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Lightning Risk Assessment

NFPA 780 is the North American standard for lightning protection systems. It contains “Simplified Risk Assessment” calculations to determine if a lightning protection system is recommended for a specific building.

Try the online lightning risk calculator 

Does your Building Require Lightning Protection?

The Simplified Risk Assessment contained in NFPA 780 takes into account the following attributes of a structure in determining vulnerability from lightning:

  • Size and height
  • Geographic location
  • Surroundings
  • Construction materials
  • Occupancy
  • Vulnerability to fire

East Coast Lightning Equipment, Inc has developed an online risk calculator which automates the calculations in NFPA 780.  After entering the criteria for a specific structure, the tool will generate a two-page report showing the results of the risk assessment.

For detailed information on how to use this tool, see User Guide for Lightning Risk Calculator

Special Risk Factors

NFPA 780 states, “There are some cases where the need for protection should be given serious consideration regardless of the risk assessment. Examples are those applications where the following are factors:

  • Large crowds

  • Continuity of critical services

  • High lightning flash density

  • Tall isolated structure

  • Buildings containing explosive or flammable materials

  • Buildings containing irreplaceable cultural heritage

Statutory, regulatory, and insurance requirements for the installation of a lightning protection system should take precedence over the results of a risk assessment.”

NFPA 780 also contains Detailed Risk Assessment criteria, which assesses additional risk factors and may prove helpful in determining a structure's tolerable lightning risk in certain applications.

Considerations for Design Professionals

Design professionals should discuss the risk assessment report with the building's owner. If calculations or special considerations recommend a lightning protection system yet the owner decides against using it, the designer should get the decision in writing.

To weigh the benefits of a lightning protection system against costs, see our cost study for preliminary cost guidelines. Or, contact ECLE to be put in touch with a certified local lightning protection specialist.

New Buildings: Conduct a lightning risk assessment based on the overall size and shape of the structure early in the design process.  This will allow for the lightning protection system to be included in your cost estimates.  It will also allow for the most flexibility in terms of aesthetics and creativity in the lightning protection system design.

Existing Buildings: Make a lightning risk assessment part of standard due diligence activities before purchasing an existing building, building an addition, remodeling major building systems, structural renovations or reroofing. 

If a lightning protection system is recommended:  A certified lightning protection specialist can help address special architectural concerns and unique requirements.
Most projects can be specified by citing recognized industry standards and delegating design to a Lightning Protection Institute certified lightning protection specialist.

A Non-Proprietary Guide Specification

Standard of Care: NFPA 780 is based upon accepted engineering and risk management principles and is the standard of care for design professionals.

  • An article discussing lightning and professional liability

    An article discussing lightning and professional liability

Try the online lightning risk calculator 

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