Uncertainty analysis is a method of quantitative expression of test
which is must be included in a complete test. Uncertainty analysis in ASME PTC 4-2013 "Fired Steam Generators Performance Test Codes" is explained detailedly.Taking efficiency test of 350 MW pulverized coal boiler as an example
uncertainty analysis of test result is calculated. The effect of each parameter is contrastively analyzed
and reducing uncertainty of efficiency test is discussed.