Any system on the roof can have lightning protection added to it. Fittings and attachments can be placed on cupolas, weather vanes, and fan units to give them the needed protection from lightning strikes. Photo courtesy of LagPro.
Lightning has a way of sneaking through the building envelope and exposing wiring, plumbing, and other vulnerable building components to a massive amount of heat. Sparks and radiant heat can start a fire in the attic or inside the wall. We’ve asked the lightning experts at LagPro, Lightning Protection Institute (LPI), and the Independent Protection Agency (IPA) to go through some of the basics to protecting your structure from lightning.
RB: How often do lightning fires occur?
LagPro: According to data from the National Fire Protection Association (NFPA), there are about 500,000 structure fires per year in the U.S. and 4.5% of those each year are identified as caused by lightning.
IPA: On average, 25,000 fires are started each year as a result of lightning strikes throughout the United States. Within those strikes they are responsible for approximately 12 civilian deaths, 47 injuries, and over $400 million in direct property damage. (NFPA Lightning Fires and Lightning Strikes, June 2013)
RB: How is installing a lightning protection system in completely new construction different than retrofitting a building with a lightning protection system?
LagPro: Installing lightning protection on new construction allows for the lightning protection to be concealed within the building and out of sight (except for the lightning rods themselves). When retrofitting an existing structure, the lightning protection components will be exposed on the exterior of the building.
RB: Who should have lightning protection?
LagPro: Anyone who wants to protect themselves and their assets from lightning strikes, which can cause major damage to structures, electronics, and appliances. However, it is essential on building such as hospitals and jails. These are examples of places where people may not be able to evacuate if a fire was caused by a lightning strike.
IPA: Rural buildings are very susceptible to being struck by lightning as they are many times the highest point of elevation for their surrounding area. These open spaces provide a greater opportunity for lightning damage. Lightning prefers to travel to the ground with least amount of resistance. Buildings provide a better conductor than the air that the lightning strike is traveling through, thus the reason for these objects to be hit at a much higher probability.
RB: Do cupolas, weather vanes, roof fan systems, or other roof additions (or metal roofs) interfere with lightning protection?
LagPro: Any system on the roof can have lightning protection added to it. We have fittings and attachments that can be placed on these units to give them the needed protection from lightning strikes.
RB: Can lightning protection systems be installed by general contractors, or do you need a specialist?
LagPro: The best way to protect your structure from lightning damage is to have a LPI certified lightning protection installer install an LPI compliant lightning protection system.
IPA: These systems should be installed by a specialized worker who is fully aware of the codes and specifications in order to provide a fully functioning system that will prevent damage in the case of a strike. A system that is not installed properly could cause a high amount of damage to the structure that was intended to be protected.
RB: What elements make up a complete lightning protection system?
The elements of a lightning protection system allow lightning to travel from the strike point to the ground on a path of least resistance. Photo courtesy of LagPro.
Lightning Protection Institute (LPI): There are five elements that need to be in place to provide an effective lightning protection system.
1. Strike termination devices: Accepts strikes before they reach insulated building materials.
2. Cable conductors: Route lightning current over and through the construction, without damage.
3. Below grade grounding electrode system: Moves the lightning to its final destination away from the structure and its contents.
4. Bonding: The interconnection of the lightning protection system to other internal grounded metallic systems to eliminate lightning to side flash internally.
5. Surge protection devices: Installed at every service entrance to stop the intrusion of lightning from utility lines. RB
This sidebar was part of an article about fire safety that you can read here.