LP-Gas Tank Explosion Kills Two Volunteer Firefighters (Carthage, Illinois - October 2, 1997) » Key Issues

Issues	Comments
LP-Gas Tank Location	The two tanks were located too close to buildings and too close to each other. Their location made application of cooling water difficult and created an exposure to the structure.
Tank Manifold	Connecting the two tanks by their liquid discharge to fill connections allowed liquid LP-Gas to back feed from the most exposed tank into the other, resulting in the hydrostatic failure of one tank.
Potential LP-Gas Tank Weakness	It is believed that a weak weld on a tank head to cylinder seam failed when it was subjected to excessive hydrostatic pressure. The condition would have been undetectable to the firefighters at the time.
Risk Assessment	The two 1,000 gallon LP-Gas tanks had been exposed to the burning grain dryer and likely gas being discharged from one of the tanks. The firefighters witnessed at least three intermittent releases from the pressure relief valves as they responded to the scene and prepared to attack the fire. The risk of tank failure exceeded the ability of the fire department to rapidly apply the volume of water necessary to cool the tanks.
Action Plan	Determination of the tank area exposed to heat and flame and time of exposure is critical to estimating the potential for BLEVE. Operating safety relief valves indicate high internal pressures that can lead to tank stress and possible failure. Operating relief valves are an indication that a direct attack to cool the tank surface is dangerous. When attampting such an attack, large volumes of water (typically master stream quantities) must immediately be directed upon the tank and firefighters must be positioned in safe locations.
Water Application Rate	The low flow rate, 60 gpm per hoseline high pressure pre-connects were unlikely to deliver the amount of cooling water needed to prevent the tanks from failing. In addition, these lines are difficult to leave unmanned. Flow rates of 250 to 500 gpm distributed over the entire tank surface are often recommended.
Attack Positioning	Attacks should always be positioned from the tank sides and from protected locations. At failure, horizontal tanks will rocket in the direction of its longest axis and leave a large fireball in its wake. Water and firefighter protective clothing will not protect firefighters from being physically injured or being burned by the ensuing fireball.

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