Engineering-out enclosed space deaths
Can improved design and planning prevent fatalities? The IMarEST’s Human Element Working Group chair, Martin Shaw, believes they can
Enclosed space accidents are the biggest occupational killer aboard ship. Often the victim and others onboard are blamed for not following complex procedures. The Human Element Industry Group (HEIG) is looking at how to design-out the hazard; the logic being that you don’t need to manage a hazard that doesn’t exist. The group promotes the long-established ‘Hierarchy of Hazard Control’ to analyse and reduce risk.
Why do people enter enclosed spaces?
It’s an important question. One reason is to clean or inspect a cargo space. In fact, the vast majority of enclosed-space deaths stem from this. A cargo-related example is the ‘Australian ladder’, a spiral stairway in bulk carriers holds, introduced to prevent falls from height. This stairway is sometimes enclosed. When the vessel is loaded, it is sealed at the bottom by cargo. The space quickly shares and traps the atmosphere from a hazardous cargo, resulting in fatalities at the discharge port. An example of unintended consequences. Our group concludes that an open frame would be a safer solution, in addition to introducing locking arrangements and signage.
Sometimes the law of unintended consequences is of benefit. On crude tankers, ‘load on top’ crude oil washing and segregated ballast tanks (SBTS) were introduced to reduce oil discharges to water. Tank entry for cleaning is seldom required, dramatically reducing tank entries between drydocks. For obvious reasons, tank entries to cargo tanks on gas carriers are rare, but could we reduce entry requirements on chemical and product ships?
Fumigation of cargo is also a problem and not a new one as you can see in the memorial to John J Selby who was awarded a medal for saving CJ Coleman from suffocation on the SS Devonian in 1916, pictured here at Liverpool’s Maritime Museum.
Generally, structural surveys are carried out at special and interim docking. This means time and resources are available to properly clean, gas free and test tanks. It is, however, possible for an owner to accept annual structural surveys, using the crew, instead of expensive repairs to tanks and coatings that create a new risk. Remote surveys may substitute for some personnel entries. Drones and cameras offer potential and could also be used for cargo inspections. A more innovative approach uses laser mapping to create a ‘digital pair’ which can be re-mapped without personnel entry. Robots can also be used to clean tanks and are already being used ashore and in the bulk trade.
Beyond classification and cargo requirements, owners may have their own requirements to inspect and clean tanks. Can such tanks be designed so they require less access or cleaning without entry? Owners should also challenge assumptions in their planned maintenance system. A historic requirement for entering tanks may not be relevant now.
Equipment fitted in an enclosed space may require entry to carry out repairs and maintenance. Our group proposes fitting reliable equipment that only requires maintenance in drydock and not ‘on the run’. When this is not possible, it should be possible to remove equipment for repair without entry, as is the case with equipment fitted in cargo oil tanks.
When enclosed-space entry is unavoidable, the group has looked at improving access especially when festooned with escape breathing apparatus, safety harnesses and toolbelts. Ventilation could be improved and more innovative use could be made of gas monitoring.
The NIOSH Hierarchy of hazard control tool. Credit: NIOSH and Martin Shaw
Once the top three options on the ‘hierarchy’ are exhausted, the residual risk has to be managed by procedures and PPE. In many cases, there may not be anyone onboard who has managed entry to a particular tank. For this purpose, the group proposes an ‘enclosed space register’ listing information necessary to do the job safely. The group also proposes a method of classifying enclosed spaces in a manner that defines the precautions required. The group is also looking at how to improve the PPE used for ‘tank diving’.
The challenge now is implementing these proposals that may require changes to regulations and industry practices. For the former, the IMO is involved with our group and we have a meeting this month to discuss the way forward. For the latter, many of the organisations that author industry practices are already members of our group.
Martin Shaw MNM MBA CEng CMarEng FIMarEST AFNI is chair of the IMarEST Human Element Working Group and also represents the IMarEST on the HEIG, an influential group of NGOs working to address safety. Martin is also responsible for the Enclosed Spaces Deaths website – an IMarEST member-only website.
Want to engage more? Catch up on member-only webinars on the IMarEST TV such as Oxygen Depletion in Enclosed Spaces and Avoiding safety incidents in confined spaces using robotic technologies
To become a member of this SIG, log into your My IMarEST account, click on My Special Interest Groups and then tick the boxes of the SIGs you’d like to join. You can then also join the group on Nexus, our networking platform.”