The HVAC/R industry has been undergoing a significant transition amid the changes to regulatory standards like CSA B52. Environmental pressure from initiatives like the Montreal Protocol, signed in 1987, followed by the Kigali Amendment kickstarted the changes we are facing today in the refrigeration and HVAC sectors.
The Montreal Protocol set a global treaty aiming to protect the ozone layer by phasing out 99 per cent of ozone-depleting substances (ODS) such as chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs). The Kigali Amendment expanded to include HFCs and vowed to reduce them by over 80 per cent in the next 30 years, and aiming to avoid raising global temperatures.
Understanding these changes is no longer optional for contractors, engineers, and system designers; it is essential. Historically, CFCs and HCFCs have been widely used in HVAC systems. Common examples of CFCs that are still being used today are R-11 and R-12; common examples of HCFCs are R-22 and R-123. The high ozone depleting potential led to global efforts to phase-down these refrigerants. This resulted in the widespread adoption of HFCs, which created a new problem to handle — global warming potential (GWP).
Today, the industry faces the challenge of reducing greenhouse gas emissions associated with refrigeration. This focus shifted towards solutions that maintain zero ozone depletion, while still maintaining a low GWP. “We are seeing the impact of global warming in our routine life. Our summers are different than it used to be maybe 10 or 15 years ago,” shared Pushpinder Rana, director of products and services for Mitsubishi Electric Sales Canada, during his presentation. “There is clear evidence in our routine life how global warming is impacting every living being, every trade, every industry, and every household.” This is where A2L refrigerants enter the conversation.
Classifications
Refrigerants are classified based on flammability and toxicity. An A2L refrigerant would receive its specific categorization based on its lower flammability (its 2L-value) and its low toxicity (it’s A-value). An A2L, like R-32 or R-454B, has a mild flammability consideration that needs to be considered when designing its systems, as additional safety measures are required. It is manageable with proper system design, installation, and adherence to updated codes. Very specific conditions are required to be met for A2Ls to ignite. Their ignition temperatures are extremely high — often in the range of 500 C to 600 C — and they don’t ignite easily under normal operating conditions. When compared to fuels already used in homes, such as natural gas, A2L refrigerants can be safely managed with proper safeguards.
Updated CSA B52 code, released in late 2023, represents a major evolution in how refrigeration systems are evaluated and installed in Canada. It incorporates new concepts and calculations that are critical for working with A2L refrigerants.
Two important parameters that are part of CSA B52 are the effective dispersal volume charge (EDVC) and the maximum refrigerant leak (MRL). Its importance lies in its relation to each other. CSA B52 requires that the MRL, which is the potential amount of refrigerant that could be released in the event of a leak, is less than the EDVC, which is the maximum allowable concentration of refrigerant in a given space. This is an extremely important system component to understand in large capacity systems that contain a large amount of refrigerant.
If the EDVC does exceed the MFL, the system design must be modified to reduce risk. These calculations depend on several factors, including room size, airflow conditions, refrigerant properties, and system configuration. In many cases, accurate MRL calculations require manufacturer-specific data, making collaboration with suppliers essential.
Not every application is required to have detection and mitigation strategies, especially small capacity equipment. This is where the best course of action is to reach out to the manufacturer of the product to confirm system design requirements.
Industry readiness
Updated requirements apply to all occupancy types, including residential, commercial, industrial, and institutional buildings. However, more stringent rules apply in environments where occupants may be more vulnerable, such as hospitals or long-term care facilities. This isn’t a new concept — similar distinctions existed under previous codes — but the introduction of A2L refrigerants adds new layers of complexity to these considerations.
To address both safety and environmental goals, manufacturers are developing new system designs that minimize refrigerant exposure in occupied spaces. This is exemplified in hybrid VRF systems, where refrigerants are limited to non-occupied areas while using water inside the building. Low-charge systems are also available to reduce the total amount of refrigerant required. These innovations not only help meet code requirements but also offer additional benefits such as improved flexibility and energy efficiency.
One of the strongest messages from this presentation is the need for continuous education and training. The updated CSA B52 code introduces new terminology, calculations, and design approaches that cannot be mastered in a single session. Tradespeople must invest time in training, whether through manufacturers, industry associations, or regulatory bodies. Hands-on experience with real projects is particularly valuable, as it helps translate this knowledge into practical application.
Understanding the relationship between CSA B52 and other standards is also critical, as not all information is contained within a single document. In some cases, additional reference materials are required to fully interpret requirements.
Typically, there is strong alignment between Canada and the U.S. in terms of regulatory rules, codes, and standards. However, for some reason, the U.S. has a well-defined fact sheet that details many of the different types of refrigeration systems and equipment, and details important installation compliance dates. In Canada, we follow ODSHAR Schedule 1.1, which, as of today, doesn’t have any timeline on the GWP limit for a lot of equipment. This includes room air conditioning equipment, heat pumps, and VRFs. It should be noted that this is specific to the comfort industry. The only known regulation in Canada is for chillers.
It should be noted that industry associations, like the Heating, Refrigeration, and Air Conditioning Institute of Canada (HRAI) are working closely with regulatory bodies, like Environment and Climate Change Canada (ECCC), to improve this misalignment. The recommendations include suitable criteria, timelines, interprovincial harmonization, import/export, sell-in/sell-thru, and other measures that work favourably for Canada without causing any major trade disruption.
The shift to A2L refrigerants represents a necessary step toward a more sustainable HVAC/R industry. There are some growing pains associated with these new codes, but they don’t disrupt how these systems operate or how professionals approach their work. Instead, it requires a more informed and methodical approach — one that prioritizes safety, environmental responsibility, and compliance with evolving standards.
For now, legacy systems remain in use, and the transition is gradual. But the direction is clear. Those who take the time to understand the new requirements and adapt their practices will be best positioned to succeed in this changing landscape.