Flash point test of bitumen
In common with all petroleum products, safety testing is carried out on all bitumens for either transportation, storage or application purposes.
Flash point test
There are many types of flash point depending on the properties of the test material. For bitumens both Pensky-Martens and Clevelando6lflash points are used.
Pensky-Martens closed cup (PMCC). IP IP34, ASTM D93
Approximately 80 g of the product is placed into a brass cup and a close-fitting lid attached. The sample is stirred while the temperature is raised at 5°C per minute and tested every 2°C. A lever is turned which opens a window in the lid and lowers a small flame through. The flash point is the temperature at which vapour from the sample first Ignites.
Cleveland open cup (COC), IP36, ASTM D92
Approximately 80 g of product is placed into a brass cup and heated at the rate of 5°C per minute. Every 2°C a flame is moved across the top of the cup until the flash point is reached.
Modified AbeI IP113
This test is used for cutback bitumens. It is very similar in appearance to the PMCC but because of the lower flash points has flame-proofed construction.
Abel flash point IP170
This test is used for low flash point materials such as petroleum spirits and kerosenes. Shelphalt Primer is tested using this procedure which involves heating the sample in a water jacket and stirring manually.
All flash points must be corrected for atmospheric pressure.
Open cup flash points, because the hot vapour is not confined, always give higher flash points than closed cup techniques. For bitumens, this difference is around 40-100°C.
| Grade | Flash point COC (°C) |
| Penetration grades | |
| 300 pen | 250-300 |
| 200 pen | 25-320 |
| 100 pen | 270-310 |
| 50 pen | 250-320 |
| 25 pen | 240-300 |
| Hard grades | |
| H100/120 | 280-340 |
| H80/90 | 280-340 |
| Oxidized grades | |
| R75/30 | 270-300 |
| R85/25 | 280-300 |
| R85/40 | 290-300 |
| R95/25 | 290-300 |
| R105/35 | 280-300 |
| R115/15 | 270-310 |
