Foster Wheeler Development Corporation (FWDC) took part in a pressurized fluidized bed combustion (PFBC) test program at the Grimethorpe PFBC facility in England. FWDC's participation included generating data to assess comparative wear rates and patterns on several different tubing alloys and surface protection techniques. The alloys and protection techniques are being used in, or are planned for, commercial atmospheric and pressurized fluidized bed boilers. Tubular specimens which were grouped into ten classes: carbon steel; finned carbon steel; finned 2-1/4%Cr-1%Mo; finned and studded carbon steel; finned and studded 2-1/4%Cr-1%Mo; finned and studded Type 347H stainless steel; chromized carbon steel; chromized 2-1/4%Cr-1%Mo; finned, studded and chromized carbon steel; and finned, studded and chromized 2-1/4%Cr-1%Mo. The materials are typical of those normally used in boiler service for carrying water, generating steam, and superheating steam. The test program and spanned approximately 1400 operating hours and was composed of three test sequences. Each test in the A2 series was run with a different fuel feedstock. The first utilized a UK coal (dry,7765 ); the second evaluated a US coal/water mixture (slurry,7765 ); the third test employed a UK coal slurry. Test runs with UK coal included a limestone sorbent while dolomite was used in the second test sequence. Exposed test specimens were removed for independent surface scale analysis before FWDC began metal wastage evaluations. The specimens were then inspected visually, analyzed dimensionally, and examined metallographically. 5 refs., 75 figs., 14 tabs.