Designs for Hidden Lightning Protection Systems
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Hidden Lightning Protection Design Specifications
Examples of hidden lightning protection systems
List of lightning protection system materials for hidden systems
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This website describes common lightning protection systems, certification, installation, and lightning protection system inspection.
We provide information about lightning strikes, lightning hazards, related equipment, sources of lightning protection system installers, and lightning strike risk assessment
Design Details for Hidden Lightning Protection Systems Using Copper Components
Example Hidden Lightning Protection System Installation Details
As with any good construction project, the contract will include a statement that "All equipment shall be installed in a neat workmanlike manner by an experienced installer.
That last part, "experienced installer" is very important in this case since sloppy or improper details can increase rather than reduce the
hazards of lightning damage.
All lightning protection system cables shall be concealed within the building, running along the ridge board, down rafters, down wall studs,
and shall exit the building as close to the ground as possible. If construction is incomplete and a chimney has not been extended above
the roof line at the time of installation of the lightning protection system, the lightning protection system cables can be concealed
within the masonry.
All components and work shall meet or exceed all national safety and electrical codes including the Lightning Protection Institute (LPI)
and the National Fire Protection Association (NFPA), and all components used shall be approved and listed for that purpose by
the Underwriters Laboratories (UL).
The source of all materials is usually listed in order to assure that they are accountable and code-compliant. These lightning protection system specifications and details were provided to us during presentations on lightning
protection systems provided to NY ASHI home inspectors and conducted by Associated Lightning Rod Co..
Example Hidden Lighting Protection System Materials
Building chimneys shall be protected with an air terminal to be placed no more than 2' from any outside corner.
Lightning protection system air terminals shall be solid copper, round, pointed, 3/8" or larger in diameter,
project at least 10" above the object or building section to be protected, and shall comply with UL and LPI requirements for lightning protection systems
and shall be located within 2' of outside corners and at intervals no greater than 20 horizontal feet (along the
ridge line).
Air terminal bases shall be made of cast bronze and shall be securely mounted using pressure-bolt or crimp connectors
and stainless steel screws, nails, or bolts.
Lightning Protection System Cabling shall all be 28-strand 16 gauge copper (230#/1000', 72,258 mils or equivalent).
Corrosion protection shall be provided by lead coating on metal components (air terminals, terminal bases, cable connectors,
strapping,) where located within 2' of the chimney top.
Cable fasteners shall be made of 1/2" wide 20 ga. copper strips and shall be spaced at 2' intervals (exceeding the UL and LPI requirements).
Ground rods shall be at least 1/2" in diameter and 11' long, and driven into the ground 10', leaving 1' of the ground rod exposed [this is the UL standard] and shall
be connected to the lightning protection system by two-bolt cast-bronze clamps at least 1.5" long and using stainless steel cap screws. UL requires that at least two ground rods shall be installed.
Metal components on the building such as antennas, weather vanes, and metal gutters are connected to the roof or down conductor
Building ground-devices such as water piping, electrical systems, telephone, cable, internet systems, and metal waste piping shall be grounded
in common and bonded to the lightning protection system using full-sized grounding conductors.
Other hardware such as miscellaneous bolts, nuts, nails, screws, shall be stainless steel.
Surge protection devices are installed at receptacles on for circuits serving electronic equipment like computers, TV's, or other electronics.
Surge protection may also be installed at the electrical panel to protect the circuit serving a well or well pump, or to protect equipment from
strikes drawn to steel well casings protruding above ground as well as to protect building appliances.
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Portions of this information are based on UL publication 200-81 11/87 and other local service company information about lightning protection systems and lightning strike hazards.
Special thanks to Associated Lightning Rod Company, Cooper Road Box 329A, Millerton NY who has been contributing technical content in presentations
to NY ASHI home inspectors since 1996. Some of that information [on lightning system material and installation details] was edited for clarity. ALRCi can be reached at 518-789-4603, 845-373-8309, 860-364-1498 and will inspect your lightning protection
system at no charge. [We have no financial nor any other business relationship with any company or product discussed at this website--DF]
Lightning strike risk assessment: for the full body of this excellent article which summarizes recent opinions about lightning
strike risk assessment and safe practices for individuals or groups needing to avoid being struck by lightning, see Updated Recommendations for Lightning Safety - 1998 Ronald L. Holle and Raul E. Lopez from National Severe Storms Laboratory,
NOAA and Norman, Oklahoma, Christoph Zimmermann Global Atmospherics, Inc. Tucson, Arizona
As we indicated in an original version of this article, a lightning strike risk assessment guide can be found in Appendix I of the
National Fire Protection Association's Lightning Protection Code, NFPA #780.
The guide considers type of structure, type
of construction, structure location, topography, occupancy, contents and lightning frequency. Contact NFPA, Batterymarch
Park, Quincy, MA 02269 617-770-3000.
Lightning Protection Institute, 3365 N. Arlington Heights Rd., Suite J., Arlington Heights IL 60004
Underwriters Laboratory Standard UL96A. These requirements cover the installation of lightning protection systems on all types of structures other than structures used for the production, handling, or storage of ammunition, explosives, flammable liquids or gases, and other explosive ingredients including dust. These requirements apply to lightning protection systems that are complete and cover all parts of a structure. Partial systems are not covered by this standard. These requirements do not cover the installation of lightning protection systems for electrical generating, distribution, or transmission systems. These requirements do not cover lightning protection components, which are covered by the Standard for Lightning Protection Components, UL 96.
Underwriters Laboratory Standard UL96: These requirements cover lightning protection components for use in the installation of complete systems of lightning protection on buildings and structures. These requirements do not cover the installation of lightning protection components. Products of this type are covered by the Standard for Installation Requirements for Lightning Protection Systems, UL 96A.
"Lightning Awareness," Gerry Schulte, BMW ON magazine, June 2007 pp. 58-60, provided some technical details about lightning, and refers readers to www.lightningsafety.noaa.gov/outdoors.htm
Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
Our recommended books about building & mechanical systems design, inspection, problem diagnosis, and repair, and about indoor environment and IAQ testing, diagnosis, and cleanup are at the InspectAPedia Bookstore. Also see our Book Reviews - InspectAPedia.
Armor Lightning Protection Inc Manchester Center, VT, 802-375-0266
state-of-the-art lightning protection and surge protection for residential and commercial buildings in Vermont, New England, and throughout the Northeast
Associated Lightning Rod Company, Inc., Box 329A, Cooper Road, Millerton, NY 12546 914/373-8309 518/789-4603
A-C Lightning Security, Inc., 2100 East First St., PO Box 329, Maryville MO 64468 816-582-8115 800-821-5575 816-562-2932. In New York, Hudson Valley, contact Christensen Electrical Power Systems, Richard G. Christensen, 518-537-4128.
Lightning Eliminators & Consultants 6687 Arapahoe Road Boulder, CO 80303 (303) 447-2828. "Engineering Solutions For Lightning, Grounding and Surge Protection Worldwide Since 1971"
UL - Underwriters Labs Lightning equipment certification program.
"Underwriters Laboratories Inc. (UL) has been testing and certifying lightning protection equipment since 1908. UL issues certificates of conformance for systems, inspecting system components and checking completed installations. Installations are required to comply with UL's internationally recognized Standards for lightning protection systems. Manufacturers, suppliers and installers demonstrate their commitment to safety by building,
selling and installing only those lightning protection products that pass UL's rigorous testing." -- (Op.Cit.)
Aluminum Wiring Information Website Aluminum Electrical Wiring Hazards and Repairs: in-depth authoritative info, photos, documents including selection of proper vs. ineffective repair methods. E.g.: Ideal 65 "Twister" purple connector fails in field and lab testing with aluminum wire.
Electrical Panels, How to Inspect in buildings, safety for electrical inspectors, electrical panel, fusing, wiring defects, defective products. Inspection Class Presentation
