Abstract
Flammability has emerged as a challenge to the adoption of refrigerants with low global warming potential (GWP) and zero ozone depletion potential (ODP). Among the flammability criteria considered in safety standards, the concentration limits of flammability (i.e., flammability limits) require further empirical study. Existing methodologies can benefit from improved precision and reproducibility, particularly for refrigerants, and the reported data for current and next-generation refrigerants remains limited. In this study, an experimental apparatus following the ASTM E681–09 test method was developed that enabled precise control of temperature, pressure, humidity, and ignition strength. Reproducibility and comparison with literature measurements was investigated using mixtures of difluoromethane (HFC-32) and air. The lower and upper flammability limits (LFL and UFL) for HFC-32 were observed at 14.2 ± 0.2 and 26.8 ± 0.2 vol %, respectively, under average conditions of 23.0 ± 2.2 °C, 8.8 ± 0.5 g water/kg dry air, and 960.3 ± 1.0 mbar.
| Original language | English |
|---|---|
| Pages (from-to) | 23105-23114 |
| Number of pages | 10 |
| Journal | Industrial and Engineering Chemistry Research |
| Volume | 64 |
| Issue number | 48 |
| DOIs | |
| State | Published - 2025 |
| Externally published | Yes |
Funding
The authors acknowledge the U.S. National Science Foundation ERC Award 2330175 Environmentally Applied Refrigerant Technology Hub (EARTH) and Hudson Technologies Company for their support of this research. The authors would also like to thank Joseph Blanchett, Morela Chapman, Caymen Barnes, Evan Dennard, Raymond Hamilton, and Oluwafemi Odusanya for their assistance with apparatus construction, initial experimental testing, and LabVIEW programming and integration.