So, Is Water Flammable?

When it comes to fire safety, there’s no such thing as being too careful. There’s always something you can do to reduce risks, and always more to learn about the flammable properties of various things we have in and around the household.

plastic water bottle with water in full sun
a plastic water bottle with water in full sun

There’s a few things that might surprise with their flammability, like steel wool or WD-40. But is there anything we can take for granted when it comes to fire safety? Surely there must be.

How about water? Could water actually be flammable?

No, water is not flammable in any way. Water will turn to steam when it’s sufficiently heated and that’s all. However, it can make a fire worse if it is sprayed or dumped on a certain materials, and certain materials can react with water to start a fire.

Turns out this is one of those things we take for granted that might have a surprising amount of exceptions.

Water cannot catch fire, that’s true, but there are things like oil that can float on the water while still aflame, and certain substances that come into contact with water will instantly ignite or even combust. Pretty crazy!

Turns out there’s always something more to learn, and when it comes to the fire hazard of water, I’ll tell you all about it in the rest of this article…

Is Water Combustible?

No, water is not combustible though steam can dangerously rupture vessels holding it- potentially with deadly effect!

Does Water Ignite at Any Temperature?

Contrary to some misconceptions, water does not ignite, no matter how high the temperature may rise. When subjected to heat, water undergoes a phase change rather than a chemical reaction.

It turns from liquid to gas, a process you are already familiar with- boiling. Beyond the boiling point of 212 degrees Fahrenheit (or 100 Celsius for non-Freedom Unit users), water simply transforms into steam.

It doesn’t have the necessary properties to catch fire or burn because it lacks the ability to combust at all. Naturally and as you know already, water thus often serves as an effective firefighting agent instead!

Does Water React with High Temperatures?

Yes, water indeed reacts to high temperatures, but not in the way that combustible materials do. When heated, water molecules gain energy and start moving faster.

As the temperature reaches the boiling point, these molecules have enough energy to break free from their liquid state and become a gas.

This transformation into steam is a physical reaction to the heat as detailed in the previous section.

And know that no matter how high the temperature increases, water will never catch fire itself. It’s inherently non-flammable due to its molecular structure.

Thus, heating water to any extreme will not make it combustible or cause any reaction except evaporating it into steam.

But Water is Made of Hydrogen and Oxygen. Both Burn, So Why Won’t Water?

Very clever! Water, or dihydrogen monoxide since we are going all scientific, is composed of two elements that are indeed quite flammable on their own: hydrogen and oxygen.

But it’s important to understand that their properties as a compound are entirely different from what they are as constituent elements…

In the case of water, it’s the chemical bonding between these elements that makes it non-flammable. When hydrogen and oxygen combine to form water, they undergo a chemical reaction that results in the release of energy.

Once this reaction has occurred, the energy is spent, and it cannot be released again. Therefore, despite being composed of two inherently (very) flammable elements, water is utterly incapable of catching fire on its own.

Flammable Substances Can Float on Water, or Even Catch Fire While on the Water!

Now, just because there is an abundance of water around does not mean that the risk of fire is completely off the table! Many substances, such as oil and certain chemicals, do not mix with water and can catch fire while floating on its surface!

These materials, known as hydrophobic substances, repel water and remain separate from it. When exposed to a heat source or a spark, they can ignite and continue to burn even though they’re surrounded by, touching, the water.

This is why we often hear oil and other chemical spills leading to large-scale fires across the surface of bodies of water.

Knowing this is a clue, too: water is a great firefighting resource but it’s not a universal extinguisher for all types of fires. I’ll talk more about that little issue in the following sections.

Can Water Ever Make a Fire Worse?

Yes, surprisingly enough, it can. Water can make certain types of fires worse. One of the most common and well-known examples is an oil fire.

Oil is less dense than water and does not mix with it. So when water is sprayed, poured or dumped onto an oil fire, it immediately sinks under the oil (because it is denser) and just as quickly evaporates due to the extreme temperature.

This causes the flaming or boiling oil to dangerously splatter all over the place, and potentially spread the fire beyond its initial confines. Neither outcome is good, obviously!

Another scenario where water can make a fire worse is when it’s used on electrical fires. Water is a great conductor of electricity, and so using water to extinguish an electrical fire can lead to your own or someone else’s electrocution.

When confronting a frightening accidental fire, keep your wits about you; spending a few seconds thinking clearly is never wasted!

Is Water Reactive with Other Substances?

Yes, water can react with many other substances, and many entail dangerous interactions!

Sodium is one such element; when sodium comes into contact with water, it reacts violently by generating intense heat and producing hydrogen gas- gas which is highly flammable as we learned above!

The result is immediate flames and sometimes dangerous combustion.

Other elements, such as magnesium and lithium also react vigorously with water. Magnesium, for instance, reacts with water to produce magnesium hydroxide and hydrogen gas.

Similarly, lithium reacts with water to form lithium hydroxide and hydrogen. In both cases, the resulting hydrogen gas will almost certainly ignite, leading to a fire.

These reactions underscore the fact water can, sometimes, cause hazardous chemical reactions and result in unintended fires.

To be clear, encountering any of these elements in their pure form outside of a lab or industrial setting is exceedingly rare, and so these problems are more theoretical exercises for most of us, but it is something to keep in mind!

How Should You Deal with Water Exposed to Fire?

When dealing with a fire near any large quantity or volume of water, you will usually have an advantage. Water is a great extinguishing agent for most types of fires due to its cooling and smothering effects.

In all but the most extraordinary kinds of fires (flammable metals, etc.) the fact that water can’t burn means that a water source in proximity to a fire does not pose any additional risk.

However, it’s important to note that not all fires can be extinguished with water as explained above. If a flammable substance is floating on the water and burning, water alone might not be effective until the fuel is expended.

In such cases, the fire will continue to burn on the surface of the water. To tackle these fires, you would typically need a special type of fire extinguisher, such as a foam or dry chemical extinguisher.

These can smother the fire by creating a barrier between the fuel and the oxygen directly, effectively cutting off the fire’s supply of both.

Leave a Comment

Your email address will not be published. Required fields are marked *