Section 4 Design principles for fuel cell power installations

4.1.1 Fuel cell power installations are to be suitable for the service profile and Design Statement as required by these Rules.

4.1.2 The design of fuel cell power installations shall comply with industry standards, such as IEC 62282-2 Fuel cell technologies - Part 2-100: Fuel cell modules – Safety and IEC 62282-3-100 Fuel cell technologies - Part 3-100: Stationary fuel cell power systems – Safety and 62282-3-100 Stationary fuel cell power systems - Safety, or at least equivalent to those acceptable to Lloyd’s Register (hereinafter referred to as LR).

4.1.3 Where fuel cell power installations supply power for propulsion of the ship or other essential services they are to satisfy the corresponding requirements relating to essential machinery and equipment in Pt 5 Main and Auxiliary Machinery and the requirements for power supplies for main or emergency services of Pt 6, Ch 2 Electrical Engineering.

4.1.4  Where fuel cell power installations which supply power for propulsion of the ship or other essential services rely on auxiliary ship services such as cooling water, compressed air, etc. loss of the auxiliary service is not to result in a loss of power for propulsion or power for other essential services.

4.1.5 Where power for propulsion of the ship or other essential services is provided entirely by fuel cell power installations, no fewer than two fuel cell power installations are to be provided so that one fuel cell power installation is retained in operation or is capable of being brought into operation in the event of a failure of the other. The capacity is to be such that in the event of any one fuel cell power installation being stopped it will be possible to supply those services necessary to provide essential services necessary for propulsion and safety, as applicable.

4.1.6 Where power for propulsion of the ship or other essential services is provided entirely by fuel cell power installations, means are to be provided to ensure that the fuel cell power installations can recover from black out and be brought into operation from the dead ship condition without external aid. Where batteries are used to provide the means of recovery, the batteries are to be protected against depletion when not in use.

4.1.7 Where fuel cell power installations are to be connected to a DC distribution system or a hybrid electrical power system incorporating other sources of electrical power, the equipment is also to satisfy the relevant requirements of Pt 6, Ch 2, 24 Hybrid electrical power systems.

4.2.1 A single failure of any part of the fuel cell power system is not to result in a hazardous release into a non-hazardous area.

4.2.2 The fuel cell power system shutdown and fuel supply isolation are to be capable of being performed locally and from a position outside the fuel cell space which will always be easily accessible even in the event of fire occurring in that space.

4.2.3  Exhaust gases and exhaust air from the fuel cell power systems shall not be combined with any ventilation except ventilation serving fuel cell spaces and shall be led to a safe location in the open air.

4.2.4 Filters which could cause a failure of the fuel cell power system if blocked are to be provided with differential pressure monitoring and a stand-by filter unit. High differential pressure is to initiate an alarm.

4.2.5 Where any part of the fuel cell power system is susceptible to attack or degradation from airborne contaminants typical of the marine environment, arrangements for filtering and drying or closed air circulation are provided to ensure that the required air quality is in accordance with the fuel cell module manufacturer’s requirements. Any parts of the system sensitive to air quality are to be sealed.

4.2.6 Where any exposed part of the fuel cell power system exceeds 220°C in normal operation or under reasonably foreseeable abnormal conditions the exposed surfaces are to be cooled or efficiently lagged so as to minimise the risk of fire or harm.

4.2.7 Means to safely remove the primary and reformed fuel from the fuel cell power system shall be provided.

4.2.8 Means shall be provided to set a fuel cell power installation into a safe state for maintenance and shutdown.

4.2.9 All pipes containing reformed fuel for fuel cell power systems, where fitted, are to be provided with fixed hydrogen detectors which are capable of detecting a hydrogen leak for places where leakage of hydrogen may occur, such as valves, flanges and seals.

4.2.10 For the auxiliary systems of the fuel cell power system where primary fuel or reformed fuel may leak directly into a system medium (e.g. cooling water), such auxiliary systems shall be equipped with appropriate extraction and detection means fitted as close as possible after the media outlet from the system in order to prevent gas dispersion. Gas extracted from the auxiliary system media shall be vented to a safe location on the open deck.

4.3.1 Fuel cell modules are to satisfy the testing requirements of a recognised international or national type testing standard as agreed by LR.

4.3.2 Fuel cell modules are to be protected against overpressure, and over- and under-temperature.

4.3.3 Arrangements are to allow purging of flammable gases or vapours and inerting of the fuel cell modules.

4.3.4 Fuel and oxidant supplies to the fuel cell modules are to be in accordance with the fuel cell module manufacturer’s requirements and are to be provided with a means of monitoring the flow, temperature and pressure of the fuel and oxidant supplied.

4.3.5 Arrangements are to prevent reverse flow of fuel and oxidant from the fuel cell modules back to the supply.

4.3.6 Fuel cell modules which utilise electrolytic fluids that are corrosive, flammable or otherwise harmful at high temperatures are to be provided with a means of monitoring the temperature of the electrolyte.

4.3.7 Exhaust arrangements are to convey exhaust gas from the fuel cell modules to a safe location on deck.

4.3.8 Arrangements are to prevent cross flow of exhaust gases between fuel cell modules.

4.3.9 Exhaust arrangements are to prevent water entering the fuel cell module and, where the possibility of condensate accumulating exists, the arrangements are to prevent the backflow of condensate to the fuel cell module and provide for condensate removal.

4.3.10 Exhaust temperature and flammable gas detection is to be provided for the fuel cell modules. An alarm is to be given at a gas concentration of 20 per cent LEL and the fuel cell module is to be shut down at a concentration of 40 per cent LEL.

4.4.1 A fuel reformer may supply fuel to multiple fuel cell modules, in which case the fuel reformer and the fuel cell modules which it supplies are considered to be a single fuel cell power system.

4.4.2 Fuel reformers are to be positioned as close to fuel cell modules as practicable.

4.4.3 Fuel reformers are to be automatic in operation and supply reformed fuel with defined composition and purity which is to be in accordance with the fuel cell module manufacturer’s requirements.

4.4.4 It is to be possible to shut down fuel reformers from an easily accessible location outside the space in which they are located, at the control position and at a position in a remote safe area.

4.4.5 Shutdown arrangements are to shut off the primary fuel and are to be of the double block and bleed type. Alternative arrangements will be considered if supported by an engineering and safety statement.

4.4.6 Arrangements are to allow purging of flammable gases or vapours from the fuel reformers.

4.4.7 Where fuel reformers incorporate fuel combustion equipment the fuel combustion equipment is to be of an approved type.

4.4.8 Fuel reformers utilising services from the ship’s supply such as cooling water, compressed air, etc. are to be compatible with expected variations in the ship’s supply and are to include arrangements to prevent reverse flow back to the supply.

4.4.9 The arrangement of any safety and pressure relief discharges from fuel reformers is to ensure that no possibility of mixing which may result in a hazardous reaction between the primary fuel and the reformed fuel or any by-products formed in the reforming process.

4.4.10 Where provision is made to isolate pressure relief valves from vessels and piping systems for maintenance purposes, not less than two relief valves are to be fitted and the isolating arrangements are to ensure that one relief valve remains in communication with the fuel reformer under all conditions.

4.5.1 Converter equipment forming part of the fuel cell power conditioning equipment is to satisfy the relevant requirements of Pt 6, Ch 2, 10 Converter equipment.

4.5.2 The electrical output of fuel cell modules is to meet the service profile and Design Statement. Each fuel cell power system is to be provided with power conditioning equipment which is to be suitable for continuous duty at its full rated output at the maximum allowable cooling air or water temperature for an unlimited period, without the limits of temperature rise stated in the Design Statement being exceeded.

4.5.3 A single power conditioning system may provide power conditioning for more than one fuel cell module provided that there is an effective means of disconnecting each fuel cell module from the power conditioning equipment. In such cases the fuel cell modules are to be considered part of the same fuel cell power installation.

4.5.4 Where power conversion equipment is fitted to a fuel cell power system to supply alternating current, power supply quality requirements are to be defined and the requirements for hybrid electrical power systems shall be applied as applicable.

4.5.5 Fuel cell modules which operate in parallel with conventional rotating electrical generators are to satisfy the provisions of Pt 5, Ch 26, 4.5 Fuel cell power installation – Power conditioning system 4.5.6 and Pt 5, Ch 26, 4.5 Fuel cell power installation – Power conditioning system 4.5.7.

4.5.6 Power conditioning equipment supplying electrical power to the distribution bus and consumers is to be capable of delivering the required currents for discrimination purposes to downstream protective devices, and automatically maintaining the supply of power and voltage to consumers after fault clearance without sustaining any damage.

4.5.7 Fuel cell modules which are to operate in parallel are to be stable from no load (kW) up to the total combined full load (kW) of the group, and load sharing is to be such that the load on any fuel cell module does not normally differ from its proportionate share of the total load by more than 15 per cent of the rated output (kW) of the largest fuel cell module or 25 per cent of the rated output (kW) of the individual module, whichever is less.

4.5.8 When fuel cell modules are operated in parallel, the kVA loads of the individual fuel cell modules are not to differ from the proportionate share of the total kVA load as stated and justified by the system integrator and/or fuel cell manufacturer.

4.5.9 There is to be a means of preventing reverse power to the fuel cell stacks. This is to ensure that the fuel cell stack manufacturer’s maximum allowable duration and levels of reverse power flow are not exceeded.

4.5.10 Means shall be provided for protection of the fuel cell installation against short circuits and flow of reverse current.

4.6.1 A thermal management system which provides cooling, heating, humidity management and condensate removal where required by the fuel cell modules is to be provided.

4.6.2 Thermal conditioning equipment utilising services from the ship’s supply such as cooling water, compressed air, etc. is to be compatible with expected variations in the ship’s supply and is to include arrangements to prevent reverse flow back to the supply.

4.6.3 Loss of fuel cell coolant shall result in an automatic shutdown of the fuel cell by the process control within a limited period of time. To prevent a potential coolant release in the fuel cell space, a secondary containment of the coolant pipe should be provided or the equipment within the fuel cell space should be protected from a coolant release. Consideration should be given to the safe removal of the coolant.

4.6.4 Where thermal conditioning equipment is fitted to the fuel cell power system exhaust, the resulting back pressure is to remain within the allowable limit of the fuel cell module.

4.6.5 A means of collecting and storing any condensate produced by the fuel cell power system is to be provided. Substances which react if mixed are to be provided with separate and distinct condensate drainage arrangements.

4.6.6 Condensate collection piping, collection tank and transfer arrangement are to be suitable for the composition of condensate.

4.6.7 Where the condensate collection tank is arranged such that more than one fuel cell module delivers condensate to the tank, each fuel cell module is to have a separate feed to the collection tank or, alternatively, the condensate collection piping is to incorporate a means of preventing the cross flow of condensate between fuel cell modules.

4.6.8 Where primary fuel or reformed fuel may leak directly into the thermal conditioning equipment, the equipment is to be provided with appropriate extraction and detection means fitted as close as possible after the media outlet from the equipment. Gas extracted is to be vented to an appropriately designated location on the open deck.

4.7.1 Provision is to be made for purging the fuel cell power system of flammable gases and vapours using an inert gas.

4.7.2 Inert gas for purging may be generated on board or supplied from an inert gas storage system with provision for refilling from ashore.

4.7.3 Where the inert gas is generated on board, the design of the inert gas generator is to ensure that inert gas meets the specified composition and purity requirements.

4.7.4 Where the inert gas is not generated on board the storage capacity is to be derived from the service profile and Design Statement.

4.7.5 Where fuel cell modules require purging to be carried out using a mixture of inert gas and flammable gas in order to avoid damage to fuel cell modules, the purging gas mixture is not to present a hazard during normal and reasonably foreseeable abnormal operating conditions.

4.8.1 Safety related parts of the fuel cell control systems shall be designed to be independent from any other control and monitoring systems or shall comply with the process as described in industry standards acceptable to LR for the performance level or equivalent.

4.8.2 The fuel cell should be monitored according to the manufacturer’s recommendations.

4.8.3 Fuel cell power installations shall be designed for automatic operation and equipped with all the monitoring and control facilities required for safe operation of the system. These facilities may be provided at the ship’s main control station or, alternatively, at subsidiary control stations. In the latter case, a master alarm display is to be provided at the main control station showing which of the subsidiary control stations is indicating a fault condition.

4.8.4 Chemical reactions, such as those taking place during fuel reforming, if fitted, or within the fuel cell modules, are to be monitored at the control station, e.g. by means of temperature, pressure or voltage monitoring.

4.8.5 Alarms are to be provided to notify of abnormal conditions and faults.

4.8.6 As a minimum, alarms are to be provided in accordance with Table 26.4.1 Fuel cell power installation alarms, safeguards. A justification is to be provided for any items considered not applicable to the fuel cell installation.

4.8.7 Alarms additional to the ones required by Table 26.4.1 Fuel cell power installation alarms, safeguards may be recommended for unconventional or complex fuel cell power installations.

4.8.8 If limit values determined for the control process (e.g. temperature, pressure, voltage, gas concentrations) which may lead to hazardous situations are exceeded, then the fuel cell power system is to be automatically shut down and interlocked by a fuel cell safety system.

4.8.9 Safeguards, including shutdowns, to be provided are to take account of any related requirements or recommendations from the engineering and safety justification. As a minimum, safeguards are to be provided in accordance with Table 26.4.1 Fuel cell power installation alarms, safeguards. A justification is to be provided for any items considered not applicable to the fuel cell installation.

4.8.10 Safeguards additional to the ones required by Table 26.4.1 Fuel cell power installation alarms, safeguards may be recommended for unconventional or complex fuel cell power installations.

4.8.11 It shall be possible to shut down the fuel cell power system from an easily accessible location outside the fuel cell spaces.

4.8.12 The output voltage, current and frequency (where applicable) of the fuel cell power installation are to be displayed at the control station for the fuel cell power installation.

4.8.13 The output voltage and current of each fuel cell module and the output voltage and current at the outlet of power conditioning equipment are to be displayed at the control station for the fuel cell power installation.

4.9.1 In order to minimise the probability of a gas explosion in a fuel cell space, the space shall meet the requirements of this sub-Section, or an equivalent safety concept.

4.9.2 The fuel cell space concept is such that the space is designed to mitigate hazards to non-hazardous levels under normal conditions, but under certain abnormal conditions may have the potential to become hazardous.

4.9.3 In the event of abnormal conditions involving gas hazards, emergency shutdown (ESD) of equipment and components that are not suitably certified safe type for the hazards concerned is to be automatically executed, while equipment or components in use or active during these conditions are to be of a suitably certified safe type.

4.9.4 The fuel cell space is to comply with at least one of the following safety concepts identified and detailed in Pt 5, Ch 26, 4.9 Fuel cell space 4.9.7.

4.9.5 Detection of liquids shall interrupt the fuel supply to the fuel cell space and de-energise the ignition sources inside the fuel cell space.

4.9.6 Actuation of the emergency shutdown push button shall interrupt the fuel supply to the fuel cell space and de-energise the ignition sources inside the fuel cell space.

4.9.8 Protection of fuel cell spaces by an external boundary that encloses components where fuel is fed shall be achieved by ventilation or inerting. These methods should be equally acceptable to ensure the safety of the space.

4.9.9 Within the fuel cell space concept, a single failure may result in a release of primary fuel, reformed fuel or hazardous gases into the space. Ventilation or inerting, if required, are to be designed to accommodate a probable maximum leakage scenario due to technical failures.

4.9.10 Failures leading to dangerous gas concentrations (e.g. gas pipe ruptures or blow out of gaskets) are to be covered by explosion pressure relief devices and ESD arrangements.

4.9.11 Fuel cell spaces containing fuel reformers shall also comply with the requirements relevant for the primary fuel.

4.10.1 Fuel cell spaces shall be arranged outside of accommodation spaces, service spaces, machinery spaces of category A and control stations.

4.10.2 Proposals for locating fuel cell spaces within machinery spaces of category A may be specially considered.

4.11.1 Where an independent and direct access to the fuel cell spaces from the open deck cannot be arranged, access to fuel cell spaces is to be through an airlock compliant with the IGF Code 5.12 Regulations for airlocks.

4.11.2 Subject to agreement by the National Administration, consideration will be given to direct access from a non-hazardous area to a Zone 2 hazardous area where the Zone 2 area has a bolted hatch that provides direct access into the space.

4.11.3 An airlock is not required if appropriate technical provisions are made such that access to the space is not required and not made possible before the equipment inside is safely shut down, isolated from the fuel system and drained of leakages, and the inside atmosphere is confirmed to be gas-free, or otherwise the space is consider non-hazardous under all conditions.

4.11.5 Escape routes from the fuel cell space are not to pass through hazardous areas.

4.12.1 Fuel cell space boundaries shall be gastight towards other enclosed spaces in the ship.

4.12.2 Piping and cabling penetrations within the boundaries of fuel cell spaces are to be approved gastight.

4.12.3 Arrangement shall be provided to rapidly detect leakages of liquid primary fuel inside the fuel cell space.

4.12.4 Detection of unintended liquid leakages in the fuel cell space should trigger an alarm. A possible means of detection would be a bilge high-level alarm.

4.12.5 An alarm shall be activated for high liquid levels in bilge wells.

4.12.6 Fuel cell spaces are to be designed to safely contain fuel leakages and be provided with suitable leakage detection systems and should be arranged to avoid the accumulation of hydrogen-rich gas (see also IEC 60079-10-1 Explosive atmospheres – Part 10-1: Classification of areas – Explosive gas atmospheres) by having simple geometrical shape and no obstructing structures in the upper part.

4.12.7 Leakage detection is to be indicated by an alarm.

4.12.8 Gas/vapour detection in a fuel cell space above a gas or vapour concentration of 20 per cent LEL shall cause an alarm.

4.12.9 Gas/vapour detection in a fuel cell space above a gas or vapour concentration of 40 percent LEL should shut down the affected fuel cell power system and disconnect ignition sources and should result in automatic closing of all valves required to isolate the leakage. If not certified for operation in Zone 1 hazardous areas, the fuel cell stack should be immediately electrically isolated and de-energised. Valves in the primary fuel system supplying liquid or gaseous fuel to the fuel cell space should close automatically.

4.12.10 Fuel cell spaces shall be arranged to avoid the accumulation of hydrogen rich gas (see IEC 60079-10-1: Explosive atmospheres – Part 10-1: Classification of areas – Explosive gas atmospheres) by having a simple geometrical shape that will minimise the accumulation of gases or formation of gas pockets and have no obstructing structures in the upper part.

4.13.1 Fuel cell spaces shall be equipped with an effective mechanical ventilation system to maintain underpressure of the complete space, taking into consideration the density of potentially leaking fuel gases.

4.13.2 For fuel cell spaces on open decks, overpressure ventilation may be considered.

4.13.3 Two or more fans shall be installed for the ventilation of the fuel cell space, providing 100 per cent redundancy upon loss of one fan. 100 per cent ventilation capacity is to be supplied from the emergency source of power.

4.13.4 In case of failure of one fan, automatic changeover to another fan shall be provided and indicated by an alarm.

4.13.5 In order to verify the performance of the ventilation system, a detection system of the ventilation flow and of the negative fuel cell space pressure shall be installed. A running signal from the ventilation fan motor is not sufficient to verify performance.

4.13.6 In case of loss of ventilation or loss of underpressure in the fuel cell space the fuel cell power system should carry out an automatic, controlled shutdown of the fuel cell and isolation of the fuel supply

4.13.7 Loss of ventilation in a fuel cell space shall result in an automatic shutdown of the fuel cell by the process control within a limited period of time. The period for the shutdown by the process control shall be considered on a case by case basis based on the risk analysis. After the period has expired, a safety shutdown should be carried out.

4.13.8 The ventilation rate in fuel cell spaces should be sufficient to dilute the average gas/vapour concentration below 25 per cent of the LEL in all maximum probable leakage scenarios due to technical failures.

4.13.9 Any ducting used for the ventilation of fuel cell spaces shall not serve any other space.

4.13.10 Ventilation ducts from spaces containing reformed fuel piping or release sources shall be designed and arranged such that any possibility for gas to accumulate is avoided.

4.13.11 In case of loss of ventilation or loss of negative pressure in the fuel cell space, the fuel cell power system shall carry out an automatic, controlled shutdown of the fuel cell and isolation of the fuel supply.

4.13.12 Ventilation air inlets for fuel cell spaces shall be taken from areas which, in the absence of the considered inlet, would be non-hazardous.

4.13.13 Ventilation air inlets for non-hazardous enclosed spaces shall be taken from non-hazardous areas located at least 1,5 m away from the boundaries of any hazardous area.

4.13.14 Ventilation air inlets for fuel cell spaces are to be positioned below the lowest point from which hydrogen rich gas may leak.

4.13.15 Ventilation air outlets from fuel cell spaces are to be designed to prevent any accumulation of hydrogen rich gas within the duct and the number of bends is to be minimised.

4.13.16 Ventilation air outlets from fuel cell spaces shall be located in an open area which, in the absence of the considered outlet, would be of the same or lesser hazard than the ventilated space.

4.13.17 Fuel cell spaces or fuel cell power systems served by a common ventilation air inlet or a common ventilation air outlet are to be considered as being part of the same fuel cell power system.

4.13.18 Verification of the strength is to be based on calculation demonstrating the ducting integrity. As an alternative to calculations, the strength can be verified by representative tests.