Understanding the differences between closed cup and open cup flash point testing methods is essential for accurate and safe testing procedures. Each method has its specific applications and advantages.
Closed Cup Testing
In closed cup testing, the sample is placed in a sealed container with a small opening that can be exposed to an ignition source. This method generally provides lower flash point values than open cup methods because the vapors are contained.
Common Closed Cup Testers:
- Pensky-Martens (ASTM D93, ISO 2719)
- Tag (ASTM D56)
- Small Scale (ASTM D3828, ISO 3679)
Open Cup Testing
In open cup testing, the sample is placed in an open container, and the ignition source passes over the surface. This method is generally used for higher flash point materials.
Common Open Cup Testers:
- Cleveland (ASTM D92)
- Tag Open Cup (ASTM D1310)
- Setafash (ISO 13736)
Important Note:
Closed cup testers typically give flash point values 5-10°C lower than open cup testers for the same material. Always specify which method was used when reporting flash point values.
