This report updates an earlier report, ''Design of the Facility as of March 1981'', which was prepared during the commissioning phase of the Experimental Pressurized Fluidized Bed Combustion Facility at Grimethorpe, South Yorkshire. Since that time numerous modifications resulting from operating experience and experimental requirements have been made. The report provides a description of the design of the process equipment and systems which together comprised the Experimental Facility, as it was in March 1984. 21 refs., 48 figs., 10 tabs.