Abstract: In this study, the commonly used test methods for closed cup flash point measurement,Pensky-Martens closed cup method, Abel closed cup method and Tag closed cup method, were analyzed comparatively. The closed cup flash points of two certified reference material samples, four organic compound samples and seven jet fuel samples were tested by these three methods. It was found that there were some differences of the three methods in application scope, instrument structure, temperature rise speed, ignition operation requirements. As a result, the closed cup flash points of the same sample determined by these three methods were slightly different. The maximum difference among the test results of the same sample by the three methods was positively correlated with its flash point. In general, the flash point determined by Pensky-Martens closed cup method was a little higher than that of Abel closed cup method. For No.3 jet fuel samples, the difference of flash points was 0-1.0 ℃, and in comparison, Abel closed cup method was the most suitable for the determination of closed cup flash point of No.3 jet fuel. For pure organic compound samples, there is a good linear relationship between the results by Pensky-Martens closed cup method and Abel closed cup method.

Key words: closed cup flash point, Pensky-Martens closed cup method, Abel closed cup method, Tag closed cup method