We outline the procedures used to establish benchmark physical property data for the Third Industrial Fluid Properties Simulation Challenge. For both challenge problems, this involved measurement of new data, including bubble-point pressures of ethanol/HFC-227ea mixtures at 343.13 K, and the viscosity of 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2-methyl-1,3-propanediol, and 1,2,4-butanetriol at 373 K and 0. 1 and 250 MPa. When possible, measurements were compared with published literature data. Recominended values are provided with corresponding uncertainty estimates. (C) 2007 Elsevier B.V. All rights reserved.