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10 Appendices

When we compare the two cargoes we see that theyWhat is the reproducibility of the methods used at

share some contamination related speciications such as loading and discharge?
appearance, iron, non-volatile residue, and acidity, while Perhaps if tested again the discharge samples would be

some are chemical speciic and related to precursors and within speciication. Similarly, maybe the cargo would fail

degradation such as methyl chloride and ethylene dichloride. speciication if the loading samples were re-tested. Test
One may also notice that colour or appearance is an methods that do not have their reproducibility determined

important speciication on many chemical cargoes, which is are not fully developed.

intended as a way of alerting the presence of contamination.
We can exemplify a problem by revisiting our hypothetical How speciic is the test method?

situation of a VCM cargo becoming off-speciication for In the above table we see that methyl chloride, another

EDC, and propose that test certiicates at discharge report chemical of similar properties, is included in the tests and
EDC levels of 7 ppm while those at loading report 1 ppm. could conceivably be ‘picked up’ by the test for EDC as

Let’s also propose that methods used to derive these values a source of error. A quality test method would include a

are only mentioned in the discharge certiicates and are characterization of speciicity so this could be better judged.
national in origin. When referring to the parameter of EDC in

the VCM speciications above, we ind that a change in the What is the sensitivity of this method?

cargo is implied to have taken place during shipment. Even Detection levels must be within an acceptably repeatable
so, situations such as these often raise more questions than range for the method, otherwise a quantitative result is

answers and may require a more authoritative round of joint not valid. Again, a quality test method would include a

testing to settle dispute. For instance, this proposed situation description of sensitivity.
begs the following questions:

What laboratory will be used?

What methods were used at loading?Phone calls with the analyst(s) handling the samples or in-
Results obtained from discharge listed national test methods, person test witnessing can be conducted by a specialist to

which implies that different methods were used at loading, verify the quality of the procedure.

making the values from the two locations non-comparable
without a careful assessment.

Conclusion

Ultimately, it is the environment around the cargo that decides if changes occur, and therefore many off-speciications or

contaminations can be prevented if ideal conditions are always provided. Careful adherence to inerting procedures, strict

observance of epoxy curing protocols, meticulous tank cleaning, due diligence for cargo compatibility, and other precautions
help to prevent incidences. Nevertheless, many situations are not under the control of crews and their management, and

a fair determination of cause is a must once a dispute arises. As we have illustrated here, problems associated with cargo

speciications are nuanced and require careful consideration. Involved parties should be critical of the way bulk liquids are
judged without being assuming or dismissive. When a problem does occur in spite of crew foresight, and when in doubt about

the above mentioned dispute features, a specialist may be necessary to help in interpreting the situation.

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