Alternatives to Wall Wash inspections could improve safety

In his presentation at the International Tanker Shipping & Trade Conference in Athens in November, Guy Johnson, owner of L&I Maritime UK, said that an increasing number of chemical suppliers were moving away from Wall Wash inspections, due to the perceived limitations and subjective nature of this method.

Wall Wash inspections are based on the application of solvent on the cargo tanks’ internal walls, coupled with testing various different parameters. However, Mr Johnson explained that the Wall Wash standards are not industry-wide, vary from case-to-case, and cover less than 0.3% of the tank’s surface area, leaving a vast portion of the tank uninspected and assumed to be clean. “To be clear,” he said, “there is no such thing as an industry-standard wall wash.”

He continued: “The Wall Wash is based entirely on how a cargo surveyor might see the tank at the time of the inspection. It therefore follows that if one cargo tank is inspected by two different surveyors, the results are unlikely to be the same.”

In that respect, the Wall Wash inspection does not provide a definitive determination of whether a cargo tank is suitable for loading, highlighting its lack of repeatability and reproducibility. These facets alone suggest that it is not a fit-for-purpose method for determining if a tank is ready to receive cargo.

But the issue has legal implications as well. “The Wall Wash inspection is not repeatable,” said Mr Johnson. “It follows that in the event of a cargo contamination claim, it is not possible to use the Wall Wash inspection as a means of definitively determining whether or not that cargo tank was suitable for loading or not.”

It is telling, noted Mr Johnson, that inspection companies which carry out Wall Wash procedures refer to the inspection as ‘advice’, and do accept responsibility for the results.

An alternative method — washing water analysis — is now being proposed, as it can detect contaminants invisible to the naked eye, represents the entire internal surface area of the tanks, and allows the optimisation of cleaning procedures.

“The Wall Wash inspection does not provide a definitive determination of whether a cargo tank is suitable for loading”

The washing water technique also reduces fuel and cleaning chemical consumption, enhances crew safety by reducing instances of confined space entry, and potentially decreases time spent alongside loading jetties.

Cleaning to a Wall Wash standard was determined to significantly increase CO2 emissions with no requisite benefit, prompting the need to address commercial pressure from cargo interests, which arbitrarily determine pre-loading inspection specifications.

In his case study, Mr Johnson cited two instances of how wash water analysis gives a clear indication of contaminants under analysis, reducing through each successive washing process, to a virtual flatline. Bearing in mind the analysis of the wash water is done at the manifold, the results are for the tank and the pipes, a far superior analysis than a small section of tank wall.

Mr Johnson noted that prominent cargo companies and receivers have shown interest in embracing washing water analysis, setting KPIs related to confined space entry and greenhouse gas emissions during tank cleaning. Efforts now need to be made to address the fear of change within the industry and communicate the advantages of this alternative inspection method.