Tank Earth Testing – Floating Roof Earth Testing

NORA Tank Farm | NORA Tank Farm - Ringsend, Dublin

Tarbert Oil Tanks, Kerry | Punch consulting

 

Floating Roof Tanks are especially vulnerable to the direct and indirect effects of lightning. Direct, or a nearby lightning strike can cause electrical current to flow across the tank shell and roof. When these lightning currents arc across the roof/shell interface, they can ignite any flammable vapours present with devastating effect.

As an example, if the lightning strike hits an adjacent Tank.  This strike can cause the charge in the tank walls to discharge rapidly.  The prolem of leaving a ‘bound charge’ suspended in the product itself. Hence, failing to earth or ground the tank robustly.

Therefore this situation can create a secondary arc. Igniting the vapours!

This typical scenario highlights why lightning does NOT have to hit the tank itself to cause an explosion or fire.