Petroleum liquids | SAM-205

One aggregate sample from one or more incremental samples taken from different heights depending on the liquid level in the tank and number of tanks chosen randomly or systematically throughout the consignment, see sampling of liquids in the General part.

For liquid level >3 m usually three samples are taken from at least three heights: approximately 15 % from the bottom, half-way up and approx. 15 % from the top surface of the product in each lot.

Check the homogeneity of the lot — if the homogeneity is in doubt, take more incremental samples. More aggregate samples should be created from tanks if containing different products or lots.

An aggregate sample is prepared from incremental samples taken from the same tank. If an aggregate sample is for multiple tanks, it must consist of proportional parts from each tank sampled.

Sample is usually taken by dipping vessel from top openings through the hatch or by means of special sampling taps placed at the side of tanks at the correct heights. Cross-sectional sampling can be also used. A vacuum pump may also be used if the depth from which the sample is to be taken does not exceed 4 m and the viscosity of the liquid is not too great.

Samples can be also taken during loading or discharging as the fuel is being moved.

Most large marine vessels have facilities for inline sampling (automatic continuous sampling). It is not possible to take manual samples due to safety and environmental regulations. Ships use airtight systems, to enable recuperation of flammable gases.

Usually, the total capacity of a marine vessel for the transport of liquid cargo is divided into a number of independent zones (reservoirs, sections, compartments, etc.), which may have different sizes. The sampling procedures and the formation of aggregate samples are the same as described for stable metal vertical or horizontal cylindrical tanks. Incremental samples are taken from each tank.

An aggregate sample is prepared from incremental samples taken from the same tank. If an aggregate sample is taken from multiple tanks, it must consist of proportional parts from each tank sampled.

Bunker tanks contain fuel for the engine of marine or river vessels. Bunker tanks are shaped to fit in places which cannot be used for other purposes. The filling pipe will often be an irregular shape. In some cases, it is possible to take a sample through the filling pipe or from the tap at the water separator and/or filter unit. If water or sediment are seen, these samples must be discarded, and a sample is taken when no further signs of water or sediment are present.

This sample is used for the test of the fuel marker.

Railway and road vehicle tanks can be considered as horizontal cylindrical tanks.

One aggregate sample from one or more incremental samples taken from different heights depending on the liquid level in the tank and number of tanks chosen randomly or systematically throughout the consignment, see sampling of liquids in the General part.

For liquid level < 3 m usually one incremental sample is taken from the middle of the tank. Check the homogeneity of the lot - if the homogeneity is in doubt, take more incremental samples. Separate aggregate samples should be created from tanks containing different products or lots.

An aggregate sample is prepared from incremental samples taken from the same tank. If an aggregate sample is for multiple tanks, it must consist of proportional parts from each tank sampled.

Sample is usually taken by dipping vessel from top openings through the hatch or by means of special sampling taps placed at the side of tanks at the correct heights. Cross-sectional sampling can be also used. A vacuum pump may also be used if the depth from which the sample is to be taken does not exceed 4 m and the viscosity of the liquid is not too great.

Sample can be also taken after loading or before discharging as fuels being moved.

One aggregate sample: Where the product is being mechanically moved by gravity, pumps or other equipment, there may be diverter valves at the side of fuel line that allow samples to be drawn at regular intervals determined by the moving speed from the fuel stream, see sampling from moving cargo in the General part.

This procedure is also used for sampling of bottom-loading vehicle tanks during loading or unloading:

• The sample is taken during fuel loading or discharging at designated places only, e.g. a petrol station or refinery or by means of closed pumping system with vapour recuperation.
• The sampling is done using equipment for continuous automatic or manual sampling, which transfers equal increments of liquid from the pipeline to the sample container.
• Before a sample is drawn, the sampling equipment, tap and tube approximately must be rinsed by the sampled product approximately three times.
• Sample is taken directly into the sampling bottle (or into the mixing vessel) when approximately 20 %, 50 % and 80 % of the total volume of the tank has been discharged.

One aggregate sample of fuel is taken by means of dispensers on the filler pipes.

At least 4 l of fuel must be discarded before sampling if there is no evidence that the tube of the fuel pump contains fresh fuel.

The sample container for the final samples is directly filled by sample using a funnel or an extension tube in order to prevent fuel evaporation. The sample container should be slowly filled in order to prevent foaming.

The container must be filled to a maximum of 80 % to 90 % of its volume, to allow expansion due to heat.

One or more aggregate samples: from incremental samples (one or more depending on the product homogeneity, number of containers) drawn from the middle of each container chosen randomly or systematically throughout the consignment, see sampling from transport packages in the General part.

Equal quantities of incremental samples are taken from different transport containers found at different positions in the transport vehicle or in the storage facility.

An aggregate sample may be formed only from containers from the same lot contained in the same consignment. If there are several lots, they should be identified and sampled separately.

If possible, always properly homogenize the content of the container.

The sampling is performed by using a vacuum pump, various pipette-type samplers or other appropriate samplers.

If a sample is taken from only one container (e.g. barrel), it is poured directly from the sampler into the sample container.

• Continuous automatic sampling (fuels being moved) is always the preferred method as opposed to manual sampling.
• Crude petroleum and residual fuel oils are usually non-homogeneous. The number of incremental samples is to be agreed to by all parties involved unless continuous automatic sampling is applied. When it is not possible to obtain an agreement of all involved parties (for enforcement or when the owner is unknown) the sample is taken using the sampling plans given above.
• Petrol and distillate products are usually homogeneous, but they are often in tanks that have clearly separated water at the bottom. Manual sampling in accordance with the procedures set out above is acceptable. When the sample bottle contains visible water, then measure the layer of water in the tank. Discard this sample and take a new sample from the fuel above the water layer. The same applies for sediment in the sample.
• After obtaining the sample, close the bottle immediately with a tight-fitting stopper and check the tightness (leakage test).
• When possible, take a running sample directly into the sample bottle. This reduces the possibility of air absorption, loss of vapours, and contamination. Just before sampling, rinse the bottle with the product to be sampled. Use pre-cooled bottles in summer months for volatiles (petrol).
• If a mixing vessel is used, it must be pre-washed with the sampled product. All incremental samples from all sampling spots are collected and after they have been thoroughly mixed, an aggregate sample is created. Use a pre-cooled mixing vessel in summer months for volatiles (petrol).
• The sample should be handled and packaged in a well-ventilated place or outdoors.
• Remember that some impurities and residual water are always present at the bottom of the tanks.

• Fill in the sampling form. One copy should be attached to the samples and one copy should be kept for the record.

• Samples must be labelled to indicate the specific nature of their hazard (symbols or code letters).
• Flammable liquids are a hazardous material the transport of which is governed by ADR rules. Exemptions for dangerous goods packed in limited quantities can be applied. When combination packages are used (consisting of an inner and an outer packaging not liable to break or be easily punctured), it is permitted to transport a maximum of 30 l, of which a maximum of 10 l may be class 1 flammable products e.g. petrol, see Transport in the General part. The transport vehicle must carry a suitable fire extinguisher.

• Store in a cool, dark, dry and well-ventilated place, away from heat sources.
• Keep container tightly closed in order to prevent loss of volatile components and cross-contamination with other samples.
• Use ventilated cabinet for flammables if available.
• Appropriate warning signs should be displayed.