Is diesel exhaust fluid(DEF) fire resistant?

This blog post will answer the question, “Is diesel exhaust fluid fire-resistant” and cover topics like fire-resistant properties of DEF and frequently asked questions related to the topic.

Is diesel exhaust fluid(DEF) fire resistant?

Diesel exhaust fluid(DEF) is fire-resistant. While DEF is introduced to diesel fuel, it is not a fuel in and of itself. It is a non-flammable chemical that is not harmful and does not pose an explosion risk.

What Is DEF and How Does It Work?

Diesel Exhaust Fluid is abbreviated as DEF. This liquid isn’t a real fuel. This fluid is often used as a fluid additive for diesel vehicles. This fluid is used to minimize pollutants from diesel vehicles’ exhaust systems. This fluid helps to minimize nitrogen oxide emissions.

This additive is also manufactured using urea & deionized water. However, this additive must work with a certain kind of diesel. 

Otherwise, the addition will be ineffective. When blended with diesel fuel, however, this fluid performs very well.

Is it possible for DEF to catch fire itself?

No, this liquid isn’t going to catch fire itself. Because in its natural state, this is not flammable. This fluid will not burn if it is kept near a fire. As a result, this fluid is fire-safe.

However, putting this chemical in the container may cause the container to catch on fire. As a result, it is dependent on the jar in which you keep this additive. The fluid may spread in the container if the container is combustible.

When the container catches fire, the fluid expands and heats up. This chemical will not catch fire if it is not ignited. As a result, it’s best to store it in a non-flammable container.

Is DEF Fluid Flammable?

DEF is not flammable under normal conditions. Since it is simply urea in water, any urea fires would be doused instantaneously by the amount of accessible water.

The DEF does not catch fire when combined with diesel but rather functions as a catalyst for the nitric oxide reduction process.

Is DEF a Potential Fire Hazard?

Diesel Exhaust Fluid isn’t usually thought to be a fire threat. Combustible fluids that catch fire are called a fire danger. This fluid, however, is not flammable. 

As a result, if it comes into contact with fire or heat, it will not ignite. As a result, under normal conditions, it will not pose a threat.

However, if you store it in a combustible container, the heat will be transferred to the fluid by the container. The liquid expands as it is heated. 

As a result, it has the potential to produce an explosion. Though this is a rare occurrence, you should be cautious when storing this fluid.

When you light DEF on fire, what happens?

When you light DEF on fire, it will not result in any danger. This is due to the fact that this additive is non-flammable. This fluid is typically made up of water & urea. As a result, the fluid has no combustible elements that may ignite a fire.

Furthermore, this fluid does not interact with diesel fuel when mixed with it. This fluid is nothing more than a liquid that helps to minimize pollutants. 

This fluid will become combustible if it is chemically combined with another flammable fluid. If you don’t do so, this fluid will not catch fire.

Does DEF Fluid Have the Potential to Explode?

DEF does not burn, thus it will not explode immediately, but like with everything kept in containers or jars, there is a risk of explosion if the storage container is heated.

The DEF might theoretically grow enough to breach the container’s walls, resulting in a “blast.”

When it comes to DEF, though, this is unlikely since the container it’s stored in should dissolve before the DEF expands enough to present a problem.

When the DEF tank is empty, what happens?

If the DEF tank is empty, there will usually be no immediate concern. However, after a certain number of kilometers, the exhaust pipe will release nitrogen dioxide gas into the atmosphere. As a result, the fluid’s fundamental goal will not be met.

As a result, you should not leave this fluid’s tank empty for an extended period of time.

What is the purpose of DEF?

DEF is added to diesel fuel at a concentration that changes depending on the system but is typically between 2 and 6percent of the total fuel volume.

The chemistry is complicated, but utilizing DEF reduces the amount of Nitric Oxide (NO2) produced by diesel combustion to harmless nitrogen gas.

If NO2 is allowed to flow uncontrolled into the atmosphere, it generates acid rain, hence DEF usage is highly ecologically benign.

Is It Okay To Leave DEF Unsealed?

Yes, it is OK to leave this fluid un-sealed. This is due to the fact that this fluid is non-flammable. As a result, this fluid has no potential of catching fire. 

This fluid is also non-toxic to people. As a result, no toxic components will be released into the atmosphere.

However, you must be cautious about the canister or bottle in which you store this fluid. Use a non-flammable bottle if possible. Otherwise, as this fluid heats up, it may expand within the container.

Is DEF Effective in Reducing Carbon Emissions?

DEF is often used to minimize pollution and harmful gas emissions from the exhaust pipe. This additive primarily decreases nitrogen oxide emissions. 

It may also help to minimize co2 emissions. As a result, this fluid aids in the reduction of hazardous gas emissions into the atmosphere.

Is it possible for a DEF to catch fire?

No, since this fluid is non-flammable, there is no risk of it catching fire. When flammable fluids catch fire, they usually explode. It will not ignite if you set this fluid on fire. As a result, it will not detonate.

In a different circumstance, however, if you keep this addition in a combustible canister or bottle, it may explode. The liquid will expand in the contained space after receiving heat from the combustible container or bottle. As a result, there’s a probability of a blast.

Is DEF Fluid Harmful to the Skin?

DEF liquid is not harmful to the skin. There are no substances in this fluid that might hurt your skin. You should not be concerned if this liquid comes into touch with your skin.

However, it is preferable if you did not leave this liquid on your skin for an extended period of time. Although the fluid will not hurt your skin, it may erode a substance that is attached to it.

What Kind of Risk Does Diesel Exhaust Fluid Pose?

DEF is non-toxic & safe to use by humans, but that doesn’t mean it isn’t dangerous. DEF’s urea component may corrode some metals.

That is, it is carried in canisters that have been selected for their resistance to corrosion when exposed to DEF.

It may be stored in any non-corroding container, such as steel, or plastic, and although it should be kept cold, dry, and well-ventilated while in storage, it won’t pose much of a concern.

Instructions on how to apply DEF


  • Only DEF should be put into the tank. Both the nozzle and the exit have distinct markings.
  • Maintain your DEF equipment by keeping it clean and clear of dust and grime.
  • When filling DEF, no protective equipment is required.
  • If DEF containers get too hot, they may be cooled by submerging them in water.
  • DEF freezes at 12 degrees Fahrenheit.
  • Only use DEF provided in specific, sealed DEF packaging.


  • Never put DEF into a diesel tank!
  • Never put diesel in the DEF tank!
  • Avoid getting DEF on your clothing or skin. If DEF gets on your body, flush it with cold water before washing it with soap and warm water. If you get DEF on your clothes, wash them separately in a different load.
  • Avoid getting DEF in your eyes. If this happens, rinse your eyes with cold water.
  • Don’t let DEF sit on surfaces for long periods of time since it may harm concrete or brickwork and cause sliding hazards. If anything has been spilled, clean it up with water.
  • Never combine DEF with water or other chemicals, mainly diesel fuel.

What happens if you use contaminated or low-quality Diesel Exhaust Fluid?

The following will occur as a result of this:

  • Nullify any warranty claims involving the vehicle’s SCR exhaust injection system or catalyst, both of which are expensive technical components to repair.
  • When the SCR system isn’t working properly, On-Board Diagnostics (OBD) might identify it and send the vehicle into crawler mode, disrupting your operations and company.
  • Because your car’s NOx emissions will exceed legal limits, it will be running illegally, and enforcement authorities will punish you appropriately.

Tips for Buying and Storing DEF in Order to Preserve Its Quality

Ensure that the inventory is cycled such that the oldest product is used first. In a shop, appropriate storage temps are also critical. The DEF’s shelf life will be shortened if it is stored at temps over 86° F. 

The following are some extra factors to think about while storing and handling DEF:

  • DEF should be stored in bulk storage tanks. Switching goods in the bulk tank without completely washing them with purified water or on-spec DEF is not recommended.
  • To avoid impurities getting into the DEF, a closed-loop method for moving DEF from a bulk tank is suggested. This is especially critical at a shop or construction site where there is a lot of dust.
  • Dispense DEF using specialized equipment. When placing DEF in a tank, don’t use funnels, hoses, or other equipment designed for other fluids.
  • Clean everything used to dispense DEF with distilled water before rinsing it with DEF. When cleaning, avoid using tap water.

Frequently Asked Questions(FAQs), “Is diesel exhaust fluid(DEF) fire resistant?”

How Long Does DEF Keep You Alive?

The DEF has a shelf life of around a year. In general, this sort of additive has a shelf life of one year. As a result, you may use this chemical for many days. However, the liquid should be kept in a non-flammable jar.

What Are DEF’s Advantages?

The biggest advantage of utilizing DEF is that it helps to reduce pollution. The diesel engine will emit nitrogen dioxide from the exhaust if this additive is not used. This gas has the potential to pollute the environment. 

Furthermore, this gas has the potential to create difficulties in the exhaust pipe. As a result, this fluid aids in the reduction of nitrogen pollution.

When Is DEF Not Appropriate?

It should not be used on any old diesel engine. As this additive must work with a certain brand of diesel fuel. This additive will not operate well to minimize pollutants from the exhaust pipe if it is not used.

Is DEF dangerous if it spills?

Diesel Exhaust Fluid is non-toxic, non-harmful, and non-dangerous. In reality, DEF is the least harmful of all the chemicals used in a truck, including diesel, engine oil, braking fluid, coolant, and windshield wash.

What happens to used DEF fluid?

We suggest calling your local environmental garbage disposal firm for recommendations on local dump sites; they will be able to tell you where and how to go. 

Totes are temporary bulk canisters that may be reused as long as a closed-loop mechanism is in place and they are only used for DEF.

Is DEF a safe product?

DEF is a solution that is non-toxic, non-hazardous, and non-flammable. It is colorless, stable, and fulfills approved international purity and composition requirements. 

When handled appropriately, DEF is harmless to manage and store, posing no major harm to persons, animals, equipment, or the environment.

What was missing from this post which could have made it better?

Leave a Comment