All engines shall have at least one lubricating oil pump of sufficient capacity for the maximum output of the engine. Machinery installations for propulsion or power generation with long roll-out times, (such as gears, and large electrical motors/generators) shall be provided with a satisfactory emergency supply of lubricating oil in case of low oil pressure. Typically, this is arranged with one attached pump and one stand-by pump with immediate activation. Alternatively, there can be two electrical pumps of same size, of which one is connected to the main switchboard and one to emergency switchboard. For propulsion gears the lubrication system shall be arranged so that the gear transmission can endure a run out of 5 minutes after a black out without jeopardizing any bearings or gear teeth. Lubrication oil pumps for pro-pulsion drivers and reduction gears shall have product certificates. //DNV-RU-SHIP Pt.4 Ch.6. Sec.1.3 and Pt.4 Ch.4. Sec.2.2
Lubricating oil systems shall be separated from other systems excluding hydraulic governing and maneuvering systems for main and auxiliary engines. In systems where the lubricating oil circulates under pressure, efficient filtering shall be arranged. Non-redundant machinery units shall be fitted with filters, that can be cleaned without interrupting filtered oil supply. I.e., two filters can be arranged parallel or a duplex filter can be used. An auto-backwash filter may also be accepted. //DNV-RU-SHIP Pt.4 Ch.6 Sec.3.2
Duplex filters shall be arranged such that it is clearly visibly which chamber is in use, opening a chamber under pressure is prevented and a chamber can be vented when put back into operation. Differential pressure monitoring shall be arranged when blocked filters can cause loss of propulsion. Auto backflush filters shall be fitted with monitoring equipment for backflush intervals, and an alarm for frequent backflushing. For auxiliary and emergency generators a single filter is acceptable, as long as the emergency generator is not used as harbor generator. Drip trays under filters for lubrication oil shall be provided. For diesel engines burning residual oil fuel, cleaning of the lubrication oil by means of purifiers shall be arranged. //DNV-RU-SHIP Pt.4. Ch.3 Sec.1.6.7 and Pt.4 Ch.6 Sec.3.2

The allowed piping thicknesses for steel pipes are defined in DNV-RU-SHIP Pt.4 Ch.6 Sec.9.1 Table 2. Fire redundance requirements and list of allowed mechanical joints can be found DNV-RU-SHIP Pt.4 Ch.6 Sec.9.5 Table 9. Lubricating oil pipes with pressure under 7 bars and temperature below 60 ⁰C can be class III pipes. Pipes with pressure range 7 -16 bars or temperature 60 – 150 ⁰C degrees shall be documented as class II pipes. Piping diagram and control system functional description for pumps and valves are subjects for class approval. //DNV-RU-SHIP Pt.4 Ch.6 Sec.1, Pt.4 Ch.6 Sec.9.1 and Pt.4 Ch.6 Sec.9.5
Quick-closing valves on lube oil tanks are required when tanks are located in machinery spaces above double bottom and have normally open valves located below top of the tank or overflow outlet. //DNV-RU-SHIP Pt.4 Ch.6 Sec.3.5
Engine sumps serving as oil reservoirs shall be so equipped that the oil level can be monitored, and if necessary, topped up during operation. Means shall be provided for completely draining the oil sump. For ships where a double bottom is required, the minimum distance between shell and circulating lubricating oil tank shall not be less than 500 mm//DNV-RU-SHIP Pt.4 Ch.3 Sec.1.2.12 and Pt.4 Ch.6 Sec.5.3.1

Last modified: Thursday, 4 May 2023, 4:21 PM