What is this About?
With sustainability and climate change becoming increasingly notable topics of consideration, state and federal legislation have sought to evolve their approaches towards the construction industry in numerous ways that impact commercial HVAC. Among these, new federal restrictions on refrigerants and their associated chemical properties have been enacted, which greatly change how the Architectural and Engineering industry will have to design projects that utilize these chemicals. Since most mechanical cooling systems include refrigerant, these impacts can be anticipated in almost all upcoming commercial construction projects that include HVAC scope.
Who’s involved?
There are a variety of entities that affect how new construction requirements are enacted. In this case related to refrigerants, the Environmental Protection Agency (EPA) enacted federal legislation related to citizen safety with respect to pollutants/chemicals. The state government in any given state is the point of authority for most commercial construction. They serve as the forefront of enforcement for building codes and are each independently responsible for the implementation of federal policy. Last, third-party industry organizations serve as non-biased industry expertise in interpreting new goals and mandates and establishing how to best execute projects moving forward to achieve those goals. The American Society for Heating, Refrigeration, and Air-Conditioning Engineers (ASHRAE) serves as one of these independent expert organizations in the construction industry. They enact design standards for commercial HVAC which standalone from building code but serve as a guide for legislation and code requirements for each state.
What Requirements Changed?
In October and December of 2023, the EPA enacted new requirements outlining the maximum allowable “Global Warming Potential” for all refrigerants in commercial HVAC equipment for comfort cooling. This “Global Warming Potential” (GWP) metric looks to quantify the effective amount of energy that a fixed amount of said refrigerant would absorb if released into the atmosphere relative to the same amount of Carbon Dioxide (CO2); effectively giving each refrigerant a rating that reflects its relative ability to be a greenhouse gas, compared to that of CO2. During this time, the EPA set the maximum limit any refrigerant can legally possess at 700. Meaning, that any refrigerant more than 700 times worse than CO2 will no longer be acceptable.
On a state level, most states reacted to these requirements with noted upcoming changes to their associated state building codes. This includes upcoming changes to 310 Massachusetts Commonwealth Regulations 10 edition.
What is Affected?
The EPA requirements set forth in 2023 affect all commercial vapor compression refrigeration equipment utilized for comfort cooling within commercial HVAC systems. Subcategories of HVAC equipment were broken out with individual timeframes applied to each subcategory.
What are ASHRAE’s Recommendations?
Equipment manufacturers, legislators, and industry experts all got to work reevaluating available refrigerant options for viability. Among the applicable industry standards, ASHREA 34 seeks to catalog and categorize all known chemicals applicable to vapor compression refrigeration with respect to their chemical properties, their GWPs, and their safety to occupants and the building. ASHRAE 15 provides recommendations for system design related to systems including refrigerants, as well as controls and other safety precautions that should be taken to keep building occupants safe from these systems. These standards, while not codes themselves, are indirectly referenced by many code standards as best practice.
After some time and careful consideration, ASHRAE, along with equipment manufacturers within the US construction industry, have unified on two refrigerants not previously commonly utilized, that best balance the motivating factors of everyone involved within the industry with respect to cost, safety, and performance. These two refrigerants are R-32, which has been commonly utilized in the European market for some time, and R545b. These refrigerants, and some other viable options that were considered, can be seen in the chart below:
Source: “Refrigerant options now and in the future: A white paper on the global trends with refrigerants in air conditioning and refrigeration seen from a Danfoss perspective,” August 2018.
Some equipment does utilize the purple highlighted options above. However, equipment manufacturers note that low density refrigerants are typically substantially more expensive to design around in order to achieve the same performance of other options.
Unfortunately, while these green highlighted refrigerants both achieve sub 700 GWPs as required, compared to more traditionally utilized refrigerants shown above in red, they are less safe. ASHRAE defines both refrigerants as ‘mildly flammable’. Meaning, while some considerable effort would be required to create a flame utilizing these chemicals, it is possible, and therefore presents new dangers to the building and its occupants that weren’t there previously.
Because of this added risk now being a requirement in HVAC systems, the latest addition of ASHRAE 15 goes into more detail, and adds recommendations for mitigating this risk. New shaft requirements are added to separate out pipes conveying these chemicals from other systems rising up and down through buildings, mitigating fire propagation. Additional requirements for monitoring for refrigerant leaks are outlined, and more detail is provided to guide manufacturers in how to configure their equipment to maximize safety.
How will it be Enforced?
Requirements will be enforced in two different ways. The federal government, and the EPA, will enforce their requirements by disallowing non-compliant equipment to be imported into the USA. State governments, which are responsible for enforcing building codes, will disallow non-compliant equipment that is slated for installation in new projects via their permit submissions through respective building permit offices.
When Does this Happen?
Prioritizing central chillers first, the due date for purchasing old refrigerant equipment was the last day of 2023, with one year grace period to install the equipment after it has been purchased. Similarly, single phase equipment was given the same date the following year in 2024, and finally three phase equipment in 2025. This prioritized the most critical equipment, while also allowing the manufacturing side of the industry to catch up and redesign their equipment to utilize these new refrigerants. Even with several years of warning, these requirements have put an immense strain on the commercial HVAC manufacturing industry, to meet these deadlines on time.
What is the Impact to Current Projects?
Current projects already underway can continue as planned with the only exception being projects slated for multi-year construction timeframes from current. Noting that the date in which a piece of equipment is installed ties back to the state level requirements. Moving forward, projects in design utilizing refrigerant equipment should consider the end of quarter 1 in each calendar year as the soft limit to when non-compliant equipment should be specified for each respective subcategory. This still gives ample time for the equipment to be procured (and potentially imported into the US) within the same calendar year and provides an additional year of time for the equipment to be installed prior to losing compliance.
Sources
ASHRAE. (n.d.). ANSI/ASHRAE Standard 15-2022, Safety Standard for Refrigeration Systems and ANSI/ASHRAE Standard 34-2022, Designation and Safety Classification of Refrigerants. ASHRAE Refrigeration Resources. https://www.ashrae.org/technical-resources/bookstore/ashrae-refrigeration-resources
Commonwealth of Massachusetts, Department of Environmental Protection. (2018, April). Code of Massachusetts Regulations Title 310. Mass.gov. https://www.mass.gov/law-library/310-cmr
Danfoss. (n.d.). Whitepaper: Refrigerant options now and in the future. Danfoss. https://www.danfoss.com/en/about-danfoss/articles/dcs/refrigerant-options-now-and-in-the-future/
Written By
Derek Day
Mechanical Project Leader
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