Astm D 4305 – 98a (Reapproved 2004)e1 pdf free download

Standard Test Method for
Filter Flow of Aviation Fuels at Low Temperatures1

This standard is issued under the fixed designation D 4305; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of the last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval

1. Scope

1.1 This test method covers the determination of low
temperature flow behavior, through a screen-type test filter, of
aviation turbine fuels, which can contain separated solids as
wax.

1.2 Procedure A employs a 26-µm test filter and is the
recommended procedure. Some existing instruments are fitted
with a 42-µm filter, and Procedure B is retained to enable their
continued use.

1.3 The use of Procedure A (26-µm test filter) with fuels that
have a viscosity of greater than 5.0 mm2
/s (CST) at −20°C, as
determined by Test Method D 445, can affect the precision and
the simulated freezing point obtained on such fuels and can
give a higher (warmer) result than the conventional freezing
point obtained by Test Method D 2386.
NOTE 1—The principle of this test method relies on flow through a
fine-mesh test filter, and, hence, the result can be affected by the viscosity
of the sample. When using Procedure A, a no-flow condition is reached
when crystals block the test filter or the viscosity exceeds about 14 mm2
/s
(CST); sample with a viscosity of greater than 5 mm2
/s (CST) at −20°C may
exceed the 14-mm2
/s (CST) threshold at a temperature before crystals are
formed. If viscosity affects the result before crystals are formed, then the
the reported value of the no-flow temperature of the sample will always be
warmer than the actual freezing point, and therefore fail-safe and an
indicator of possible flow anomalies at low temperatures.