scope:

FOREWORD

Addendum g to ANSI/ASHRAE Standard 15-2019 makes several changes addressing refrigerant concentration limits (RCLs) of occupied spaces by adding new definitions and the concept of releasable charge (also found in IIAR2, UL/CSA 60335-2-40, and IEC 60335-2-40) and further utilizing a new concept added to Standard 15-2019 by Informative Appendix A (as published in Addendum f). Addendum g completely rewrites Section 7.2, "Concentration Limits," and Section 7.3, "Volume Calculations," by reversing the existing sections, first addressing the volume of spaces for consideration (new Section 7.2), then determining acceptable refrigerant charge quantity (new Section 7.3). Additionally, the addendum adds several definitions for connected spaces, effective dispersal volume, effective dispersal volume charge (EDVC), independent circuit, releasable refrigerant charge (m_rel), and system refrigerant charge (m_s).

New equations have been added for the following to further address the concept of connected spaces:

• Natural ventilation opening size required for Class 1 refrigerants

• Natural ventilation opening size required for Class 2 and Class 3 refrigerants

• Effective dispersal volume charge

• Releasable charge

Release mitigation controls are included, and a flow chart has been added to clarify the compliance path for chart limits.

Note: In this addendum, changes to the current standard are indicated in the text by underlining (for additions) and strikethrough(for deletions) unless the instructions specifically mention some other means of indicating the changes.