Classification societies will typically
require arrangement drawings indicating all the hazardous areas on the vessel. As a guideline for ME-GI type engines, Figure 8 shows a typical installation and designation of hazardous areas.
LNG bunkering and tanks Typically, the location and arrangement of the bunker station will need to be included in the ship design. Furthermore, it may be required to specify in detail all the piping and equipment used in the bunker station. When designing the bunker station, one of the key factors is the filling capacity requirement. Tis needs to be matched with both
the bunker barge or terminal and the amount of time the vessel has to bunker. Moreover, it is important to consider the allowable LNG tank pressures onboard the vessel, and how this will affect the LNG bunkering process. It is certainly recommended to have an LNG bunkering procedure in place at this stage, so it is already factored in at the design stage. As the most expensive item in the
LNG package, it is expected during construction that the vessel is made ready for tank installation at a later stage. Te LNG tank will have the biggest influence on the vessel design and will require some relatively detailed investigation as to the size, arrangement and location of the tank/s at this early stage. This is perhaps the most difficult factor to
Figure 8: Hazardous area designation scheme
estimate for the “gas-ready” vessel, as it is unlikely that the route of the vessel in five-10 years’ time is known.
Fuel Gas Supply system Te second most costly item is the FGS system; therefore, it is expected that this will also be installed at a later stage. Te typical layout of the FGS system will be similar regardless of supplier, as the delivery conditions are already specified by MAN Diesel & Turbo.
Inert gas system Some vessels may already have an inert gas system installed, in which case it is recommended to incorporate the additional volume required from the ME-GI, the gas piping and the FGS
into the inert gas system at the time of newbuilding. It is strongly recommended to consider
routing of all gas piping from LNG bunker stations to LNG tanks, from LNG tanks to FGS, and from FGS to main engine, and if relevant, gensets. Further material and safety requirements should also be considered in the PID.
Gas Valve Train Te gas valve train (GVT) is MAN Diesel & Turbo’s designation for the high-pressure gas valve unit, familiar to low-pressure gas systems. MAN Diesel & Turbo has worked closely with sub-suppliers to develop a novel solution, which is both compact, easy to maintain and flexible with regard to the vessel design requirements. NA
Figure 9: An assembled gas valve train The Naval Architect March 2016 35
Feature 3
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