Section 11 Factory Acceptance Test and Shipboard Trials of Internal Combustion Engines
Clasification Society 2024 - Version 9.40
Clasifications Register Rules and Regulations - Rules and Regulations for the Classification of Naval Ships, January 2023 - Volume 2 Machinery and Engineering Systems - Part 2 Prime Movers - Chapter 1 Reciprocating Internal Combustion Engines - Section 11 Factory Acceptance Test and Shipboard Trials of Internal Combustion Engines

Section 11 Factory Acceptance Test and Shipboard Trials of Internal Combustion Engines

11.1 Safety

11.1.1 Before any test run is carried out, all relevant equipment for the safety of attending personnel is to be made available by the manufacturer/ shipyard and is to be operational. This is to include crankcase explosive conditions protection, overspeed protection and any other shutdown function.

11.1.2 The overspeed protective device is to be set to a value which is not higher than the overspeed value that was demonstrated during the type test for that engine. This set point is to be verified by the Surveyor.

11.2 General

11.2.1 Engines which are to be subjected to trials on the test bed at the manufacturer’s works and under attendance by the Surveyor(s) are to be tested in accordance with the scope of works trials specified in Vol 2, Pt 2, Ch 1, 11.3 Works trials (factory acceptance test). The scope of the trials is to be agreed between the LR Surveyor and the manufacturer prior to testing.

11.2.2 Where multiple engines of the same design are manufactured, a quality assurance approach to approval may be applied if the manufacturer meets the requirements of and is registered on the Quality Assurance Scheme for Machinery (QAM), see Vol 2, Pt 2, Ch 1, 10 Safety arrangements.

11.2.3 Before any official testing the engines are to be run in as prescribed by the engine manufacturer.

11.2.4 Adequate test bed facilities for loads as required in Table 1.11.1 Scope of works trials for engines are to be provided. All fluids used for testing purposes such as fuel, lubrication oil and cooling water are to be suitable for the purpose intended, e.g. they are to be clean and if necessary, pre-heated to achieve the recommended operating temperature. This applies to all fluids used temporarily or repeatedly for testing purposes only.

11.2.5 Survey of the engine is to include:
  1. Jacketing of high-pressure fuel oil lines including the system used for the detection of leakage.
  2. Screening of pipe connections in piping containing flammable liquids.
  3. Insulation of hot surfaces by taking random temperature readings that are to be compared with corresponding readings obtained during the type test. This is to be done while running at the maximum approved rating for the actual application. Use of contact thermometers may be accepted at the discretion of the attending Surveyor. If the insulation is modified subsequently to the Type Approval Test, LR may request more enhanced temperature measurements as required by the LR’s Type Approval Test Specification No. 4, Chapter 2, 1.3.10 (Fire Protection Measures).

These surveys are normally to be made during the works trials by the manufacturer and the attending Surveyor, but at the discretion of LR parts of these surveys may be postponed to the shipboard testing.

11.2.6 Where the type test was not carried out on the complete engine, as described in Vol 2, Pt 2, Ch 1, 1.2 Scope 1.2.2, integration tests are to be conducted as part of the works or shipboard trials to confirm satisfactory operation of the complete engine. This includes satisfactory functioning on all fuel types on which the engine is to operate. See also Vol 2, Pt 2, Ch 1, 11.4 Shipboard trials 11.4.6.

11.3 Works trials (factory acceptance test)

11.3.1 The purpose of the works trials is to verify design parameters such as power, adherence to approved limits (e.g. maximum pressure) and functionality, and to establish reference values or base lines for later reference in the operational phase.

11.3.2 During testing the environmental conditions are to be recorded, including ambient air temperature, ambient air pressure and atmospheric humidity.

11.3.3 For each load point the parameters to be recorded include: power and speed; fuel index (or equivalent reading); maximum combustion pressures; exhaust gas temperature before turbine and from each cylinder (or from manifold, see Note 5 in Table 1.7.1 Engines for propulsion purposes: Alarms and slow-downs); charge air temperature and pressure; and turbocharger speed (only for category B and C turbochargers).

11.3.4 For all stages of the works trials the pertaining operation values are to be measured and recorded by the engine manufacturer. All results are to be compiled in an acceptance protocol to be issued by the engine manufacturer. Where the engine designer requires through life monitoring of crankshaft deflections, such measurements are also to be taken before and after works acceptance trials in accordance with the engine designer’s requirements.

11.3.5 In each case given in Table 1.11.1 Scope of works trials for engines, all measurements conducted at the various load points are to be carried out at steady operating conditions. The readings for MCR, i.e. 100 per cent power (rated maximum continuous power at corresponding rpm) are to be taken twice at an interval of at least 30 minutes. For all load points provision should be made for time needed by the Surveyor to carry out visual inspections.

11.3.6 Calibration records for the instrumentation are, upon request, to be presented to the attending Surveyor.

Table 1.11.1 Scope of works trials for engines

Main engines driving propellers and waterjets
Trial condition Duration Note
100% power (rated power) at rated engine speed, R ≥60 minutes
110% power at engine speed corresponding to 1,032*R 15 minutes Or after having reached steady conditions, whichever is shorter, see Notes 1 and 4
Approved intermittent overload (if applicable) Testing for duration to be agreed with the manufacturer
90% (or maximum continuous power), 75%, 50% and 25% Powers in accordance with the nominal propeller curve, sequence to be selected by the manufacturer
Reversing manoeuvres (if applicable)
Testing of governor and independent overspeed protective device See Vol 2, Pt 2, Ch 1, 7 Control and monitoring of main, auxiliary and emergency engines
Shutdown device See Vol 2, Pt 2, Ch 1, 7 Control and monitoring of main, auxiliary and emergency engines
Engines driving generators for electric propulsion or driving generators for auxiliary purposes
Trial condition Duration Note
100% power (rated power) at rated engine speed, R ≥60 minutes
110% power 15 minutes Or after having reached steady conditions, see Note 2. For auxiliary engines, see Note 1
75%, 50% and 25% power and idle run See Note 2
Start-up tests
Testing of governor and independent overspeed protective device See Vol 2, Pt 2, Ch 1, 7 Control and monitoring of main, auxiliary and emergency engines
Shutdown device See Vol 2, Pt 2, Ch 1, 7 Control and monitoring of main, auxiliary and emergency engines
Propulsion engines driving power take off (PTO) generator
Trial condition Duration Note
100% power (rated power) at rated engine speed, R ≥60 minutes
110% power 15 minutes Or after having reached steady conditions, see Note 3
Approved intermittent overload (if applicable) Testing for duration to be agreed with the manufacturer
90% (or normal continuous cruise power), 75%, 50% and 25% For variable speed engines. Powers in accordance with the nominal propeller curve or at constant speed R, sequence to be selected by the manufacturer
Engines driving mechanical auxiliaries
Trial condition Duration Note
100% power (rated power) at rated engine speed, R ≥30 minutes
110% power 15 minutes Or after having reached steady conditions, see Note 1
Approved intermittent overload (if applicable) Testing for duration to be agreed with the manufacturer
75%, 50% and 25% For variable speed engines. Powers in accordance with the nominal propeller curve, sequence to be selected by the manufacturer
Note 1.After running on the test bed, the fuel delivery system of main engines is normally to be so adjusted that overload power cannot be given in service unless intermittent overload power is approved by LR, in which case the limit is to be adjusted to that power. The setting of the restriction is to be made as applicable to the intended fuel. Any restriction settings, and other changes to the engine’s fuel injection equipment required for operation on special fuels, are to be recorded and included by the engine manufacturer.
Note 2. After running on the test bed, the fuel delivery system of diesel engines driving generators is to be adjusted so that full power plus a 10 per cent margin for transient regulation can be given in service after installation on board. The transient overload capability is required so that the required transient governing characteristics are achieved also at 100% loading of the engine, and so that the protection system utilised in the electric distribution system can be activated before the engine stalls.
Note 3. After running on the test bed, the fuel delivery system of propulsion engines also driving power take off (PTO) generators is to be adjusted so that full power plus a margin for transient regulation can be given in service after installation on board. The transient overload capability is required so that the electrical protection of downstream system components is activated before the engine stalls. This margin may be 10% of the engine power but at least 10% of the PTO power.
Note 4. Only required once for each different engine/turbocharger configuration.

11.3.7 Alternatives to the detailed tests may be agreed between the manufacturer and LR when the overall scope of tests is found to be equivalent. The scope of the trials may be expanded depending on the engine application, service experience, or other relevant reasons.

11.3.8 Turbocharger surge margin for propulsion engines is to be demonstrated as required by Vol 2, Pt 2, Ch 1, 12.4 Matching with engine 12.4.2.

11.3.9 For electronically controlled engines:
  1. integration tests in accordance with Vol 2, Pt 2, Ch 1, 1.4 Submission requirements 1.4.2; and
  2. verification of engine configuration, see Vol 2, Pt 2, Ch 1, 4.3 Control engineering systems 4.3.2, and that the approved software quality plans, including the software configuration management process, are to be applied.

11.3.10 Checks of components to be presented for inspection after the works trials are left to the discretion of the Surveyor.

11.3.11 The testing of exhaust gas emissions is to comply with MARPOL - International Convention for the Prevention of Pollution from Ships as applicable.

11.4 Shipboard trials

11.4.1 The purpose of the shipboard testing is to verify compatibility with power transmission and driven machinery in the system, safety, control and auxiliary systems necessary for the engine and integration of engine/ shipboard control systems, as well as other items that had not been dealt with in the FAT (Factory Acceptance Testing).

11.4.2 After installation on board, engines are to undergo shipboard trials as specified in Table 1.11.2 Scope of shipboard trials for engines. The scope of the trials may be expanded depending on the engine application, service experience or other relevant reasons, and is to be agreed between the LR Surveyor and the Shipyard prior to testing.

Table 1.11.2 Scope of shipboard trials for engines

Main engines driving fixed-pitch propeller or waterjet (see Note 1)
Trial condition Duration Note
At rated engine speed, R ≥ 4 hours
At engine speed corresponding to normal continuous power ≥ 2 hours
At engine speed corresponding to 1,032*R 30 minutes Where the engine adjustment permits, see Vol 2, Pt 2, Ch 1, 11.2 General 11.2.6
Approved intermittent overload (if applicable) - Testing for duration as agreed with the manufacturer
Minimum engine speed to be determined
Starting and reversing manoeuvres See Vol 2, Pt 2, Ch 1, 9 Starting arrangements (see Note 5)
Reverse direction of propeller rotation is to be demonstrated (during the dock or sea trials) 10 minutes See also Vol 2, Pt 2, Ch 1, 11.4 Shipboard trials 11.4.7 and Vol 2, Pt 2, Ch 1, 11.4 Shipboard trials 11.4.8 (see Note 6)
Control, monitoring, alarms and safety systems Operation to be demonstrated
Where imposed, test to ensure engine can pass safely through barred speed range
Main engines driving controllable pitch propellers
Trial condition Duration Note
At 100% power ≥ 4 hours See Note 2
Approved intermittent overload (if applicable) Testing for duration as agreed with the manufacturer
With reverse pitch suitable for manoeuvring See Vol 2, Pt 2, Ch 1, 11.4 Shipboard trials 11.4.7 and Vol 2, Pt 2, Ch 1, 11.4 Shipboard trials 11.4.8 for additional requirements in the case of a barred speed range
Control, monitoring, alarm and safety systems - Operation to be demonstrated
Engine(s) driving a generator(s) for electrical propulsion and/or main power supply
Trial condition Duration Note
100% power (rated electrical power of generator) 60 minutes See Notes 3 and 4
At normal continuous propulsion power ≥ 2 hours See Note
110% power (rated electrical power of generator) ≥10 minutes See Note 4
Starting manoeuvres See Note 5
Control, monitoring, alarm and safety systems Operation to be demonstrated
Demonstration of the generator prime movers’ and governors’ ability to handle load steps - See Vol 2, Pt 2, Ch 1, 7.3 Auxiliary and emergency engine governors
Propulsion engines driving power take off (PTO) generator
Trial condition Duration Note
100% engine power (MCR) at corresponding speed, R ≥ 4 hours
100% propeller branch power at engine speed, R (unless already covered above) 2 hours
100% PTO branch power at engine speed, R ≥ 1 hour -
Control, monitoring, alarm and safety systems - Operation to be demonstrated
Engines driving mechanical auxiliaries
Trial condition Duration Note
100% engine power (MCR) at corresponding speed, R ≥ 30 minutes -
Approved intermittent overload (if applicable) - Testing for duration as approved
Control, monitoring, alarm and safety systems - Operation to be demonstrated
Note 1. For main propulsion engines driving reversing gears the tests for main engines driving fixed-pitch propellers apply as appropriate.
Note 2. Controllable pitch propellers are to be tested with various propeller pitches. The 100% power test is to be conducted at rated engine speed R with a propeller pitch set of MCR (or to the maximum achievable power if 100% cannot be reached).
Note 3. The tests are to be performed at rated speed with a constant governor setting.
Note 4. Tests are to be based on the rated electrical powers of the electric propulsion motors.
Note 5. Starting manoeuvres are to be carried out in order to verify the capacity of the starting media. The ability of reversible engines to be operated in the reverse direction is to be demonstrated. See Vol 2, Pt 1, Ch 3, 4.8 Astern power.
Note 6. Where R, or the nominal ahead propeller speed is taken at the normal ship service speed (or cruising speed). Acceptance of alternative trial conditions will be subject to consideration by LR.

11.4.3 Engines driving electrical generators are to be tested either:

  1. at 100 per cent electrical power for at least 60 minutes and 110 per cent of rated electrical power of the generator for at least 10 minutes; or
  2. During the electrical propulsion plant test which requires testing with 100 per cent propulsion power (i.e. total electric motor capacity for propulsion) by distributing the power on as few generators as possible. The duration of this test is to be sufficient to reach stable operating temperatures of all rotating machines or for at least 4 hours.

11.4.4 Trials are to include demonstration of engine control, monitoring, alarm and safety system operation to confirm that they have been provided, installed and configured as intended and in accordance with the relevant requirements for main, auxiliary or emergency engines except items already verified during the works trials.

11.4.5 For electronically controlled engines:
  1. shipboard tests in accordance with Vol 2, Pt 2, Ch 1, 1.4 Submission requirements 1.4.3; and
  2. verification of engine configuration, see Vol 2, Pt 2, Ch 1, 4.3 Control engineering systems 4.3.2 and Vol 2, Pt 2, Ch 1, 1.4 Submission requirements 1.4.3.(a), and that the approved software quality plans, including the software configuration management process, are to be applied.

11.4.6 The suitability of an engine to burn residual or other special fuels is to be demonstrated where the machinery installation is arranged to burn such fuels in service. Dual- or multi-fuel engines are to be tested on all fuels that the engine is specified to use. Where engines operate on a mix of different fuels, then this is to be demonstrated. See also Vol 2, Pt 9, Ch 12, 1.7 Unattended machinery space operation - UMS notation.

11.4.7 For both manual and automatic engine control systems, acceleration and deceleration through any barred speed range, is to be demonstrated. The transit times are to be equal or less than the times stated in the approved documentation and are to be recorded. This also applies when passing through the barred speed range in reverse rotational direction, especially during the stopping test. The ship’s draught and speed during all these demonstrations are to be recorded. Where a controllable pitch propeller is fitted, the pitch is also to be recorded.

11.4.8 The engine is to be checked for stable running (steady fuel index) at both upper and lower borders of the barred speed range. Steady fuel index means an oscillation range less than five per cent of the effective stroke (idle to full index).

11.4.9 In addition to the tests listed in Table 1.11.2 Scope of shipboard trials for engines, other tests may also be required by statutory regulations (e.g. the testing of exhaust gas emissions is to comply with MARPOL - International Convention for the Prevention of Pollution from Ships as applicable).


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