Risk Assessment & Design

FOLPS provides through it’s member services a risk assessment with a design & specification in accordance with the following standards –

– IEC / EN 62305
– NF C 17-102

We can provide you with everything you need:

– risk assessment
– lightning protection Level and efficiency statement
– detailed specification
– Calculation for the radius of protection (Rp)

Risk assessment (IEC / EN 62305)

The level of protection is calculated for a lightning protection system by the guidelines contained within IEC / EN 62305 and an appropriate risk level given from levels I, II, III, IV depending upon a pre ascertained risk criteria ( R1, R2, R3, R4)

Lightning protection efficiency (IEC / EN 62305)

The probability that a peak current will exceed the maximum stated values in (kA) gives rise to the following efficiency for each assigned level of protection –

Level I ( 200 KA @ 10/350) 99%
Level II (150 KA @ 10/350) 97%
Level III ( 100 KA @ 10/350) 91%
Level IV (100 KA @ 10/350) 84%

The efficiency of the system is quite literally its ‘guarantee’ to perform. As part of an overall due diligence, the level and corresponding efficiency is communicated to both insurer and end client. The optimum efficiency is Level I and this provides a 99% guarantee.

Detailed Specification (IEC 62305 / EN 62305 / NF C 17-102)

Calculation for the radius of protection ( NF C 17-102)

With the level assigned, the protective umbrella (Rp) is calculated in accordance with the ESE product / performance specification (



Rp = radius of protection in a horizontal plane
h = height of SafeStrike tip above roof line to be protected
r(m) 20m level I
30m level II
45m level III
60m level IV

∆ = initiation advance of upward leader in accordance with appendix C of NF C 17-102 (2011)