Risk assessment is a essential step in the application of IEC 62305. Risk assessment is required to determine the need and extent of protection measures to reduce the risk of loss due to lightning below an acceptable level.
The values assigned for certain parameters are values proposed by the IEC 62305. It is recognized by IEC that these identified values may not be appropriate for application in all the countries that utilize IEC 62305. Different values suitable to the locality may be assigned by each national committee based upon each relevant risk category.
The risk assessment process is complicated, requiring so much information not likely to be available to the lightning protection designer at the initial design and tender stage. It is vital therefore that the lightning protection contractor undertakes a calculation using the information provided, in conjunction with any reasonable assumptions identifying all parameters used in order for the client or their technical representatives evaluate that all areas have been considered and included in the final assessment.
IEC 62035- 2 states that the decision to provide lightning protection may be taken regardless of the outcome of risk assessment where there is a desire that there be no avoidable risk.
Flowchart below outlines the risk assessment process as required by IEC 62305.