Flash point testing determines the minimum temperature at which a liquid gives off enough vapor to become ignited near its surface. To determine a liquid’s flash point, a sample is heated, often while stirring, until a nearby ignition source is able to ignite the vapors. For samples with particularly low flash points, refrigeration is often required before analysis.

The sample cup used for flash point analysis can be open or closed. One advantage of the closed-cup test is that no fumes are released into the lab. However, confining the vapors in the closed cup results in a lower measured flash point compared with an open-cup measurement.

The most common applications for flash point analysis are for crude and refined fuels, and lubrication oils. In addition to standard laboratory instruments, online flash point analyzers exist for fuel processing operations. One particular function is the analysis of used lubricant; as engine oils change chemically through use, their flash points change, signaling degradation. This analysis is also often used to classify hazardous materials and waste for transport or disposal. In the US, the Department of Transportation considers a liquid flammable if it has a flash point lower than 100 °F (38 °C). Other applications include the testing of aroma products such as flavors and fragrances, as well as solvent-based paints and varnishes.

In most cases, flash point testing must be conducted with a particular test method based on certain regulations. For example, the Cleveland open-cup method (ASTM D92) tests petroleum products with flash points greater than 79 °C, while the Pensky-Martens closed-cup method (ASTM D93) tests fuel oils and liquids with suspended solids. Both of these methods require sample volumes of 75 mL. Flash point apparatuses are often capable of performing more than one method.

PAC, a Roper Technologies company, is one of the top suppliers of flash point testers through its Herzog brand. In September 2014, the company introduced the Herzog Optiflash Pensky-Martens flash point instrument (see IBO 12/31/14). It is capable of detecting flash points up to 400 °C and is compliant with global standards such as ASTM D93 and ISO 2719.

Grabner Instruments, a subsidiary of AMETEK, is known for its Miniflash series of closed-cup flash point analyzers. These instruments require only 1–2 mL of sample, the result of their compliance with ASTM D6450 and ASTM D7094.

Koehler Instrument is also a leading vendor, offering numerous models that conform to all major test methods. Anton Paar entered the market in February 2012 with its acquisition of Petrotest (see IBO 02/29/12).

Other significant vendors of instruments for testing flash point include Eralytics, Stanhope-Seta and TANAKA Scientific, and many small vendors also offer the technology. The laboratory market for flash point analysis was about $25 million in 2014.

Flash Point Analyzers at a Glance:

Leading Suppliers

• PAC (Roper Technologies)

• Koehler Instrument

• Grabner Instruments (AMETEK)

Largest Markets

• Energy

• Petroleum

• Chemicals

Instrument Cost

• $900–$30,000