Lightning Strike Damage and Losses – IEC 62305

IEC 62305 identifies four main sources of damage:

  1. S1 Flashes to the structure
    • mechanical damage, fire and/or explosion due to the hot lightning plasma arc, over-heated conductors or melted metal;
    • fire and/or explosion triggered by sparks;
    • injury to living beings by electric shock;
    • failure or malfunction of internal systems due to Lightning Electromagnetic Pulse (LEMP).
  2. S2 Flashes near to the structure
    • failure or malfunction of internal systems due to LEMP.
  3. S3 Flashes to a service
    • fire and/or explosion triggered by sparks;
    • injury to living beings by electric shock;
    • failure or malfunction of internal systems due to overvoltages.
  4. S4 Flashes near to a service
    • failure or malfunction of internal systems due to overvoltages induced on connected lines and transmitted to the structure.

Each source of damage may result in one or more of three types of damage:

  1. D1 - Injury of living beings due to step and touch voltages
  2. D2 - Physical damage (fire, explosion, mechanical destruction, chemical release) due to lightning current effects including sparking
  3. D3 - Failure of internal systems due to Lightning Electromagnetic Impulse (LEMP)

The following types of loss may result from damage due to lightning:

  1. L1 - Loss of human life
  2. L2 - Loss of service to the public
  3. L3 - Loss of cultural heritage
  4. L4 - Loss of economic value

Losses of type L1, L2 and L3 may be considered as loss of social values, whereas a loss of type L4 may be considered as purely an economic loss.

The relationship between source of damage, type of damage and loss is reported in Table 1.

Table 1: Damage and loss in a structure according to different points of lightning strike (IEC 62305-1 Table 2)
Point of strike Source of Damage Type of damage Type of Loss
Structure
Strike Direct to Structure
Strike Direct to Structure
S1 D1
D2
D3
L1, L4**
L1, L2, L3, L4
L1*, L2, L4
Near a structure
Strike Near Structure
Strike Near Structure
S2 D3 L1*, L2, L4
Service connected to the structure
Strike to Line Connected to Structure
Strike to Line Connected to Structure
S3 D1
D2
D3
L1, L4**
L1, L2, L3, L4
L1*, L2, L4
Near a service
Strike Near a Line Connected to Structure
Strike Near a Line Connected to Structure
S4 D3 L1*, L2, L4
* Only for structures with risk of explosion and for hospitals or other structures where failures of internal systems immediately endangers human life.
** Only for properties where animals may be lost.

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A Filipino Engineer, Registered Professional Engineer of Queensland (RPEQ) - Australia and Professional Electrical Engineer (PEE) - Philippines with extensive experience in concept select, front-end engineering, HV & LV detail design, construction and commissioning of Hazardous and Non-Hazardous Area electrical installations in water and waste water pipeline and pumping facilities, offshore platforms, hydrocarbon process plants and pipelines including related facilities. Hazardous area classification and design certification (UEENEEM015B, UEENEEM016B, UEENEEM017B).