What is DEF and AdBlue ?

What is DEF and AdBlue ?

AdBlue dispensing equipment
To use Adblue in your system to reduce emissions you need to utilise the right Adblue dispensing equipment.

To understand what DEF and AdBlue is and why particular AdBlue dispensing equipment is required here’s a quick history lesson.


Several years ago European Emissions Standards made a legal requirement for diesel run vehicles’ emissions be reduced to certain levels. Consequently due to this directive an advanced pollution control technology was designed to be installed within vehicle’s exhaust systems. Hence this new technology was referred to as the SCR or Selective Catalytic Reduction system. Therefore the main feature of this system is reducing the amount of harmful nitrogen oxides that gets released into the atmosphere.

Finally the two main components in the SCR system is DEF (Diesel Exhaust Fluid), this fluid is a synthetic, Aqueous Urea Solution (AUS32) which comprises of 32.5% high purity urea and 67.5% deionised water.

The system works by injecting DEF into the exhaust it then vaporizes and splits into ammonia and carbon dioxide. The ammonia turns the nitrogen oxides into water and nitrogen, which are both harmless.


AdBlue™ is the European trademark for DEF (Diesel Exhaust Fluid), which is governed by the Verband der Automobilindustrie e V. (The German Association of the Automotive Industry). This board ensure that fluids branded as AdBlue™ are meeting the strict quality control standards of DIN 70070, ISO 22241.

In 2005 the first wave of vehicles using SCR technology were introduced along with the Euro IV Emission Standards. This was boosted further with the Euro V Emission standard in 2009. These new standards meant any new build of coach, bus, lorry or large agricultural machinery had to limit their emissions. This has caused a large growth in the use of AdBlue™ in these types of vehicle. Euro VI was introduced in 2014 which saw the start of construction equipment, light commercial vehicles and some passenger cars begin using AdBlue™.

AdBlue dispensing equipment

Vehicles using AdBlue have a separate tank into which it is dispensed just the same as diesel is. Consequently businesses using vehicles utilising AdBlue will now purchase it as a standard fuel type and store it. Hence they require a bulk storage tank, IBC or drums for storing their AdBlue depending on the amount they use. Like diesel transfer pumps, an AdBlue pump is the component within AdBlue dispensing equipment filling systems that does the transferring. Other AdBlue dispensing equipment would include the hose, flow meter nozzle and all pipe connections.

Therefore it is crucial that a specifically designed pump is used for dispensing AdBlue DEF. It’s important that people do not assume the same pump they use for diesel can be used for AdBlue. The main reason for this is that AdBlue needs to kept free of contamination. The purity of the fluid needs to be maintained for the SCR system to work correctly. Also should the deionised water content in the solution evaporate due to air in the system AdBlue can crystalise. Subsequently this can cause damage to the pumps components due to uneven wear. Additionally, the crystallisation can cause damage to the ceramic head on the SCR system.

Equipment Features

Similar to fuel transfer pumps there are many different types available to select from. Features can differ but depending on your requirements complete AdBlue dispensing equipment can be purchased as well as individual components. A complete kit would comprise of a pump, hose, nozzle and flow meter. Theses kits are available in either mains powered, battery or manual powered. Mains powered pumps would be selected where dispensing is done at a regular fixed point. Battery powered pumps would be used where mains power is not available. Subsequently a manual pump would be used in a temporary or mobile dispensing situation.

Other factors would dictate which style of dispensing is selected, for instance, in small quantities where dispensing from barrels would take place.  Kits specifically designed for this purpose would come with drum connectors, suction pipes and a manual AdBlue rotary hand pump.

Where medium usage of AdBlue is required the solution would more likely be stored in an IBC container. IBC AdBlue pump kits are available that come complete with a SEC fitting for IBC and are mounted on a hanging plate.

With the continuing growth in the AdBlue market and as more vehicles require it, there is a shift to bulk storage of the solution. This not only has the cost benefit of buying in bulk but also a supply timing saving too. For larger AdBlue storage tanks, more sturdy pumping equipment can be used usually on a mounted pedestal or wall mounted box. Some tanks can be purchased with AdBlue pumps already fitted.