What is DEF?

Diesel Exhaust Fluid (DEF) is a solution made up of 67.5% deionized water and 32.5% high purity urea. It plays a critical role in reducing harmful emissions produced by diesel engines.

DEF is injected into the exhaust stream of diesel vehicles. When introduced, it breaks down and vaporizes, converting harmful nitrogen oxide (NOx) emissions into harmless nitrogen and water vapor. This process is known as Selective Catalytic Reduction (SCR): a technology essential for meeting the strict emission standards set by the Environmental Protection Agency (EPA).

Why is DEF Important?

DEF plays an essential role in reducing emissions produced by diesel-powered vehicles and equipment. Without DEF, engines equipped with SCR technology cannot properly control emissions and may experience reduced performance or eventually limit vehicle speed until the DEF tank is refilled.

Using high-quality DEF helps:

• Reduce harmful NOx emissions
• Meet federal and state emissions regulations
• Maintain engine performance
• Protect SCR system components
• Help avoid unnecessary downtime

Is DEF the Same as Diesel Fuel?

No.

Diesel Exhaust Fluid is completely separate from diesel fuel.

• DEF is stored in its own dedicated tank.
• DEF should never be added to a diesel fuel tank.
• Diesel fuel should never be added to the DEF tank.

Storage and Handling

For best results:

• Store DEF in a cool, dry location away from direct sunlight.
• Keep containers tightly sealed to prevent contamination.
• Use clean equipment designed specifically for DEF.
• Avoid contact with fuels, oils, grease, dirt, or other chemicals.

DEF begins to freeze at approximately 12°F (-11°C). This is completely normal and does not damage the product. Once thawed, DEF returns to its original composition and remains effective.

Packaging & Delivery Options

Simple DEF offers solutions designed to meet the needs of businesses of every size.

Available options include:

• Intermediate Bulk Containers (totes)
• Bulk DEF delivery
• Storage tanks
• Customized DEF solutions

Whether you need a single delivery or ongoing bulk supply, we’ll work with you to provide a solution that fits your operation.

Best Practices for DEF

To ensure optimal performance and product longevity:

• Check DEF levels regularly
• Avoid cross contamination – always keep containers sealed
• Store DEF in a cool, dry place out of direct sunlight
• Be mindful of shelf life: DEF typically lasts up to two years when stored properly