"Richard Harrison" wrote

Jack Painter wrote:
"Modeling examples listed below appear to be incorrect for lightning,
similar to how modeling for ocean waves cannot be done in a bathtub and
even a swimming pool does not closely replicate the action of waves in a
large body of water."

OK. Here are full-scale examples. My company had radio towers over much
of the earth. Standard practice was protection of the beacon atop the
tower with a Copperweld ground rod alongside the beacon with its sharp
tip pointed at the sky. No protected beacon was ever damaged by
lightning.

Our company headquarters skyscraper was protected by short air terminals
ringing the perophery of the builsing at short regular intervals. No
lightning damage yet in half a century.

You may say it is squivalent to the fellow who walks into a bar with a
strange contrivance suspended around his neck. Asked what the gadgst
does, the new arrival says: "it`s an elephant whistle". Reply is:
"There`s no elephants around here." New arrival says: "See. It works,
doesn`t it?"

I can assure that there have been plenty of lightning strikes safely
bypassed to ground around the protected people and equipment, just as
Ben Franklin and others have predicted.

Best regards, Richard Harrison, KB5WZI


Hi Richard, because it is completely unlike you to so widely miss the point,
I question whether I understood your responses correctly. The standard
Franklin rods (with pointed tips) have been completely validated in their
application of safely terminating lightning strikes. Nothing in the new
study repudiates that in any way. It simply finds that a lightning rod of
similar length, thickness and composition but with a rounded or blunt-tip,
has attached lightning that was coming to it's twenty-odd foot area
everytime and missed the nearby Franklin rods everytime. The study clearly
restates what engineers all over the world already know, that Franklin rods
work just fine. But it ADDS that the blunt-tip rods work better, end of
study.

Because lightning is impossible to predict, and often it strikes areas of a
grounding system and building below the lightning rods (evidence is the
Empire State Bldg, which has video showing dozens of strikes bypassing the
Franklin rods), then if an improved rod-tip design is validated, then it is
validated, simple as that. Your experience describing a pointed tip
protecting a radio tower sounds rather simplistic as examples, don't you
agree? Nothing could be easier than attaching lightning to the top of a
tower for Pete's sake. Where lightning rod placement and design becomes
critical, is in areas such as multi-level/shaped building corners,
appurtenances, high explosive and flammable liquid storage, etc. Here, the
best available science is used to describe how many feet apart, at what
elevations, etc the air terminal system must be in order to achieve the
desired level of confidence that no lightning attachment will cause damage
to structures, materials or personnel.

Happy New Year and best wishes,

Jack Painter
Virginia Beach, Virginia