The AIM Act, signed into law in December of 2020, requires a switch to a new refrigerant that has a GWP (Global Warming Potential) of less than 700. GWP is based on CO2 which has a GWP of 1. R410A has a GWP of over 2000, so it's 2000 times worse than CO2!
The Residential Light Commercial Air Conditioning equipment manufacturers selected two new refrigerants: R32, with a GWP of 677, and R454B, with a GWP of 467. They are both A2L or Mildly Flammable refrigerants. R454B has a low burning Velocity, less than ½ miles per hour. It also has an LFL (Lower Flammability Limit) of 11.8%, which means we need a lot of it to ignite. The goal is to safely remain below the LFL.
To ensure safety when working with A2L refrigerants like R454B, follow our tips below!
Make sure the work area has adequate ventilation. Use a leak detector as a personal alarm to warn of refrigerant concentration. Remember to stay below the LFL.
Before brazing on an existing A2L system, you must:
Ensure that any power tool that you are using around an A2L, including Vacuum Pump and Recovery Machines, is A2L compatible. It is recommended that you check with the manufacturer or AHRI at www.ahrinet.org/saferefrigerant.
All components of any air conditioning system must be rated and labeled for use with R454B. R454B uses the same POE oil, so line sets can be reused provided they are the correct size and clean. All replacement components must be rated for use with an A2L.
New Condensing units and coils have straight stubs with no swage so press fittings can be used directly. Brazing is also allowed, but a swage must be added.
Any system that holds or can hold over 3.9 lbs of refrigerant will require a leak dissipation system provided by the coil manufacturers. In the presence of a leak, the heat or cool call will be suspended, and the blower will come on. The blower will run to ensure the refrigerant from the leak is dissipated and diluted throughout the space. Staying below the LFL.
Install and test the dissipation system for proper operation.
Check the product’s latest installation instructions for minimum area and refrigerant charge requirements. For example, 5.3 lbs of refrigerant will require a minimum of 79 sq ft.
Record the system charge with a permanent marker on the label provided with the condensing unit.
