Pensky-Martens is the most popular method as described in the standards above. It is made up of 3 parts ‘A’, ‘B’ and ‘C’. Method ‘A’ is for testing fuels and light to medium oils. Method ‘B’ is generally for samples which are solid or highly viscous at room temperature. Method ‘C’ is applicable for biodiesel. The sample is heated and stirred at a steady rate of temperature increase which is specified according to the material being tested. The ignition source is applied at regular intervals until the vapours of the sample ignite, indicating the flash point temperature.
It is used to determine the flash point of petroleum products in the temperature range from 40 to 370°C by a manual or automated Pensky-Martens closed-cup apparatus, and biodiesel in the temperature range of 60 to 190°C by an automated Pensky-Martens closed cup apparatus.