EXPLOSION BEHAVIOR OF THE NON-FLAMMABLE CFC SUBSTITUTE 1,1,1,2-TETRAFLUORETHANE (R134A)

The explosion ranges of R134a/nitrogen/oxygen mixtures have been inves tigated at atmospheric pressure. The results of these full flammabilit y tests at 20 degrees C and at 280 degrees C are presented in a triang ular diagram. In addition, the influence of pressure on the flammabili ty of R134a/air mixtures has also been studied. Under normal condition s, R134a is a non-flammable gas but exhibits an explosion range at hig her oxygen percentages than those in air. At increased temperatures or pressures, R134a also has an explosion range in air, i.e. without any higher oxygen percentage. Using a detonation tube, the detonability o f R134a/air mixture has been investigated for pressures between 8-20 b ar and temperatures from room temperature to 200 degrees C. Stable det onations with detonation velocities of 1506-1535 m s(-1) were initiate d by incoming detonation waves. For an oxygen-enriched R134a/nitrogen/ oxygen mixture at 10 bar, using a glowing wire as the ignition source a pressure-piling effect was observed. In this experiment a pressure o f more than 1200 bar was attained.