ASHRAE has issued a call for comments on Addendum h to ANSI/ASHRAE Standard 15-2013, Safety Standard for Refrigeration Systems. This addendum proposes to allow A2L refrigerants in applications requiring machinery rooms, but does not change how the standard deals with A2L refrigerants in high-probability systems for human comfort, industrial applications, or refrigerated rooms. Those topics are expected to be handled in separate addenda proposals. The comment deadline has been extended to September 26. Access the Public Review Drafts by visiting ASHRAE’s Standards, Research & Technology/ Public Review Drafts web page and following the instructions to access the online comment database. To obtain a paper copy, contact Michael Woodford at mwoodford@ahri.net