[en] Heat transfer measurements were made for film condensation of steam on the underside of a horizontal surface in a closed vessel. Data were obtained as condensing heat flux vs. temperature difference at constant pressures and noncondensable gas (air) contents. Heat fluxes varied from about 0.04 to 0.8 MW/m² (13,000 to 250,000 Btu/h-ft²) and temperature differences from about 30 to 150⁰C. Pressures ranged from 0.31 MPa (45 psia) to 1.24 MPa (180 psia). Gas contents ranged from the maximum the system could contain at atmospheric pressure to negligible amounts. It appears that the effect of noncondensable gas can be correlated reasonably well based on a heat-mass transfer analogy. However, the data for negligible gas contents exhibit a significant effect of the system pressure which cannot be accounted for by existing correlations or models such as the one due to Gerstmann and Griffith