UL 142 2021-01 PDF

Full title and description

UL 142 — Steel Aboveground Tanks for Flammable and Combustible Liquids. Standard requirements for the design, fabrication, inspection and testing of steel primary, secondary and diked atmospheric aboveground storage tanks intended for noncorrosive, stable flammable and combustible liquids (typical specific gravity ≤ 1.0), including permitted shapes, orientations and testing/marking requirements for safe aboveground storage and shipment as assembled vessels.

Abstract

UL 142 establishes construction, material, venting, test and marking requirements for shop-fabricated steel aboveground tanks used to store flammable and combustible liquids. The 2021 revision (published January 21, 2021) updates references, clarifies leakage test procedures, adds requirements for some double-wall features and alignment of structural members, and aligns OSHA and other referenced code citations with current practice. The standard is intended to be used alongside codes such as NFPA 30 and applicable fire and installation codes for safe use and installation.

General information

• Status: Active (UL standard maintained and available through UL/ANSI distribution channels).
• Publication date: Revision published January 21, 2021 (revision to Edition 10 / redline released in 2021).
• Publisher: Underwriters Laboratories (UL).
• ICS / categories: Fluid storage / tanks and pressure equipment classification (fluid storage devices / aboveground storage tanks; commonly referenced in fire protection and petroleum storage categories).
• Edition / version: Edition 10 (document redline/revision dated 2019 with a 2021 published revision entry commonly cited as UL 142: 2021).
• Number of pages: Format- and publisher-dependent; published copies and PDF editions are distributed by UL/ANSI stores (page counts vary by release package and redline annexes).

Scope

The standard covers steel primary, secondary and diked aboveground atmospheric storage tanks intended for noncorrosive, stable flammable and combustible liquids (normally spg ≤ 1.0), in a variety of shapes (cylindrical, rectangular, obround) and orientations (vertical, horizontal), with or without multiple compartments. It excludes tanks specifically covered by other specifications (API shop- or field-welded production tanks, portable transport tanks, or tanks intended for pressures above low‑pressure limits where specifically excluded). UL 142 is intended for tanks that are fabricated, inspected and factory-tested for leakage prior to shipment and to be installed per applicable fire and installation codes.

Key topics and requirements

• Materials and construction: steel materials, welding and fabrication requirements for primary and secondary/diked tanks.
• Design configurations: provisions for cylindrical, rectangular and obround shapes; vertical and horizontal orientations; compartmentalization.
• Venting and openings: emergency and normal vent sizing and location requirements to prevent pressure/vacuum damage.
• Leakage and tightness testing: distinct requirements for performance (type) and production (routine) leakage tests; factory testing before shipment.
• Double-wall / interstitial features: requirements for double-wall manways, interstitial monitoring and related construction details added/clarified in the 2021 revision.
• Marking, labeling and documentation: identification marking, capacity and limitations, and documentation to support installation and code compliance.
• Referenced codes and coordination: alignment with NFPA 30 (Flammable and Combustible Liquids Code), NFPA 31/30A and applicable fire and building codes for installation and use.

Typical use and users

Manufacturers of aboveground steel tanks, tank fabricators, testing laboratories, third‑party certifiers, fire and code officials, facility engineers, fuel‑storage system designers, and end users in industrial, commercial, agricultural and municipal settings use UL 142 to ensure tanks meet accepted safety and performance criteria for storing flammable and combustible liquids.

Related standards

Standards commonly cross‑referenced with or related to UL 142 include: UL 142A (special purpose aboveground tanks), UL 2080 (fire‑resistant tanks), UL 2085 (protected aboveground tanks), API standards for tanks (API 12F/12D/650 where applicable), and NFPA 30 (Flammable and Combustible Liquids Code). UL 142 is also referenced by various installation and regulatory codes.

Keywords

aboveground tank; steel tank; UL 142; flammable liquids; combustible liquids; leakage test; venting; double‑wall; secondary containment; tank marking; NFPA 30.

FAQ

Q: What is this standard?

A: UL 142 is the Underwriters Laboratories standard that sets safety, construction, testing and marking requirements for steel aboveground atmospheric storage tanks used for flammable and combustible liquids.

Q: What does it cover?

A: It covers materials, fabrication, venting, leakage/performance testing, markings, and specific construction features (single- and double‑wall, diked tanks, multiple shapes and orientations) for shop-fabricated tanks intended for aboveground storage of noncorrosive, stable flammable and combustible liquids.

Q: Who typically uses it?

A: Tank manufacturers, fabricators, certifying bodies, fire and code officials, facility and mechanical engineers, and purchasers of aboveground fuel/chemical storage tanks use UL 142 to design, build, inspect and approve tanks for code-compliant installations.

Q: Is it current or superseded?

A: The 2021 revision (published January 21, 2021) is a maintained revision of Edition 10 and is listed as active by UL distribution channels; users should check UL/ANSI product listings for the latest edition or subsequent revisions/editions.

Q: Is it part of a series?

A: Yes — UL 142 is part of a family of tank‑related UL standards (for example UL 142A, UL 2080, UL 2085) and is often used alongside API tank standards and NFPA fire codes for installation and special purpose tanks.

Q: What are the key keywords?

A: Aboveground tank; steel tank; flammable liquids; combustible liquids; leakage testing; venting; double‑wall; secondary containment; UL 142; NFPA 30.