Section 10 Safety arrangements

10.1.1 Scavenge spaces in open connection with cylinders are to be provided with explosion relief valves.

10.1.2 Crankcases are to be provided with lightweight spring-loaded valves or other quick-acting and self-closing devices, to relieve the crankcases of pressure in the event of an internal explosion and to prevent any inrush of air thereafter. The valves are to be designed and constructed to open quickly and be fully open at a pressure not greater than 0,2 bar.

10.1.3 The valve lids are to be made of ductile material capable of withstanding the shock of contact with stoppers at the full open position.

10.1.4 Each valve is to be fitted with a flame arrester that permits flow for crankcase pressure relief and prevents the passage of flame following a crankcase explosion. The valves are to be type tested in a configuration that represents the installation arrangements that will be used on an engine and in accordance with Vol 2, Pt 2, Ch 1, 13.3 Crankcase explosion relief valves. The valves are to be positioned on engines to minimise the possibility of danger and damage arising from emission of the crankcase atmosphere. Where shielding from the emissions is fitted to a valve, the valve is to be tested to demonstrate that the shielding does not adversely affect the operational effectiveness of the valve.

10.1.5 The valves are to be provided with a copy of the manufacturer's installation and maintenance manual that is pertinent to the size and type of valve being supplied for installation on a particular engine. The manual is to contain the following information:

• Description of valve with details of function and design limits.

• Copy of type test certification.

• Installation instructions.

• Maintenance in service instructions to include testing and renewal of any sealing arrangements.

• Actions required after a crankcase explosion.

10.1.6 A copy of the installation and maintenance manual required by Vol 2, Pt 2, Ch 1, 10.1 Relief valves 10.1.5 is to be provided on board ship.

10.1.7 Plans showing details and arrangements of the relief valves are to be submitted for approval. See Vol 2, Pt 2, Ch 1, 1.4 Submission requirements.

10.1.8 The valves are to be provided with suitable markings that include the following information:

• Name and address of manufacturer.

• Designation and size.

• Month/Year of manufacture.

• Approved installation orientation.

10.2.1 Internal combustion engines having a cylinder bore of 200 mm and above or a crankcase volume of 0,6 m³ and above shall be provided with crankcase explosion relief valves.

10.2.2 In engines having cylinders exceeding 200 mm but not exceeding 250 mm bore, at least two relief valves are to be fitted; each valve is to be located at or near the ends of the crankcase. Where the engine has more than eight crankthrows an additional valve is to be fitted near the centre of the engine.

10.2.3 In engines having cylinders exceeding 250 mm but not exceeding 300 mm bore, at least one relief valve is to be fitted in way of each alternate crankthrow with a minimum of two valves. For engines having 3, 5, 7, 9, etc. crankthrows, the number of relief valves is not to be less than 2, 3, 4, 5, etc. respectively.

10.2.4 In engines having cylinders exceeding 300 mm bore, at least one valve is to be fitted in way of each main crankthrow.

10.2.5 Additional relief valves are to be fitted for separate spaces on the crankcase, such as gear or chaincases for camshaft or similar drives, when the gross volume of such spaces exceeds 0,6 m³.

10.3.1 The combined free area of the crankcase relief valves fitted on an engine is to be not less than 115 cm²/m³ based on the volume of the crankcase.

10.3.2 The free area of each relief valve is to be not less than 45 cm².

10.3.3 The free area of the relief valve is the minimum flow area at any section through the valve when the valve is fully open.

10.3.4 In determining the volume of the crankcase for the purpose of calculating the combined free area of the crankcase relief valves, the volume of the stationary parts within the crankcase may be deducted from the total internal volume of the crankcase.

10.4.1 Through ventilation, and any arrangement which could produce a flow of external air within the crankcase, is in principle not permitted except for trunk piston type dual fuel engines where crankcase ventilation is to be provided. Where crankcase vent or breather pipes are fitted, they are to be made as small as practicable and/or as long as possible to minimise the inrush of air after an explosion. Vents from crankcases of main engines are to be led to a safe position on deck or other approved position.

10.4.2 If provision is made for the extraction of gases from within the crankcase, e.g. for oil mist detection purposes, the vacuum within the crankcase is not to exceed 25 mm of water.

10.4.3 Lubricating oil drain pipes from engine sump to drain tank are to be submerged at their outlet ends. Where two or more engines are installed, vent pipes, if fitted, and lubrication oil drain pipes are to be independent to avoid intercommunication between crankcases.

10.5.1 A warning notice is to be fitted in a prominent position, preferably on a crankcase door on each side of the engine, or alternatively at the engine room control station. This warning notice is to specify that whenever overheating is suspected in the crankcase, the crankcase doors or sight holes are not to be opened until a reasonable time has elapsed after stopping the engine, sufficient to permit adequate cooling within the crankcase.

10.6.1 Where access to crankcase spaces is necessary for inspection purposes, suitably positioned rungs or equivalent arrangements are to be provided as considered appropriate.

10.6.2 When interior lighting is provided it is to be flameproof in relation to the interior and details of which are to be submitted for approval. No wiring is to be fitted inside the crankcase.

10.7.1 Crosshead type engine scavenge spaces in open connection with cylinders are to be provided with approved fixed or portable fire extinguishing arrangements which are to be independent of the fire extinguishing system of the engine room.

10.8.2 Where crankcase oil mist detection/monitoring arrangements are fitted, they are to be Type Approved by LR, tested in accordance with Vol 2, Pt 2, Ch 1, 13.4 Crankcase oil mist detection system and comply with Vol 2, Pt 2, Ch 1, 10.8 Oil mist detection 10.8.9 to Vol 2, Pt 2, Ch 1, 10.8 Oil mist detection 10.8.16.

10.8.3 The oil mist detection system and arrangements are to be installed in accordance with the engine designer's and oil mist manufacturer's instructions/recommendations. The following particulars are to be included in the instructions:

1. A schematic layout of the engine oil mist detection and alarm system showing locations of engine crankcase sample points and cabling/piping arrangements together with pipe dimensions to the detector.

2. Evidence of study to justify the selected location of sample points and sample extraction rate (if applicable) in consideration of the crankcase arrangements and geometry and the predicted crankcase atmosphere where oil mist can accumulate.

3. The manufacturer's maintenance and test manual.

4. Information relating to type or in-service testing of the engine with engine protection system test arrangements having approved types of oil mist detection equipment.

10.8.4 A copy of the oil mist detection equipment maintenance and test manual required by Vol 2, Pt 2, Ch 1, 10.8 Oil mist detection 10.8.3 is to be provided on board ship.

10.8.5 Oil mist detection and alarm information is to be capable of being read from a safe location away from the engine.

10.8.6 In the case of multi engine installations, each engine is to be provided with individual, dedicated oil mist detection arrangements and alarm(s).

10.8.7 Oil mist detection and alarm systems are to be capable of being tested on the test bed and on board when the engine is at a standstill and when the engine is running at normal operating conditions in accordance with test procedures that are acceptable to LR.

10.8.8 Alarms and safeguards for the oil mist detection system are to be in accordance with Vol 2, Pt 9 Electrotechnical Systems as applicable.

10.8.9 The oil mist detection arrangements are to provide an alarm indication in the event of a foreseeable functional failure in the equipment and installation arrangements. See Vol 2, Pt 9, Ch 7, 4.5 Control systems, general requirements 4.5.4.

10.8.10 The oil mist detection system is to provide an indication that any lenses fitted in the equipment and used in determination of the oil mist level have been partially obscured to a degree that will affect the reliability of the information and alarm indication.

10.8.11 Where oil mist detection equipment includes the use of programmable electronic systems, the arrangements are to be in accordance with Vol 2, Pt 9 Electrotechnical Systems as applicable.

10.8.12 Schematic layouts showing details and arrangements of oil mist detection and alarm systems are to be submitted. See Vol 2, Pt 2, Ch 1, 1.4 Submission requirements.

10.8.13 The equipment together with detectors is to be tested when installed on the test bed and on board ship to demonstrate that the detection and alarm system functions correctly. The testing arrangements are to be to the satisfaction of the Surveyor.

10.8.14 Where sequential oil mist detection arrangements are provided, the sampling frequency and time is to be as short as reasonably practicable.

10.8.15 Where alternative methods are provided for the prevention of the build-up of oil mist that may lead to a potentially explosive condition within the crankcase, detailed information is to be submitted for consideration. The information is to include:

1. Engine particulars - type, power, speed, stroke, bore and crankcase volume.

2. Details of arrangements designed to prevent the build-up of potentially explosive conditions within the crankcase, e.g. bearing temperature monitoring, oil splash temperature monitoring, crankcase pressure monitoring, and recirculation arrangements.

3. Evidence to demonstrate that the arrangements are effective in preventing the build-up of potentially explosive conditions together with details of in-service experience.

4. Operating instructions and the maintenance and test instructions.

10.8.16 Where it is proposed to use the introduction of inert gas into the crankcase to minimise a potential crankcase explosion, details of the arrangements are to be submitted for consideration.

10.9.1 Engines and their service systems are to be capable of operation for a period of not less than eight hours when the engine compartment is flooded by sea-water to a mean level corresponding to the height of the lowest part of the engines' crankshaft main bearing journals with the ship in the most limiting trim.