Aboveground Flammable Liquid Tanks: Compliance with UL 142, UL 2080 and UL 2085

By Brian Orr, Principal Engineer, Energy and Industrial Automation, UL Solutions
Kelly Nicolello, Senior Regulatory Engineer, UL Solutions and Distinguished Member of Technical Staff — William Henry Merrill Society

Professional engineers, contractors and fire code officials who are designing, installing and approving systems that include aboveground flammable liquid tanks require a strong understanding of fire code requirements and certification standards. Many fire code officials and contractors rely on tanks bearing a UL Listing (Certification) Mark; however, not all UL certified tanks are created equal. Depending on the application, code requirements may be met using one of three different Standards: UL 142, the Standard for Steel Aboveground Tanks for Flammable and Combustible Liquids; UL 2080, the Standard for Fire Resistant Tanks for Flammable and Combustible Liquids; or UL 2085, the Standard for Protected Aboveground Tanks for Flammable and Combustible Liquids.

Understanding the differences between these Standards and what the UL Mark represents in each case is essential for proper selection and installation, safety, and code compliance.

Model codes recognize the use of UL 142, UL 2080 and UL 2085 Listed tanks

National Fire Protection Association (NFPA) 30, Flammable and Combustible Liquids Code, and NFPA 30A, Code for Motor Fuel Dispensing Facilities and Repair Garages, require atmospheric tanks to be designed and constructed in accordance with one of several recognized engineering standards. UL 142, UL 2080 and UL 2085 Standards meet those requirements. Additionally, the International Fire Code and NFPA 1, Fire Code, require tanks to be designed, constructed and installed in accordance with NFPA 30 and NFPA 30A.

1. Types of tanks covered by UL 142

UL 142 outlines the construction and performance criteria for steel primary, secondary and diked type atmospheric tanks used to store noncorrosive, stable flammable and combustible liquids. The tanks covered can be built in a variety of shapes, including cylindrical or rectangular, and orientations, such as horizontal or vertical. They may also feature single or multiple compartments, depending on the application.

The Standard specifically applies to shop fabricated tanks, meaning they are manufactured in a controlled facility rather than assembled on site. It also does not apply to portable tanks used for transporting liquids or to mobile tanks mounted on vehicles or trailers.

2. Types of tanks covered by UL 2080

UL 2080 expands on UL 142 by introducing additional fire protection features. Specifically, it requires that the tank construction limits heat transfer to the primary tank when exposed to a two-hour hydrocarbon pool fire. It also includes provisions for impact resistance, offering protection against projectile strikes and vehicle collisions.

This Standard applies to shop-fabricated, aboveground atmospheric tanks designed to store stable flammable or combustible liquids with a specific gravity of 1.0 or less, provided the liquid is compatible with the tank’s materials and construction.

3. Types of tanks covered by UL 2085

UL 2085 enhances the fire and impact protection features found in UL 2080 by adding stricter requirements. It mandates that the tank construction must further reduce heat transfer to the primary tank during a two-hour hydrocarbon pool fire. Additionally, it requires built-in secondary containment to help prevent any leaks from reaching the environment. The Standard also includes reinforced protection against physical damage, such as from projectiles or vehicle collisions, provided the tank is properly labeled to indicate these features.

This Standard also applies to shop-fabricated, aboveground atmospheric tanks designed for storing stable flammable or combustible liquids with a specific gravity of 1.0 or less, assuming the liquid is compatible with the tank’s materials and construction.

Design criteria for tank certification

The three UL Standards provide detailed criteria that manufacturers can use when designing and building aboveground steel storage tanks; they also guide certification bodies, such as UL Solutions, in evaluating and certifying these tanks.

Construction Standards

Performance testing

Labeling and quality control

• Tanks must display specific product markings to indicate compliance with applicable codes and regulations.
• Manufacturers are required to leak test every tank, primary and secondary containment types, before they leave the production line.

Listing Marks

A permanently affixed UL Certification Mark identifies aboveground tanks that meet the requirements of applicable UL Standards. This Mark includes the UL symbol, the word “LISTED” (or the newer term “CERTIFIED”), a control number, and a description of the tank type, such as “Secondary Containment Aboveground Tank” or “Generator Base Tank,” as specified in the manufacturer’s certification.

The specific UL Standards met by a marked product can be found by researching the control number. Although the International Fire Code requires the UL Standard to be identified, NFPA 1, 30 and 30A do not impose the same requirement.

Because these tanks are often relocated or resold, there is growing interest in updating UL Standards to require a tank marking to include the standard number for easier identification in the field.

Accessing UL Certified tank information on UL Product iQ®

UL certification for aboveground flammable and combustible liquid tanks can be verified by using Product iQ. A complimentary account is required to view detailed product listings and guide information.

UL 142, the Standard for Steel Aboveground Tanks for Flammable and Combustible Liquids

Product category code – EEEV

• Covers standard steel atmospheric tanks used for storing flammable and combustible liquids
• Includes tanks in various shapes and orientations (horizontal, vertical, cylindrical and rectangular)
• Listings can be found under the Aboveground Flammable-Liquid Tanks category.

Special-purpose tanks

Product category code – EFVT

• Includes generator base, work-top, day/utility, lube oil and waste oil tanks
• These are specialized designs certified under UL 142.

UL 2080, the Standard for Fire Resistant Tanks for Flammable and Combustible Liquids

Product category code – EEZI

• Designed to limit heat transfer to the primary tank during a two-hour hydrocarbon pool fire
• Listings are found under the Fire-Resistant Tanks for Flammable and Combustible Liquids category.

UL 2085, the Standard for Protected Aboveground Tanks for Flammable and Combustible Liquids

Product category code – EELU

• Offers enhanced fire resistance, integral secondary containment and impact protection
• Listings are found under the Protected Aboveground Tanks for Flammable and Combustible Liquids category.

Tanks, features, limitations and intended use features covered by UL Listings

Tanks certified under UL 142, UL 2080 or UL 2085 include the following built-in features as part of their Listing:

Features not covered

The UL Listing does not include:

• Any external accessories or components that are:
  • Shipped with the tank
  • Attached after manufacturing
  • Installed on site

These items fall outside the scope of the UL certification and must be approved separately by the code authority.

Venting and leak detection

• Primary tanks are equipped with both normal and emergency vent openings.
• Secondary containment spaces include emergency venting provisions.
• Final venting systems must be installed in accordance with local codes and standards at the job site.

Intended use and installation

UL Listed tanks are designed for aboveground use only and must be installed per applicable codes, including:

• NFPA 1, NFPA 30 and NFPA 30A
• NFPA 31 and NFPA 37
• International Fire Code (IFC)

These tanks are not evaluated for underground installation, but they may be used in UL 2245 Listed below-grade vaults if permitted by the installation code.