Lightning

LIGHTNING
Lightning is an often overlooked weather hazard. In the contiguous 48 states, there are an average of 20 million cloud to ground flashes every year, and almost half of those strike multiple spots. Numerous building fires start every year due to direct lightning strikes to a structure, its roof, or to adjacent utility lines. A study conducted for the years 1991 - 1995 found 30,000 house fires causing $175 million in damages annually. Other studies indicate annual property damages in the billions.
Lightning originates around 15,000 to 25,000 feet above sea level when raindrops are carried upward until some of them convert to ice. For reasons that are not widely agreed upon, a cloud-to-ground lightning flash originates in this mixed water and ice region when interaction between ice crystals and water produce electric charges. These charges then move toward the ground, producing a channel along which charge is deposited, and eventually encounter something on the ground that provides a good connection. The circuit is completed at this time, and the charge is lowered from cloud to ground, producing a lightning bolt.
					The highest frequency of cloud to ground lightning occurs in Florida, where the persistent high moisture content of the atmosphere at low altitudes and the high surface temperatures generate excellent conditions for lightning. Lightning frequency generally decreases across the US from the southeast to the northwest, but western mountains see a large number of strikes due to the often ideal atmospheric conditions at higher altitudes. The Gulf of Mexico coast, inland from the Gulf, westward into Texas, and the Atlantic coast in the southeast also see high frequency strike levels. Most lightning occurs in the summer months when the land surface temperatures are higher, causing near-surface air to rise far into the atmosphere.
Damage to a home is most likely if the structure is located in an exposed area, at a locally prominent elevation, or near tall isolated objects or water. Direct lightning strikes usually end up hitting
the highest point on a building, usually the roof or chimney. The point of strike contact itself often causes little or no damage since a typical lightning bolt is only about as large as a half-dollar, and damage done at that point may not be much larger. Damage on that scale is easily repaired. However, since temperatures inside the strike can reach an estimated 50,000° F, the odds of a resulting fire are great even though not immediately noticeable. Lightning is also a major cause of forest and range fires, a fact that can be very troubling for homes located near forested or grassland areas. View a profile of U.S. forested lands and a discussion of wildfires.
The best protection against fire due to lightning is a non-conducting, fire resistant roof. Wood shakes may be treated with fire resisting chemicals, but these treatments do not last, creating maintenance issues that building departments cannot economically monitor. Therefore, wood shakes are simply being banned in most fire prone jurisdictions. While metal roofs are fire resistant, they can also serve as a grounded target for lightning bolts, they conduct heat easily and rapidly to adjacent flammable building materials, and they increase the difficulty of locating and ventilating a fire should one start in the attic. Older asphalt shingle products can be fire hazards; newer shingles with a fiberglass base are not. Concrete roofing is not susceptible to fire by lightning.
Ce·DUR and Lightning
Ce·DUR comes in individual shakes so is easily replaced if damaged by lightning. Ce·DUR is not an electrical conductor. Ce·DUR is non-combustible and self-extinguishing. Ce·DUR is available with a Class A fire rating.

ENDUR•ALL Technologies, Inc., 6200 So. Syracuse Way, Suite 125, Greenwood Village, CO 80111 303-670-0774