We have noted, whilst analysing claims, an increase in the number of contamination incidents. The defence of claims of this nature relies heavily on the samples taken during loading and discharging operations.
However we are increasingly seeing cases of poor labelling, incorrect sealing, the use of dirty sample bottles or the incorrect bottle type for the product. In some cases samples were not even taken. Therefore we have produced these guidelines to assist and advise Members on the general procedures required for taking samples.
General Advice
These procedures apply only to clean petroleum products, typically diesel, gas oil, gasoline, jet fuels, condensates, and similar. They are not applicable to crude oil, chemicals or liquefied gases. Samples are drawn to protect the Master, owners or charterers from contamination or specification related claims and to provide evidence that the cargo had been loaded, carried and discharged in good condition without any deterioration.
However, to be fully effective the sampling procedure must be thorough, and must positively identify samples months after they were taken. Sample bottles must not be reused even if “cleaned”, as traces of contaminants could remain inside and may affect subsequent samples.
Masters, tanker officers and owners should be aware that cargo inspectors are rarely working for the vessel’s interests. They usually receive their instructions from charterers and/or shippers.
Masters must always seek confirmation of who the cargo inspector is representing when boarding vessels to draw samples and calculate quantities. If it is considered necessary the Member should appoint an additional cargo inspector.
This sampling procedure should be implemented irrespective of the attendance on board of independent inspectors.
Safety
This document is not intended to deal with the safety aspects of drawing samples, but we would remind vessels’ officers that they must wear the necessary personal protective clothing at all times, including gloves and respirators where necessary. Material Safety Data Sheets must be consulted for each product being loaded. Also, vessels’ officers must be aware of the possibility of pressure in pipelines and tanks before drawing samples.
Sample receptacles
Clear glass bottles or metal cans can be used for almost all clean petroleum products. Plastics must not be used. Each sample should not be less than 500 ml (half litre).
Number of samples
Normally a single sample drawn from each tank and manifold is sufficient for key test analysis in the event of an alleged contamination. If the Master has reason to suspect that there may be quality issues then extra samples should be drawn from each tank and manifold.
If the independent inspector/surveyor takes any additional samples, these should also be duplicated by the ship’s officers.
Samples to be drawn 1. Before loading
The Chief Officer must ensure that the sampling equipment is clean and suitable for the cargo to be sampled. Particular care should be taken when sampling the more sensitive cargoes such as jet fuel. There have been many instances where claims for contamination have occurred when the cargo was in perfect condition but the samples were contaminated by dirty sampling equipment. Ideally it is preferable to have a set of sampling equipment for each type of product to be handled.
2. At the start of loading
The Chief Officer or Officer of the Watch, should draw:
- One sample from each manifold at the start of loading for all grades.
- One sample from each manifold five minutes after start of loading for all grades.
Note: The manifold sampling point should be cleared first to ensure that no water or residues of previous cargo remain trapped in the sample point.
3. During loading
- One sample from each of the vessel’s tanks when approximately 25cm (or one “foot”) has been loaded into the tank.
Notes: Almost all shore terminals will draw “first foots” when loading jet fuels and lubricating oils. They may or may not draw “first foots” with other grades. Notwithstanding the shipper’s requirements it is always prudent for the vessel’s officers to draw their own “first foot” samples.
Loading need not be stopped when drawing “first foots” but many terminals will insist that loading is suspended until analysis is carried out by their representatives.
4. After loading
- One sample each from the upper, middle and lower part of each loaded cargo tank (i.e. three from each tank).
Notes: If the vessel has a limited number of sample bottles or cans then a composite can be made for each cargo tank. This composite must be made up of a third drawn from the upper part, a third drawn from the mid part, and third drawn from the lower part of each individual tank.
Running samples¹ should not be drawn.
5. Prior to discharge
- One sample each from the upper, middle and lower part of each cargo tank to be discharged, (i.e. three from each tank).
6. At the start of discharge
- One sample from each manifold at the start of discharging for each and every grade.
Sample management 1. Examination of samples
Tanker officers must visually examine samples when they draw them: Specifically, they must check for:
- Water - Are there any droplets of water on the inside of the sample receptacle? Is there any free water in the sample?
- Particles - Are there any visible particles? If so, what are they and where did they come from?
- Colour - Is the sample colour typical for that grade? Is there any deterioration in colour? Officers should be familiar with the expected colour of each grade. A comparison can be made with the samples drawn from the shore tanks before loading (if available).
- Odour - Is the odour typical for that grade? NOTE: it is often very easy to detect the presence of a highly volatile product (such as gasoline) in a less volatile product (such as diesel) by smell.
If the Officer suspects that the samples are contaminated in any way, then in the first instance it is prudent to take a second sample to confirm the findings. The Chief Officer and/or Master must be informed immediately if the Officer has any doubt about the quality of the samples.
2. Labelling
Labels to be fixed to each sample receptacle showing:
- Name of ship
- Port and berth number
- Tank or manifold number
- Grade of product, and load or discharge operation
- Date and time
- Name, rank and signature of the sampler
- Name and signature of a witness (preferably a shore representative) Samples should always be sealed and the seal numbers should be recorded in a separate sample log book.
3. Retention
Samples to be retained for a minimum of three months, or until the cargo has been delivered without complaint (whichever is the longer).
Samples must be kept locked up out of direct sunlight.
4. Disposal
Labels to be removed from samples before disposal from the vessel.
Samples must only be disposed of in a proper way, in accordance with environmental legislation. Samples must not, under any circumstances, be “dumped” into the sea. It may be possible for samples to be added to a future cargo or the slop tanks.
A quick reference checklist is included below detailing the optimum times for samples to be taken. We are grateful to C F Spencer & Co Ltd (Tel: +44 1934 822666 - Web: www.cfspencerandcoltd.com) for providing this information.
At Loading:
- The Manifold(s)
- First Foot
- Top / Middle / Bottom
- At Discharging:
- The Pump(s) inlet / outlet
- Top / Middle / Bottom
- The Manifold(s)
When: - At Start and after five minutes - As soon as a problem has arisen
Check:
Pipeline Tank and IG isolations? Clean equipment? (Check inspector’s equipment too!) Separate high flash/ low flash sampling gear?
Advise: The shore / The Master / P&I Club
¹ “A sample obtained by submerging an un-stoppered beaker or bottle from the surface of the liquid to a point as near as possible to the shore tank draw off point or about one foot above the level of the free water in a ship tank, and then raising it without letting it rest, at a rate so that it will be about 75% full as it emerges from the liquid” taken from the American Petroleum Institute “Manual of Petroleum Measurement Standards (MPMS)”.