Potential replacements for current hydrofluorocarbon (HFC) refrigerants include pure and blended hydrocarbon refrigerants since they have a lower global warming potential (GWP) and comparable working fluid properties.

The current barrier to broader application of these refrigerants is their classification as flammable A3 substances according to ASHRAE 34. As a result, their use is accompanied by additional design constraints to minimize safety hazards.

A current design constraint for A3 refrigerants is a 150 g charge size limit in portable unit systems.

The objective of this project was to understand the severity of ignition events involving R-290 (propane) at charges sizes above the current limit of 150 g to evaluate the viability of class A3 refrigerants as replacements for HFCs in more HVAC&R applications.

Scope and Objectives

  1. Model refrigerant releases and subsequent ignition events with FLACS. 
  2. Perform actual-scale room tests to evaluate consequence and severity.
  3. With FLACS, simulate post-ignition combustion events involving flammable refrigerants leaked from refrigerated display cases in commercial kitchen and retail settings.
  4. Quantify the risk of hydrocarbon refrigerants based on charge size.

You can download the official report PDF from the NFPA website by clicking here.


Contact Information

Scott G. Davis

President and Principal Engineer, Gexcon US
E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.

Phone: +1 617-407-3300


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