- A2L Refrigerants Are Here -

Is Your Shaft Ventilation Ready?

The AIM Act deadline has passed. New HVAC equipment now
requires A2L refrigerants. Here’s what that means for VRF projects 
and how PurgeSafe® makes compliance and safety simple.

THE CHALLENGE

VRF Systems Now Require Shaft Ventilation

As of January 1, 2025, the EPA’s AIM Act requires new HVAC equipment to use refrigerants with a GWP of 700 or less. For VRF systems, this means R-32 and R-454B — both classified as A2L (mildly flammable).

A2L refrigerants introduce a new code requirement that didn’t exist with R-410A: refrigerant pipe shafts must be ventilated. Both ASHRAE Standard 15 and the 2024 International Mechanical Code now require this for any VRF piping that penetrates two or more floor/ceiling assemblies.

PurgeSafe™  

A2L Refrigerant Leak Ventilation System

Introducing PurgeSafe™, a next-generation A2L refrigerant leak ventilation system engineered for full compliance with ASHRAE 15-2024 and IMC 2024. As the HVAC industry transitions to A2L refrigerants for improved environmental performance, building safety requirements have become more stringent than ever. PurgeSafe™ delivers a complete leak detection and ventilation system through intelligent automation, helping protect occupants, equipment, and facilities.



Combining advanced detection technology with automated ventilation response, PurgeSafe™ provides facility managers and building owners with confidence and peace of mind. Whether retrofitting existing buildings or designing new construction, PurgeSafe™ delivers the reliability and performance required for today’s evolving refrigerant landscape.

The PurgeSafe™ System:

Detect → Ventilate → Protect

✓  Three NDIR sensors (UL 60335-2-40) monitor LFL% continuously at 1 Hz

✓  L450 controller (UL 508) activates DEF exhaust fan and opens fresh air damper

✓  HVAC compressor interlock shuts down the VRF system to limit refrigerant loss

✓  FACP/FSCS alarm relay for coordinated fire safety response

✓  BMS integration via Modbus RTU/TCP, Ethernet (BACNet available)

✓  Automatic monthly self-test verifies fan, damper, and sensors — satisfies IMC §1109.1

✓  R-290 ready — sensors already detect A3 refrigerants for future-proofing

Size Your System in 60 Seconds

LF Systems has created a free shaft ventilation system selector. Just enter your shaft dimensions and you'll get the required CFM, select the right DEF fan, generate a CSI specification, and print a PDF report in less than a minute. No account needed, just click on the button below.

Click the button below for the brochure, data sheets, and system diagrams

Simplify Safety and Code-Compliance

Contact your local representative or LF Systems for more information on PurgeSafe™.