The report gives results of field tests conducted to determine the emission characteristics of a Babcock and Wilcox Circular Burner and Dual Register Burner (DRB). The field tests were performed at two utility boilers, generally comparable in design and size except for the burner equipment. The Circular Burner was evaluated at Unit 2 of the Colorado Public Services Comanche Generating Station, and the DRB was evaluated at Unit 1 of the Wyodak Generating Station of the Pacific Power and Light Company and the Black Hills Power and Light Company. Of particular interest was the development of NOx emission correlations for the performance of Circular burners and DRBs under boiler conditions which could be used in interpreting individual burner tests in a subscale burner test facility. The field tests were conducted with both boilers operating at nominal full-load conditions. During each test, boiler performance and operating conditions were monitored using plant equipment, while gaseous emissions of NOx, O2, CO, SO2, and CO2 were continuously monitored using a mobile test trailer.