Nearly everyone spends time around cooling appliances, such as refrigerators and air conditioners. However, most people don’t handle refrigerants on a daily basis. Those who do must understand how to safely handle and store these dangerous chemicals, including those designated as A2L refrigerants. 

New international agreements related to acceptable refrigerants have emerged due to recent regulatory changes to minimize ozone depletion and global warming. As the older refrigerants are phased out, the replacements pose new hazards. Awareness of these hazards and best practices for use and storage should be a priority for those working in the refrigeration and HVAC industries.

What Does an A2L Designation Mean?

Classification of refrigerants is based upon the ASHRAE 34 designation and classification of refrigerants, which looks at toxicity and flammability. 

  • Toxicity
    • A – lower toxicity
    • B – higher toxicity
  • Flammability
    • 1 – no flame propagation
    • 2L – lower burning velocity equal to or less than 10 centimeters per second
    • 2 – lower flammability
    • 3 – higher flammability

The main difference between A1 refrigerants and A2L refrigerants is the ability to propagate a flame. A2L refrigerants will burn, but with a lower burning velocity than A3 refrigerants, which have the potential to burn explosively when ignited. Practically speaking, A2L gases are difficult to ignite, but precautions should still be taken when handling, storing and transporting these chemicals.  

A2L Regulations in the United States

Flammable refrigerants are relatively new to the US refrigeration and air-conditioning industry, but they have been used safely in other parts of the world for years. Currently, there is no federal framework for regulating the use of refrigerants. While the EPA attempted to implement SNAP rules 20 and 21, these regulations were vacated by the DC Circuit Court of Appeals because they determined that the EPA did not have Congressional authority to regulate these chemicals.

This absence of federal regulations has resulted in some states implementing statewide policies, with various regulatory requirements from state to state. Several organizations, such as the Air-Conditioning, Heating and Refrigeration Institute, ASHRAE, and the United States Department of Energy (DOE) have been in collaboration to explore potential hazards and recommend standards and codes. Federal policies and regulations are anticipated, with most people only questioning when they might be implemented–it’s not a question of “if,” only “when.”

 While there are no official federal regulations, there are multiple standards that have been developed. The one that is adopted most widely is ASHRAE’s Standard 15, published in 2019. The ASHRAE 15 requirements establish safeguards for life, health, and property through the recommendations for handling A2L refrigerants. They also address building code requirements for commercial and industrial applications using A2L refrigerants. 

Working Considerations

Even though there are no federal laws requiring practices when working with A2L refrigerants, it’s imperative to follow all best practices and recommendations to maintain a safe working environment, such as:

  1. Ensure that all relief and purge vent piping is routed outdoors and away from all air intakes per local, state, national, and international codes. 
  2. Ensure that the area is well-ventilated. If auxiliary ventilation is recommended, such as blowers or fans that disperse refrigerant vapors, ensure that it is rated for A2L refrigerants.
  3. Employ oxygen testing equipment and leak detection monitors to identify potentially hazardous leaks and ensure that adequate oxygen is present.
  4. Review the Safety Data Sheet (SDS) when working with refrigerants. Follow any recommendations and don the appropriate personal protective equipment (PPE), such as gloves, eyewear, etc. 
  5. Use equipment and tools certified for use with A2L flammable refrigerants.
  6. Ensure that a dry-powder Class B fire extinguisher is accessible.
  7. Check the area for obvious sources of sparks or flames before beginning work on equipment that uses A2L refrigerants.
  8. Do not operate appliances that utilize open flames, igniters, or have hot surfaces while servicing the appliance.
  9. If moving equipment containing A2L refrigerant, take care to prevent damage to the appliance, and especially the refrigerant lines.
  10. If the gas leak detector reports the presence of a leak, immediately ventilate the room, evacuate the area, notify those in the vicinity and wait until the device reads a safe level before returning.
  11. Purge refrigerant lines with oxygen-free dry nitrogen before and after a repair. 
  12. Ensure the equipment is properly grounded If the system is in operation while replacing the refrigerant.
  13. Follow all manufacturer’s recommendations when replacing the refrigerant. 
  14. During transportation of A2L refrigerant:
    1. Ensure that a dry-powder Class B fire extinguisher is available on the vehicle.
    2. Review all local, state, and federal regulations applicable in the jurisdiction of transport.
    3. Do not store refrigerant cylinders near heat or a source of ignition.
    4. Label all refrigerant cylinders following the guidelines in US 49 CFR part 172.417.
    5. Secure flammable refrigerant cylinders to prevent theft, tampering, or movement during transport.


ASHRAE 15 also outlines when leak detection monitors are required. Clause states that, “Each refrigerating machinery room shall contain a detector, located in an area where refrigerant from a leak will concentrate, that actuates an alarm and mechanical ventilation in accordance with Section 8.11.4 at a value not greater than the corresponding TLV-TWA (or toxicity measure consistent there with). The alarm shall annunciate visual and audible alarms inside the refrigerating machinery room and outside each entrance to the refrigerating machinery room.”

When identifying an optimal refrigerant leak detection sensor, there are several factors to consider, including:

  • Speed: To address leaks quickly and ensure a safe workplace, you need a detector that can alert you quickly of a leak – so your response can be just as quick!
  • Easy to Use: A good detector should be easy to use and to understand to prevent you from fumbling with it while hazardous conditions are present.
  • Accuracy: Accuracy is essential, although it can be difficult to obtain when there is low oxygen or high humidity. Identify a sensor that works under all potential environmental conditions that may exist in your workplace.
  • Total Cost: Initial cost is important, but don’t forget to consider additional calibration or replacement costs when determining the total cost of ownership.

Reviewing these factors when looking for a gas leak detector can help you to ensure leaks are detected quickly and your workplace remains safe when A2L refrigerant is being used. 

Learn more about NevadaNano’s MPS™ Refrigerant Gas Sensor