Section 4 Machinery room arrangements

4.1 Accessibility

4.1.1 Accessibility, for attendance and maintenance purposes, is to be provided for machinery plants.

4.2 Machinery fastenings

4.2.1 Bedplates, thrust seatings and other fastenings are to be of robust construction, and the machinery is to be securely fixed to the ship's structure to the satisfaction of the Surveyor.

4.3 Resilient mountings

4.3.1 The dynamic angles of inclination in Table 1.3.2 Inclination of ship may be exceeded in certain circumstances dependent upon ship type and operation. The Shipbuilder is, therefore, to ensure that the vibration levels of flexible pipe connections, shaft couplings and mounts remain within the limits specified by the component manufacturer for the following conditions:

Maximum dynamic inclinations to be expected during service;
Start-stop operation; and
The natural frequencies of the system.

Due account is to be taken of any creep that may be inherent in the mount.

4.3.2 For equipment of installed power greater than 375 kW, see Pt 6, Ch 2, 1.6 Definitions 1.6.10 (b), a calculation report is to be submitted to demonstrate that the requirements of Pt 5, Ch 1, 4.3 Resilient mountings 4.3.1 are met. The calculation report is to include as a minimum:

A plan showing the arrangement of the machinery including mounts, exhaust bellows, and flexible couplings and pipe connections, as applicable; and
Maximum allowable loads and deflections and any appropriate type approval documentation for each flexible element (resilient mounts, exhaust gas bellows, flexible couplings and any other applicable flexible pipe connections) for the conditions identified in Pt 5, Ch 1, 4.3 Resilient mountings 4.3.1; and
Calculations including natural frequencies and maximum expected loads and deflections of each flexible element (resilient mounts, exhaust gas bellows, flexible couplings and any other applicable flexible pipe connections) for the conditions identified in Pt 5, Ch 1, 4.3 Resilient mountings 4.3.1.

4.3.3 Chocks are to be fitted, together with positive means to ensure that manufacturers' limits for lateral or vertical motion are not exceeded. Where resilient mounts are approved for collision loading, then the extent of any additional chocking that may be required will be specially considered. Suitable means are to be provided to accommodate the propeller thrust.

4.3.4 Mounts are to be shielded from the possible detrimental effects of oil and, where appropriate, paint and other contaminants.

4.3.5 Shafting, piping connections and electrical cable connections are to be provided with sufficient flexibility to accommodate expected movements. Particular attention should be paid to exhaust bellows and the effectiveness of flexible couplings.

4.4 Resin chocks

4.4.1 Synthetic resin compounds used as materials for chocks under machinery components for which alignment is critical, e.g. main engine, gearbox and auxiliary installations where the engine and generator do not share a common baseplate, are to be of a type approved by LR.

4.4.2 The resin chock materials referred to in Pt 5, Ch 1, 4.4 Resin chocks 4.4.1 are to be tested in accordance with Ch 14, 2.11 Machinery chocking compounds (resin chocks) of the Rules for the Manufacture, Testing and Certification of Materials, July 2022.

4.4.3 Materials for chocks are to be approved for the maximum service temperature that the chock will experience.

4.4.4 The use of resin for chocking gas turbine casings or similar high temperature applications will be specially considered.

4.5 Ventilation

4.5.1 All spaces including engine and cargo pump spaces, where flammable or toxic gases or vapours may accumulate, are to be provided with adequate ventilation under all conditions.

4.5.2 Machinery spaces of category A shall be adequately ventilated so as to ensure that when machinery or boilers therein are operating at full power in all weather conditions, including heavy weather, a sufficient supply of air is maintained to the spaces for the safety and comfort of personnel and the operation of the machinery. Any other machinery space shall be adequately ventilated, as appropriate for the purpose of that machinery space.

4.6 Fire protection

4.6.1 All surfaces of machinery where the surface temperature may exceed 220°C and where impingement of flammable liquids may occur are to be effectively shielded to prevent ignition. Where insulation covering these surfaces is oil-absorbing or may permit penetration of oil, the insulation is to be encased in steel or equivalent.

4.7 Means of escape

4.7.1 For means of escape from machinery spaces, see SOLAS 1974 as amended Regulation II-2/ 4.1 Means of escape on passenger ships or 4.2 Means of escape on cargo ships, as applicable.

4.8 Communications

4.8.1 Two independent means of communication are to be provided between the bridge and engine room control station from which the engines are normally controlled, see also Pt 6, Ch 1, 2 Essential features for control, alarm, monitoring and safety systems .

4.8.2 One of these means is to visually indicate the order and response, both at the engine room control station and on the bridge.

4.8.3 At least one means of communication is to be provided between the bridge and any other control position(s) from which the propulsion machinery may be controlled.

4.9 Category A machinery spaces

4.9.1 ‘Machinery spaces of Category A’ are those spaces and trunks to such spaces which contain:

internal combustion machinery used for main propulsion; or
internal combustion machinery used for purposes other than main propulsion where such machinery has in the aggregate a total power output of not less than 375 kW; or
any oil-fired boiler or fuel oil unit.