Furuno WR2120 Installation Manual page 59

LPL Condition
I
II
III
IV
4. Protection of Structures Against Lightning
4.1. Old lightning and angle of protection standard
Old standard stated the protection angle of lightning rods for
protecting of people from lightning, electrical facilities, petroleum
complexes, gas tanks, plant, and equipment was 60º or less for
general buildings. Factory handling hazardous materials such as
explosives, flammable gas, liquids, and etc., would be slightly
narrower as 45º. Because these specifications were old they did not
take height in consideration. Also the protection area was too large
and therefore not safe enough even within the protection angle.
The basic data of this standard was created using results of an
experiment that tested using an artificial lightning generation
apparatus. Since the electrical discharge size generated was too
small when compared to actual lightning, it was found that the
experiment data results varied from actual lightning observation.
Table A-9: Height requirement for the new lightning rod
17
S2E-17-0209_IM_WR2120_C
Height
[m]
7.4
7.305 m
5.5
5.475 m
4.472 m
4.5
4.0
4.0 m
α
Figure A-5:
Protection range
α: Protected angle