What You Need to Know About Storage Tank Standards UL-142 & UL-2085

At Worldwide Power Products, we sell and rent generators. This includes diesel generators for a variety of applications. The diesel needed to power these generators requires proper storage in tanks often located onsite. Companies and site operators must maintain specific requirements for these storage tanks. It’s up to the property owner and company to learn about the specific standards for their tanks and fuel type. However, we’ve gathered some key information on UL-142 and UL-2085 standards, the most likely type for these applications.

These standards are not just for storing diesel, nor for the tanks used to supply our generators. They are standards set for a number of liquid types and for various applications.


Does My Storage Tank Need to Comply with UL-142?

Various factors play a role in this determination. Specifically, what the tank stores, where it is used, and what it is made from defines when UL-142 applies to your situation. UL-142 is a national standard that covers most types of tanks for flammable and combustible liquids. It also applies to those tanks that are made from steel and located above ground.

These standards apply for various shaped tanks including rectangular, round, or cylindrical. It also applies for all orientations and both with and without compartments included. It only covers fabricated tanks and not portable tanks used for transporting these liquids. It doesn’t apply to shipping containers, or any tanks mounted to or used on a trailer for mobile applications.


What Liquids Are Classed as Flammable and Combustible?

It’s important to know if the fuel or liquids you use are considered flammable or combustible, as these would require adherence to UL-142. You can download a free copy here of the codes and standards for specific clarity on the liquids you use based on their flash point.

This includes the following:

  • Class 1A liquids such as diethyl ether, ethylene oxide and some types of crude oils.
  • Class IB liquids which include most forms of motor and aviation fuels, as well as lacquer thinner, lacquers, and toluene.
  • Class IC which includes some paints, most types of solvent-based cements, and xylene products.
  • Class II liquids which include diesel fuel (most common application for our generators) as well as paint thinner.
  • Class IIIA which includes liquids for home heating fuels such as oils.
  • Class IIIB which are liquids such as lubricating oils, typical motor oil, and cooking oils.


Who Makes the Rules?

These standards are set by the National Fire Protection Association (NFPA) as well as state and local regulations. These are clearly defined in the NFPA 30 Flammable and Combustible Liquids Code. UL-142 is considered one of several standards that are acceptable engineering standards to meet NFPA 30 regulations.

The goal of UL-142 is to reduce the amount of risk associated with hazards related to these liquids with the goal of keeping the public safe. They are designed to limit interference in terms of use while ensuring the public is not at risk such these liquids become misused or mishandled. In short, they are not necessarily designed to limit the use of these liquids. Rather, they create rules that limit the risks associated with those liquids to ensure safe operation. 

The standards not only protect the public and the land, they also protect the liquid you are storing. Anyone storing diesel in a sub-standard tank will see its life span reduced significantly through contamination. You’ll either need to buy more diesel or use contaminated diesel. If it’s the latter, you’ll soon be coming to us looking for a new generator engine.


Where Does the UL-142 Standard Come From?

Underwriters Laboratories (UL) provides for the guidance on UL-142. A global company, it handles the inspection of as well as advisory services for these standards. It also manages educational, training, and testing requirements. UL also provides certification software solutions, analytics as well as verification of marketing claims.


How Do I Know if My Tank Complies with the UL-142 Standard?

When you purchase or obtain a tank, you can learn immediately if it complies with UL-142. Look for a permanent mark on the tank to provide this information. It will include the UL symbol on it. The mark should also state “LISTED” on it. This, along with a control number and the tank’s manufacturer’s name is also listed. The manufacturer’s listing should also include information about the tank construction as well as details about the structure. If these details are not evident on the exterior of the tank, it may not meet specific compliance requirements set under UL-142 and should not be used or should be verified first.


What if My Tank Is Not UL Listed?

In some situations, customized tanks may be used. However, in all situations, if a tank is to hold combustible and flammable liquid that falls under the ruling of UL-142, you must provide documentation to back up its ability to comply. That is, as the user or owner of the tank, you must show documentation that clearly shows the tank’s design and construction has been completed according to the UL-142 standards.


What Are the Requirements of UL-142?

There are numerous requirements under UL-142. The requirements focus on:

  • The materials used to manufacture the tank.
  • Specific design features such as the fitting and joints.
  • Testing requirements to ensure the tank meets strength tests, leakage tests as well as buoyancy requirements.
  • Marking requirements are also required to communicate whether the tank meets compliance requirements.
  • It takes into consideration the intended use of the tank, venting requirements, and leak detection as well.

It’s possible to purchase a copy of the complete standard here. Those within the industry should obtain a copy. As of this writing, the latest edition is the 9th edition, from 2006 with a revision in 2007. This may be updated at a future point.


What is the UL-2085 Standard?

A second standard that may apply to the use of storage tanks is UL-2085. It is also from UL and carries many of the same requirements as UL-142. However, it offers specific, stricter requirements for storage tanks.

Specifically, these tanks must meet the UL-142 standard in their construction. However, they also add requirements for the material to classify the tank as a protected tank. This type of tank has been able to meet specific construction design requirements that ensure a two-hour, fire resistance and secondary containment are present. It must also provide protection from physical damage. You can buy the full standard here if this applies to the tanks you use.


Does My Storage Tank Need to Meet UL-2085 Standards?

Rules on this differ from one community to the next. Business owners should contact their local fire marshal to discuss their specific needs here. Other rules may be required as well. Local regulating agencies can provide insight based on your specific use. The manufacturer may offer some insight on this requirement as well depending on its intended use and design.


What Are the Differences Between UL-142 and UL-2085 Standards?

There are a few key differences. For basic purposes, manufacturers have worked to increase the design of those tanks that meet UL-2085 standards to ensure they offer further protection. For example, this may include double-walled tank designs. They work to provide stronger carbon steel materials, for example, to create a rigid, more protective design. Some may also feature inside containment walls or insulation from the outside walls.

Those tanks that offer these features are able to handle more challenging situations. This includes withstanding fire through a two-hour liquid pool and furnace fire test. It also includes testing to determine if the tank is impact-resistant and resistant to projectiles. These more difficult standards provide a higher level of protection overall to meet higher specifications.