The principle of uncertainty analysis from heat loss method of boiler thermal efficiency has been presented

including the establishment of uncertainty analysis model

the evaluation of uncertainty components as A and B kind

and their composition

as well as the calculation method of the expand uncertainty etc.

and the evaluation of uncertainty in boiler thermal efficiency test being carried out.Results show that the affecting factors upon test results from heat loss method of boiler thermal efficiency are mainly as follows:the oxygen content in discharged flue gas;the temperature of discharged flue gas;and dissipation heat loss curves recommended to use at the time of calculation etc..In order to reduce the uncertainty of test result

it is necessary to mainly consider how to reduce the uncertainty of these parameters.