In the Tagliabue Open Cup Test, the liquid sample is placed in an open cup apparatus, and the temperature is gradually increased. An ignition source, like a small flame, is periodically introduced above the surface of the liquid. The flash point is the temperature at which a flash is observed, indicating that the vapor concentration has reached a flammable level. This test provides an open environment, unlike the closed cup test, and is typically used for less volatile substances.
