Water and Magnesium Fires: Developing an Attack Plan

Eric James explains the changes that fire departments need to consider when responding to magnesium fires.

This is the same way that fire departments across the country need to handle magnesium incidents.  We as a whole need to know how to handle the magnesium incidents on a hazardous materials basis as well as a fire basis. Magnesium is considered to be in the Class D Fire category. It has a melting point of 1,202 degrees F and a boiling point of 2,024 degrees F. When Magnesium is in its metal form it burns very easily in air. When the Magnesium burns it reacts with the oxygen to form Magnesium Oxide. The Magnesium Oxide is the bright white light you see when the Magnesium is burning. In order to start the reaction the Magnesium needs a source of energy. 

Activation energy is the minimum energy required in order for a chemical reaction to proceed with its process.  Magnesium acts like wood due to the smaller it is then the easier it is to react or ignite like saw dust.  The larger it is the harder it is for the Magnesium to react due to the whole surface area of the magnesium has to be heated to its ignition point. When part of the metal is heated that does not mean that the whole piece of metal will react; it might just be that one spot that reacts and the rest of it never does react because it never got heated enough to react. A welder takes a torch to one area of the metal and not the whole piece that one place will ignite and not the rest. The rest never got heated enough to ignite so if you are at a magnesium fire and it is contained to a certain area and the rest of the magnesium has not ignited, keep the rest of the magnesium cool with water due and either put the ignited metal out with a Class D extinguisher or just let it burn itself out since it cannot spread to the rest of the metal.  When magnesium interacts with water it will form a hydrogen gas which ignites violently due to the excessive heat and oxygen supply.  When it reacts it will burn hot enough to decrease the water molecule in which turns to a Hydrogen Gas.  The Chicago Fire Department performed tests which showed that if you use large quantities of water quickly it can be used to cool the Magnesium and later be extinguished the quantities were not noted.

Depending on your operating guidelines there needs to be a look at vehicle fires due to Magnesium is being placed in all vehicles.  The department should be consider using a Class D extinguisher along with the selected hoseline. The hose stream could be used to cool the vehicle while the Class D extinguisher could be used extinguish the magnesium fire. The Class D extinguisher will act as a smothering agent on the metal fire. If you are without a Class D extinguisher, it would be a good idea to stand back, open your hoseline and cool the vehicle in order to advance slowly on the vehicle to finish extinguishing. Remember if you cool the magnesium down then it has a high potential to be extinguished.  A carbon dioxide extinguisher should not be used as it will become a hazard and become a fuel. Carbon dioxide? becomes a combustive oxidizer and can cause a violent reaction. Looking at vehicles with Magnesium we knew that the metal was found in older Volkswagens and Fords. 

Magnesium Use Growing In Vehicles

That is not true anymore.  Everyone is looking to save a dollar and still have something strong and light.  Over the next 10 years car companies will be adding magnesium to other places in their cars, including BMW, Ford, Mercedes, GMC, Audi, Jaguar, and other vehicles.  Magnesium casings will be added to their transmissions. Ford is adding magnesium to their dashboards and radiator covers.  GM is moving to figure out new ways for magnesium to be used by placing it in door panels, hoods, and trunks. Chrysler has begun painting their vehicles with a pearl finish which is actually magnesium.  Vehicle companies have moved to add magnesium to truck grills, rims, air conditioner parts, large whole truck frames, intake manifolds, as well as engine blocks. 

Household appliances have gone to magnesium because it is lightweight. You will find it in refrigerators, pots and pans, toasters, ovens, cabinets, microwaves, energy saving light bulbs, and more things over the years to come.

There have not been a lot of findings with health issues dealing with Magnesium because our body ingests a certain amount of magnesium daily. When  magnesium ignites, this is where health issues rise. The magnesium ignites and you stare at the light you will run the risk of getting a Welder's Flash Fever. This involves fever, vomiting, diarrhea, chills, and muscle pain. There also have been findings of firefighters suffering severe brain trauma when they were next to the ignition of the magnesium.