This is the ISA version of 60079-0. The ISA Version is identical to the UL version of this standard. You'll note that the copyright is for both ISA and UL (see PDF page 2), Page 5 (under "General Notes") further confirms this with the below statement:
This is the common ISA and UL standard for Explosive atmospheres Part 0: Equipment - General Requirements. It is the sixth edition of ANSI/ISA-60079-0 (superseding ANSI/ISA-60079-0 (12.00.01)-2009) and the sixth edition of ANSI/UL 60079-0.
ANSI/ISA-60079-0 and ANSI/UL 60079-0 contain identical requirements, and identical publication dates. The presentation and format of the standards material may differ between the two published standards.
This common standard was prepared by the International Society of Automation (ISA) and Underwriters Laboratories Inc. (UL).
I hope to have the other current version of the ISA documents soon.
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