Pour Point — ISO 3016 / ASTM D97

What Is Pour Point?

Pour point is the lowest temperature at which a petroleum product can still flow under specified conditions. The sample is cooled in a controlled manner and the flow is observed by tilting the container within defined temperature ranges; One step above the temperature at which the flow stops is recorded as the pour point.

Purpose of Pour Point

The aim is to evaluate the pumpability and storage behavior of the product in cold weather. Below the pour point, the product does not flow and pipeline and tank transfer stops.

Which Products Is Pour Point Applied To?

Diesel and heating fuels
Residual marine fuels
mineral oils
Ham petrol
Bitumen and heavy products

In Which Sectors Is Pour Point Used?

Oil & GasPetrokimyaEnergyMaritimeAutomotive

Standards Related to Pour Point

TS ISO 3016 (pour point determination)
ASTM D97 (pour point)
ASTM D5950 (automatic method)
TS EN 23015 / ISO 3015 (cloud point — relevant parameter)

Pour Point Conditions

Pre-heating: The sample is preheated according to the standard; heat history affects outcome
Cooling rate: Controlled cooling defined in the standard
observation range: It is observed by tilting the container at defined temperature levels.
Repeatability: Resolution is limited because the result is gradual

Equipment for Pour Point

Pour point cooling baths
Automatic pour point device
Kalibreli termometreler
Standard test tubes

Sample Requirements for Pour Point

Sampling determines the validity of the result in fuel analysis: ISO 3170 (manual) and ISO 3171 (automatic in-line) define the sampling rules. The sample must be taken into a clean container of a suitable material, filled with no air gap, and kept cold for volatile products.
Sample temperature history must be known; preheated sample gives different result
The sample must not contain water
For heavy products, the sample must be homogenized

Duration of Pour Point

Due to controlled cooling, the experiment takes several hours; The time is extended for products with very low pour points.

Pour Point Procedure

1The sample is preheated according to the standard.
2It is filled into the test tube at a defined level.
3It is cooled at a controlled rate.
4The flow is observed by tilting the tube at defined stages.
5The temperature at which the flow stops is determined.
6The yield point is reported as one step above.

Pour Point Acceptance Criteria

The acceptance criterion comes from the relevant product specification and varies by season, market and class. Specification versions are updated; the limit values in force for your product are confirmed from the specification text at the quotation stage.

Evaluation of Results

Yield point is a gradually measured parameter and has limited resolution; Small differences may not be significant. It alone is not sufficient to evaluate the cold behavior of diesel fuel: filter clogging begins at a temperature much higher than the pour point, so CFPP must be measured together.

Pour Point Report

Sample description and heat history
Standard and method applied
Measured pour point
Cloud point and CFPP results if available
Comparison with specification limit

Accreditation

EUROLAB holds internationally recognised accreditation obtained from accreditation bodies party to the IAF and ILAC multilateral recognition arrangements, under ISO/IEC 17025 for laboratory testing, ISO/IEC 17020 for inspection and surveillance, and ISO/IEC 17021-1 and ISO/IEC 17065 for system and product certification. This chain ensures the reports and certificates issued are accepted worldwide.

Whether this test can be offered within accredited scope depends on your product and the standard applied; since accreditation is method-based, the scope is confirmed in writing at the quotation stage.

Scope and authorisations

Related Regulations

Fuel and LPG market technical regulations (EPDK)
EU 2009/30/EC (fuel quality directive)
Communiqués on the placing of lubricating oils on the market

Petroleum, Fuel and Oil Analysis — What Does This Testing Field Cover?

The section below describes the field that the Pour Point test belongs to; the conditions and acceptance criteria of this particular test are given in the sections above. The scope specific to your product is confirmed in writing at the quotation stage.

Petroleum, fuel and oil analysis determines whether a fluid meets its specification and how it behaves in use. Standards in this field consist largely of ASTM and EN publications, with a separate method defined for each parameter.

What distinguishes this family is that product specifications are written as PARAMETER LISTS. Specifications such as EN 590 (diesel), EN 228 (petrol), EN 14214 (biodiesel) and ISO 8217 (marine fuels) state for each parameter both the limit and the method by which that limit is to be measured. If the method changes the result may change too; the specification therefore binds the method as well, and the use of an "equivalent method" is possible only where the specification allows it.

On the fuel side, parameters describe three different properties of the product. Physical properties (density, viscosity, distillation curve, pour point, cloud point) determine pumpability and cold weather behaviour. Combustion properties (cetane number, octane number, calorific value) indicate performance in the engine. Contaminant and stability parameters (sulphur, water, sediment, oxidation stability, copper strip corrosion) affect both emissions and storage life.

Oil analysis is carried out for two different purposes and the two must not be confused. Analysis of NEW oil verifies the conformity of the product to its specification: viscosity index, additive content, flash point. Analysis of USED oil, by contrast, is done to read the condition of the machine — elemental analysis shows wear metals (iron, copper, chromium, aluminium), water and fuel contamination point to leaks, and oxidation and acid number determine the remaining life of the oil.

Used oil analysis is therefore a PREDICTIVE MAINTENANCE tool. The trend of samples taken at regular intervals is followed; it is the trend rather than a single result that is meaningful. Iron levels climbing over the course of months allow intervention before a failure occurs.

Marine fuels are the most active sub-body of the field. The global tightening of sulphur limits has brought new blended fuels onto the market; for these fuels stability, compatibility (whether two fuels form deposits when mixed) and catalytic fines content have become critical parameters.

Sampling is part of the result in this family too. A sample taken from the bottom of a tank shows different water and sediment content from one taken from the upper level; in commercial deliveries the sampling point and method are set by contract.

Method groups in this field

Physical properties
Density (oscillating U-tube and hydrometer), kinematic viscosity, distillation, pour and cloud point, flash point.
Combustion properties
Cetane number and cetane index, research and motor octane number, calorific value.
Sulphur and elements
Sulphur by UV fluorescence and XRF; elemental analysis and additive content by ICP.
Stability and corrosion
Oxidation stability, copper strip corrosion, water and sediment, filter blocking tendency.
Composition analysis
Boiling range distribution by gas chromatography, hydrocarbon types (FIA), benzene and aromatics content, fatty acid methyl ester content.
Used oil
Wear metals, contamination (water, fuel, soot), oxidation, acid and base number, change in viscosity.

Commonly confused in this field

The specification binds the method as well; a result measured by a different method may not be accepted for specification conformity.
A single result on used oil is not meaningful; the decision is made on the trend.
The sampling point determines the result; the tank bottom and the upper level show different water and sediment.
The cetane index is a calculated value and is not the same thing as a measured cetane number.
Fuels blended with biodiesel behave differently in terms of storage life and microbial growth; classical diesel parameters are not sufficient.
Mixing marine fuels from different sources can cause deposits; compatibility is assessed separately.

Which decisions these results support

Conformity of a fuel lot to specification and commercial delivery
Predictive maintenance decisions based on used oil analysis
Determining parameters for customs and tax classification
Quality verification after storage, blending and transport
Compliance with sulphur limits under emissions legislation

Related Tests

Frequently Asked Questions About Pour Point

The pour point is suitable, but the vehicle does not start in winter, why?

Because filter clogging starts long before the flow point. The determining parameter is CFPP; The pour point only indicates the limit at which the product does not flow at all.