This Code provides procedures for the conduct and reporting of performance tests of flue gas desulfurization systems (FGDS). The application of this Code is limited to the process and equipment employed to remove sulfur dioxides from flue gas or other sulfur-dioxide-laden gas streams. The methodology described may be adapted for assessment of removal of other emissions if agreed to by the parties to the test. This Code does not apply to removal of sulfur oxides from gases during the combustion process.