We present experimental speed of sound data for the saturated fluorocarbons used most frequently in particle detector cooling systems. Data were collected over the moderate range of pressure (<= 0.4 MPa) and temperature 250-340K. A commercial sound/density analyzer operating on the vibrating tube principle was employed for the measurements in liquid state. A dedicated sonar analyser - described in detail - was recently redesigned and developed for the speed of sound measurements in gas phase. Data for speed of sound in saturated fluorocarbons presented in previous papers [V. Vacek, G. Hallewell, S. Hie, S. Lindsay, Fluid Phase Equilib. 174 (2000) 191-201; V. Vacek, G. Hallewell, S. Lindsay, Fluid Phase Equilib. 185 (2001) 305-314] were reanalyzed and corrected and some new measured data were added. Our experimental data were then used to validate a theoretically based equation of state application rather than the empirical or semi-empirical equations of state mostly used up to now in fluorocarbon applications. (C) 2010 Elsevier B.V. All rights reserved.