What is ANSI/ISA 12.12.01-2007 and how does it affect UL1604? December, 27, 2009 We received a letter from UL (Underwriters Laboratories Inc.) on January, 29, 2007. (See the attached file below). UL1604 v.s. ISA 12.12.01 .doc file link For Hazardous Locations testing, UL recommended that the newer ANSI/ISA 12.12.01-2007 standard be used, then the Hazardous Locations certifications statement in our documentation be changed from UL1604 to ANSI/ISA 12.12.01-2007.     <Old Statement for Hazardous Locations>     UL1604     <New Statement for Hazardous Locations>     ANSI/ISA 12.12.01-2007 UL also stated that all Hazardous Locations products must use ANSI/ISA 12.12.01-2007 by July 31, 2012. Based on future UL requirements, Pro-face has tested to ANSI/ISA 12.12.01-2007 for new products, which were launched in 2007, 1Q or later. Summarized as follows     - UL1604 will be discontinued by July 31, 2012.     - ANSI/ISA 12.12.01-2007 is the new standard listed to show Hazardous Locations certification.     - These requirements were officially announced and will be implemented by UL. Best Regards, Pro-face America Marketing division, solution marketing Manager