What factors are important when taking oil samples from a tank?

When taking oil samples from a tank, the day’s weather and the temperature of the oil are crucial factors. The weather conditions can influence the viscosity of the oil and its behavior when sampled. For instance, colder temperatures can increase oil viscosity, potentially affecting the collection process and the representativeness of the sample. Additionally, oil temperature at the time of sampling is vital because it can affect the stability of the oil's components and any contaminants that may be present. Taking samples at varying temperatures can lead to inconsistent results, and care should be taken to ensure that the oil is sampled at a temperature that reflects its typical operating conditions.

Other factors, while they may hold some relevance, do not directly impact the sampling process as significantly as weather and oil temperature do. For example, aspects like tank pressure or service history can provide context for the oil's condition or potential contaminants but do not affect the immediate sampling methodology or the accuracy of the sample in the way that temperature does.