Who said anything about Chapter 6? Look at the other chapters of NFPA 780.
NFPA 780 and UL are the two sources of criteria for lightning protection installations in the US.
Keep in mind, this whole question is largely academic unless you are the LP system installer. What you need for your installation is a "UL Master Label", which is provided by the installer. Your installer is the one who will determine what he needs to do before he slaps the label on there (and he'll do that in accordance with NFPA 780 and UL). So long as he's reputable, and gives you the label, it shouldn't much matter to you what the criteria are (other than things like if you want the cables exposed/concealed, copper vs. aluminum, etc).
Comment: The NFPA 780 is an official guide for the lighting protection where it applies. It bases the lightning protection on the "Faraday Cage" concept. This approach is most suitable to objects that are large and not so tall. When a tall structure, e.g. cooling tower, is to be protected against lightning, another model called a "Franklin Cone" can be considered. The Franklin Cone is not detailed in the NFPA 780. Also, Franklin Cone air terminals are somewhat different from Faraday Cage air terminals.
NFPA780 uses the "rolling sphere" concept to define the zone of protection. The 1-to-1 "Franklin cone" was previously used to define the zone of protection around tall objects but is no longer recognized by most codes. The rolling sphere concept results in a smaller area of protection for tall objects.
The Franklin cone of protection is not dependent on any particular type of air terminal. Some manufacturers of air terminals claim their devices attract lighting thereby providing broader protection of the Franklin cone area. NFPA780 and U.L. do not recognize that claim.
I would like to thank you for very good comments, but that what I wonna know is :
Install or Not to Install LIGHTNING PROTECTION for existing Cooling Tower. In that Area, a new Cooling Tower is installed with the LIGHTNING PROTECTION.
That's a rather subjective question. There's no code in the US that specifically requires LP.
There is a Risk Analysis procedure included in the back of NFPA 780 that helps add some objectivity to this question. Given the locality (and frequency of thunderstorms), the site details (on a hill, surrounded by higher buildings, etc), the nature & criticality of the business (explosives warehouse, communications center, etc), and the cost of operations, it will assign a number which corresponds to how strongly LP is recommended.
Your insurance company may have some thoughts on this too, you might want to check with them.
Other than that, it largely comes down to gut feeling. Lots of people who have never experienced a hit think it's all a waste of money. Then, after they take a hit, they install LP every time. Of course, it's kind of silly to put it in AFTER the lightning's hit!!!
Suggestion: Shopping around for lightning protection reveals that for example Heary Brothers offer lightning protection based on the Franklin Cone concept while having their approach UL listed. Also, French National Standard recognizes the lightning protection based on the Franklin Cone concept.
I agree with peebee's summary of the code situation. One of my clients in the midwestern U.S. (high lightning frequency area) replaced fan motors and controllers on an unprotected cooling tower as a result of a lightning strike last summer. I'm sure a lightning protection system would have been less costly.
Most manufacturers do not offer no-damage guarantees for Faraday systems. Insteady they provide a U.L. "Master Label", which certifies the materials and installation comply with standards. Some manufacturers of other types of systems have a no-damage guarantee.
One clarification on early streamer systems. While the devices may be UL Listed, they are listed only as an ordinary air terminal device, not as providing the claimed zone of protection.
It's not clear as to which Standard you want to follow. NFPA 780, BS, IEC etc each have a different criteria for risk assessment based on isokeraunik level, collection area, height etc. If you can elaborate on the applicable standard I can forward you some good material. In our projects, we routinely provide lightning protection as per NFPA/IEC/BS based on the geographical area ( which more or less determines the applicable standard ). One comment on JBartos reply : Early streamer technology is not approved by NFPA and draft standard NFPA 781 never saw the light of the day !!!
Comment on the previous posting marked ///\\One comment on JBartos reply : Early streamer technology is not approved by NFPA and draft standard NFPA 781 never saw the light of the day !!!
///I never stated anywhere that it was approved by NFPA. NFPA selected Faraday Cage (Rolling Sphere) lightning protection concept that is very good except it tends to be more demanding on lightning protection hardware volume and labor; therefore, it tends to be more expensive. Those who adhere to Faraday Cone claim that this approach is sufficient, equally good as the Faraday Cage concept, if properly applied. Ultimately, it will be the local Fire Chief who decides which concept is adequate, i.e. local Authority Having Jurisdiction.\\
