Lightning protection risk assessment

Context:
For an industrial site, we were asked to evaluate the risk of a lightning strike on a process building. The building had several floors, instrumentation and sampling points, some of which were located in ATEX zones . Since this was an environment with explosion risks, the impact of lightning protection was crucial for protecting both staff and installations.

Approach:
Prohead Engineering carried out a lightning risk assessment in accordance with IEC 62305-2 and the Belgian annexes (NBN EN 62305-2), using a detailed model of the building and the environmental factors. The analysis included:

• Identification of all sources of damage (direct strike, indirect strike, incoming supply lines).
• Division of the building into lightning protection zones (LPZ 0B and LPZ 1), taking the existing ATEX zones into account.
• Calculation of the risk of loss of human life (R1) and comparison with the normative limit value.
• Analysis of incoming lines and electrical distribution, including high-voltage, low-voltage and instrumentation cables.
• Listing of existing and required protection measures, such as:
  • external lightning protection (LPS class IV),
  • equipotential bonding of piping,
  • coordinated surge protection (SPD),
  • potential control and insulation of piping.

Result:
The calculation showed that the initial risk was significantly above the normative limit value (R1 = 8.56E-04 versus RT = 1.00E-05). By implementing the proposed measures, the risk could be reduced to an acceptable level (R1 = 8.46E-06).

Added value:
With this risk assessment, the operator has a fully substantiated lightning protection plan. The file can serve directly as the basis for the engineering and implementation of the protection measures and provides conclusive proof of compliance with IEC 62305 and Belgian regulations.