All vessels with combustion engine plant shall be equipped with at least two starting air compressors, of which at least one shall be independently driven. The total capacity shall be sufficient to charge the starting air receivers from atmospheric to full pressure within one hour. There shall be at least two starting air receivers of approximately same size with enough capacity to allow 12 starts for reversible propulsion engines/ 6 starts for non-reversible propulsion engines and 3 starts for each for other engines (i.e. engines driving generator sets, emergency generator and engines for other purposes) without reloading air receivers. For multi-engine propulsion plant the capacity shall be enough for three starts per engine, anyhow the total capacity shall not be less than 12 starts and does not need to exceed 18 starts. //DNV-RU-SHIP Pt.4 Ch.6 Sec.5.9.4
If the emergency generator is arranged for pneumatic starting, the air supply shall be from a separate air receiver. The emergency starting air receiver shall not be connected to other pneumatic systems, except for the starting system in the engine room. If such a connection is arranged, then the pipeline shall be provided with a screw-down non-return valve in the emergency generator room. //DNV-RU-SHIP Pt.4 Ch.6 Sec.5.9.4
Starting air compressors shall be protected by safety valves. Starting air receivers shall have safety valves, or in cases where the receiver is already protected by the safety valve on compressor, alternatively a melting fusion plugs for quick release of pressure in case of fire can be installed. Air intakes for the compressors shall be located so that they minimize the intake of oil or water contaminated air. Pipes from air compressors with automatic start shall be fitted with a separator or similar device to prevent condensate from draining into the compressors. There shall be a non-return valve installed at the compressor outlet pipe, and no connections to other machinery systems between the compressor and receiver. An isolation non-return valve or equivalent shall be installed at the starting air supply connection to each engine. //DNV-RU-SHIP Pt.4 Ch.3.2.11.5, Pt.4 Ch.7 Sec.5.2.2 and Pt.4 Ch.5.4.2
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. For starting air system pipe class III is sufficient. Control system functional description for pumps and valves is subject 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

Starting air compressors shall be delivered with product certificates. Compressors shall be equipped with water trap and an after-cooler. Each compressor stage shall be fitted with a pressure gauge with a scale indicating the relevant maximum working pressure. Depending on the size and the type of compressor other control and monitoring devices may be required as per DNV-RU-SHIP Pt.4 Ch.5 Sec.4.5.1.1 Table 11. //DNV-RU-SHIP Pt.4 Ch.5 Sec.4
Low starting air pressure alarm shall be provided on the navigating bridge and in the machinery space. The alarm level shall be set at a level to permit further main engine starting operations. If the remote-control system of the propulsion machinery is designed for automatic starting, the number of automatic consecutive attempts which fail to produce a start shall be limited in order to safeguard sufficient starting air pressure for starting locally. //SOLAS Ch. II-1/31.2.9 and DNV-RU-SHIP Pt.4 Ch.1 Sec.4

Last modified: Thursday, 4 May 2023, 4:28 PM