From lightning.org
Often considered the grandfather of lightning protection, NFPA 780 provides valuable resource information for AHJs, project designers, engineers, insurance professionals and anyone responsible for the protection of lives and property from dangers associated with lightning. NFPA also serves as the basis for the LPI-175 Standard of Practice for the Design-Installation-Inspection of Lightning Protection Systems reference document, which is commonly used by LPI-certified designers and installers and LPI-IP inspectors. NFPA 780 covers lightning protection system installation requirements for structures, watercraft, wind turbines, industrial stacks and other special occupancies. Lightning protection guidance for new construction and building trends (including solar systems, arrays, catenary systems, airfield lighting, rooftop equipment) are also addressed, with new information and sections added to the Standard in conjunction with the three-year review process. Information added to the 2017 edition of NFPA 780 to address new safety challenges includes:
Occupancy-specific safety, design and protection protocol
Updated information for hazardous, combustible and explosive conditions
Revisions to address protection for structures containing flammable vapors, gases or liquids.
Revisions to assist facility managers, installers, inspectors and AHJ’s with on-site inspections and periodic maintenance.
New definitions for commonly misunderstood and miscommunicated lightning protection terms.
Updated illustrations for the placement of lightning protection components.
New bonding requirements for metal bodies.
New Annex sections (there are now 15 in total in the 2017 edition) added to address additional new building technologies (protection of smart structures and SPD guidance for the selection of SPD’s for photovoltaic installations.)
The 2020 document addresses the newest lightning protection applications and provides updated resource material for known safety challenges. NFPA 780 continues to serve as the basis for the LPI-175 reference document, used by LPI-certified designers, installers and inspectors.
The new document includes new references and sections to address applications including:
Revisions in Section 4.9 Conductors: Clarification of general requirements for main conductors with emphasis on one-way paths, dead ends and when upward conductor paths are permitted.
Chapter 7: Acknowledgement of lightning electromagnetic pulse (LEMP) as a source of ignition in classified locations.
Revisions in Chapter 11, Protection for Airfield Lighting Circuits: Clarification of the application of the requirements for lightning protection at airfields.
New Annex N, Considerations for Nonmetallic Tanks Containing Flammable Vapors or Liquids that Give off Flammable Vapors: Information has been added to provide guidance on lightning protection of nonmetallic tanks containing combustible or flammable materials. ( NFPA notes that further study and public input is necessary before provisions for lightning protection requirements for tanks can be added to the body of the 780 safety standard .)
The NFPA first adopted “Specifications for Protection of Buildings Against Lightning” in 1905. Revised editions of the early code (and subsequent standard) continued to be adopted by NFPA throughout the century. In 1992 the numerical designation of the document was changed from “78 “to “780” and the name “Lightning Protection Code” was revised to “Standard for the Installation of Lightning Protection Systems” to conform with the NFPA’s routine method of naming documents. Since NFPA 780 contains installation requirements, it is more appropriately termed an installation “standard” rather than a “code.”
NFPA 780 is the principle lightning protection Standard in the U.S. and a primary implementing document for the IEC 62305 (International Electrotechnical Commission) series of documents. NFPA 780 also provides the foundation for numerous specialized lightning protection documents for organizations such as the DOD, DOE, NASA and the FAA. Prior to the development of the IEC series, NFPA 780 was routinely referenced and used worldwide.