Lessons Learned: Implosion Of Chemical Tank


IMCA highlights the lessons learned during the implosion of the chemical tank.

What happened?

A chemical tank, partly filled with Monoethylene Glycol (MEG), imploded on the back deck of a vessel, resulting in a spillage of around two cubic metres of MEG to the back deck and to sea, and unrepairable damage to the tank itself. There were no injuries. The tank was a 26 cubic metre tank, containing 10 cubic metres of MEG.

What went wrong?

The implosion happened due to a vacuum in the tank because the MEG was pumped out into a storage reservoir on the vessel during mobilisation.

A 20 cubic metre tank had been planned for and agreed, but a different and larger type of tank, of 26 cubic metre capacity, was delivered;

The new tank was unfamiliar to the third-party operators and no documentation was available before starting pumping operations. This type of tank requires a manual air inlet valve to be opened on top of the tank, allowing air inlet and avoiding vacuum. Due to a lack of knowledge and documentation, this valve was not opened as it should have been, hence creating a sufficient vacuum in the tank to cause it to implode five days later.

The supplier of the tank and pre-commissioning services was new to the company;

  • Although the supplier had been audited before the work, the audit did not generate sufficient insight into the capabilities and experience of the supplier;
  • The possible risks arising from the fact that the supplier was new were not recognised in the risk assessment;
  • Only a “standard” onboarding/scope familiarisation was done, there was no adaptation specific to new suppliers.

The tank type and specification (it was a carbon fibre tank) were unknown to both the third-party operators and the suppliers;

The suppliers’ personnel did not inform any company personnel that they were not familiar with this type of tank;

The tank was operated without manuals/datasheets reviewed at the time.

Actions taken

  • Increased focus and follow-up of new suppliers, with specific onboarding arrangements to offshore routines and in-depth familiarisation with to scope of work;
  • Ensure that operators of equipment are familiarised with equipment specifications and modes of use, including risk assessment and documentation requirements;
  • Ensure that Management of Change (MoC) is properly applied when equipment is changed out, and also when it involves third-party equipment.

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Source: IMCA