GB/T 5208-2008 introduces the fast equilibrate closed cup method for flash point determination. This method is suitable for many liquid samples. The flash point is determined by allowing the sample to quickly reach the gas-liquid equilibrate in a specific closed cup device, and then introducing an ignition source. The standard specifies the technical requirements of the required instruments, such as the specifications of the closed cup container, the characteristics of the ignition device, etc., and elaborates the sample preparation process in detail, covering the selection and injection methods of the sample. It also specifies key operating points such as the heating procedure, equilibrate time, and ignition timing. According to this standard, the flash point can be determined efficiently and accurately, providing key data for evaluating the risk of liquid fire.