ASHRAE Standard Safety Standard for Refrigeration Systems 15-2022 & 34-2022

The ASHRAE Standard Safety Standard for Refrigeration Systems 15-2022 & 34-2022 describes a shorthand way of naming refrigerants, and it assigns safety classifications and refrigerant concentration limits based on toxicity and flammability data. The 2022 edition of the standard adds safety designations for twenty new refrigerants, modernizes submission application requirements for new refrigerants, and is updated to capture flammability limits used for non-A1 refrigerant maximum charge calculations.

Key Aspects of ASHRAE 15‑2022:

• Safety in Design, Installation, Operation & Maintenance
• Inclusion of Non‑A1 Refrigerants & Low‑Flammability (A2L) Refrigerants
• Refrigerant Leak Detection & Mitigation Requirements
• Ventilation & Exhaust System Capacity
• Updated Piping, Overpressure Protection, & Charge/Volume Limits
• Definition of “Machinery Room” and Occupancy Implications

Key Aspects of ASHRAE 34‑2022:

• Uniform System for Refrigerant Designation & Classification
• Safety Classifications Based on Toxicity & Flammability Data
• Refrigerant Concentration Limits (RCLs)
• Addition of New Refrigerants & Updated Criteria

Highlights of Standard 15‑2022:

• Expanded requirements for non‑A1 refrigerants, including A2L low‑flammability refrigerants, affecting ventilation, system design, leak detection, and safety controls.
• New or revised overpressure protection and piping requirements to ensure safety under higher pressures or potentially more hazardous refrigerants.
• Updated formulas and methods for calculating refrigerant charge limits and room‑volume considerations in the event of a leak, including “releasable charge” concepts.
• Enhanced refrigerant detection & mitigation actions, including when detection must trigger alarm or automatic shutdown, especially for flammable substances.

Highlights of Standard 34‑2022:

• Addition of safety designations for twenty new refrigerants and modernization of filing/application requirements for new refrigerants.
• Safety classifications (toxicity / flammability) clarified and updated; these classifications feed into Standard 15’s safety rules for systems using those refrigerants.
• Incorporation of flammability limits for non‑A1 refrigerants into charge limit and safety evaluation, ensuring that safety rules correspond with the characteristic properties of newer refrigerants.

About SSPC

The ASHRAE Standing Standards Project Committee 90.1 (SSPC 90.1) is a multidisciplinary group of professionals responsible for developing and maintaining the ANSI/ASHRAE/IES Standard 90.1, one of the most widely used energy codes for commercial buildings. The committee is composed of engineers, architects, lighting specialists, energy modelers, code officials, utility representatives, manufacturers, and sustainability experts from across the building industry. Its primary mission is to ensure that the 90.1 standard reflects current technologies, energy performance goals, and real-world building practices.

Other Works:

• ANSI/ASHRAE/IES 90.1-2022, Energy Standard for Sites and Buildings Except Low-Rise Residential Buildings