendment that requires dwellings and most commercial buildings to be elevated at least 2 feet above the base flood elevation (BFE). (endorsed)
  • requirement that essential facilities be elevated or protected to the higher of the 500-year flood elevation or the elevation required by the American Society of Civil Engineers (ASCE) Standard 24, Flood Resistance Design and Construction.

 

For New York State, the MAT recommended revising the minimum elevation requirement for non-residential buildings to 2 feet above the BFE. Furthermore, the New York State Hospital Code is considering revision to require elevation to 0.2% annual chance of a flood.

Along the same lines, the Building Resiliency Task Force, convened in June, 2013, at the request of the City of New York, made several recommendations to improve building resiliency and maximize preparedness for future weather emergencies.

The task force put forth 33 changes to better protect NYC residents from effects of a wide-reaching storm. These included: locating building equipment higher in buildings to avoid damage from floodwaters (now code); installing temporary flood barriers on sidewalks outside certain classes of buildings (now code); installing sewage valves to prevent backflow into basements during rainstorms and floods (now code); natural gas generators for powering lighting, elevators, fire safety, and other building systems (recommended); quick connects for portable generators (recommended).

Another code change that hopefully will make a difference: in NYC, new hospital and nursing home buildings must include hookups that support quick connection to temporary generators and boilers. Existing buildings, however, have 20 years to comply with that.

Pan American Health Organization and the British government instituted a Smart Hospitals program in the Caribbean to retrofit hospitals considered vulnerable to storm damage to make them safer, better able to be self-sustaining, and more energy efficient. Last year (2014), the program benefited one hospital in St. Vincent and another in St. Kitts and Nevis. This year (2015), the program aims to address retrofitting at a minimum of 12 hospitals. The anticipated expenditure at each hospital would be about half a million dollars. The work would include installation of backup generators, installation of solar panels for electricity and hot water, and air-conditioning in at least some areas of each hospital. Other implementations include reinforcing roofs and windows to better withstand hurricane force winds.

The concept of what is considered 100-year storms in terms of the ability to inflict damage on people and property may have to be revised if communities are to adequately protect against them. For example, sand dunes built at beaches along the New Jersey coast after Hurricane Sandy did not fare well from three days of battering rain and wind (a nor’easter) during late September/early October while Hurricane Joaquin tracked hundreds of miles east in the ocean.

The resulting erosion created dangerous fall-off. Some beaches were closed and many require now expensive rebuilding with extensive replenishment of sand to recreate the dunes.

With the apparent increase of severity and frequency of storms that can create severe damage – and may disturb the energy infrastructure – it seems facilities and communities would benefit from faster implementation of code changes and additions.

What do you think of the changes thus far with respect to how they address the likelihood of increased power reliability during and after a major storm? What other changes would you recommend?

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