[en] The global recombination rate coefficient for hydrogen has been measured for the ISX-B tokamak vacuum vessel for various surface conditions. The measurements were performed by observing the rate of decrease of gas pressure in the vessel during a glow discharge. The parameters of the glow discharge and the complete experimental method are described. Previously published analytic and numerical models are used for data analysis. The effects of surface contamination on the results are described. For ''unclean'' wall conditions sigmak/sub r/ = 1.8 x 10^-28 cm⁴/atom.s at 296 K and increases to sigmak/sub r/ = 4.4 x 10^-28 cm⁴/atoms.s for ''clean'' conditions and remains constant until subsequent exposure to air