Diesel Exhaust Fluid and the Marine Industry

As of 2014, the EPA (Environmental Protection Agency) started phasing in the new regulations for diesel emissions in the marine industry. Now, diesel exhaust fluid (DEF) is all the more important, even required, for commercial vessels.

Marine yacht and other small boats in the ocean

An Increasing Need for DEF

The EPA started with their plans to implement new emission standards on diesel engines back in 1998. The first target was the commercial trucking industry. Years Later, the new emission standards requiring selective-catalytic-reduction (SCR) systems moved outside of trucking to include off-road vehicles such as backhoes, tractors, dump trucks, combines, large generators, bulldozers, and other similar equipment and vehicles for land use.

DEF is a solution of about one part urea to two parts water. It is designed to be used in SCR (Selective Catalytic Reduction) to help break down harmful chemicals that are prevalent in exhaust from diesel engines. There are alternatives to using SCR systems to reduce emissions, like exhaust gas recirculation. The problem with the alternatives is that they aren’t as effective at reducing emissions and they decrease the efficiency of the engine.

With SCR being widely used across many industries to reduce diesel emissions, DEF is more accessible than ever before. Alternative fuels have struggled to gain momentum because access to the fuels for end users has been limited. There are so many diesel engines being used in various applications throughout the world that DEF is now widely available and easy to find.

Diesel Engines in Marine Use

Cost efficiency, safety, and effective maneuvering of a boat are all important in today’s world, especially when it comes to shipping. While there are a number of different types of marine propulsion systems, diesel is the most common. Other alternatives like gas turbines and liquid natural gas engines aren’t as common. This is because fuel for these engines isn’t as widely available as diesel and running costs are often higher.

Emissions standards have recently moved to include commercial water vessels. When the EPA passed the new standard back in 2004, with plans to phase into it over the next decade, the expectation was to require a reduction in the allowable amount of sulfur in marine diesel fuel by 99%. Such a drop would require not only a new design to diesel engines, but also a SCR that implemented diesel exhaust fluid (DEF) to aid in the reduction of sulfur.

With these regulations in full force, those in the marine industry have a new, very valuable asset to protect: DEF. It has storage requirements that need to be adhered to in order to ensure its longevity and efficiency.

DEF Storage

DEF is used in SCR systems in order to greatly reduce the level of toxins in the emissions of diesel engines. However, like many chemical liquids, DEF needs to be kept within ideal temperature ranges when in storage and transportation, or else its chemical qualities could be compromised. It probably won’t surprise anyone to learn that the ideal temperature for DEF is well above freezing. However, the problem becomes how to keep large amounts of DEF protected from freezing during the cold months. 

Ideally, DEF should be stored in a cool and dry area that’s protected from direct sunlight. While exposure to heat and cold doesn’t usually cause problems if it’s short-term, it can be hard to keep DEF protected from harsh weather year-round.


Temporary exposure to heat may not cause major problems, but over time it can decrease the quality and shelf life. This is especially true when exposed to direct sunlight. Since DEF should never be stored for long amounts of time above 86° F, careful temperature regulation becomes extremely important. Even without direct sunlight, normal summers day could potentially degrade your DEF. Use a quality storage tank made of certain plastic or stainless steel that protects the fluid from hot temperatures, and never store in direct sunlight.


Protecting DEF from freezing temperatures can be even more difficult without the right tools. Heating solutions for DEF have been around for a long time, but finding the proper and most convenient heating solution for this liquid can be tricky. Some tote, barrel, or drum heaters will heat to a high enough temperature, but will do so unevenly. This can cause cold and hot spots that could ruin your DEF storage.

The proper heating solution for DEF protection needs to be able to deliver consistent and regulated heat distribution. Using DEF tank heaters to maintain optimal temperatures even in very cold conditions can give you peace of mind. With reliable tank heaters, you can easily prevent your DEF from overheating and freezing.

Along with meeting temperature regulation requirements, you’ll also want a solution that can fit the common DEF storage unit with customizable options that can both insulate and heat at the same time.  What’s more, when it comes to protecting large quantities of DEF in multiple storage units, you’re going to want a product that you can set and forget. Thermostatic controllers give you even more control over how and where you monitor your heaters. Powerblanket’s tank heaters offer all these options with easy set up.

From agriculture to the marine industry, understanding new and changing regulations regarding diesel emissions is important. To protect your DEF, Powerblanket offers agriculture heating solutions and customized tank heaters for those in any industry. With reliable and efficient products to store DEF, you don’t have to worry about wasting time and money.

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DEF Freezing and DEF in Cold Weather

The Polar Vortex is sliding down over the country.  Have you taken precautions to prevent DEF freezing in the increasingly cold temperatures swiftly approaching?  We have tips and guidelines to help you with DEF in cold weather.

Understanding DEF and SCR

Diesel Exhaust Fluid (DEF) is a non-hazardous solution, which is 32.5% urea and 67.5% deionized water. DEF is sprayed into the exhaust stream of diesel vehicles to break down dangerous NOx emissions into harmless nitrogen and water. NOx is an element in exhaust that has been blamed for acid rain, smog and raising the overall greenhouse gas levels of the planet.  DEF is not a fuel additive and never comes into contact with diesel. It is stored in a separate tank, typically with a blue filler cap. This system is called Selective Catalytic Reduction (SCR).  SCR and DEF have been used for decades in other commercial and agricultural applications.

Storing DEF

DEF should be stored in a cool, dry, well-ventilated area. The ideal storage temperature for DEF is between 15ºF and 65ºF (-9ºC and 18ºC). It should not be exposed to direct sunlight for long periods of time as the urea will decompose. When possible, DEF packages and bulk storage should be kept indoors in temperature-controlled environments.  Use the right container. DEF is mildly corrosive, and should be stored in containers of HDPE plastic or stainless steel. 

DEF Freezing Protection guide graphic

DEF Expires

Check the expiration. The storage life of DEF varies. The urea is vulnerable to degradation from sunlight and higher temperatures. In favorable storage conditions (proper container, away from direct sunlight, temperatures between 15 and 65°F), DEF can maintain its qualities for about 12 months. 

Be Good to DEF

Handle it like fuel. Per EPA guidelines, vehicles using DEF must include sensors to continually analyze the quality of the DEF being consumed. These sensors will trigger a fault code whenever an imbalance is detected. Most commonly, this results from a higher percentage of water as a result of foreign matter, condensation or rainwater in the DEF storage container or during transfer.  The quality and integrity of DEF must be maintained for proper machine operation. It must be protected against evaporation and temperature extremes, and kept free of contaminants. Doing so could change DEF density, impacting its performance.

At what temperature does DEF freeze?

DEF Freezing

DEF, because of the urea, doesn’t have the freezing point of water. The urea mixture has a much lower freezing point of 12°F/-11°C. This solution doesn’t break into just urea and just water, either. The solution freezes at the same rate, and also thaws at the same rate. This means that at no point does the DEF freezing cause the solution to become over concentrated or diluted. DEF will begin to slush and then freeze.  There is no harm to the product which means that the urea solution is still safe to use if it has been frozen.

DEF Freezing and Expansion

Though it is safe to use again once thawed, expansion from freezing could cause problems.  Since DEF is a mixture of deionized water and urea, it reacts somewhat like water in that it does expand when frozen. DEF freezing usually causes about a 7% expansion. It is important to note that DEF freezing is usually taken into account when creating the packaging and tanks that are supposed to hold DEF. DEF packaging and tanks allow for expansion. However, one must be aware of the expansion of DEF when filling.  When storing equipment overnight or longer in temperatures that could result in DEF freezing, it is important to make sure the DEF tank on the equipment is not completely full or that it has an appropriate heat source. This will allow for expansion and help prevent cracking of the storage reservoir.

How to Prevent DEF Freezing?

DEF freezing was taken into account by the OEMs prior to creating the Selective Catalytic Reduction (SCR) systems. Therefore, the SCR systems are designed to provide heating for the DEF tank and supply lines; however, if the vehicle is shut down and exposed to freezing temperatures, then it is likely that the DEF will freeze. Diesel owners do not need to worry about DEF interfering with their vehicle, however. If DEF freezes when the vehicle is shutdown, startup and normal operation of the vehicle will not be inhibited. In most cases, the SCR heating system will quickly thaw the DEF in order to return it to liquid form and resume normal operation.


Can Anything Be Added to Prevent DEF Freezing?

Many want to know if anti-gelling or freeze-point-improver can be added to the DEF mixture to prevent freezing. DO NOT put additives into the urea solution because DEF must remain pure. The quality of DEF is extremely important for proper performance. Adding any additives would damage its ability to perform correctly and could even result in damages to the SCR system. No additives are approved for DEF at this time.

DEF Tote Heaters from Powerblanket

Powerblanket has a solution for DEF freeze prevention:  Powerblanket DEF Tote Heaters maintain optimal heating conditions for temperature sensitive materials.  Powerblanket DEF Tote Heaters are temperature specific for the Diesel Exhaust Fluid to protect from freezing and maintain optimal temperatures.

DEF FreezingHere’s How

  • Distribute heat evenly around the tote
  • Fully enclose and heat the tote and pump housing unit
  • Designed to be durable and weather resistant
  • Easy access to fill with a removable top
  • Simple plug and play operation, temperature is automatically regulated
  • Safely heat and protect a wide variety of chemicals and materials
  • 330 and 275  gallon versions feature an easy to access flap to the pump
  • Heated wraps for customized DEF bulk storage tanks available upon request
  • Include a frame to easily enclose and heat pump and hose


Learn More About DEF Totes

Get The DEF Tote Spec Sheet

Keep Propane Tanks from Freezing with a Propane Tank Heater

If you rely on propane for year-round operations, then you already know what a headache winter weather can be. If you have a cold propane tank as a result of dropping temperatures, you’re going to lose a lot of efficiency. Thankfully, there’s a simple solution to keeping your propane tank from freezing, and the solution is something some refer to as a propane tank blanket.


thousand gallon propane tank

Propane Performs Best Under Heat

Did you know that propane can freeze up completely if the ambient temperature drops below -44° F? Granted, -44° F is pretty darn cold, but in terms of gases, it’s a rather high freezing point. As cold as this temperature is in general terms, there are regions North America that experience extremes within this range and even lower, and if you operate a propane tank under these conditions without freeze protection, catastrophe is inevitable.

Worst-case scenario aside, propane tank efficiency will fall substantially as the temperature drops, even if it never plummets as low as -44° F. As the temperature drops, so does the pressure in your propane tank, and the pressure in your propane tank coincides with the volume of propane you have to work with. As pressure drops, not only will the volume of your propane deplete, but your extraction rate (how quickly and smoothly you can extract propane from the tank) will suffer as well. If you don’t have a heating source to assist in the pressure maintenance of your tank, then you’re going to have to keep it as full as possible in order to keep it working, even if temperatures are mildly cold.


Keep Propane Tanks from Freezing with a Propane Tank Heater

More On Propane Extraction or Pressure Rate

Cold weather is the most common dilemma facing propane tank failure, but it isn’t the only one. Another cause of propane tank freezing has to do with the rate of extraction, or the pressure rate. If you’re drawing out a substantial amount of propane from your tank in a short amount of time, then you could cause the tank to freeze and ice up. This is assuming, of course, that you don’t have a heat source to assist with the problem.

Filling your propane tank more often isn’t going to solve a problem like this. And to be quite frank, it’s only a Band-Aid for cold weather dilemmas as well. No, the only real solution to both problems mentioned here is to keep your tank at the ideal temperature, regardless of outside forces. The safest, most efficient way to do this is to employ an external heating system that both insulates your tank and adds regulated and controlled heat to the exterior service.

In the case of heating propane, SAFETY IS MOST IMPORTANT. Propane, as we’re sure you know, is a highly flammable gas, so using any old make-shift solution isn’t safe. On the other hand, using a heating solution design specifically for the process, one that is certified and pronounced safe by reputable, third-party testing laboratories is the only way to go. With that said, let us introduce you to the Powerblanket Propane Tank Heater.



Powerblanket Propane Tank Heater

Powerblanket has the best propane tank heating solution on the market. And we aren’t just saying that because we are Powerblanket. No, we’re saying it because we know of no other company that puts more thought, time, and testing into such a product offering.  Our heating blankets will help maintain pressure and efficiency on just about any size tank.

What’s more, if your tank isn’t the common propane unit, well, that’s no problem. Our custom approach to heating solutions can tailor a blanket to fit your specific dimensions and needs. In addition to this, and most importantly, our product is safe! All Powerblanket heating blankets are certified with ETL certification to the highest standards of safety and efficiency.

Keep Propane Tanks from Freezing

Benefits of Powerblanket Propane Tank Heaters:

  • Increase performance and efficiency of propane tanks
  • Provide even heat distribution
  • Save money by optimizing gas and material usage
  • Safety certified by UL/CSA/CE
  • Eliminates unnecessary cylinder refills in cold weather



Learn more about how to care for your propane tanks with our complete propane guide:

Propane Tank Guide