DENSITY AND VISCOSITY MEASUREMENTS OF 1,1,1,2-TETRAFLUOROETHANE (HFC-134A) FROM 199-K TO 298-K AND UP TO 100-MPA

New density results for liquid 1,1,1,2-tetrafluoroethane (HFC-134a) al ong five isotherms from 199 K to 298 K and at pressures up to 100 MPa are presented. The measurements were performed with a new vibrating-wi re instrument operated in the forced mode of oscillation and were carr ied out on a round-robin sample of refrigerant HFC-134a. The viscosity of the fluid was measured simultaneously with the density, using the same vibrating-wire sensor, at temperatures above 248 K over the entir e pressure range. The results are compared with recent literature data . The precision of the present values is +/- 0.03% for the density and +/- 0.6% for the viscosity. The corresponding estimated accuracies ar e +/- 0.05% and +/- 2.5%, respectively.