The inferno at the IOC fuel depot near Jaipur on October 29, 2009, reportedly due to an explosion and faulty valve, lasted several days before it was doused leaving six company officials dead and 150 injured. The organisation could do nothing but just stand and watch as barrels of fuel at the 1,00,000 kilolitre capacity Indian Oil Depot at Sitapura industrial area just burnt away, It is hard to believe that the fire turned uncontrollable. Effective measures could not be taken to control the spread and damage. Nor were there adequate safety provisions in such a fire hazard prone tank farm establishment.
Whether the depot has been flouting norms is a matter of conjecture and the five-member committee headed by M B Lal, former chairman and managing director, Hindustan Petroleum Corp Ltd, will go into the causes of the fire and suggest safety measures. The incident has raised several questions regarding the adequacy of safety measures followed at the IOC depot.
Petroleum minister Murli Deora, who rushed there to take stock of the situation, expressed that the fire had to die down on its own and there was ‘no other solution’. It is an irony that, where the possibility of fire hazard is like a ticking time-bomb, a situation of helplessness exists. Shouldn’t the designers, planners and authorities have provided for prevention of such an accident and provision for damage control?
There are a large number of such installations in the country — while some are in remotely populated areas there are several in close proximity of heavily populated areas such as in Khetrajpur, Orissa near the hub of wholesale trading. There is an urgent need to provide for managing such accidents in order to minimise the impact on life and property at all the tank farms. It will not be out of place to suggest that the investigating committee invite engineers and scientists’ having specific experience to contribute before another Jaipur happens elsewhere.
Disaster planning and response require scientific elaboration. The objective must be at preventing a fire disaster and manage a fire to minimise its destructive impact before it acquires catastrophic proportions. While the committee is going into the details of cause of the fire, I am putting forth a few suggestions based on my experience in the field of passive fire protection. The sequence of events is an indication to the spread of fire. Some of them are:
All the tanks were not on fire simultaneously and the fire progressed from one tank to the next
The leaping and high rising flames carrying the enormous radiant heat energy due to chimney effect were observed to be intensely dense and as high as 70 ft.
Fire continued till the combustible oil were consumed and burnt out to very low levels in tanks.
It is a known fact that oil fires, particularly in a contained column would burn at the top-floating surface in contact with the oxygen, while the remaining column of oil within the tank depth remains almost unaffected.
The extent of damage could be drastically curtailed if it had been possible to drain out the contents of the unaffected column of fuel from adjacent tanks. This can be achieved by:
Remote operated quick opening emergency drain valves installed close to each tank, and
Provision of emergency safe storage facility where the drained oil can be safely transferred.
In an emergency the oil stored in the over ground tanks can be transferred to the safe storage facility. Such storage tanks can be provided underground beneath the over ground tank to facilitate transfer by gravity. The underground covered tanks would be fire-safe being isolated from oxygen. To prevent the spread of fire, ways have to be found to barricade the flying flames/sparks and more importantly to block heat radiation from a flaming tank to other tanks not yet on fire.
For preventing the spread of fire, barricades to shield the adjacent tanks from radiating high flames shall have to be installed in between the adjacent tanks. The water flow rate and height of vertical throw as well as the dense pattern of throw of the cooling water curtain as well as its angle of throw shall have to be designed to barricade, douse and cool the surrounding areas.
The movement within the tank farm premises for movement of operating and maintenance personnel and equipment cannot be restricted. In such a situation a vertical dense water curtain of appropriate height with water capacity designed to outlive the combustible contents and of cooling capacity could be an ideal solution. In normal times such a system shall not physically restrict any movement within the premises. Only in the event of fire occurrence the curtain needs to be activated. The curtain can be designed to activate either manually or automatically. The safety systems can be installed indigenously at minimal cost.
(The writer is a mechanical engineer and has served the passive fire protection industry for almost two decades)