ASHRAE Refrigerant Safety Standard Changes Flammability Classification of Four Refrigerants

The 2013 editions of ASHRAE’s major refrigerants-related standards, incorporating  41 new addenda, have been published.

These editions can be purchased through the ASHRAE bookstore.

Requirements in ANSI/ASHRAE Standard 34-2013, Designation and Safety Classification of Refrigerants, and ANSI/ASHRAE Standard 15-2013, Safety Standard for Refrigeration Systems, complement each other in that Standard 34 describes a shorthand way of naming refrigerants and assigns safety classifications based on toxicity and flammability data. Standard 15 establishes rules for safe application in equipment and systems when the refrigerant classification system.  ASHRAE sells the standards as a set.

Standard 34-2013 contains the 2010 standard and 36 published addenda. Among the key changes incorporated into the standard are:

• assignment of designations and safety classifications for one new single compound refrigerant and 14 new refrigerant blends.
• changed the refrigeration concentration limits (RCL) values of 19 refrigerants listed in the 2010 standard to comply with more current methodology.
• changed the flammability safety classifications of four refrigerants from Class 2 to Subclass 2L, based on optional burning velocity measurement data.
• added Toxicity Code Classification assignments for 18 refrigerants that had been unassigned in the 2010 standard.
• clarified methodology for conducting flammability tests and for determination of fractionated compositions for flammability testing.
•  updated methodology by which the heat of combustion is calculated for refrigerant blends, and provided heat of combustion calculation examples for refrigerant blends.
• defined requirements that applicants shall provide evidence of the existence of an azeotropic blend, if requesting an R-500 series designation.
• modified sections of the standard to add bubble-point and dew-point definitions and test conditions, clarified applicant documentation requirements related to GLP compliance and added critical pressure data and specific volume calculation methodology for applicant submissions.

Standard 15 contains the 2010 standard plus five published addenda. Key changes to the standard include:

• clarification of the location requirements for machinery room mechanical ventilation.
• clarification that design pressure is expressed in terms of relative pressure or gauge pressure (not absolute pressure).
• wording to ensure the standard more closely harmonizes with the 2012 International Mechanical Code (IMC) section 1101.10.