Meeting New EPA Standards

Diesel Exhaust Fluid: Meeting New EPA Standards for Highway Diesel Trucks

In 2010, the US EPA (Environmental Protection Agency) and DOT (Department of Transportation) proposed the first-ever fuel efficiency and vehicular gas emissions standards for medium- and heavy-duty trucks and buses, many of which use diesel. According to the American Council for an Energy-Efficient Economy (, “the affected vehicles, ranging from large pickup trucks to big rigs, today consume about 2.5 million barrels of crude oil equivalent per day, one-fifth of total US transportation crude oil use.” EPA standards are published in the Congressional Federal Registrar, 40 CFR Part 86, with a detailed discussion of these standards to be found at

In order to meet 2010 EPA emissions standards for highway diesel trucks and buses ( Diesel Exhaust Fluid (DEF), a 32.5 percent automotive grade urea solution in deionized water, is used in diesel engines with SCR (selective catalytic reduction) technology. Automotive grade urea, which is produced from the reaction of carbon dioxide and ammonia, meets ISO 22241 and industry established performance requirements for DEF quality, testing methods, handling, transportation and storage, and refilling. Typically, about two gallons of DEF solution is injected in the catalyst for 100 gallons of diesel, although manufacturers’ usage may be lower or higher depending on engine technology and duty cycle. Seventy percent of new diesel trucks brands (e.g. Mack Truck) use DEF with the remaining share using alternative technology. In addition to meeting the new vehicular emission standards, the use of DEF improves diesel engine fuel efficiency by as much as five percent, net of costs.

According to Integer Research (, estimated usage in the US has grown from 16 million gallons of DEF in 2010 to a projected 63 million gallons in 2011. DEF, which is produced by several US ammonia producers including Terra (now CFI) and Yara, is then sold directly or through a network of distributors to end-users. Our company, RelaDyne of Cincinnati, OH, is a super-regional distributor of lubes, fluids, etc. for vehicles and trucking. The American Petroleum Institute (API) certifies players in the supply chain that meet ISO specifications for DEF. (See list of certified brands at

DEF's Function in SCR Engines

DEF Delivery Systems*

* Data is based on vehicle mileage of 50,000-120,000 miles per year; fuel consumption of 5-6.5 MPG; and a DEF rate of 2 gallons of DEF per 100 gallons of diesel.

Many other users with a smaller concentration of SCR units use totes to store and dispense their DEF. Specifications for tote systems require materials of construction to meet the ISO 22241 standard. Typical tote equipment includes: a coupler to connect to the tote’s extractor (this creates a closed system to prevent contamination); suction hose; pump; flow meter; discharge hose; and a nozzle with automatic shut off.  Between 2010 to 2011, the supply chain for DEF changed dramatically, moving from 2.5 gallon jugs, to 55 gallon drums, to 330 gallon totes. (This supply chain development, albeit in a much shorter time frame, is similar to the gas industry’s evolution from high pressure to liquid cylinders to “micro-bulk” and regular bulk deliveries.) Certain commercial fleets and truck stops, which have a high concentration of SCR power units (with approximately 50 or more trucks and/or tractors), now have terminals equipped with bulk storage and transfill systems for DEF.

As shown in the table above, a tote delivery system can meet the requirements for a broad range of fleet conditions.

There are two types of tote supply chains. In one, DEF is delivered to customers via a “Drop and Swap” method. This type of supply can require a fork lift to exchange “fulls” for “empties” as well as to arrange tote inventory to minimize DEF residuals and costs.

Alternative, suppliers can refill their totes in a method we have coined, “Just leave it and forget it.” In this method, a “box” truck that stores several hundred gallons of DEF and other products for the customer, or a tank truck with several thousand gallons of DEF capacity, can supply and fill trucks with DEF at the customer site.

Similar to the gas industry’s micro-bulk supply system, the DEF “Just leave it and forget it” system allows trucks to be serviced quickly and efficiently, maximizing operational uptime and minimizing DEF losses. Further, additional inventory is not needed to avoid product run out, and invoicing and paperwork are minimized.