Section 1 Arrangements And System Design

101. General

1. For any new or altered concept or configuration, a risk analysis is to be conducted in order to en- sure that any risks arising from the use of the fuel cell systems affecting the structural strength and the integrity of the ship are addressed. Consideration is to be given to the hazards associated with installation, operation, and maintenance, following any reasonably fore-seeable failure.

2. The risks are to be analysed using acceptable and recognized risk analysis techniques and loss of function, component damage, fire, explosion and electric shock are as a minimum to be considered. The analysis is to ensure that risks are eliminated wherever possible. Risks which cannot be elimi- nated are to be mitigated as necessary. Details of risks, and the means by which they are miti- gated, are to be included in the operating manual.

3. An explosion in any space containing open gas sources is not to:

(1) cause damage to any space other than that in which the incident occurs;

(2) disrupt the proper functioning of other zones;

(3) damage the ship in such a way that flooding of water below the main deck or any

progressive flooding occur;

(4) damage work areas or accommodation in such a way that people who stay in such areas under normal operating conditions are injured;

(5) disrupt the proper functioning of control stations and switchboard rooms for necessary power distribution;

(6) damage life-saving equipment or associated launching arrangements;

(7) disrupt the proper functioning of fire-fighting equipment located outside the explosion-damaged

4. space; or

(8) affect other areas in the vessel in such a way that chain reactions involving, inter alia,

cargo,

gas and fuel oil may arise.

5. In case where the power supply to propulsion or essential service is delivered by the fuel cell sys-

tem this power supply to propulsion or essential service is to be maintained even if one compo-

102. Materials and welding

1. General

(1) Materials and welding are in general to be in accordance with the requirements in Pt. 2 of the Rules for Steel Ships and are to be satisfactory without defect. However, in case where the ma- terials or welding not stipulated in this Guidance are intended to be used, documents for them are to be submitted to the Society and to be approved.

(2) The flammable materials is not to be used outside the FC stack.

(3) The flammable materials may be used inside the FC stack by approval of the Society.

2. Material requirements for hydrocarbon gas

(1) Materials and welding used in gas tanks, gas piping, process pressure vessels and other compo nents in contact with gas are to be in accordance with the requirements in Pt. 7 Ch. 5 Sec. 6 of the Rules for Steel Ships.

(2) Materials for compressed gas tanks, not covered by Pt. 7 Ch. 5 of the Rules for Steel Ships, may be used by specially consideration of the Society.

3. Material requirements for hydrogen gas

(1) The materials for hydrogen gas are to comply with following.

(A) Austenitic stainless steel (e.g. 304, 316, 304L and 316L) is to be used for materials in con- tact with hydrogen. In case where other materials than austenitic stainless steel are intended

to be used for storage and transport of hydrogen, documents for them are to be submitted to the Society and to be approved.

(B) For testing of tank materials, relevant parts of Pt. 7 Ch 5 Sec. 6 of the Rules for Steel

Ships are to be applied, and where this is not sufficient, special considerations will have to be done.

103.

Location and separation of spaces

1. The arrangement and location of spaces

(1) All parts of fuel cells and the directly associated components containing fuel during normal op- eration(evaporator or pre-heaters, compressors, filters, reformers, etc.) are to be arranged in an enclosed space or suitable enclosure.

(2) Fuel cell stacks, fuel cell conditioning system (such as pre-heater, compressor, filter, reformer, etc.) and gas storage system are to be located in spaces separated from each other and from

other spaces. For fuel cell systems with aggregate power lower than 375 kW, the installation of the whole fuel cell system in the same compartment may be accepted by the Society provided that suitable arrangements are made in order to prevent gas from reaching the fuel cell stacks in case of a leakage from the storage or conditioning system (e.g. screen or suitable enclosure with exhaust arrangement).

(3) The installation spaces of FC stacks and directly associated components are to be arranged out- side of accommodation, service and machinery spaces and control rooms, and are to be sepa-

rated from such spaces by means of a cofferdam or an A-60 bulkhead. Installation in conven- tional machinery spaces is not permitted. However, in case where the requirement for a separate space is met by a suitable form of enclosure for the components containing the fuel, the in- stallation in conventional machinery spaces is admissible.

(4) Spaces in which fuel storage tanks are located are to be separated from conventional machinery spaces and the other parts of the FC system.

(5) The arrangement and location of spaces for FC fuel storage, distribution and use are to be such that the number and extent of hazardous areas is kept to a minimum. These spaces are to have as simple geometrical and internal arrangement as possible in order to minimize the possibility of entrapping explosive mixtures.

2. Gas compressor room

(1) Compressor rooms, if arranged, are to be located above freeboard deck, unless those rooms are arranged and fitted in accordance with the requirements of these Guidance for tank rooms.

(2) If compressors are driven by shafting passing through a bulkhead or deck, the penetration is to

be of gastight type.

3. Fuel cell spaces

(1) The arrangement and number of FC spaces, the distribution thereof, and the design of the safe- ty systems are to be such that, in case of fuel or oxidant leakage originating anywhere in the spaces, the automatic safety actions will not result in the loss of essential functions of the ship (propulsion, electrical production).

(2) When more than one FC space is required for fuel cell power system and these spaces are separated by a single bulkhead, the arrangements are to be such that the effects of a gas ex- plosion in either space can be contained or vented without affecting the integrity of the adjacent space and equipment within that space.

(3) Fuel cell spaces are to have as simple geometrical shape as possible.

(4) Fuel cell spaces where hydrogen may be present are to have no obstructing structures in the upper part and are to be arranged with a smooth ceiling sloping up towards the ventilation outlet. Support structure like girders and stiffeners are to be facing outwards. Thin plate ceiling to cover support structure under the deck plating is not acceptable.

(5) Access to all components of the fuel cell installation are to be possible for survey.

4. Tank rooms

(1) Tank room boundaries including access doors are to be gastight.

(2) The tank room is not to be located adjacent to machinery spaces of category A. If the separa-

tion is by

means of a cofferdam, the separation is to be at least 900 mm and insulation to

class A-60 is to be fitted on the machinery space side.

104. Arrangement of entrances and other openings

1. Entrances, openings and ventilation openings to accommodation, service and machinery spaces and to control stations are to be arranged at a distance of at least 3m from the openings of the in- stallation space of the fuel cells. If it is necessary to deviate from this provision on small craft, etc. the approval of the Society is required.

2. Openings for exhaust air and residual gases of the FC stack are to be located on the open deck with a horizontal distance of at least 3m to any sources of ignition and to the openings of accom- modation, service and machinery spaces, control station and other spaces containing sources of ignition. If it is necessary to deviate from this provision on small craft, etc. the approval of the Society is required.

3. Direct access through doors, gastight or otherwise, is generally not to be permitted from a gas-safe space to a gas-dangerous space. Where such openings are necessary for operational reasons, an air lock which complies with the requirements of the Rules for Steel Ships Pt. 7 Ch. 5, 306 (para 2 to 7) is to be provided.

4. If the compressor room is approved located below deck, the room is, as far as practicable, to have an independent access direct from the open deck. Where a separate access from deck is not practi- cable, an air lock which complies with the requirements of the Rules for Steel Ships Pt. 7 Ch. 5, 306 (para 2 to 7) is to be provided.

5. The tank room entrance is to be arranged with a sill height of at least 300 mm.

6. Access to the tank room is as far as practicable to be independent and direct from open deck. If the tank room is only partially covering the tank, this requirement is also to apply to the room surrounding the tank and where the opening to the tank room is located. Where a separate access from the deck is not practicable, an air lock which complies with the requirements of the Rules for Steel Ships Pt. 7 Ch. 5, 306 (para 2 to 7) is to be provided. The access trunk is to be fit- ted with separate ventilation. It is not to be possible to have unauthorized access to the tank room during normal operation of the FC fuel system.

7. If the access to an ESD-protected FC space is from another enclosed space in the ship, the en- trances is to be arranged with self-closing doors. An audible and visual alarm is to be provided at a permanent manned location. Alarm is to be given if the door is open continuously for more than 1 min. As an alternative, an arrangement with two self-closing doors in series may be acceptable.

105. Design for FC fuel piping system

1. This requirements apply to FC fuel piping. The Society may accept relaxation from these require- ments for the piping inside FC fuel tanks and open-ended piping after special consideration, such as risk assessment.

2. FC fuel piping is to be protected against mechanical damage and the piping is to be capable of as- similating thermal expansion without developing substantial tension.

3. The piping system is to be joined by welding with a minimum of flange connections. Gaskets are to be protected against blow-out.

4. The wall thickness of pipes is not to be less than:

ᾼL ÑᾎÑᾏ

ᾼ Ņ Üᾍ Nᾩᾩ Ń Ì Ň ÜÌLL

where:

ᾼL = theoretical thickness (mm )

ᾼ ČÁ

with:

L Ņ ÜĪÅᾙ Ñ Č

Č = design pressure (MPa) referred to in Par 5

Á = outside diameter of pipe (mm )

Å = allowable stress (NÕmmĪ) referred to in Par 6

ᾙ = efficiency factor equal to 1.0 for seamless pipes and for longitudinally or spirally welded pipes, delivered by approved manufacturers of welded pipes, which are considered equiv- alent to seamless pipes when non-destructive testing on welds is carried out in accordance with Recognized Standards. In other cases an efficiency factor of less than 1.0, in accord- ance with recognized standards, may be required depending on the manufacturing process.

ᾎ = allowance for bending (mm ). The value of ᾎ is to be chosen so that the calculated stress in the bend, due to internal pressure only, does not exceed the allowable stress. Where such justification is not given, ᾎ is to be:

Ü

ᾎ Ņ ÁᾼL

ĪǾJᾮ

with :

ᾮ = mean radius of the bend (mm )

ᾏ = corrosion allowance (mm ). If corrosion or erosion is expected, the wall thickness of the piping is to be increased over that required by other design requirements. This allowance is to be consistent with the expected life of the piping.

ᾍ = negative manufacturing tolerance of thickness (%).

The minimum wall thickness is to be in accordance with recognized standards.

5. The greater of the following design conditions is to be used for piping, piping systems and compo- nents as appropriate:

(1) for systems or components which may be separated from their relief valves and which contain only vapour at all times: the superheated vapour pressure at 45°C or higher or lower if agreed upon by the Society (See 402. 6 (2) of the Rules for Steel Ships Pt. 7 Ch. 5), assuming an initial condition of saturated vapour in the system at the system operating pressure and temper- ature; or

(2) the MARVS of the FC fuel tanks and FC fuel processing systems; or

(3) the pressure setting of the associated pump or compressor discharge relief valve if of sufficient capacity; or

(4) the maximum total discharge or loading head of the FC fuel piping system; or

(5) the relief valve setting on a pipeline system, if of sufficient capacity; or

(6) The design pressure is not to be less than 1.0 MPa gauge except for open ended lines where it is to be not less than 0.5 MPa gauge.

6. For pipes made of steel including stainless steel, the permissible stress to be considered in the for- mula for t in Par 4 is the lower of the following values:

ĈᾩÕA or ĈᾙÕÆ

where:

ᾩ

Ĉ = specified minimum tensile strength at room temperature (NÕmm Ī)

Ī

Ĉᾙ = specified minimum yield stress or 0.2% proof stress at room temperature (NÕmm )

A = 2.7 and

For pipes made Society.

Æ = 1.8.

of materials other than steel, the allowable stress is to be considered by the

7. Where necessary for mechanical strength to prevent damage, collapse, excessive sag or buckling of pipes due to superimposed loads from supports, ship deflection or other causes, the wall thickness is to be increased over that required by Par 4, or, if this is impracticable or would cause ex- cessive local stresses, these loads are to be reduced, protected against or eliminated by other design methods.

8. FC fuel piping systems are to have sufficient constructive strength. For high pressure piping sys- tems, this is to be confirmed by carrying out stress analysis and taking into account:

(1) stresses due to the weight of the piping system;

(2) acceleration loads when significant; and

(3) internal pressure and loads induced by hog and sag of the ship.

9. Flanges, valves and other fittings are to comply with recognized standards, taking into account the design pressure defined in Par 5.

10. All valves and expansion joints used in high pressure gas systems are to be of an approved type.

11. The following types of connections may be considered for direct connection of pipe lengths (without flanges):

(1) Butt-welded joints with complete penetration at the root may be used in all applications. For design temperatures below -10°C, butt welds are to be either double welded or equivalent to a double welded butt joint. This may be accomplished by use of a backing ring, consumable in- sert or inert gas back-up on the first pass. For design pressures in excess of 1.0 MPa and de- sign temperatures of -10°C or lower, backing rings are to be removed.

(2) Slip-on welded joints with sleeves and related welding, having dimensions in accordance with recognized standards, are only to be used for open-ended lines with external diameter of 50 mm

or less and design temperatures not

(3) Screwed couplings are only to be ternal diameters of 25 mm or less.

12. Flanges in flange connections are to

lower than -55°C.

used for accessory lines and instrumentation lines with ex-

be of the welded neck, slip-on or socket welded type. For

all piping except open ended line, the following restrictions apply:

(1) For design temperatures lower than -55°C, only welded neck flanges are to be used.

(2) For design temperatures lower than -10°C, slip-on flanges are not to be used in nominal sizes

above 100 mm and socket welded flanges are not to be

13. Piping connections, other than those mentioned in Par

Society upon consideration in each case..

used in nominal sizes above 50 mm .

11 and 12, may be accepted by the

14. Post-weld heat treatment is to be required for all butt welds of pipes made with carbon, car- bon-manganese and low alloy steels. The Society may waive the requirement for thermal stress re-

lieving of pipes having wall thickness less than 10 mm in relation to the design temperature and

pressure of the piping system concerned.

15. When the design temperature is -110 °C or lower, a complete stress analysis for each branch of the piping system is to be submitted to the Society. This analysis is to take into account all stress- es due to weight of pipes with FC fuel (including acceleration if significant), internal pressure, thermal contraction and loads induced by movements of the ship. For temperatures above -110°C, a stress analysis may be required by the Society. In any case, consideration is to be given to thermal stresses, even if calculations need not be submitted. The analysis is to be carried out according to a recognized code of practice.

16. FC fuel pipes are not to be located less than 760 mm from the ship's side.

17. FC fuel piping is not to be led through other machinery spaces. Alternatively, double gas piping may be approved, provided the danger of mechanical damage is negligible, the gas piping has no discharge sources and the room is equipped with a gas alarm.

18. An arrangement for purging FC fuel bunkering lines and supply lines (only up to the double block and bleed valves if these are located close to the FC fuel utilization unit) with nitrogen is to be provided.

19. The FC fuel piping system is to be installed with sufficient flexibility. Bellows will cepted in enclosed spaces. Arrangement for provision of the necessary flexibility is to strated to maintain the integrity of the piping system in all foreseen service situations.

not be ac- be demon-

20. FC fuel pipes in ESD-protected FC space are not to include expansion elements, bellows or other pipe components with poorer strength, fatigue or leakage properties than the butt-welded pipe with complete penetration.

21. FC fuel pipes are to be colour marked based on a recognized standard(Refer to ISO 14726:2008 Ships and marine technology-Identification colours for the content of piping systems).

22. If the fuel gas contains heavier components that may condense in the system, knock out drums or equivalent means for safely removing the liquid are to be fitted.

23. All pipelines and components which may be isolated containing liquid gas are to be provided with relief valves.

24. Where tanks or piping are separated from the ship's structure by thermal isolation, provision is to be made for electrically bonding to the ship's structure both the piping and the tanks. All gasketed pipe joints and hose connections are to be electrically bonded.

106. System configuration

1. Following two alternative system configurations may be accepted:

(1) Gas safe FC spaces : Arrangements in FC spaces are such that the spaces are considered gas safe under all conditions, normal as well as abnormal conditions, i.e. inherently gas safe.

(2) ESD-protected FC spaces : Arrangements in FC spaces are such that the spaces are considered

non-hazardous under normal conditions, but under certain abnormal conditions may have the po- tential to become hazardous. In the event of abnormal conditions involving gas hazards, emer-

gency shutdown (ESD) of non-safe equipment (ignition sources) and machinery is to be auto- matically executed while equipment or machinery in use or active during these conditions are to be of a certified safe type.

2. Gas safe FC spaces are to comply with the following.

(1) All FC fuel supply piping within FC space boundaries are to be enclosed in a gastight enclo- sure, i.e. double wall piping or ducting(Hydrogen piping is to be arranged in ESD-protected FC spaces, see 107. 1).

(2) In case of FC spaces for fuel cell power system used to propulsion or essential service, the

following are to be complied with.

(A)In case of leakage in a FC fuel supply pipe making shutdown of the FC fuel supply neces- sary, a secondary independent fuel supply is to be available. Alternatively, in the case of multi fuel cell power systems, independent and separate FC fuel supply systems for each fuel cell power system may be accepted.

(B) The FC fuel storage is to be divided between two or more tanks of approximately equal size. The tanks are to be located in separate compartments.

3. ESD-protected FC spaces are to comply with the following.

(1) FC fuel supply piping within ESD-protected FC spaces may be accepted without a gastight ex- ternal enclosure on the following conditions:

(A) Fuel cell power system used to propulsion or essential service are to be located in two or more FC spaces not having any common boundaries unless it can be documented that the

common boundary can withstand an explosion in one of the rooms. Distribution of fuel cell

power system between of fuel supply to any

the different FC spaces is to be such that in the case of shutdown one FC space, it is possible to maintain at least 40% of the pro-

pulsion power plus normal electrical power

supply for sea-going services. However, where

the requirements of continuity specified in Pt 6 Ch 1, 201 of the Rules for Steel Ships are

satisfied by other means in ships and the fuel cell systems are installed additionally, the fuel cell power system may be located in one FC space.

Incinerators, inert gas generators or other oil fired boilers are not to be located within an ESD- protected FC space.

(B) All FC fuel pipes that are not inside a double wall piping or ducting are to be butt-welded pipe with complete penetration only and the ventilation rate in the space is to be sufficient

to avoid gas concentration in the flammable range in all leakage scenarios, including pipe rupture. Pipe components with poorer strength, fatigue or leakage properties than the- butt-welded pipe with complete penetration are not accepted in FC fuel piping. Valves in

the FC piping are to be subjected to leakage test for the FC fuel used.

(C) The gas machinery, tank and valve installation spaces are to contain only a minimum of such necessary equipment, components and systems as are required to ensure that any piece of equipment in each individual space maintains its principal function.

(D) Pressure in gas supply lines within FC spaces is to be less than 1.0 MPa, e.g., this concept can only be used for low pressure systems.

(E) A gas detection system arranged to automatically shutdown the FC fuel supply and dis-

connect all non-explosion protected equipment or installations are to be fitted, as outlined in

404 and 405.

(2) The FC fuel storage is to be divided between two or more tanks of approximately equal size.

The tanks are to be located in separate compartments.

107. FC fuel supply system in fuel cell spaces

1. General

(1) In general, the temperature of installations in the fuel cell space is never to be above the self ignition temperature for the fuel used.

(2) The double wall principle is not to be used for hydrogen pipes. Hydrogen pipes are in general

to be located in well ventilated spaces, and as far as practicable to be butt-welded with com- plete penetration.

2. Gas FC fuel supply system for gas safe FC spaces is to comply with the following.

(1) FC fuel supply lines passing through enclosed spaces are to be completely enclosed by a dou- ble pipe or duct. This double pipe or duct is to fulfil one of the following:

(A) The FC fuel piping is to be a double wall piping system with the FC fuel contained in the inner pipe. The space between the concentric pipes is to be pressurized with inert gas at a pressure greater than the FC fuel pressure. Suitable alarms are to be provided to indicate a loss of inert gas pressure between the pipes. When the inner pipe contains high pressure FC fuel, the system is to be so arranged that the pipe between the master gas valve and the

the fuel cell power system is automatically purged with inert gas when the master gas valve is closed; or

(B)

The FC fuel piping is to be installed within a ventilated pipe or duct. The air space be-

tween the FC fuel piping and the wall of the outer pipe or duct is to be equipped with mechanical under pressure ventilation having a capacity of at least 30 air changes per hour. This ventilation capacity may be reduced to 10 air changes per hour provided automatic fill- ing of the duct with nitrogen upon detection of gas is arranged for. The fan motors are to be placed outside the ventilated pipe or duct, or are to comply with the required ex- plosion protection in the installation area. The ventilation outlet is to be covered by a pro- tection screen and placed in a position where no flammable gas-air mixture may be ignited.

(2) The connecting of FC fuel piping and ducting to the fuel cell system fuel inlet is to be so as

to provide complete coverage by the ducting. The arrangement is to facilitate replacement and/or overhaul of valves and other components. The double ducting is to be required also for fuel pipes on the fuel cell system itself.

(3) For high-pressure piping, the design pressure of the ducting is to be taken as the higher of the following:

(A) The maximum built-up pressure: static pressure in way of the rupture resulting from the gas flowing in the annular space;

(B) Local instantaneous peak pressure (ᾬ) in way of the rupture: this pressure is to be taken as the critical pressure and is given by the following expression: