Home » Numbers Up Numbers Up February 27, 2009 Reprints No Comments In the 1950s, DuPont released its registered refrigerant numbering system for general use to avoid confusion and proliferation of different names for similar products. Did you enjoy this article? Click here to subscribe to The NEWS Magazine Related Articles CIPH Report: Industry Numbers Up for Summer Monthly Numbers Jump, Yearly Numbers Level Off HVAC Industry Numbers Send Mixed Messages AHR Expo Shows Strong Advance Numbers Related Products DeWALT HVAC Professional Reference You must login or register in order to post a comment. Report Abusive Comment Thank you for helping us to improve our forums. Is this comment offensive? Please tell us why.