What will push LNG shipping towards condition-based maintenance? By Capt. Kuba Szymanski

First, let’s talk about floating storage and regasification units (FSRUs). The majority of InterManager members who have FSRUs do have condition-based maintenance on board.

That’s logical. A traditional shipping approach would repair equipment when time-based overhaul (TBO) calls for it – but when you have an FSRU, a breakdown is the last thing you want.

In order to prevent this, condition-based maintenance should be standard practice rather than a matter of waiting until time comes to carry out maintenance.

Let’s not be too hasty though, condition-based maintenance is quite complicated and the capabilities to do it effectively can be tricky to execute.

Many of the maintenance plans written by manufacturers are based upon the worst-case scenario and not necessarily for a marine environment, therefore there may be a considerable amount of slack in the TBOs if run under optimum conditions or run infrequently. This would be one of the main benefits of a condition-based maintenance plan.

We must be aware that owners seem to be working to short time scales, and condition-based maintenance just cannot deliver on a short-term basis.

The main engine manufacturers are regularly offering advice concerning extending the TBO for main components. Generally they will maintain the nominal overhaul interval in their maintenance plan, but provide recommendations for additional inspection that may allow the TBO to be extended.

There is always a sentence in these plans indicating that overhaul intervals may be reduced or extended based upon operating conditions, together with the results of physical inspection – which is essentially condition-based maintenance.

As we are seeing, only for FSRUs – for which stoppages cost a lot of money – is condition-based maintenance being considered. Members of InterManager have reported that they actually perform a lot of condition-based monitoring already, although this is sometimes forgotten, including:

  • Bunker analysis
  • Lube oil analysis
  • Cylinder oil scrap-down analysis
  • Boiler and freshwater analysis
  • Engine performance analysis (snapshot and in real time)
  • Shock pulse/vibration analysis
  • Physical inspection/measurement
  • Bearing temperature monitoring
  • Impressed current cathodic protection and marine growth protection system
  • Logging/review
  • Hull stress analysis
  • Containment system (IS and integrated bridge system) monitoring
  • Insulation testing

Based upon the maintenance package agreed with the engine maker, they can carry out performance analysis in real time or companies can provide them with recordings at agreed intervals. Therefore it should be reasonably simple to implement a condition-based maintenance plan with this level of monitoring.

There is quite an involved administrative process managing the condition-based maintenance plan. However, this should be offset by reduced unnecessary maintenance and fewer equipment failures.

 

Similar stories found at http://www.lngworldshipping.com/

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