This method is for determining the relative stability ofdistillate fuels such as home heating oils or diesel fuels undershort-term, high temperature, aging conditions involving airexposure. It may also be used to evaluate the effectiveness ofadditives in inhibiting sediment formation and color degradation ofdistillate fuels under conditions of the test. The test does notcorrelate well with field storage or 3 month 43°C (110°F) darkstorage.

The method, and modifications of it, have been used since 1942(C & NW RR), and it has been known by a variety of titlesincluding EMD-Diesel Fuel Stability Test, Union Pacific DieselBlotter Test (U P-Blotter Test), Santa Fe Blotter Test, Nalco 300°FTest and the DuPont F21-61 Test. Of the tests listed, the DuPontpublication is probably the most commonly used.