9. Sampling
9.1 To obtain valid results, use an appropriate means of bulk sampling (see Practice D 4057) to obtain a representative sample of test oil free from suspended solid material and water. When the sample in its container is received below the dew point temperature of the room, allow the sample to warm to room temperature before opening its container. When the sample contains suspended solid material, use a filter or centrifuge to remove particles greater than 5 µm in size. Do not shake the sample of test oil. This leads to entrainment of air, and a false viscosity reading.
