How to calculate protection area

How to Calculate Protection Area ?

KNIGHT and HAWK can provide a protection area much greater then a simple rod. The protection level and the ∆T value are used together to calculate the protection area. Protection Level has been determined by the Standarts. The ∆T value of KNIGHT and HAWK has been determined by an independent lab test.

 

 The ESE Lightning Rods KNIGHT and HAWK can protect a Radius (Rp)related to their ∆T value. It can be calculated according to following formula;

 

The protection radius of an ESEAT is related to its height (h) relative to the surface to be protected, to

its efficiency and to the selected protection level (see Annex A).

R (h) = 2rh h2 + Δ(2r + Δ) p for h ≥ 5 m

and

Rp = h x Rp(5) / 5 for 2 m ≤ h ≤ 5 m

where

Rp (h) (m) is the protection radius at a given height h

h (m) is the height of the ESEAT tip over the horizontal plane through the furthest

point of the object to be protected

r (m) 20 m for protection level I

30m for protection level II

45m for protection level III

60m for protection level IV

Δ (m) Δ = ΔT x 106

Field experience has proved that Δ is equal to the efficiency obtained during

the ESEAT evaluation tests

 

To  have Protection Radius; needed to know what is the protection level for the structure that you want to protect.

According to IEC and NFC Standarts; there are two main parameters. First one is the Protection Level which is determinated in the standarts. There are 4 Protection Levels such as;

Protection Levels

LEVEL 1

Very High Risk Structures

LEVEL 2

High Risk Structures

LEVEL 3

Medium Risk Structures

LEVEL 4

Low Risk Structures

 

There is a calculation method in the standarts consisting of basic questions such as; if the object is inhabited or not; if the object is explosive or not..etc.

The values obtained according to the answers of these questions are used together with Annual Average Thunder Days value to determine the protection level.