Can Ocean Water Be Used to Fight Fires?

Putting out massive fires requires huge amounts of water. Freshwater is generally used, but it’s a precious limited resource.

With the enormous mass of seawater available on our planet, a common question that arises is, “Can ocean water be used to fight fires?” Keep reading to find out.

Fighting Fire with Salt Water

The quick answer is yes, ocean water can be used to fight fires. Saltwater provides similar qualities to fresh water and will extinguish a fire.

But there is a catch to using ocean water to fight fires. Not only one but many reasons why ocean water isn’t the primary source for fighting fires.

This post will cover all you need to know. First, we’ll go over the ways to extinguish fires.

Then compare how saltwater and freshwater behave in fighting fires. And review the many reasons why ocean water isn’t usually used in fighting fires.

Extinguishing a Fire

Pouring fresh water on fires is the most used method of fighting fires. But that’s not the only way.

It’s crucial to be aware of the many ways to extinguish a fire because sometimes freshwater can’t do it.

People can fight fires through four different methods, as follows:

  1. Cooling: limit temperature increase needed for ignition (douse with water)
  2. Smothering: prevent oxygen from reaching fire (blow out a candle)
  3. Starving: reducing available fuel source (get things out of the way)
  4. Interrupting: adding a chemical agent to stop the reaction (using specialty extinguishers)

How Water Fights Fires

Fresh and ocean water can be used to fight fires by cooling them down. By reducing the temperature, the fire can’t reach the ignition point, and it will go out.

This is possible with both freshwater and saltwater. The difference in the chemical makeup of the water has little impact. Both evaporate, cool, and are effective in fighting fires.

That’s why it is possible to answer the question, “Can ocean water be used to fight fires?” with an enthusiastic “Yes!”

Why Isn’t Ocean Water Used to Fight Fires?

There are many reasons why ocean water isn’t used to fight fires—these range from practical problems to long-term consequences.

Not Available (Except in Rare Cases)

One of the most practical reasons is that ocean water isn’t always available. Fires spread quickly. Any solution needs to be available immediately.

There isn’t a lot of time to fetch water. The water source needs to be as close as possible.

Fire trucks often carry around 500 gallons for this reason. And that’s why they search for other water sources like hydrants and pools.

If the fire occurs next to an ocean, it might be possible to use ocean water to fight fires. But otherwise, in the time it takes to fetch ocean water, a fire may get out of control.

It could be different. If we designed our fire-fighting systems to use ocean water, it could be possible. But that causes serious concerns about corrosion.

Salt is Corrosive

We could use ocean water to fight fires. The San Francisco Auxiliary Water Supply System is a prime example.

Created in the early 20th century, it uses freshwater or saltwater. However, it uses freshwater first to avoid damage to metal components.

The corrosive elements of salt are present in ocean water. Pushing it through pumps and equipment results in more maintenance. Parts need replacement much more often too.

The corrosion leads to the failure of many metal aspects and results in costly repairs. Since fire equipment uses metal pumps and hose fittings, saltwater isn’t preferable.

Harms Plant Life and Soil

Another reason why ocean water isn’t used to fight fires is that it is harmful to plant life and soil. While stopping a fire is crucial, adding salt to a small vicinity can cause harm. Plants die. Animals flee.

It can salt the earth. By changing the soil’s composition, growing anything else in the future is a challenge.

That’s why the current answer to “Can ocean water be used to fight fires?” is usually “No.”

Napa Valley Example

When massive fires broke out in Napa Valley in 2020, the vineyard owners had many concerns. The existing buildings and vines were foremost, of course.

But they also had concerns about the future of their land. They can rebuild structures and grow vines as long as the land is in good shape.

But if the techniques damaged the land by using salt, nothing would be possible. Regrowing their beloved grapevines might be impossible.

Choppy Water

Another reason why ocean water isn’t used to fight fires is the unpredictable water. The helicopters and planes used to fight fires rely on various methods to bring water up to their system.

While they can handle extreme conditions, they are susceptible to risk.

Oceans are full of rough waters, big swells, and unpredictable waves. A small helicopter is susceptible to failure getting water out of any source. Using the ocean increased that risk.

Obtaining water from backyard pools and reservoirs presents much less risk. Unfortunately, most of the time, these sources are full of freshwater.

Myth Busting: Salt in Fighting Fires

Your buddy may have told you some nonsense related to, “Can ocean water be used to fight fires?” It’s time to put some truth to the topic and let the myths die.

Some things cause more harm if added to a fire. The obvious ones are fuels like gasoline and dry wood. Some people say that salt can cause a fire to combust. That is not true.

Flour and baking powder can be problematic. If large quantities of flour hit a fire source, they might combust.

This does not happen with salt. And it would not occur with ocean water.

Salt would act more like baking soda. Salt is quite heavy and would be able to smother a fire if added in large quantities. The level in ocean water has a negligible impact, but it definitely won’t make things worse.

Baking soda acts differently because it chemically extinguishes a fire. It’s a good thing to reach for when you have an oil-based fire in a kitchen, or you don’t have water nearby. Make sure you don’t accidentally grab the baking powder instead!

Fireboats: A Notable Exception

In addition to the San Francisco AWSS, there is another exception that uses saltwater to fight fires. That’s fireboats.

Found in saltwater worldwide, fireboats respond to fires wherever they can reach. Often, fireboats pull water from the water they are resting in, even if it’s saltwater. They will use ocean water to fight fires.

Fireboats are a unique exception because the problems we’ve talked about don’t apply to them since they:

  • Rest on a giant reservoir of saltwater most of the time;
  • Deal with corrosion regularly and can maintain the system;
  • Won’t be using saltwater in sensitive environments; and
  • Can handle choppy water.

We’ve now gone over two examples of how ocean water is used for fighting fires. Maybe the future could bring more.

The Future of Fighting Fires

In a world with depleting water supplies, we have to be careful about our freshwater usage. We can try to limit freshwater use in many ways. Fire fighting techniques could be one.

The future of fighting fires could look a lot different from the current methods. Can ocean water be used to fight fires might have a different answer in the decades to come? Let’s consider what that world could look like.

Systems Design for Saltwater Use

Right now, we pull most fire-fighting water from the same source as drinking water. But it doesn’t have to be that way.

We could create systems to use water from oceans to fight fires, like the ones in San Francisco.

Even if they’re not as closely situated to the ocean, we could plumb saltwater into extensive waterways and reservoirs. These systems would not need to be exclusively for fire-fighting purposes.

Of course, the corrosive issues will be a real problem. But perhaps we could create systems that are less likely to suffer from it. Applying rust-resistant films or using plastics could help avoid corrosion problems.

Cost Problems

Of course, installing a wholly separate water system will come with a large bill. As we all know from the experience in Flint, Michigan, it can take a lot of time to repair water systems.

Designing, creating, and implementing an entirely new saltwater-based firefighting system could preserve freshwater. But it will be expensive and might not be feasible in most places.

If our freshwater supplies continue to become depleted, perhaps we could justify the expense of these systems. But as for right now, ocean water is unlikely to become a major source used for fighting fires.

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