Risk Management

24/03/2023

Introduction:

Lightning strike is a natural phenomenon of sudden discharge of charges from highly concentrated cloud or any objects Lightning cannot be avoided but the damages can be reduced by proper preventive measures.

IS/IEC 62305 part 2 explains about the damages due to lightning strikes, sources of such damages, Losses due to lightning and the corresponding risks. In this article, we shall explore about the risk management process as specified by IS/IEC 62305 part 2.

Risk and Risk components:

IS/IEC 62305 describes the risk components for each source of damage. Each risk is the sum of different risk components. When calculating the risk, the risk components of same category will be grouped together.

The risk component also depends on the nature of the structure and its purpose. For highly sensitive areas like hospitals and storage of explosives, the lightning strikes near the structure or near the line connected to the structure may also result in loss of human life.

The summary of risk components associated with each type of loss provided by IS/IEC62305 is as follows

Risk Management:

IS/IEC 62305 part 2 explains the basic procedure for evaluating the risks associated with the structure to be protected.

1) Identify the characteristics of the structure to be protected.

2) Identify all the losses (L1 to L4) for the structure due to lightning and the corresponding risks (R1 to R4).

3) Evaluate the risk (R1 to R4) by calculating the corresponding risk components for each type of risks.

4) Compare the values R1, R2 and R3 with the tolerable risk RT for evaluating the need of protection. The risk R4 shall be used for evaluating the cost effectiveness.

5) Compare the costs of total loss with and without protection measures for evaluating the cost effectiveness of the LPS.

The following procedures shall be followed to evaluate each risk (R1 to R3).

Identify each component (Rx) of the risk Calculate the individual risk components.
Calculate the total risk (R)
Identify the tolerable risk (RT) limit.
Compare the calculated risk value (R) with the tolerable risk (RT)

If R ≤ RT, then lightning protection is not necessary.

If R > RT, protection measures shall be adopted.