Diesel exhaust fluid (DEF) is a common substance in households using vehicles with diesel engines, not just diesel truck enthusiasts. While protecting the environment from emissions, you should also consider your safety.
This article answers the question: Is DEF flammable? And what should you know about the safe handling of this substance?
Is DEF Flammable?
The answer is no. Even though it mixes with diesel in the engine, it can't ignite on its own due to its high water content. Diesel exhaust fluid has a water content of almost 70 percent. It won't burn efficiently or effectively as DEF is non-flammable and non-combustible.
What Is Diesel Exhaust Fluid?
Diesel exhaust fluid (DEF) is a solution used in diesel vehicles to reduce air pollution caused by emissions released from diesel engines. It's created from deionized water and urea that helps lower the concentration of nitrogen dioxide and nitric oxide, breaking it down to harmless nitrogen and water.
What Happens When Diesel Exhaust Fluid Gets Too Hot?
It evaporates when your diesel exhaust fluid gets hot, even under direct sunlight. The optimal storage temperature for diesel exhaust fluid is between 12°F and 86°F. At high temperatures, DEF loses quality due to the formation of ammonia before usage.
Evaporation happens when a liquid turns to gas. Contrary to popular opinion, this can occur at any temperature, not necessarily just its boiling point. This means that although the boiling point of diesel exhaust fluid is 212°F, at temperatures higher than the recommended storage temperatures, it will turn into vapor.
When DEF gets heated, water is given off, leaving a more concentrated solution. This concentrated solution has a shortened lifespan. In diesel engines, emissions are reduced by selective catalytic reduction (SCR).
This reduction reaction reduces harmful nitrogen emissions vehicles release by converting them to harmless nitrogen and water. This DEF is usually converted to vapor after it's injected into the exhaust.
Heat in the engine will lead to the evaporation of water and decomposition of the urea to create ammonia that will partake in the reduction reaction. When this happens in the engines, it's a good thing.
Still, when this occurs in storage, it reduces the DEF quality, allowing it to freeze at higher temperatures and preventing the efficiency of selective catalytic reduction.
Is Diesel Exhaust Fluid Corrosive?
Diesel Exhaust Fluid is considered a very corrosive substance. DEF corrodes metals like zinc, carbon steel, brass, aluminum, and copper upon contact. It's important to clean up any spilled DEF fluid immediately and wash with soap and water. Dumping DEF recklessly is illegal in many states because it can damage plants and other materials.
The presence of urea causes the corrosivity of Diesel Exhaust Fluid. Urea is very corrosive, especially at high temperatures. Stainless steel drums and high-density polyethylene plastic totes are used to store DEF at lower temperatures to reduce this corrosive effect.
How Toxic Is Diesel Exhaust Fluid?
Diesel exhaust fluid is non-toxic, non-polluting, and a non-hazardous substance. However, contact with the skin can cause redness, cracking, drying, and edema. When inhaled or in contact with the eye, it can irritate the eye and respiratory tract. It also causes nausea, vomiting, and stomach distress when ingested.
What To Do If You Put Diesel Exhaust Fluid In The Diesel Tank
Firstly, it is important to note that although it's non-flammable, accidents arise in the usage of DEF. The DEF tank is usually placed next to the fuel filler, and a common accident is pouring DEF into the diesel tank.
This can damage the engine and fuel system, leading to the replacement of the entire fuel system. The damages are often limited to the fuel pump module, tank, and pipe, especially when you realize the mistake before starting the vehicle engine.
However, once you start the engine, the entire fuel system will need replacing because DEF will spread and contaminate the fuel system, corroding the engine's metal parts and crystallizing sensitive parts as time passes.
This damage can cost up to $10,000, and most insurance doesn't cover it – so be careful. You can use different colors for the DEF and diesel tank caps to avoid this mistake. You could also visit truck stops with a DEF misfill prevention device while equipping your DEF port with the magnetic safety device.
Safety Precautions For Handling Diesel Exhaust Fluid
Take these steps to ensure your safety as well as anyone else working with DEF.
Keep The Fluid Away From Open Flames Or Fire
Your diesel exhaust fluid will not catch fire; however, exposure to high temperatures will lead to vaporization and decomposition, compromising the product's quality. And if used in its compromised state, it could release more emissions and reduce the efficiency of your engine.
Properly Label And Store Your Diesel Exhaust Fluid
Most manufacturers have custom containers that nullify corrosion. Therefore, transferring the fluid to new containers is not advisable, especially ones made from metals, due to its corrosivity.
Also, you should prevent the fluid from being misused or mistaken for another by ensuring the new container is labeled correctly. Finally, keep the container closed when not in use and stored away from children or pets to avoid inhalation or ingestion.
Ensure Proper Disposal
Please avoid dumping it into the drain, as this pollutes the water supply system and corrodes metal pipes. Instead, you could drop it off at the nearest recycling center when you need to dispose of DEF. You could also consult the product's safety data sheet for the manufacturer's proper disposal information.
Take Care Of Spills And Use The Fluid In A Well-Ventilated Area
Diesel exhaust fluids are very corrosive and can damage painted surfaces and metals. Ensure you control the spread of spilled fluid and clean up spills during refills. Use an absorbent material to mop the liquid and clean the area with detergent and water afterward.
When topping up or filling your DEF tank, ensure this is done in a well-ventilated area, preferably an open space. This helps reduce the risk of inhalation, which is a health hazard.
There is no debating the answer to the question: Is DEF flammable? DEF contains 67 percent deionized water, preventing it from igniting easily. But although it's neither flammable nor a fire hazard, it's corrosive and should be handled carefully and stored in approved containers.