UL 913 2022-05 PDF

Full title and description

UL 913 — Standard for Intrinsically Safe Apparatus and Associated Apparatus for Use in Class I, II, and III, Division 1, Hazardous (Classified) Locations. This document sets safety, design, marking and testing requirements for electrical apparatus and associated apparatus intended to be used where flammable gases, vapors or combustible dusts may be present under Division/Zone classification systems.

Abstract

UL 913 (Edition 8 with a May 10, 2022 revision) provides requirements to ensure electrical equipment and associated apparatus do not ignite surrounding hazardous atmospheres under normal and specified abnormal conditions. The standard addresses Division 1 installations (and corresponding Zone/Group assignments), associated apparatus located outside classified areas whose construction can affect intrinsic safety, and recent additions for 2‑Wire Intrinsically Safe Ethernet (2‑WISE) for Division applications.

General information

• Status: Current revision (Edition 8 with revision dated May 10, 2022).
• Publication date: Edition 8 originally published December 6, 2013; last revision / ANSI approval May 10, 2022.
• Publisher: Underwriters Laboratories (UL).
• ICS / categories: Electrical apparatus for explosive atmospheres — ICS 29.260.20 (and related explosion-protection groups/categories).
• Edition / version: Edition 8 (with multiple redline/revision updates; latest revision 2022-05-10).
• Number of pages: Page count is not consistently published on vendor listing pages and may vary by format; official UL distribution or reseller copies should be consulted for an exact page total.

Scope

Applies to apparatus or parts of apparatus intended for installation and use in Class I, II, or III, Division 1 hazardous (classified) locations in accordance with NFPA 70 (National Electrical Code), and to associated apparatus located outside hazardous locations whose design affects intrinsic safety. The 2022 revision explicitly extends coverage to construction, marking and documentation for the 2‑Wire Intrinsically Safe Ethernet (2‑WISE) concept where applicable.

Key topics and requirements

• Design and construction requirements for intrinsically safe apparatus intended for Class I, II, III, Division 1 (and corresponding Zone/Group) hazardous locations.
• Testing protocols for electrical circuits, components and systems to demonstrate intrinsic safety under specified conditions, including temperature and atmospheric considerations.
• Requirements for associated apparatus located outside classified areas whose characteristics may influence the safety of circuits inside the hazardous location.
• Marking, documentation and installation information (including reference to NFPA 70 / NEC installation practices).
• Inclusion of 2‑Wire Intrinsically Safe Ethernet (2‑WISE) for Division applications (physical layer considerations for 10BASE‑T1L / IEEE 802.3cg).
• Relationship and coordination with IEC/other intrinsic-safety guidance (e.g., IEC 60079 series) where applicable for system-level or international projects.

Typical use and users

Used by manufacturers of intrinsically safe equipment, certification and testing laboratories, design and safety engineers, inspection authorities, facility owners and maintenance personnel in industries such as oil & gas, petrochemical, chemical processing, mining, utilities and other sectors where explosive atmospheres may be present. The standard is used for product development, compliance testing, listing/certification and installation guidance.

Related standards

Commonly referenced standards and documents include the IEC/EN 60079 series (notably IEC 60079‑11 and IEC 60079‑25 for intrinsic safety practices), NFPA 70 (National Electrical Code) for installation practices, and other UL standards that reference intrinsic-safety requirements. For system-level intrinsically safe electrical systems, coordination with IEC 60079‑25 is typical.

Keywords

intrinsic safety; UL 913; Division 1; hazardous locations; Class I, II, III; 2‑WISE; intrinsically safe Ethernet; associated apparatus; NFPA 70; explosion protection; Group IIC/IIB; marking; testing; certification.

FAQ

Q: What is this standard?

A: UL 913 is a UL safety standard that establishes requirements for intrinsically safe apparatus and associated apparatus intended for use in classified hazardous locations (Class I/II/III, Division 1) to reduce ignition risk from electrical or thermal sources.

Q: What does it cover?

A: It covers design, construction, testing, marking and documentation of devices and associated apparatus (including some apparatus outside the hazardous area) whose characteristics affect intrinsic safety; the 2022 revision also addresses 2‑Wire Intrinsically Safe Ethernet (2‑WISE) for Division applications.

Q: Who typically uses it?

A: Manufacturers, test labs, compliance engineers, certifiers, installation/maintenance staff and facility owners/operators working with equipment to be used in hazardous (explosive) atmospheres. The standard supports product certification and safe system design.

Q: Is it current or superseded?

A: The document is Edition 8 with a revision dated May 10, 2022 (ANSI approval recorded May 10, 2022). No later UL revision was listed on the official product/revision pages at the time of this summary. Users should confirm on UL's official standards distribution or with UL Standards & Engagement for any updates after May 10, 2022.

Q: Is it part of a series?

A: UL 913 is part of the body of standards addressing equipment for hazardous locations and is frequently used alongside IEC/EN 60079 series documents (such as IEC 60079‑11 and IEC 60079‑25) and NEC/NFPA 70 installation guidance to achieve comprehensive compliance for intrinsically safe systems.

Q: What are the key keywords?

A: Intrinsic safety, hazardous locations, Division 1, Class I/II/III, explosion protection, associated apparatus, 2‑WISE, marking, testing, UL certification.