Section 5 Machinery space arrangements

5.1 Machinery spaces

5.1.1 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 of not less than 375 kW; or
any oil-fired boiler or fuel oil unit.

5.1.2 Machinery spaces are all machinery spaces of Category A and all other spaces containing propulsion machinery, boilers, fuel oil units (defined in Vol 2, Pt 1, Ch 3, 5.1 Machinery spaces 5.1.3), steam and internal combustion engines, generators and major electrical machinery, oil filling stations, refrigerating, stabilising, ventilation and air-conditioning machinery, and similar spaces and trunks to such spaces.

5.1.3 A fuel oil unit is the equipment used for the preparation of fuel oil for delivery to an oil-fired boiler, or equipment used for the preparation for delivery of heated oil to an internal combustion engine, and includes oil pressure pumps, filters and heaters dealing with oil at a pressure of more than 0,18 N/mm².

5.1.4 Aluminium is not to be used for the crowns or casings of Category A machinery spaces. Where the hull is constructed of aluminium or composite material, consideration will be given to the use of aluminium for the crown or casings for such spaces where the fire safety issues relating to the use of aluminium have been addressed to the satisfaction of LR.

5.1.5 Windows are not to be fitted in machinery space boundaries. However, this does not preclude the use of glass in control rooms within the machinery space.

5.1.6 Machinery space skylights, where fitted, are not to contain glass.

5.1.7 In addition, the requirements of Vol 1, Pt 3, Ch 2, 6 Machinery space arrangements are to be complied with.

5.2 Accessibility

5.2.1 Accessibility, for attendance and maintenance purposes, is to be provided in all spaces for machinery and engineering systems and equipment.

5.2.2 Removal routes for items of machinery and equipment are to be established where routine removal of major items of equipment is envisaged.

5.3 Machinery fastenings

5.3.1 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. For NS3 type ships or where specified, the arrangement is to be such that it is sufficient to restrain the dynamic forces arising from vertical and horizontal acceleration appropriate to the intended service, see Vol 2, Pt 1, Ch 3, 3.3 Calculations and specifications 3.3.5 and Vol 2, Pt 1, Ch 3, 5.4 Collision load.

5.3.2 Machinery may be installed on rafts of rigid construction and these are to be of robust construction to ensure that alignment is maintained under all conditions of ship motion. The rafts are to be securely fixed to the ship's structure.

5.4 Collision load

5.4.1 Unless an accurate analysis of the collision load is submitted and found acceptable by LR, the collision load is to be determined from:

where the load P_coll is taken as the lesser of:

P_coll

460 (M C_L)^2/3 (E C_H)^1/3 kN

P_coll

9000 M C_L [C_H(T + 2)]^1/2 kN

where

C_H

a factor given in Table 3.5.1 Factor C_H

C_L

ship depth, in metres, from the underside of keel amidships to the top of effective hull girder

0,5Δ V ² kNm

H_T

minimum height, in metres, from tunnel or wet-deck bottom to the top of effective hull girder for catamarans and surface effect ships

D for air cushion vehicles

L_WL

ship waterline length, in metres

1,3 for high tensile steel

1,0 for aluminium alloy

0,95 for mild steel

0,8 for fibre reinforced plastics

buoyancy tank clearance to skirt tip, in metres, (negative) for ACVs

lifted clearance from keel to water surface, in metres, (negative) for hydrofoils

ship's deep draught to the underside of keel amidships, in metres, for all other ships

operational speed of ship, in m/s

gravitational acceleration = 9,806 m/s²

ship displacement, to be taken as the mean of the lightweight and maximum operational weight, in tonnes.

Table 3.5.1 Factor C_H

Factor C_H	Catamarans, SES	Mono-hulls, H’Foils	ACVs
C_H
where
f = 0 for	T + 2 < D – H_T	T + 2 < D	—
f = 1 for	D > T + 2 ≥ D – H_T	T + 2 ≥ D	H_T > 2
f = 2 for	T + 2 ≥ D M	—	H_T ≤ 2

5.5 Resilient mount

5.5.1 The dynamic angles of inclination in Table 3.4.2 Inclinations 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.

5.5.2 For equipment of installed power greater than 375 kW, see Vol 2, Pt 1, Ch 3, 5.1 Machinery spaces 5.1.1, a calculation report is to be submitted to demonstrate that the requirements of Vol 2, Pt 1, Ch 3, 5.5 Resilient mount 5.5.1 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 Vol 2, Pt 1, Ch 3, 5.5 Resilient mount 5.5.1; 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 Vol 2, Pt 1, Ch 3, 5.5 Resilient mount 5.5.1.

5.5.3 Positive means are to be fitted 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 anti-collision chocking that may be required will be specially considered. Suitable means are to be provided to accommodate the propeller thrust.

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

5.5.5 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.

5.6 Additional requirements for resilient mounts

5.6.1 Where the ship has specified military requirements that include the ability of machinery to withstand shock, the flexible element(s) (resilient mounts, exhaust gas bellows, flexible couplings and any other applicable flexible pipe connections) are to be approved in accordance with such requirements. See also Vol 1, Pt 1, Ch 2, 3.8 Military Distinction notations, Vol 1, Pt 4, Ch 2, 5.7 Shock mounts and Vol 2, Pt 1, Ch 3, 4.11 Machinery shock arrangements.

5.6.2 Where the ship has specified military requirements for underwater signature, the flexible element(s) (resilient mounts, exhaust gas bellows, flexible couplings and any other applicable flexible pipe connections) are to be approved in accordance with such requirements. See also Vol 2, Pt 1, Ch 3, 4.10 Guidance for underwater signature.

5.7 Resin chocks

5.7.1 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 accepted by LR.

5.7.2 The resin chock materials referred to in Vol 2, Pt 1, Ch 3, 5.4 Collision load 5.4.1 are to be tested in accordance with Ch 14, 2.11 Machinery chocking compounds (resin chocks), Ch 14, 3.9 Machinery chocking compounds and Ch 14, 5.14 Synthetic chocking compounds of the Rules for the Manufacture, Testing and Certification of Materials, July 2022.

5.7.3 Materials for chockings are to be approved for the maximum service temperature that the chock will experience.

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

5.7.5 Where the ship has specified military requirements that include design and installation of machinery to withstand shock, the resin is to be approved for this application.

5.8 Additional requirements resin chocks

5.8.1 Where the ship has specified military requirements that include design and installation of machinery to withstand shock, the resin is to be approved for this application. See also Vol 1, Pt 1, Ch 2, 3.8 Military Distinction notations, Vol 1, Pt 4, Ch 2, 5.6 Seat design and Vol 2, Pt 1, Ch 3, 4.11 Machinery shock arrangements.

5.9 Ventilation

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

5.9.2 Machinery spaces are to be 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 of personnel and the operation of machinery.

5.9.3 The selection and arrangements of machinery and associated equipment are to minimise the emission of noxious substances into machinery spaces.

5.10 Fire protection

5.10.1 All surfaces of machinery where the surface temperature may exceed 220ºC 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.

5.11 Means of escape

5.11.1 Except as permitted in Vol 2, Pt 1, Ch 3, 5.11 Means of escape 5.11.2, two means of escape are to be provided from each machinery space of Category A. In particular, one of the following provisions are to be complied with:

Two sets of steel ladders as widely separated as possible leading to doors in the upper part of the space similarly separated and from which access is provided to the open deck. In general, one of these ladders shall provide continuous fire shelter from the lower part of the space to a safe position outside the space. The shelter is to be of steel, insulated, where necessary and provided with a self-closing steel door. The shelter will not be required if, due to the special arrangement or dimensions of the machinery space, a safe escape route from the lower part of the space is provided.
One steel ladder leading to a door in the upper part of the space from which access is provided to the open deck and additionally, to the lower part of the space and in a position well separated from the ladder referred to, a steel door capable of being operated from each side and which provides access to a safe escape route from the lower part of the space to the open deck.

Alternative arrangements in accordance with the requirements as specified by the Naval Administration may also be acceptable.

5.11.2 Where specified and agreed by the Naval Administration, in a NS3 category ship, one of the means of escape required in Vol 2, Pt 1, Ch 3, 5.11 Means of escape 5.11.1 may not be required with due regard being paid to the dimension and disposition of the upper part of the space.

5.11.3 When access to any machinery space of Category A is provided at a low level from an adjacent shaft tunnel, there is to be provided in the shaft tunnel, near the watertight door, a light steel fire-screen operable from each side.

5.11.4 From machinery spaces other than those of Category A, escape routes are to be provided having regard to the nature and location of the space and whether persons are normally employed in the space.

5.11.5 Lifts are not to be considered as forming one of the required means of escape.

5.12 Communications

5.12.1 At least two independent means of communication are to be provided between the bridge and engine room control station from which the engines are normally controlled.

5.12.2 One of the two means required by Vol 2, Pt 1, Ch 3, 5.12 Communications 5.12.1 shall visually indicate the order and response, both at the engine room control station and on the bridge.

5.12.3 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.

5.12.4 At least two independent means of communication are to be provided between the main and emergency switchboards.

5.13 Personnel safety

5.13.1 All moving parts of machinery are to be provided with suitable railings and/or guards to prevent injury to personnel.

5.13.2 Protection is to be provided to prevent injury from hot surfaces, i.e. by suitable lagging or guards.

5.13.3 Assemblies incorporating pre-loaded springs are to be engineered such that spring forces can be released in a controlled and safe manner during the removal and/or disassembly process.

5.13.4 Open ends from relief valve pressure release pipes are to be arranged so that any discharge is directed away from positions where personnel might reasonably be expected to be. If relief pipes cross citadel boundaries, the relief valves are to relieve through sealed tundishes able to withstand the citadel over-pressure.

5.13.5 Sufficient deck plates, platforms and handholds are to be fitted to provide safe access to all parts of the machinery and ensure safe passageway between machinery and adjacent equipment.

5.13.6 Materials used in the construction of machinery and installation of engineering systems are not to be a recognised hazard to personnel. This includes the prohibition of asbestos.

5.13.7 Means are to be provided for automatically giving audible warning of the release of fire-extinguisihing medium into any space in which personnel normally work or to which they have access, see also Vol 2, Pt 9, Ch 9, 5.8 Fire extinguishing media release 5.8.1

5.14 Machinery enclosures

5.14.1 Where machinery is installed within enclosures, the requirements of Vol 2, Pt 1, Ch 3, 5.14 Machinery enclosures 5.14.2 and Vol 2, Pt 1, Ch 3, 5.15 Fire detection, alarm and extinguishing arrangements are to be complied with.

5.14.2 Enclosures are to be treated as unattended machinery spaces and comply with the relevant Rules for such spaces and installed equipment.

5.14.3 Enclosures are, as far as reasonably practicable, to be gastight with flexible sealing arrangements between air induction, exhaust and ventilation systems.

5.14.4 The arrangements are to prevent contamination of the machinery space in an CBRN environment.

5.14.5 Enclosures are to be constructed to form a suitable fire boundary.

5.14.6 An access door, adequate internal lighting and observation windows, with suitable fire rating, are to be located to afford a clear view of both sides of the equipment within the enclosure.

5.14.7 Suitable means of drainage of any liquids which may accumulate are to be provided without compromising the citadel.

5.14.8 Enclosures are to be suitably ventilated and designed to maintain all components within their safe working temperature under all operating conditions. The ventilation system is to be independent from the machinery space ventilation arrangements and provided with suitable closing devices for fire control purposes.

5.14.9 Enclosures are to be provided with a means to enable gas purging with a portable fan in addition to the fixed ventilation system.

5.14.10 Means are to be provided to monitor the enclosure air temperature and differential pressure.

5.15 Fire detection, alarm and extinguishing arrangements

5.15.1 Machinery spaces and enclosures are to be provided with fire detection, alarm and extinguishing systems in accordance with the fire safety arrangements required by the Regulations in Vol 1, Pt 1, Ch 2, 1.1 Framework of Classification 1.1.9 For unattended machinery spaces a fire detection system in accordance with Vol 2, Pt 9, Ch 1, 4.5 Fire detection alarm system is to be fitted.

5.15.2 The design of fire extinguishing arrangements in any machinery space or enclosure are to take the following into consideration:

The flammable materials and potential sources of ignition within the space or enclosure;
any need for machinery and equipment to remain operational during operation of the fire extinguishing arrangements;
the need for machinery and equipment to continue to function normally following operation of the fire extinguishing arrangements; and
any need for personnel to enter or remain within the space or enclosure during operation of the fire extinguishing arrangements.

In spaces where electrical equipment is located, consideration is to be given to providing separate enclosures where appropriate. See also Vol 2, Pt 1, Ch 3, 3.3 Calculations and specifications 3.3.14.

5.16 Location of emergency installations

5.16.1 Emergency sources of electrical power, fire pumps, bilge pumps except those specifically serving the spaces forward of the collision bulkhead, any fixed fire-extinguishing system and other emergency installations which are essential for the safety of the ship, except anchor windlasses, shall not be installed forward of the collision bulkhead.