Risk Evaluation (Marine Application)

In order to support our customers to evaluate the individual risk arising from the turbocharger for their specific application and to provide them with a basis for appropriate decisions about suitable measures to enhance containment safety, we have asked the independent institute “FutureShip”, an affiliate to Germanischer Lloyd, to carry out a risk analysis for each individual turbocharger type.

Methodology of Risk Analysis

For the maritime environment the International Maritime Organization (IMO) has established a “Guideline for the Formal Safety Assessment FSA (MSC.83 INF 2; 2007)”. In the annex of this guideline IMO provides a recommendation on the acceptance of individual risk for crew members. This recommendation refers to the cumulated risk on board seagoing vessels. IMO classified the cumulated risk as listed below:

• Negligible cumulated risk (risk number < 1E-06)
• As low as reasonably practicable (ALARP) (1E-06 < risk value < 1E-03)
• Intolerable cumulated risk (risk number > 1E-03)

whereas the risk value is defined as the likelihood of a fatal injury of an individual crew member per year. For the ALARP section, measures to limit the risk are mandatory inasmuch as they are reasonably practicable. It is common practice to carry out a cost-benefit assessment to determine the gross cost to avert a fatality. The above-mentioned IMO annex provides more concrete figures.

Based on this Formal Safety Assessment and for illustration purposes and as a reference, the Lloyds Maritime Investigation Service (“LMIS”) accident database provides the individual personal risk for different ship types. This LIMIS study is based on historical fugures and does therefore not reflect the most recent incident rates however, it represents the latest set of figures publicly available and should provide the frame of reference.

Risk values per turbocharger type and engine crew member

The given risk values per turbocharger type and engine crew member consider the average length of stay of a crew member in the hazardous area for each application, whereas for 2- and 4-stroke main engines a conservative and a favorable engine arrangement were considered:

• 2-stroke propulsion: 0.9% (favorable), 3.5% (conservative)
• 4-stroke propulsion (single engine): 0.5% (favorable), 2.3% (conservative)
• 4-stroke propulsion (multi engine): 0.9%
• 4-stroke auxiliary: 2.3 %

The further methodology of the risk assessment for NA- and NR turbochargers is described in the below documents:

• Methodology of T/C Risk Assessment for 2-Stroke Main Engines
• Methodology of T/C Risk Assessment for 4-Stroke Single Main Engines
• Methodology of T/C Risk Assessment for 4-Stroke Multi Main Engines
• Methodology of T/C Risk Assessment for 4-Stroke Auxilliary Engines

Please note that containment tests at MAN’s test facilities have shown a loss of containment in high load situations also for turbochargers with relatively low risk statistics based on observed cases or without any containment incident in the field.