Improper storage and handling of diesel exhaust fluid (DEF) could result in major consequences for a fleet's vehicles. From highway issues such as derating to damaging your selective catalytic reduction (SCR) equipment to downtime for the vehicle, it is in a fleet's best interest to ensure the DEF going into vehicles contains no contaminants.
“Use of API-licensed DEF is recommended,” says Jeff Harmening, team lead at American Petroleum Institute (API). “We only license products that meet the ISO (International Organization for Standardization) specifications that all the OEMs require in their equipment.”
API is a national trade association representing all facets of the natural gas and oil industry.
When it comes to the specifications set by the ISO concerning DEF, part three of the 22241 ISO specifications deals specifically with the handling, transportation, and storage of DEF.
“I highly recommend that anybody that has a fleet location that is going to be storing DEF to review that document down to the letter,” Harmening advises.
Two main conditions must be considered when handling and storing DEF – the temperature and the container it's being stored in.
Temperature
“Temperature is probably the number one most important environmental factor in terms of how you should be storing your DEF,” Harmening says.
Depending on the amount of DEF a fleet is storing, storage temperatures can vary. For smaller containers, like one- or two-and-a-half-gallon jugs, the manufacturer’s label will contain information for the correct storage temperature.
If bulk amounts of DEF are stored at a higher temperature for a prolonged period of time, it causes the DEF to degrade at a faster rate and can throw off the concentration of the DEF.
“If you reference the specifications – part three of the ISO 22241 – there’s a little table in there that basically explains what the useful shelf-life of DEF is as a function of time," Harmening explains. "The basic rule of thumb … is that if you’re storing DEF at about 86 degrees Fahrenheit, that DEF can be expected to last only 12 months before the quality of it comes into question.”
Storage containers
A list of recommended materials for transferring and storing DEF can also be found in part three of the ISO 22241, Harmening says. The specifications not only provide the recommended materials but also give a smaller list of materials not recommended for use with DEF. Not all materials react well with DEF, so being aware of what it is stored in is important.
It should also be noted that whatever container is used for storing DEF should not be openly vented. If the container allows access to the outside atmosphere, this will allow contaminants to taint the DEF. Once exposed to contaminants, that DEF should not be used in a vehicle.
“DEF specification has an insoluble quality built into the specifications, and if you’ve got a bunch of stuff floating around in your DEF, you’re going to be clogging up your injectors … [and] your filters, so it’s important to make sure that the DEF is stored in what we call [a] closed-loop system,” Harmening says.
A closed-loop system is essentially a system in which a fleet is able to fill a tank with DEF and dispense from that tank in a similar manner with no interaction between the DEF and the outside atmosphere, therefore keeping the contaminants out of the DEF.
If you manually fill the tank, the tools and equipment you use should not be used for any other jobs.
“Everything that is used with DEF needs to be dedicated to DEF,” Harmening advises.
In the event that any of these tools need to be cleaned, fleets should use either DEF itself or distilled or de-ionized water to rinse them before using them again. Distilled or de-ionized water is one of the two ingredients found in DEF and is free of any of the contaminants found in untreated water, meaning it will not contaminate the DEF.
Other considerations
If a small spill should occur when handling DEF, the area can simply be flushed with water, Harmening says. Spilled DEF doesn’t cause any harm. Over time it evaporates and leaves behind some white metallic crystals, which again can be rinsed away with water.
For a larger spill, Harmening recommends contacting the manufacturer of the DEF to see what should be done or reviewing the safety data sheet (SDS) for instructions.
Overall, it is important to ensure DEF is meeting ISO specifications. Proper handling and storage of DEF should be done with the utmost care because failing to keep these specifications in mind could be detrimental to vehicle uptime.
