[BC] AM transmitter lightning sensitivity issue

[dynotherm at earthlink.net]

-----Original Message-----
>From: Ron Nott <ron at nottltd.com>
>Sent: May 22, 2008 6:02 PM
>To: Broadcasters' Mailing List <broadcast at radiolists.net>
>Subject: Re: [BC] AM transmitter lightning sensitivity issue
>
<snip>

>Several years ago, a manufacturer of a multiple point dissipation 
>system applied to NFPA to have their equipment listed.  The NFPA 
>lightning protection committee is composed of representatives of the 
>manufacturers of the NFPA system.  So they denied the listing based 
>on the fact that the multi-point system had not been scientifically 
>tested.  The manufacturer replied by saying that the conventional 
>NFPA system also has not been scientifically tested.  The NFPA 
>committee had to acknowledge that this was true and there was quite a 
>haggle.  However, in the end they continue to endorse the 
>conventional method and deny the multipoint method based on two 
>factors:  Money and petty politics.  To sum up, I suggest that you 
>take info from the Lightning Protection Institute with a big dose of salt.

Ron,

You missed a MAJOR point in the ESE vs. Franklin rod issue, and it is
the reason the NFPA has consistently refused approval of ESE equipment.

ESE rods are extremely expensive compared with Franklin rods therefore
therefore the ESE rod manufacturers have tried to sell them by saying
they are far more effective than Franklin rods and can be used in VERY
small numbers, thus justifying an inflated markup. The proven result of
these attempts has been disasters in high lightning zones around the
world ranging from lives lost in Sri Lanka to oil refinery fires in
South America all because lightning STRUCK STRUCTURES supposedly 
protected by ESE devices which FAILED to dissipate the energy of the
strike.

It is clear that ESE devices are hit less often than ordinary Frankilin
rods. In other words, they seem to REDUCE the number of strikes however
they do not eliminate them. The critical point is that when they are 
installed in small numbers as manufacturers recommend, the structure is
not protected from absorbing the brunt of the bolt, and fires and other
structural damage - the things the NFPA is in business to prevent - are
not prevented or reduced in any way. In fact, the results may be no better
than having no protection whatsoever.

Broadcasting is one of the few places where ESE devices may have value
because towers are inherently capable of conducting a strike to the
conventional grounding of our industry without major structural damage;
and the early streamer emission does reduce the number of strikes. In
addition, a tower has only one small top thus there is no large 
perimeter to be protected in the case of a building. Thus, while ESE
rods may have value in broadcasting, it is entirely unwarranted to 
attack the NFPA (National Fire Prevention Association) for their stand
on ESE devices, especially when there is overwhelming evidence that they
do not work as marketed to protect lives and property. 

Phil Alexander, CSRE, AMD