Perspective on Refrigerant Selection

By Elvis L. Hoffpauir, MACS president and COO

This column appeared in the March/April 2012 issue of MACS ACtion magazine read more here.

The following was authored by Ward Atkinson and Bill Hill, co-chairs of SAE International’s Interior Climate Control Standards Committee.

As interest has increased in using lower Global Warming Potential (GWP) refrigerants, the industry has spent considerable time and effort in establishing engineering requirements that meet this demand and provide safety for the consumer.

After several years of extensive SAE Cooperative Research engineering evaluations and testing, vehicle OEMs have decided that future mobile A/C systems will use a mildly flammable, low GWP refrigerant R-1234yf (HFO-1234yf). These efforts involved extensive investigation into the flammability of this refrigerant and a comprehensive assessment of the risk involved in using this refrigerant.

These efforts are the results of cooperation of the SAE International Interior Climate Control Standards Committee members, including international vehicle manufacturers, system component and equipment suppliers.

It should be brought into perspective that natural hydrocarbon refrigerant used in a direct expansion MAC system have certain consumer safety and potential liability issues that must be considered. The information in the chart below compares flammability of several chemicals. Of specific note is that R-152a and hydrocarbons are in the higher flammable group. Both SAE Standards and the U.S. EPA use requirements mandate that R-152a cannot be used in a direct expansion MAC system and can only be applied in a secondary loop MAC system.

SAE engineering standards have been established when evaluating the use of any refrigerant in a MAC system covering the safety issue for both the consumer and the service technician regarding toxicity and flammability.
To provide MAC system design guidance there are many SAE International Standards. These listed below are some of the basic SAE standards required when considering any refrigerant for MAC systems.

  • J2772 Measurement of passenger compartment refrigerant concentrations under system refrigerant leakage conditions
  • J2773 Standard for refrigerant risk analysis for mobile air conditioning systems
  • J2842 R-1234yf and R-744 design criteria and certification for OEM mobile air conditioning evaporator and service replacements

In addition to these standards, there are others that are specific to the refrigerants for leak detection and service. Should a hydrocarbon refrigerant be used in MAC systems, all of these standards are needed to protect the consumer and the service technician.
No one has approached the SAE Interior Climate Control Standards Committee to develop standards covering the use of hydrocarbon refrigerants in MAC systems.

The Mobile Air Conditioning Society’s blog has been honored as the best business to business blog in the Automotive Aftermarket by the Automotive Communications Awards and the Car Care Council Women’s Board!

When having your mobile A/C system professionally serviced, insist on proper repair procedures and quality replacement parts. Insist on recovery and recycling so that refrigerant can be reused and not released into the atmosphere.

If you’re a service professional and not a MACS member yet, you should be, click here for more information.

You can E-mail us at or visit to find a Mobile Air Conditioning Society member repair shop in your area. Visit to find out more about your car’s mobile A/C and engine cooling system.

The 33rd annual Mobile Air Conditioning Society (MACS) Worldwide Training Conference and Trade Show, Be the Best of the Best will take place February 7-9, 2013 at the Caribe Royale, Orlando, FL.


About macsworldwide

Mobile Air Conditioning Society (MACS) Worldwide Founded in 1981, MACS is the leading non-profit trade association for the mobile air conditioning, heating and engine cooling system segment of the automotive aftermarket. Since 1991, MACS has assisted more than 600,000 technicians to comply with the 1990 U.S. EPA Clean Air Act requirements for certification in refrigerant recovery and recycling to protect the environment. The Mobile Air Conditioning Society (MACS) Worldwide’s mission is clear and focused--as the recognized global authority on mobile air conditioning and heat transfer industry issues.
This entry was posted in Automotive, Automotive training, Mobile Air Conditioning and tagged , , , , , , . Bookmark the permalink.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s