Effect of environmental condition on the flammability limits of two isomers of tetrafluoropropene

In this study, experiments and analysis addressed the flammable difference between chemical isomers of 2,3,3,3-tetrafluoropropene (R1234yf) and trans-1,3,3,3-tetrafluoropropene (R1234ze(E)). All measurements of the flammability limits were conducted with a self-made apparatus system with temperature ranging from 5 to 55 degrees C and relative humidity of air ranging from 0 to 100% corrected for 25 degrees C. The temperature dependences of flammability limits of R1234yf and R1234ze(E) were larger than the predictions by White's rule, but they could be predicted by a linear model accurately. Meanwhile, the results revealed that water vapor expanded the flammability limits of both R1234yf and R1234ze(E), but the sensitivity of these two isomers is very different, especially for the lower flammability limits (LFLs). The humidity dependence for R1234yf was linear, while it was not for R1234ze(E). (C) 2019 The Combustion Institute. Published by Elsevier Inc. All rights reserved.