ESDU 86022 presents correlations for external heat transfer coefficient and static pressure loss for single-phase flow over plain circular fins of either rectangular or tapered cross-section on round tubes. They were derived by a regression analysis of experimental results extracted from the literature for a wide range of tube bundle configurations. They covered fin densities of 4 to 11 per inch (equivalent to fin pitches of 6.4 to 2.3 mm), tube outside diameters of 3/8 to 2 inch (10 to 51 mm), fin heights of 1/4 to 5/8 inch (6 to 16 mm) and ratios of fin tip to fin root diameter of 1.2 to 2.4. For heat transfer the range of Reynolds number based on tube outer diameter was from 2 000 to 40 000 and for pressure drop from 5 000 to 50 000. Comparison of prediction with experiment shows that for heat transfer 85 per cent of the data points were within 10 per cent of estimated and for pressure drop 72 per cent were within 10 per cent. A comprehensive worked example showing the use of the method for an air cooled heat exchanger bundle is included. The applicability of the method to non-integral fins is considered and factors influencing the thermal resistance of the interface are discussed. Effects of fouling are also considered.