scope:

FOREWORD

Addendum b makes several relatively small changes to the standard.

• Removes a restriction on higher-flammability refrigerants where used in small, portable-unit systems. The use of higher-flammability refrigerants is restricted only by the total refrigerant charge in the self-contained system (limited to 0.331 lb [150 g] of Group A3 refrigerants).

• Defines "low-probability pumps" and provides requirements pertaining to their use. Recognition of low-probability pumps acknowledges the superior leak resistance of these pumps and encourages their use to increase safety. The approach is modeled after current allowances for low-probability systems. Because low-probability systems are inherently more resistant to atmospheric releases than high-probability systems, Standard 15 permits more widespread use of low-probability systems. With respect to pumps, experience has shown that pump leaks are typically associated with failed seals on rotating (dynamic) parts, which can result in events ranging from a simple nuisance release to a hazardous condition requiring an emergency response. This addendum encourages the use of liquid pumps that are hermetically sealed or similar in lieu of pumps that rely on dynamic seals to contain refrigerant. This change is consistent with the 2018 IMC (changes proposed) and with IIAR 2.

• Eliminates a requirement for industrial occupancies and refrigerated rooms pertaining to floor area per occupant While the requirement has been in place for some time, upon re-examination by the committee, there is no logical reason for this section to establish a maximum occupancy limit based on providing a minimum floor area per occupant simply because someone is in a refrigerated area. This change is consistent with the 2018 IMC (changes proposed) and IIAR 2.

Note: In this addendum, changes to the current standard are indicated in the text by underlining (for additions) and strikethrough (for deletions)