Radius of Protection
The radius of protection of Forend Early Streamer Emission(E.S.E) lightning conductor is related to its height (h) relative to the area to be protected, to its; triggering advance and to the selected protection level.
Rp = √ h(2D – h) + ∆L (2D + ∆L) with h ≥ 5m.
Rp = radius of protection
h = tip of Forend ESE
D = triggering distance
20m for protection level I,
30m for protection level II,
45m for protection level III,
60m for protection level IV.
∆L = upward leader length gain
∆L₍m₎ = V₍m/µs₎ • ∆T₍µs₎ (V = 1m/µs)
∆T = triggering advance
Reference: French Standard NFC 17 -102