What a Can Test Can Do

When carrying a Group A cargo, the IMSBC Code requires the shipper to provide the Master of the vessel with a cargo declaration and show the cargo is safe for carriage by testing representative samples using approved test procedures in a laboratory.

However, in some trades these declarations and laboratory test result certificates are not always reliable. So, how can the crew help protect themselves?

There is a test that can provide an early warning of a cargo’s potential to liquefy, and when carried out properly can save lives – the ‘Can Test’.

What a Can Test CAN do and what it CANnot do

The Can Test is a simple and useful check available to the ship’s crew. When performed correctly, it can help determine if a cargo might be unsafe.

But importantly, the Can Test is not a replacement for proper laboratory testing and as such is not to be used as a means of determining if the cargo is safe for loading.

The IMSBC Code recognises that the Can Test determines the “possibility of flow”. It is not an absolute indicator. If, after the test has been conducted properly, the surface of the sample has free moisture or displays fluid conditions, then there is the possibility the cargo could liquefy.

Furthermore, section 8.4.2 of the Code says:

“if samples remain dry following a can test, the moisture of the material may still exceed the transportable moisture limit”

It is clear therefore, that the Can Test cannot be used to assess if a cargo is safe for loading. There is no such thing as a ‘PASS’ or ‘FAIL’ result for a Can Test.

Masters and attending surveyors are reminded to only use the Can Test as a complementary test and not as a replacement for correct geotechnical testing.

If a Can Test shows free moisture or fluid conditions the Master should make further enquiries about the cargo’s suitability for loading, but it may not mean the cargo is definitely unsafe for carriage.

Stop and ask

If you have a Can Test result showing free moisture or fluid conditions, stop loading and seek expert assistance.

If you have concerns on the reliability of documentation or the Can Test results (even if the result of the test appears dry), take photographs of the Can Test, before and after, and seek expert geotechnical advice.

Find out more

North has produced a briefing on cargo liquefaction that can be read here.

North has also produced an onboard training pack for crews on the importance of the Can Test, how to do it properly and how to interpret the results, which can be found here.

The Can Test – how to do it right

Section 8.4 of the IMSBC Code gives instruction on how to conduct a Can Test, which is summarised below:

• Take a rigid cylindrical can – (0.5 to 1 L capacity)
• Half fill with a sample of the material
• Bring it down sharply from a height of about 0.2 m
• Repeat 25 times – at 1 to 2 second intervals
• Take high definition pictures and video
• Examine the surface for free moisture or fluid conditions
• If free moisture or a fluid condition appears DO NOT LOAD and SEEK ADVICE