Propane Tank Fires

In rural areas propane tanks are used regularly for many more things than just the barbeque. Propane tanks can easily explode when they are overfilled. Overfilling the tank to greater than 85% liquid propane will result in an overpressure if the tank is exposed to hot weather (liquid propane thermally expands more than the steel tank). The overpressure causes a propane release through the tank pressure relief valve. The 15% vapor space in the tank is a reserve for the liquid to expand without overpressurizing the tank.

In the picture to the right, a huge and dangrous fire ensued most likely caused by the overfilling of the propane tanks that were exposed to the sun in the back of the pick-up truck.

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Gas Can Explosion

Gas Cans, or Jerry Cans can and do explode. 4D Imaging engineers established for the first time the exact conditions required for a gas can to explode. At the 4D Imaging Fire and Explosion Lab, our engineers have developed unique sensors to measure gasoline vapor concentrations in situ. The results show that there are three conditions needed to cause a gas can to explode when it comes close to a flame or hot surface: (1) Gasoline has been in a can for several months (aged), (2) there is little gasoline left in the can, and/or (3) temperature of the gas is low. The graph below shows the relationship between vapor concentration and temperature for different amounts of gasoline.

The video image frames below show the results of one of our gas can explosion tests. Note, there are 9 frames from the time the gas can was exposed to a flame until explosion (0.31 seconds total).

It is quite common to pour gasoline on a debris pile to assist in burning. If a gas can has no flame arrestor, and the conditions described above exist, the can will explode, causing severe harm to persons handling the can and those nearby. If the gas can has a flame arrester our tests conclusively show the gas can will not explode.

Weed Wacker

A commonly used handheld week wacker experienced a mechanical failure of the commutator (red arrow) which set the wacker on fire. Sooting (blue arrow) indicates the fire traveled through the windings to the plastic case. Fortunately, in this instance no one was hurt and the fire was quickly put out.

This large brush fire was started by a weed wacker, that was used to cut brush. 4D Imaging has examined many different weed wackers and has determined the cause of large fires

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Fire Caused by Leaking Fuel Lines

4D Imaging has extensive experience performing mechanical related fire investigation. One example is the van fire shown on the left. In this case, we determined that the fuel lines leading to the fuel injectors had been leaking due to a faulty fitting design.

Propane Powered Pickup

Water Heater Fires

Barbecues