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HVAC system regulations

Despite its origins in the US, ASHRAE has a presence in more than 100 countries and currently has more than 50,000 members. The organization was founded in 1894 and has been going strong for hundreds of years. 

Understanding ASHRAE Standards in HVAC

Air conditioning standards

While the contents of the standards vary, they cover important topics like installation rules and testing HVAC units to rate them. 

Besides ASHRAE standards, all states nationwide must create their own design and building codes under these standards since ASHRAE is a federal organization. HVACR technicians and their crew must follow all regulations when working on heaters and air conditioning units. 

Additionally, organizations within the HVAC industry also maintain safety standards, although each has slightly different definitions of what those standards are. They include the Institute of Electrical and Electronics Engineers or IEEE, the National Fire Protection Association or NFPA, and the Sheet Metal and Air Conditioning Contractors’ National Association or SMACNA. 

What Are the Standards of Various Types of Refrigerant?

As an HVACR technician, it’s critical you understand the ASHRAE standards implemented for different types of refrigerants. Here’s an overview. 

  • R-508B (an azoeotropic mixture that’s 54 percent R-116A and 46 percent R-23) – A1
  • R-507A (an azeotropic mixture that’s 50 percent R-143A and 50 percent R-125) – A1
  • R-410A (a zeotropic mixture that’s 50 percent R-125 and 50 percent R-32) – A1/A1 
  • R-407C (a zeotropic mixture that’s 52 percent R-134A, 25 percent R-125, and 23 percent R-32) – A1/A1
  • R-404A (a zeotropic mixture of four percent R-134A, 52 percent R-143A, and 44 percent R-125) – A1/A1
  • R-245ca (propane) – A2
  • R-245fa (propane) – A2
  • R-134A (ethane) – A1
  • R-125 (ethane) – A1
  • R-32 (methane) – A2L 

What do these classifications mean? Let’s explore.


Under ASHRAE, data center equipment can be rated in one of four categories or classes, A1 to A4. Equipment classified as A1 should be operated at temperatures between 18 and 27 degrees Celsius or 64.4- and 80.6-degrees Fahrenheit based on ambient conditions. 

The relative humidity must be between 20 and 80 percent. 


The next classification under A1 is A2, which has the second strictest set of requirements regarding operating temperature and humidity. The temperature must be between 10 and 35 degrees Celsius or 50 and 95 degrees Fahrenheit. The relative humidity should be between 20 and 80 percent.

Since your HVACR team will probably use ASHRAE class equipment than A1 and A2, here are the requirements for A3 and A4 equipment. 

For A3 equipment: an operating temperature of 5 to 40 degrees Celsius and 41 to 104 degrees Fahrenheit in an altitude of over 2,953 feet or 900 meters. The ambient temperature value drops by 1 degrees Celsius and 1.8 degrees Fahrenheit when the altitude increases every 574 feet or 175 meters.

For A4 equipment: an operating temperature of 5 to 45 degrees Celsius and 41 to 113 degrees Fahrenheit at an altitude of 2,953 feet or 900 meters. The ambient temperature decrease should occur by the same level as A3 equipment, 1 degrees Celsius and 1.8 degrees Fahrenheit, but for every 410 feet or 125 meters of altitude gained. 

Tips for HVACR Technicians to Meet ASHRAE Standards 

Indoor air quality standards

Undergo Training

ASHRAE standards continuously evolve, which is why the organization provides training opportunities to interested parties. Some of these opportunities are more formal, such as e-learning and instructor training courses, while others are self-directed and able to be finished at one’s own pace. 

eLearning training is especially advantageous for HVACR professionals, as the materials include more than 90 courses. Many are corporate programs. Some examples of courses are Fundamentals: HVAC Systems, HVAC Control Systems, and Hydronic Systems. 

Get Certified 

You can always pursue a certification program under ASHRAE. More than 30 local government, state, and national bodies acknowledge these certifications, which can include:

  • ASHRAE Certified HVAC Designer or CHD
  • Operations & Performance Management Professional or OPMP
  • Building Energy Assessment Professional or BEAP
  • Building Commissioning Professional or BCxP
  • High-Performance Building Design Professional or HBDP
  • Healthcare Facility Design Professional or HFDP
  • Building Energy Modeling Professional or BEMP

Having a CHD certification as an HVACR technician can unlock myriad opportunities in your career. If you decide to look for a new job, your certification will make you more attractive to hiring managers. As a result, you might be able to command more money.

Even if you stay where you are, you could potentially take on new responsibilities at work and increase your earnings. You’ll certainly inspire customer confidence, as a certification through ASHRAE means you do safe, reliable work.