Integrating Flammable Refrigerants Under Environmental Protection Requirements
Introducing new refrigerants will necessitate changing components, which will require evaluation for both performance and safety.
As a follow-up to its Clean Air Act of 1990, the U.S. Environmental Protection Agency (EPA) created the Significant New Alternatives Policy (SNAP), to identify and evaluate substitutes for ozone-depleting substances. The program evaluates overall risks to human health and the environment of existing and new substances and substitutes. Under the policy, the EPA generates lists of acceptable and unacceptable substitutes for major industrial use sectors. SNAP also promotes a smooth transition to safer alternatives for the affected industries and provides the public with valuable information about the substances, substitutes and products.
For the commercial refrigeration and HVACR industries, two subsequent rules (Rules 20 and 21) prohibit the use of certain high-global warming potential (GWP) alternatives, with Rule 20 prohibiting various hydrofluorocarbons (HFCs) and HFC-containing blends previously listed as acceptable alternatives. Additionally, Rule 19 lists climate-friendly refrigerant alternatives that offer better protection to the climate while being less harmful to the ozone.
Overall, while most commercial refrigerant manufacturers in the industry have historically relied on two popular refrigerant materials—R-134a and R-404A—they will no longer be able to produce units operating on those refrigerants given their high GWP. Instead, manufacturers are encouraged/required to pursue more natural refrigerants. SNAP Rules 19, 20 and 21 pave the way for the use of five substitute refrigerants:
- Ethane – A climate-friendly hydrocarbon, ethane is non-toxic with zero ozone depletion potential (ODP) and very low GWP. At room temperature, ethane is flammable. When mixed with air at certain volumes, it is explosive.
- Isobutane – Also known as R-600A when used as a refrigerant, isobutane is a hydrocarbon, like ethane. Blends of pure, dry isobutane have negligible ODP and very low GWP. However, isobutane carries an explosion risk.
- Propane – Like ethane and isobutane, propane is a hydrocarbon that also has negligible ODP and very low GWP. Propane is also used as a fuel and, as such, is flammable and can be explosive.
- R-441A – This refrigerant is a hyrodcarbon blend, with zero ODP and very low GWP. As a hydrocarbon blend, it too is flammable and potentially explosive.
- HFC-32 – Also called difluoromethane, this refrigerant has zero ODP and one-third the GWP of conventional refrigerants it is intended to replace.
Ethane, isobutane, propane and R-441A are all considered acceptable in stand-alone commercial and household refrigerators and freezers, very low temperature refrigeration, non-mechanical heat transfer, vending machines, and room air conditioning units. HFC-32 is listed as acceptable in room air conditioning units. While all of these substances have little-to-no ODP and lower GWP than conventional refrigerants, they are also flammable and/or explosive. This means that the industry must be prepared for new considerations as they incorporate these substances.
The rules impact not only refrigeration manufacturers but also suppliers, from whom manufacturers will need to source new refrigerant materials, as well as components, such as compressors. As products and processes are redesigned to accommodate these changes, there are a variety of considerations and decisions to be made. New product components may require product safety listings to be revised or reissued to allow for the continuation of the safety certification mark. Introducing new refrigerants will necessitate changing components, which will then require evaluation for both performance and safety.
Perhaps most importantly, incorporating flammable refrigerants like ethane, isobutane, propane, R-441A and HFC-32 into a manufacturing process requires risk assessment of the facilities and processes. Areas specified for research and development, testing, and production will now become potentially explosive atmospheres, affecting not only facilities but also personnel and products in a number of ways.
For facilities, a Hazardous Area Classification will be required. Hazardous areas are typically classified with either a class/division or a zone system. It determines the requirements for both protection techniques and methods for electrical installations in a given setting. As an example, a room with a propane gas installation is typcially given a Class I, Division 2, Group D classification in a class/division system. This same room is given a classification of Zone 2, Group IIA in a zone system. Both of these classifications equate to an area where ignitable concentrations of flammable gases, vapors or liquids are not likely to exist under normal operating conditions, making it a lower risk setting. However, it still is a hazardous location and will have requirements to mitigate risk and keep it low.
One requirement will be the need to ensure that electrical equipment used in a particular setting is appropriate. There are three different categories of equipment, depending on the product’s protection level. Category 1 equipment, for example, may be used in areas designated as zones 0, 1 or 2; Category 3 equipment can only be used in areas with a zone 2 classification.
A number of factors are considered in determining a product’s categoty. Types of protection that would be necessary when using ethane, isobutane, propane, R-441A and HFC-32 might include:
- Equipment that is non-incendive, or non-sparking
- Equipment that has been properly pressurized
- Equipment that is intrinsically safe and robust with high quality components
- Encapsulation and other special protections
Existing labs will likely need to be redesigned and special considerations for new facilities will be necessary to accommodate the reclassification as a hazardous location. Some considerations that will need to be made in the facility itself include: sources of electricity, corrosion, temperature control, fire control and prevention. The reclassification will also require manufacturers to create emergency procedures in case an accident does occur. Manufacturers should also be prepared to document maintenance and repairs to the facility and equipment under hazardous locations requirements.
In regard to personnel, employees will need special training for working in explosive atmostpheres. This will include ongoing education around the regulations and standards that apply to hazardous locations settings. It may also include competency assessment programs, site safety training, emergency procedures, equipment usage and more. Finally, hazardous materials certification for workers who handle, remove or ship hazardous materials, such as these refrigerants, will be necessary. To identify the necessary training, conduct a hazard assessment and consult an expert in hazardous locations to ensure your compliance.
A hazard assessment will also inform decisions regarding personal protective equipment (PPE) for the new setting. PPE is worn to minimize exposure to hazards that cause serious workplace injuries and illnesses. Many types of PPE must meet requirements set forth by the American National Standards Insititute (ANSI), which includes standards for eye and face protection, head protection and foot protection.
Finally, manufacturers and suppliers will need to address new considerations for shipping and handling, such as using covered or closed containers, as well as bonding and grounding them. Using approved storage and transfer equipment is also critical. Additionally, product maintenance instructions and labelling must be updated to account for the use of flammable refrigerants.
The EPA’s efforts to protect health and safety of the environment and consumers have led to multiple changes in the industry. The recent focus on refrigerants with low GWP and ODP have meant adjustments for many manufacturers. However, understanding what the use of these flammable refrigerants entails and preparing accordingly will help to make the transition smooth, ensuring a product that not only meets EPA requirements, but consumer demand for environmentally friendly products.