The globe where we live, is being very active with innumerable natural activities on its surface at every moment. It ranges from the movement of electrons in a minuscule atom to vast phenomenons such as sunrise, thunder, rain, lightning, cyclones and etc. Inspite of the fact that nature is supporting the mankind in all possible ways, sometimes we are troubled by event such as lightning, unavoidably.
We all know, the various causes for fire accidents are electric short circuit, unquenched flames of cooking devices, manual negligence, oil spillage, overheating and many more. Apart from all these reasons, lightning is one of the cause for fire accidents and it occurs because of very high electric charge difference developed in the cloud.
About the incident
Recently, a minor Fire accident happened in Hindustan Petroleum Corporation Limited (HPCL) in Visakhapatnam in Andhra Pradesh on 29th of July at 7 pm. The lightning hit the crude oil storage tank, which holds thousands of liters of oil and fire blaze broke out from the tanker immediately. Fire tenders rushed to the spot immediately and firemen settled the fire within an hour without any casualty. Fortunately, there was continuous and heavy rainfall, which minimized the effects of the incident; otherwise fire could have spread to nearby oil tanks.
Risks due to lightning
- There are nearly 2000 thunderstorms happening worldwide at any moment of time. Each thunder is capable of producing about 200 lightning strikes.
- Lightning discharges about 1-10 billion Joules of energy and produces the current of 30,000 Amperes to 50,000 Amperes.
- The air temperature around the lightning strike increases up to 20,000 degree Celsius.
- In a year, around 15 to 20 Oil tank fire breakouts are happening worldwide because of lightning attacks.
- 31% of the fire accidents in petroleum refineries are occurring by lightning.
How Lightning causes fire accident
On account of the fact that lightning cables of the lightning protection system are vulnerable to the risk of fire, they will be burnt when high current flows through it due to lightning. This open flame could lead to explode the nearby inflammable materials. If suppose, lightning attacks the electrical wirings, it will make the wires overheated and evaporate it, sometimes. Wear & tear in the roof of the oil containers due to ageing, possibilities of fume leakage, internal protrusions and irregularities, localized heating and bound charge problems and secondary arc risk are some other risk factors of the fire accidents in oil refineries.
- Automatic fire sprinklers should be installed, which will put down the fire whenever accidents happen.
- Thickness standards for the roof material of the oil tanks must be maintained.
- Good lightning protection system should be installed.
- Floating Roof Tanks – (FRT) grounding methods could be implemented.
- The Oil tanks could be equipped with Dissipation Array System Technology (DAS), which will prevent accidents due to lightning.