In two previous papers a class of equations of state with four or five parameters was constructed for which the Helmholtz energy is given as F=F-H+F-A+F-Pol, where F-H denotes the hard body contribution, F-A the contribution due to the attractive dispersion forces and F-Pol the contribution of polar interactions. Without F-Pol, the equation is a modification of the BACK equation and hence called MOBACK; inclusion of dipolar interactions yields DIBACK and that of quadrupolar interactions QUIZBACK. Firstly, each of these four equations is used here to correlate simultaneously large sets of pvT together with Maxwell data of the dipolar refrigerants R22 and R152a. In comparison with the BACK equation the standard deviation for reproducing the pvT data, for example, decreases by a factor of about 2 for MOBACK and QUABACK, and for the physically most meaningful DIBACK equation it decreases by a factor of about 4. In a second, perhaps even more interesting application, the five parameters of DIBACK are fitted to only three vapour pressures and three bubble densities of R22 and R152a, with no use of any critical data and with the aim of predicting all other thermodynamic properties. The vapour pressures and the bubble densities are predicted over a large temperature range, except close to the critical point, with a maximum deviation of 0.25%. The predicted pvT data show a standard deviation which is still smaller by a factor of 2 compared to that of the BACK equation when used to correlate the available data. Predictions of the caloric data of R152a could not be tested owing to the lack of experimental data. For R22, however, the enthalpies of vaporization are predicted within the experimental uncertainties, and isobaric heat capacities are predicted, except close to the critical point, with an absolute average deviation of 1.4%.