NI518 - Offshore LNG Terminals - VeriSTAR Practice 2A – WSD - for the Planning, Designing and...

Classification and Certification of Offshore LNG Terminals

November 2005

Guidance Note NI 518 DT R00 E

17 bis, Place des Reflets – La Défense 2 – 92400 Courbevoie Postal Address : 92077 Paris La Défense Cedex

Tel. 33 (0) 1 42 91 52 91 – Fax. 33 (0) 1 42 91 53 20 Email : [email protected]

Web : http://www.veristar.com

MARINE DIVISION

GENERAL CONDITIONS

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NI 518 DT R00 E

CLASSIFICATION AND CERTIFICATION

OF

OFFSHORE LNG TERMINALS November 2005

NI 518

2 Bureau Veritas November 2005

NI 518

November 2005 Bureau Veritas 3

CONTENT

1 GENERALITIES....................................................................................................................................7 1.1 SCOPE...........................................................................................................................................7 1.2 GENERAL......................................................................................................................................7 1.3 DEFINITIONS ................................................................................................................................8 1.4 CLASSIFICATION AND CERTIFICATION APPROACH...............................................................8 1.5 NATIONAL AND INTERNATIONAL REGULATIONS ...................................................................9 1.6 NOTATIONS ..................................................................................................................................9 1.7 DOCUMENT TO BE SUBMITTED ..............................................................................................10 1.8 LAYOUT AND CONCEPTS.........................................................................................................10 1.9 OFFSHORE INSTALLATIONS PARTICULARS..........................................................................12

2 IMPACT AND SAFETY ASSESSMENT ............................................................................................14 2.1 GENERAL....................................................................................................................................14 2.2 SCOPE.........................................................................................................................................14 2.3 DEFINITIONS ..............................................................................................................................14 2.4 HAZARD AND RISK ANALYSIS .................................................................................................15 2.5 OUTCOMES TO THE RISK ANALYSIS......................................................................................15

3 ENVIRONMENTAL CONDITIONS -- LOADINGS ...........................................................................17 3.1 GENERAL....................................................................................................................................17 3.2 ENVIRONMENTAL DATA ...........................................................................................................17 3.3 DESIGN LOADS ..........................................................................................................................18

4 STABILITY AND SUBDIVISION ........................................................................................................21 4.1 GENERAL....................................................................................................................................21 4.2 STABILITY CALCULATIONS ......................................................................................................22 4.3 STABILITY CRITERIA .................................................................................................................23 4.4 WATERTIGHTNESS AND WEATHERTIGHTNESS...................................................................27

5 MAIN STRUCTURE OF THE TERMINAL..........................................................................................33 5.1 GENERAL....................................................................................................................................33 5.2 DESIGN APPROACH ..................................................................................................................34 5.3 DESIGN REVIEW BY THE SOCIETY.........................................................................................35

6 PROCESS, TRANSFER AND STORAGE SYSTEMS.......................................................................40 6.1 INLET AND GAS TREATING FACILITIES..................................................................................40 6.2 LIQUEFACTION UNIT .................................................................................................................40 6.3 LNG STORAGE TANKS..............................................................................................................41 6.4 PIPING SYSTEMS.......................................................................................................................46 6.5 LOADING/OFFLOADING SYSTEMS ..........................................................................................47 6.6 PUMPS, COMPRESSORS AND VALVES ..................................................................................48 6.7 VAPORIZATION UNITS (RE-GASIFICATION) ...........................................................................49

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6.8 BOIL-OFF RECOVERY SYSTEM............................................................................................... 50 6.9 MODULARIZATION CONCEPTS ............................................................................................... 51

7 ELECTRICAL EQUIPMENT .............................................................................................................. 52 7.1 GENERAL ................................................................................................................................... 52 7.2 HAZARDOUS LOCATIONS AND TYPES OF EQUIPMENT...................................................... 54 7.3 PRODUCT CLASSIFICATION.................................................................................................... 59

8 UTILITIES........................................................................................................................................... 60 8.1 NITROGEN SUPPLY .................................................................................................................. 60 8.2 COMPRESSED AIR CIRCUITS.................................................................................................. 60 8.3 WASTE TREATMENTS .............................................................................................................. 60 8.4 LIVING AND TECHNICAL QUARTERS ..................................................................................... 60 8.5 ESCAPE ROUTE & LIFESAVING .............................................................................................. 60 8.6 SECURITY .................................................................................................................................. 60

9 FIRE PROTECTION........................................................................................................................... 61 9.1 GENERALITIES .......................................................................................................................... 61 9.2 PASSIVE PROTECTION ............................................................................................................ 61 9.3 FIRE DETECTION AND LIQUEFIED GAS RECOVERY SYSTEM............................................ 62 9.4 FIRE PROTECTION.................................................................................................................... 62 9.5 INSTRUMENTATION.................................................................................................................. 63 9.6 PROTECTION OF PERSONNEL ............................................................................................... 63

10 SAFETY EQUIPMENT & SYSTEMS ................................................................................................. 64 10.1 SCOPE........................................................................................................................................ 64 10.2 EQUIPMENT & SYSTEMS ......................................................................................................... 64 10.3 MONITORING / control SYSTEM ............................................................................................... 69

11 CONSTRUCTION SURVEY & COMMISSIONING............................................................................ 72 11.1 GENERAL ................................................................................................................................... 72 11.2 REVIEW OF FABRICATION DOCUMENTS FOR STRUCTURES ............................................ 72 11.3 SURVEY OF FABRICATION OF STRUCTURES AND SUB-ASSEMBLIES ............................. 73 11.4 SURVEY OF EQUIPMENT & SYSTEMS INSTALLATION and TESTING................................. 74 11.5 MANUFACTURING RECORDS BOOK REVIEW ....................................................................... 75 11.6 COMMISSIONING ACTIVITIES.................................................................................................. 75

12 APPENDIX 1: RULES & STANDARDS ....................................................................................... 77 12.1 BASIC RULES............................................................................................................................. 77 12.2 OTHER RELEVANT CODES, STANDARDS AND RECOMMENDED PRACTICES................. 78

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Foreword The present guidance note is summarizing a set of recommendations and guidelines applicable to the classification and/or certification of Offshore Liquefied Natural Gas (LNG) terminals. It has been built based on some specific documents such as: Bureau Veritas Rules for the Classification of Offshore Units (NR 445); Bureau Veritas Rules for the Classification of Steel Ships, API Recommended Practice 2A – WSD - for the Planning, Designing and Constructing Fixed Offshore Platforms – Working Stress Design, IMO IGC code (including 1994, 1996 and 2000 amendments), and NFPA 59A, the National Fire Protection Association Standard for the Production, Storage, and Handling of Liquified Natural Gas (LNG). It is to be considered as an initial document to be used during the construction of such terminals. It summarizes the experience and technical background existing, on one hand, for up-stream activities, regarding the construction of onshore LNG terminals, for either the liquefaction of the natural gas, its storage and offloading onto shuttle carriers, or for down-stream terminals, covering the activities of offloading the LNG from shuttle vessels to the re-gasification LNG “near” shore terminals, before its final use. On the other hand, it is associating the experience of the Society in the field of classification and certification of offshore units, based on fixed or floating installations, covering the multiple purposes that could be concerned for the oil and gas production activities. The present guidance note is not intended to supersede the existing rules issued by the Society or by National and International Organizations that could apply in case of the construction of offshore LNG terminals, but it is to be used as a reference document, which points out some additional requirements and important aspects to be considered, when dealing with the classification and/or certification of such kind of installations. Two distinct families of offshore LNG terminals are covered within the scope of the present guidance note: the first one regarding the Gravity Based offshore LNG terminals (GB LNG units) and the second one considering the Floating LNG terminals (F LNG installations). These two families, from a historical point of view, could be identified by considering the chronological evolution of the state of the art for the construction of LNG production units, departuring from its original achievements for the case of onshore installations, which have been formely adapted to permit the implementation of offshore LNG fixed installations, to converge to the concept of offshore LNG floating terminals. Assuming the innovating approach to make possible the design and the construction of offshore LNG units, especially those of floating type, it is recommended for such new developments, at an advanced stage of the design, to systematically perform complementary risk analysis studies, focusing the most sensitive components, for example, those of the containment system, the liquefaction production units, and regarding the transfer of the cryogenic fluids.

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1 GENERALITIES 1.1 SCOPE

This Guidance Note published by the Society gives requirements and recommendations to be considered for the classification and/or certification activities regarding the offshore LNG terminals, including, both Gravity Based Structures (GBS) and Floating Installations (FLNG). Four typical configurations for LNG offshore terminals, as described under [1.8.1], are covered by this document, for steel and concrete based structures. Requirements of the present Guidance Note are to be complied with by offshore LNG terminals to be classed or certified by Bureau Veritas, called also in the following the Society. The terminal has to comply with the Bureau Veritas Rules for the Classification of Offshore Units and the relevant additional standards, that are to be adopted in the scope of each specific project. The Class and Marks notations for LNG offshore terminals are those described under [1.6]. The classification and/or certification of LNG terminals of special type, not included in the above listed features, will be considered by the Society on a case by case basis. The general conditions of classification and/or certification are laid down in the Marine Division General Conditions.

Different parts of the present guide are covering the following: • Classification, Certification and Surveys • General arrangement assessment • Safety Assessment • Global structure and Stability • Machinery and Systems • Materials and Welding • Service Notations applying to offshore LNG terminals, for both, gravity-based and floating units.

1.2 GENERAL The present Guidance note considers offshore gas production wells located in remote areas from the energy demanding centres, therefore, the global LNG chain will be mainly including:

1. Gas production (upstream) Facilities 2. Inlet and gas treating Facilities 3. Liquefaction and fractionation Facilities 4. LNG storage installations 5. LNG export terminal (including jetty and berthing) 6. Transport capabilities from remote areas (via LNG carriers) 7. LNG unloading system, including jetty and berthing 8. LNG storage tanks 9. LNG vaporisers (re-gasification unities) 10. In-tank and external LNG pumps 11. Vapour handling system 12. Supporting utilities, piping, valves, control systems, and safety systems required for both,

export and import terminal’s safe operation Transport via a pipeline is not considered inside of this document (pipe in pipe techniques, to convoy cryogenic liquids) A LNG terminal covered by the present guidance note will include various items of the above list and will correspond to one of the service notations as defined in [1.6].

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1.3 DEFINITIONS

The following general definitions are used in this document : • Society means the Bureau Veritas Classification Society with which the offshore unit is classed

or certified • Rules means Rules to comply with as specified by this Guidance note • Surveyor means technical staff acting on behalf of the Society to perform tasks in relation to

classification or certification and survey duties • Survey means an intervention by the Surveyor for assignment or maintenance of class or

certification status, or interventions by the Surveyor within the limits of the tasks delegated by the Administrations

• Administration means the Government Authority of the State whose flag the offshore unit is entitled to fly or the State Authority under whose authority the offshore LNG terminal is operating in the specific case

• Interested Party means a party, other than the Society, having responsibility for the classification or certification of the terminal, such as the Owners of a unit and his representatives, or the Builder, or materials and equipment Manufacturers and Suppliers, or the Supplier of parts to be tested

• Owner means the Registered Owner or the Disponent Owner or the Manager or any other party having the responsibility to keep the offshore unit seaworthy, having particular regard to the provisions relating to the maintenance of class or certification status

• Approval means the review by the Society of documents, procedures or other items related to classification or certification, verifying solely their compliance with the relevant Rules requirements, or other referential where requested. The reviewed plans and documents receive a formal approval with or without comments.

• Type approval means an approval process for verifying compliance with the Rules of a product, a group of products or a system, and considered by the Society as representative of continuous production

• Essential service means a service necessary for an offshore unit to proceed at sea, be steered or manoeuvred, or undertake activities connected with its operation, and for the safety of life, as far as class or certification is concerned.

1.4 CLASSIFICATION AND CERTIFICATION APPROACH

Safety design aspects are a fundamental part of the overall design of an offshore Liquefied Natural Gas terminal and are among the major engineering tasks to be carried out in the scope of this kind of project. The safety assessment of an offshore LNG terminal in accordance with this Guidance Note is to be achieved by:

a) Enforcing the strict compliance of the LNG project to selected rules (codes, standards, regulations …) that already proved to adequately address the relevant issues on the matter. Reference is made to requirements, codes and recommended practices described in the present Guidance.

b) Proposing alternative solutions deviating from the conventional rules requirements that will

achieve: • At least an equivalent level of performance required by the acceptable/prescriptive

solutions • A level of performance that is agreed by the Administration, or a recognised Authority

c) Adopting a combination of both, a) and b) approaches.

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The risk based approach is then to be considered, according to this Guidance, as an alternative or as a complement to conventional design rules to support the adoption of deviations or modifications from these rules requirements. This alternative approach is authorized and encouraged as far as the class and/or the certification are/is concerned, under reserve of the agreement of the Owner to accept any deviation from the Rules. In case of application of statutory requirements, attention is drawn upon the necessary agreement of the flag and/or coastal Authorities. The use of prescriptive rules is not contradictory with the use in parallel of risk analysis methods, as they can be complementary, and as the rules are resulting from large collection of data and analysis of past experience. The classification covers the verification of the compliance to the Society Rules for floating units. The certification covers the verification of the compliance to the Society Rules and/or to relevant National codes and recognised standards for the case of fixed units and components.

The application of any BV rules and documents referred to in this guidance note is to be made for the applicable parts and possibly adapted to the intended use of the terminal in agreement with the Society. 1.5 NATIONAL AND INTERNATIONAL REGULATIONS Fixed units and floating units, as well, operating in national waters are to comply with the Administration rules in addition to the Society rules. In case of disagreement between rules, the Administration rules will prevail on the Society rules, except when the later provide a higher safety level. In this case, decision will be taken in agreement between the Society and the Owner, on a case by case basis. 1.6 NOTATIONS According to [1.8.1], and considering both concepts of Gravity-Based and Floating structures, the following class notations are considered: The terminal notation is composed by a type notation, a service notation and a material notation. The type notations are:

GB corresponding to Gravity-Based terminals F corresponding to Floating terminals

The service notations are:

LNG-GPE corresponding to Global Production and Exporting terminals LNG-PE corresponding to Production and Exporting terminals LNG-R corresponding to Receiving terminals LNG-S corresponding to Storage terminals

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The material notations are:

Steel the whole supporting structure is in steel Concrete the whole structure is in concrete Composite the supporting structure is partially in steel, partially in concrete

A terminal notation can be so: GB LNG-R STEEL 1.7 DOCUMENT TO BE SUBMITTED The documents to be submitted to the Society for classification are classed in three categories:

• Plans and documents to be submitted for approval. They are to be supplemented by further documentation which depends on the service notation and, possibly, the additional class notation to be assigned to the terminal. Structural plans are to show details of connections of the various parts and, in general, are to specify the materials used, including their manufacturing processes, welded procedures and heat treatments.

• Plans and documents to be submitted for appraisal. They are directly linked with the terminal

structural or operational safety, but they are not referring to compulsory requirements. The reviewed plans and documents may be the subject of remarks from the Society which may impact the approval of submitted plans or documents.

• Plans and documents to be submitted for information: Documents not directly concerned by

classification or certification rules, but providing information necessary for the appraisal or approval of the submitted plans and documents. They could include plans and documents such as, for example: general arrangement, capacity plan, etc. Moreover, when direct calculation analyses are carried out by the Designer according to the rule requirements, they are to be submitted to the Society. These documents are not subjected to any assessment by the Society.

1.8 LAYOUT AND CONCEPTS 1.8.1 TERMINAL CONFIGURATIONS From the global LNG chain presented here above under [1.2], the following terminal configurations are considered:

1) Global Production and Exporting Terminal, mainly including items 1 to 5 of [1.2] of the global LNG chain:

LNG-GPE

2) Production and Exporting Terminal, mainly including items 2 to 5 of [1.2] of the global LNG chain: LNG-

PE

3) Receiving Terminal, mainly including items 7 to 9 of [1.2] of the global LNG chain: LNG-R

4) Storage Terminal, mainly including storage tanks and import/export terminal (jetty and berthing): LNG-S

The above listed terminal configurations are also to include relevant features listed under items 10 to 12 of [1.2] of the global LNG chain.

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Based upon terminal general arrangement, the following items could apply:

Fixed steel structures (Jacket, accommodation, bridges, etc.), Fixed concrete structures (tanks, etc.), Floating steel structures, Floating concrete structures, Facilities :

• Gas processing and production, liquefaction, storage, offloading facilities. o When the terminal receives well gas, process it and

liquefies the natural gas and condensate for storage and offloading (configurations 1) or 2), here above)

• Storage and regasification facilities o When the terminal receives LNG from an LNG carrier

vessel, stores it, re-gasifies and discharges the gas ashore (configuration 3), here above)

• Storage and offloading facilities o When the terminal receives, stores and offloads LNG

(configuration 4), here above). The general layout of the installation shall be provided for approval. It must include exact location of main process and storage components, civil works details including dykes and impounding basins, if applicable, control rooms, utilities, pipeworks, warehouses and access for operation maintenance and evacuation. Hazardous areas are to be indicated together with fire pumps locations, emergency generators and gas detectors. 1.8.2 GLOBAL STRUCTURE AND BASE MATERIALS Two global families of LNG offshore terminals are considered:

1) Gravity Based Structures (GBS), which are fixed structures laid down on the sea bed, with suitable station keeping foundations. These structures are in general built in pre-stressed watertight concretes, but can also be of a steel construction type.

2) Floating Structures (FLNG), designed either in concrete or steel, and including a position mooring

system. The Offshore LNG GBS type installations and facilities are quite similar to those used in Onshore projects, with some specific requirements regarding the choice of pre-stressed watertight concrete structure, the design of adequate foundation, and the berthing and loading/offloading of LNG carriers. This type of installation is suitable to areas of shallow waters, with a stable sea bottom and with moderate environmental conditions. The Offshore FLNG type installations are more similar to the one considered for the LNG carriers, with associated mooring, suitability to operate at deep water conditions, and with special care to handle LNG transfer (loading/offloading operations of cryogenic components), which is much sensitive to relative motions between the terminal and LNG carriers.

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1.8.3 TYPES OF LNG OFFSHORE STORAGE TANKS 1.8.3.1 GENERAL Conceptual configurations of cryogenic products are based upon a primary containment system in direct contact with the cryogenic liquefied gas, and a secondary containment system capable of containing temporarily, any leakage, in a liquid or gaseous phase, from the primary containment system. This double containment concept is adopted to reduce the risk of any cryogenic product leakage, and then to protect structural materials, not designed to work at cryogenic temperatures, against a brittle fracture. Complete or a partial secondary barriers will be required, depending on the type of the storage tank, giving origin to definitions of full and partially full containment tanks. 1.8.3.2 RECOMMENDED SYSTEMS Basic tank types that are more suitable for LNG offshore applications are Membrane tanks with full primary and secondary barriers and self-supporting tanks, including IGC Code Independent Type B tanks (Moss and SPB types), and circular metal (or concrete) tanks, according to NFPA 59A and/or EN 1473, taking into account marine specific environment conditions. NFPA 59A is the “Standard for the Production, Storage, and Handling of Liquefied Natural Gas (LNG), of the National Fire Protection Association, and EN 1473 is the European standard regarding “Installation and Equipment for liquefied natural gas – Design of onshore installations”. 1.8.3.3 MEMBRANE TANKS Membrane tanks are double containment systems with the primary containment (the membrane) supported through insulation by the outer mechanical structure. Membrane tanks are non self-supporting tanks. 1.8.3.4 INDEPENDENT TANKS Independent tanks are self-supporting structures, constructed apart from the global mechanical structure of the offshore terminal. Storage tanks are also classified by considering the ability of the primary containment system to mechanically withstand alone to all cargo conditions, without any contribution from the outer structure. This category of storage tanks is classed under self-supporting structures. 1.9 OFFSHORE INSTALLATIONS PARTICULARS Some specific problems arise when dealing with LNG offshore terminals. They are mostly related to the fact that past experience with onshore installations are concerning sheltered water locations, have large areas for the implantation of production and storage installations, making easy the respect of the minimum safety distances between critical areas, without major confinement problems encountered in case of offshore terminal units.

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Some of these aspects to be dealt with, which remain a major hazard concern, are pointed out hereafter:

• Safety management of the eventual combination of oil/condensate and LNG storage in one single unit

• Adaptation of the LNG production facilities to operate in remote offshore locations • Review of possible layout configurations to completely integrate oil/condensate production and

LNG liquefaction facilities, keeping in mind that safety requirements are to be met. • Mode of LNG carrier berthing, to be either in a side-by-side arrangement (in case of relatively

benign environmental conditions), or in a tandem mooring arrangement (in case of harsher weather conditions)

• Design of dynamic loading/offloading LNG systems, suitable for prevailing offshore metocean conditions. To enable a safe and efficient transfer of cryogenic product in open sea conditions, on a routine basis, loading/offloading systems have to be duly tested for the site conditions.

• Structural damage and loss of stability of the offshore terminal, caused by important leakages of LNG from the containment system, and subsequent discharge of LNG into the sea. Risk analysis studies have to demonstrate that ALARP (As Low As Reasonably Practicable) level is achieved.

• Logistical and emergency support at site, and land based support

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2 IMPACT AND SAFETY ASSESSMENT 2.1 GENERAL The risk based approach may be used as a complementary study to conventional design rules to support application for deviations or modifications from these rules requirements. Hazard analysis, risk analysis and environmental impact analysis are usually carried out under request either of local Authorities or of the Owner of the offshore unit. It can be also motivated by the need to know the influence of some additional risk factors, related to:

• Adapting equipment design for a marine environment • Adapting process operation, in case of floating installations, for a moving environment • Fit similar equipment as used onshore into about one-half or even to one-quarter of the foot print

This alternative approach is authorized and encouraged as far as the class is concerned, under reserve of the agreement of the Owner to accept any deviation from the Rules. The use of prescriptive rules is not contradictory with the use in parallel of risk analysis methods, as they can be complementary, and as the rules are resulting from large collection of data and analysis of past experience. In case of application of statutory requirements, attention is drawn upon the necessary agreement of the flag and/or coastal Authorities. 2.2 SCOPE The equipment confinement, and the choice of liquefaction technology, refrigerant types and line-up, are to be assessed with respect to their influence on the occurrence of hazardous situations, that could lead to eventual explosion overpressure generation. A good understanding of the mitigation measures is required to minimize overpressures, and incident escalation to other parts of the topsides and the storage systems. It can be at the origin of HAZID and Concept QRA studies. Two types of analyses are identified in case of LNG offshore installations, as follows:

• Hazard and Risk analysis, when eventual harms caused on the installation and its environment are resulting from accidental events

• Health Safety and Environmental (HSE) study, when eventual harms caused on the installation and its environment are resulting from normal operating conditions

2.3 DEFINITIONS Some concepts and definitions concerning risk analysis techniques are hereafter recalled: ACCIDENT: within the context of Hazard and Risk analysis, an accident is any unwanted specific event, or more generally a chain of events, having a detrimental effect on health, safety, asset integrity or the Environment.

HAZARD: refers to any characteristic of a system, a process or a situation which is capable of causing an accident or contributing thereto.

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RISK: risk is a measure of a hazard, in term of the probability, or the frequency, of an accident it can generate or to which it can contribute, and of the gravity of such an accident.

RESIDUAL RISK: is the risk that remains after a risk ranked as “unacceptable” had been reduced to an acceptable level.

ALARP risk level: As Low As Reasonably Practicable acceptance criterion.

2.4 HAZARD AND RISK ANALYSIS 2.4.1 TARGET Main drivers leading to the performance of such kind of analysis can be of quite different nature. Most commonly encountered are:

• Assess that the installation will remain for operational conditions below a specified level of risk • Assess environmental impact of the installation • Give a rational basis for Safety Management System implementation • Assess the effect of a significant change in the process or in the general installation in term of

implied possible risk increase • Assess “residual risk” level to be monitored via RCM or RBI • Compare effectiveness (eventually cost effectiveness) of two possible technical options during

design or following an in-service modification The risk levels obtained by the arrangement resulting from the analysis are to be as low as reasonably practicable (ALARP), as defined by the interested parties and agreed by the Administration. 2.4.2 APPROACH From a methodological point of view, any risk analysis will be involving the following steps:

1. Data gathering 2. Process description (as necessary for hazard analysis purposes) 3. Hazard identification 4. Scenarios of accidents 5. Frequency analysis 6. Consequence analysis 7. Acceptance criteria 8. Risk reduction measures 9. Management of residual risk

2.5 OUTCOMES TO THE RISK ANALYSIS 2.5.1 RESIDUAL RISK MANAGEMENT At the end of the process, risk is – at least theoretically – under control, i.e., located under the conventionally agreed acceptable level. If nothing is done during normal operating life of the installation, risk level will spontaneously and progressively increases beyond accepted limits. This is the consequence of possible faulty practices, inappropriate management of change, uncontrolled ageing of the equipment, instability of the process … It is therefore necessary to enforce a systematic safety management system (SMS) aimed at paying due consideration to the management of identified hazards.

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2.5.2 SAFETY RULES AND SMS Each safety plan should be subject to a comprehensive set of rules covering the aspects of the terminal activities, with respect to operation, maintenance and emergency conditions. These rules must incorporate knowledge gained from engineering specification, taking into account past experience, best practices and standards as well as applicable statutory requirements. As far as possible they must incorporate findings from hazard/risk analysis if available. These rules should be formalised under the form of written procedures, the content of which being known by the concerned personnel. These procedures are to be managed by the formal “Safety Management System” (SMS). This system is to be able to:

• Identify the necessity of creating a new rule • Issue this rule • Check its relevance and efficiency • Update, if necessary • Make sure that the concerned personnel is able to understand and properly apply the rule

The system is to be subject to regular updating and audit. A “commitment for progress” should be agreed by corporate and the personnel. 2.5.3 CONTINGENGY & EVACUATION PLAN A complete set of procedures on emergency response in case of an accident is to be written and made available to the whole staff of the terminal. Regular training should ensure emergency preparedness and reactivity of the personnel as well as efficiency of the emergency procedure. Co-ordination with local Safety Authorities should be clearly defined and regularly tested if required.

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3 ENVIRONMENTAL CONDITIONS -- LOADINGS

3.1 GENERAL It is the responsibility of the Party applying for the classification to specify the data on which the structural design of the unit is based, for each condition of operation, as follows:

• Working conditions • Severe storm condition • Transit condition • Any additional condition

These data are to include, for each condition, a description of:

• The general configuration of the unit • Environmental conditions • Any other relevant data

Environmental data required for the structural design of the unit are to be specified by the party applying for classification. Environmental data are to include:

• Data for extreme condition (for example, severe storm) • Data for the threshold environmental conditions, for the applicable limit states of the unit (working

condition, transit condition, if applicable, and any relevant design condition) • The long term distribution of environmental data, to be used for fatigue design • Data for any other particular design condition

It remains under the responsibility of the party applying for the classification to ascertain that the environmental parameters are correct and complete. Loads are to be specified by the party applying for classification, covering, at least, the following categories of loads: fixed, operational, environmental, accidental, testing and temporary construction loads. 3.1.1 UNIT SITUATION AND LAYOUT The general layout of the site shall be provided, indicating draught or elevation, for each specific operating condition. It must include exact location of main process and storage components, civil works details including dykes and impounding basins, if applicable, control room, utilities, pipeworks, warehouses, as well as access for operation maintenance and evacuation. When adequate procedures are provided in the Operating Manual to point out any relevant adjustment of operational parameters, required for specific conditions, the corresponding data for these specific conditions, are to be clearly specified and will be entered in the Design Criteria Statement. 3.2 ENVIRONMENTAL DATA 3.2.1 DOCUMENTATION TO BE SUBMITTED

The party applying for classification or certification is to specify the data defining the environmental conditions to which the unit may be subject in each condition of operation, as defined from [3.3.2] to [3.3.5].

Documents concerning fixed loads [3.3.2], operational loads [3.3.3] and accidental loads [3.3.5] are to be provided for information. Documents concerning environmental loads [3.3.4] are to be provided for appraisal.

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3.3 DESIGN LOADS 3.3.1 GENERAL

The following categories of loads are considered: fixed, operational, environmental, accidental, testing and temporary construction loads.

3.3.2 FIXED LOADS

Fixed load or light weight is the weight of the unit complete with all permanently attached vessels, machineries, equipment and other items of outfit such as:

• piping;

• deckings, walkways and stairways;

• fittings;

• spare parts;

• furniture.

The light weight includes the weight of all permanent ballast and other liquids, such as lubricating oil and water in the boilers, to their normal working level but excludes the weight of liquids or other fluids contained in supply, reserve or storage tanks or vessels.

3.3.3 OPERATIONAL LOADS

Operational loads are loads associated with the operation of the unit; they include:

• the weights of moving equipment and machineries;

• variable loads of consumable supplies weights such as:

• casing, drill and potable waters,

• mud,

• cement,

• oil,

• gas,

• chemical products;

• other storage loads;

• hydrostatic loads (buoyancy);

• liquids in tanks;

• ballast loads;

• riser tensioner forces;

• hook or rotary table loads;

• loads resulting from lifting appliances in operation;

• loads due to pipelaying, etc.

Dynamic loads induced by equipment in operation are to be considered as operational loads.

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3.3.4 ENVIRONMENTAL LOADS

Environmental loads are loads resulting from the action of the environment and include loads resulting from:

• wind;

• tides;

• waves;

• current;

• sea floor, when relevant

• ice and snow where relevant;

• earthquake where relevant.

Dynamic loads induced by unit's motions (inertia forces) or by dynamic response to environment action are to be considered as environmental loads.

Reactions to environmental loads (such as those of foundations, or mooring loads) are to be considered as environmental loads.

For permanent installations, the party applying for classification is to submit, in addition to the required documentation, and in accordance with provisions of Chapter 1, adequate documentation describing the environmental conditions at site.

The party applying for classification is to derive as necessary from these data the characteristic parameters required for the purpose of Rules application.

The statistical techniques used to derive the required characteristic parameters are to be documented to the satisfaction of the Society.

For waves, wind, current, and for water level when relevant, the extreme omnidirectional data, with a return period of 100 years, are to be presented (independent extremes).

Directional data may be considered, where applicable, if sufficient information is available to support their use, subject to the agreement of the Society.

When adequate information is available on the joint occurrence of elements, design data may be further specified as sets of associated values. Attention is drawn about the freak wave phenomenon which may occur, depending on the unit location. 3.3.5 ACCIDENTAL LOADS

Accidental loads are loads that may be sustained during accidental events, such as:

• collisions by supply boats or other craft;

• impact by dropped objects;

• breaking of mooring lines.

• fire or explosions

Accidental loads also include loads resulting of such event (damaged situations), or of other exceptional conditions to be determined with regard to the activities of the unit.

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The risk of accidental damage is normally minimised by suitable preventive and protective measures such as:

a) Adequate operation and maintenance of structures and equipment. Procedures are to specify operational limits and related limiting environmental conditions.

b) Appropriate safety requirements for visiting vessels and aircraft with respect to the limiting environmental conditions, the communication and survey procedures for berthing, landing, stowage and disconnection.

c) Adequate arrangement of structure and facilities.

d) Adequate protective arrangements such as guarding, fendering, weak links, quick release mechanisms, shut-off means for high pressure piping systems, etc.

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4 STABILITY AND SUBDIVISION

4.1 GENERAL 4.1.1 SCOPE The present chapter applies to floating units, except for the section [4.4.3], which is also dedicated to fixed units. 4.1.2 CLASSIFICATION REQUIREMENTS

Unit stability and watertightness are to comply with the applicable requirements of the present Chapter, or, subject to a preliminary agreement, in accordance with other particular specifications based on the same principles or relevant National or International Regulations.

Damage stability requirements are applicable to floating LNG offshore terminals covered by the present note.

4.1.3 STATUTORY REQUIREMENTS

Attention is drawn to special legal provisions enacted by National Authorities which units may have to comply with according to their flag, structural type, size, operational site and intended service, as well as other particulars and details.

Adequate instructions and information related to the stability and watertight integrity of the unit are to be provided by the Owner and included in the Operating Manual.

4.1.4 INCLINING TEST AND DEADWEIGHT SURVEY

An inclining test is to be carried out on each unit at the time of construction or following conversion, to determine accurately the light unit data (weight and position of centre of gravity).

The inclining test is to take place, when the unit is as near as possible to completion, in the presence and to the satisfaction of the attending Surveyor. The testing programme is required to be submitted to the Surveyor prior to being carried out.

The results of the inclining test are to be submitted to the Society for appraisal.

A deadweight survey is to be conducted at intervals not exceeding 5 years. An inclining test is to be carried out in the following cases:

• where the deadweight survey indicates a change from the calculated light unit displacement in excess of 1 % of the displacement in working condition or

• where this survey indicates a change from the longitudinal position of the unit centre of gravity in excess of 1 % of the unit's length.

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For successive units of a design or for units undergoing only minor alterations, the Society may, at its discretion, waive the above requirements and accept the light unit data of the first unit of the series in lieu of an inclining test, provided that, notwithstanding minor differences in machinery, outfitting or equipment, both following conditions are fulfilled:

• the deadweight survey indicates a change from the light ship displacement calculated for the first of the series less than 1 % of the displacement in working condition, and

• this survey indicates a change from the longitudinal position of the unit centre of gravity as determined for the first of the series less than 1 % of the unit's length.

4.2 STABILITY CALCULATIONS 4.2.1 GENERAL

Stability calculations are to be carried out and submitted to the Society for review for the following cases:

a) Transit departure and arrival conditions, anchors to be on board and with the maximum related deck loads.

b) Normal working at maximum draught with the maximum deck loads and equipment in the most unfavourable positions.

c) Severe storm condition assuming the same weight distribution as in a) above except for the necessary ballast adjustments to bring the unit to the survival draught and for the possible dumping of variable deck load if such is specified in the operating procedures.

d) Severe storm condition assuming the same weight distribution as in b) above with the necessary ballast adjustments to place the unit in the survival draught configuration. In this condition:

• equipment liable to be disconnected, such as marine riser of drilling units, is assumed disconnected;

• equipment liable to be disconnected and stored on deck, such as stinger of a pipelaying unit, is assumed disconnected and secured on deck;

• equipment having a rest position, such as crane booms, is assumed in rest position;

the maximum amount of loads is assumed to be stored on deck. Account may be taken of dumping of variable deck load if specified. 4.2.2 MAXIMUM ALLOWABLE KG CURVES

The maximum allowable vertical centre of gravity (KG) curves are to be established and submitted to the Society for approval. Computations are to be made on the basis of the Rules intact and damage stability criteria, as defined in [4.3], for the complete range of operating draughts.

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4.3 STABILITY CRITERIA 4.3.1 INTACT STABILITY 4.3.1.1 STABILITY CRITERIA

The stability of a unit in each mode of operation (transit - working - severe storm) is to meet the criteria given, as follows:

• For surface units the area under the righting moment curve to the second intercept, or the angle of downflooding, whichever is less, is not to be less than 40 % in excess of the area under the wind heeling moment curve to the same limiting angle.

• For semi-submersible units the area under the righting moment curve to the second intercept, or the angle of downflooding, whichever is less, is not to be less than 30 % in excess of the area under the wind heeling moment curve to the same limiting angle.

• The righting moment curve is to be positive over the entire range of angles from upright to the second intercept.

4.3.1.2 SEVERE STORM CONDITION

When ballast adjustments to bring the unit to the survival draught are required for the purpose of meeting the intact stability criteria under extreme environment wind speed, the unit is to be capable of attaining the said draught within a period of time of 3 hours

The procedures recommended and the approximate length of time required to attain severe storm condition, considering both working and transit conditions, are to be contained in the Operating Manual.

It is to be possible to achieve the severe storm condition without the removal or relocation of solid consumables or other variable loads. However, the Society may accept that a unit is loaded past the point at which solid consumables would have to be removed or relocated to go severe storm condition under the following conditions, provided the allowable KG requirement is not exceeded:

a) In a geographic location where weather conditions annually or seasonally do not become sufficiently severe to require a unit to go to severe storm condition.

b) Or, where a unit is required to support extra deckload for a short period of time that falls well within a period for which the weather forecast is favourable.

The geographic locations, weather conditions and loading conditions in which this is permitted are to be identified in the Operating Manual.

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4.3.1.3 ALTERNATIVE CRITERIA

Alternative stability criteria may be considered by the Society, provided an equivalent level of safety is maintained and if they are demonstrated to afford adequate positive initial stability. In determining the acceptability of such criteria, the following will be considered:

• environmental conditions representing realistic winds (including gusts) and waves appropriate for world-service in various modes of operation;

• dynamic response of the unit. Analysis is to include the results of wind tunnel tests, wave tank model tests, and non-linear simulation, where appropriate. Any wind and wave spectra used are to cover sufficient frequency ranges to ensure that critical motion responses are obtained;

• potential for flooding taking into account dynamic responses in a seaway;

• susceptibility to capsizing considering the unit's restoration energy and the static inclination due to the mean wind speed and the maximum dynamic response;

• an adequate safety margin to account for uncertainties. 4.3.2 SUBDIVISION AND DAMAGE STABILITY 4.3.2.1 ALL TYPES OF UNITS

1) Units, according to their structural type, are to comply either with [4.3.2.2] or [4.3.2.3]. This

compliance is to be determined by calculations which take into consideration the proportions and

design characteristics of the unit and the arrangements and configuration of the damaged

compartments.

2) The ability to reduce angles of inclination by pumping out or ballasting compartments or

application of mooring forces, etc., will not be considered as justifying any relaxation of the

requirements.

3) Anchor handling, bilge and ballast systems, lifesaving equipment, means of escape and

emergency power supply and lighting are to be capable of operating in the flooded final equilibrium

condition. In particular the angle at equilibrium in the worst damage condition is not to prevent the

safe access to and the safe launching of lifeboats and liferafts.

4.3.2.2 SURFACE UNITS Every unit is to have sufficient freeboard and be subdivided by means of watertight decks and bulkheads to provide sufficient buoyancy and stability to withstand in general the flooding of any one compartment in any condition of operation (transit, working, severe storm) consistent with the damage assumptions set out in [4.3.3].

The unit is to have sufficient reserve stability in damaged condition to withstand the wind heeling moment based on a wind speed of 25,8 m/s (50 knots) superimposed from any direction. In this condition the final waterline, after flooding and heeling due to the effect of wind, is to be below the lower edge of any opening through which progressive flooding of buoyant compartments may take place.

Such openings include air pipes (regardless of closing appliances), ventilation air intakes or outlets, ventilators, non watertight hatches or doorways not fitted with watertight closing appliances.

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4.3.2.3 COLUMN STABILIZED UNITS

The unit is to have sufficient freeboard and be subdivided by means of watertight decks and bulkheads to provide sufficient buoyancy and stability to withstand a wind heeling moment induced by a wind speed of 25,8 m/s (50 knots) superimposed from any direction in any working or transit condition, taking the following considerations into account:

a) The angle of inclination after the damage set out in [4.3.3.2] is not to be greater than 17°.

b) Any opening below the final waterline is to be made watertight, and openings within 4 m above the final waterline are to be made weathertight.

c) The righting moment curve, after the damage set out in a) above, is to have, from the first intercept to the lesser of the extent of weathertight integrity required in b) above and the second intercept, a range of at least 7°. Within this range, the righting moment curve is to reach a value at least twice the wind heeling moment curve, both measured at the same angle.

The unit is to provide sufficient buoyancy and stability in any working or transit condition to withstand the flooding of any watertight compartment wholly or partially below the reference waterline, which is a pump-room, a room containing machinery with a salt water cooling system or a compartment adjacent to the sea, taking the following considerations into account:

a) The angle of inclination after flooding is not to be greater than 25°.

b) Any opening below the final waterline is to be made watertight.

c) A range of positive stability is to be provided, beyond the calculated angle of inclination in these conditions, of at least 7°.

4.3.2.4 ALTERNATIVE CRITERIA

Alternative subdivision and damage stability criteria may be considered by the Society, provided an equivalent level of safety is maintained. In determining the acceptability of such criteria, the following will be considered:

• extent of damage as set out in[4.3.3];

• on semi-submersible units, the flooding of any one compartment as set out here before;

• the provision of an adequate margin against capsizing. 4.3.3 EXTENT OF DAMAGE 4.3.3.1 SURFACE UNITS

In assessing the damage stability of surface units, the following extent of damage is to be assumed to occur between effective watertight bulkheads:

a) Vertical extent: from the baseline upwards without limit.

b) Horizontal penetration perpendicularly to the skin: 1,5 m.

The distance between effective watertight bulkheads or their nearest stepped portions which are positioned within the assumed extent of horizontal penetration are not to be less than 3 m; where there is a lesser distance, one or more of the adjacent bulkheads are to be disregarded.

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Where damage of a lesser extent than defined in a) and b), here above, results in a more severe condition, such lesser extent is to be assumed.

Piping, ventilation systems, trunks, etc., within the extent of damage referred to in a) and b), here above, are to be assumed to be damaged; positive means of closure are to be provided, in accordance with [4.4.2], at watertight boundaries to preclude the progressive flooding of other spaces which are intended to be intact.

4.3.3.2 SEMI-SUBMERSIBLE UNITS

In assessing the damage stability of semi-submersible units, the following extent of damage is to be assumed:

a) Only those columns, underwater hulls and braces on the periphery of the unit are to be assumed to be damaged and the damage is to be assumed in the exposed outer portions of columns, underwater hulls and braces;

Notes:

- the outer portions of a member are defined as portions located outboard of a line drawn through the centres of the peripheral columns of the unit;

- special consideration will be given to units of particular design and to units provided with efficient fendering.

b) Columns and braces are to be assumed to be flooded by damage having a vertical extent of 3 m occurring at any level between 5 m above working draught and 3 m below transit draught.

Where a watertight flat is located within this region, the damage is to be assumed to have occurred in both compartments above and below the watertight flat in question.

Lesser distances above or below the draughts may be applied to the satisfaction of the Society, taking into account the actual conditions of operation. However, the required damage region is to extend at least 1,5 m above and below the draught specified in the Operating Manual.

c) No vertical bulkhead fitted in columns is to be assumed to be damaged, except where bulkheads are spaced closer than a distance of one eighth of the column perimeter, at the draught under consideration, measured at the periphery, in which case one or more of the bulkheads are to be disregarded.

d) Horizontal penetration of a member damage is to be assumed to be 1,5 m, measured at right angle to the shell of the member.

e) Underwater hull or footings are to be assumed to be damaged when the unit is in a transit condition in the same manner as indicated in a), b), d) and either c) or f), having regard to their shape.

f) Piping, ventilation systems, trunks, etc., within the extent of damage are to be assumed to be damaged; positive means of closure are to be provided, in accordance with [4.4.2], at watertight boundaries to preclude the progressive flooding of other spaces which are intended to be intact.

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4.4 WATERTIGHTNESS AND WEATHERTIGHTNESS 4.4.1 GENERAL 4.4.1.1 DEFINITIONS

A closing appliance is said to be watertight if it remains tight and is capable of withstanding the hydrostatic pressure under service and damage conditions defined in [4.3.2]. The waterhead under damage conditions is to account for the sinkage and inclinations of the unit induced by the combined effect of wind and flooding.

A closing appliance is said to be weathertight if it is capable, under any sea conditions, of preventing the penetration of water into the unit. A weathertight closing appliance is not required to remain tight under the hydrostatic pressure occurring after damage.

A manually operated closing appliance meeting the requirements of one of the two previous paragraphs is not to be considered water or weathertight unless, simultaneously:

a) The closing appliance is unambiguously required in the Operating Manual to be closed in a particular mode of operation of the unit.

b) The closure of the appliance has been ascertained by the party applying for classification to be fully practicable and compatible with the particular mode of operation of the unit.

A buoyant space is a space the buoyancy of which is taken into account in the stability calculations.

A weathertight enclosure is a decked structure above a buoyant space with enclosing bulkheads of adequate strength with any opening fitted with weathertight closing appliances. Enclosed superstructures meeting the requirements of the International Convention on Load Lines, 1966 are considered as weathertight enclosures.

Exposed herein means directly exposed to or not protected from the effect of the sea, spray and rain by a weathertight enclosure. 4.4.1.2 BUOYANT SPACES

1) Except where otherwise stated, spaces considered buoyant for the purpose of the stability

computations are to comply with the following requirements.

2) If the space is considered buoyant in the damage stability calculation all its openings not fitted with

watertight closing appliances are to be located above any final damage water plane.

3) If the space is considered buoyant in the intact stability calculation any opening in the space,

which may become submerged before the heeling angle at which the required area under the

intact righting moment curve is achieved, is to be fitted with a weathertight closing appliance or

protected by a weathertight enclosure. In addition watertight closing appliances are to be provided

for openings which may become submerged before the first intercept equilibrium angle.

4) Watertight and weathertight boundaries of the considered compartments, spaces and their closing

appliances are to have adequate strength to be determined in accordance with the applicable

requirements of the Rules.

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4.4.2 WATERTIGHT INTEGRITY (FLOATING UNITS) 4.4.2.1 GENERAL REQUIREMENTS

All units are to be adequately subdivided with an adequate number of watertight decks and bulkheads to meet the Rules damage stability requirements.

The number of openings in watertight subdivisions is to be kept to a minimum compatible with the design and proper working of the unit. Where penetrations of watertight decks and bulkheads are necessary for access, piping, ventilation, electrical cables, etc., arrangements are to be made to restore the integrity of the enclosed compartments.

In order to minimise the risk of progressive flooding, pipes and ducts are to be, insofar as practicable, routed clear of areas liable to be damaged as defined in [4.3.3]. When pipes and ventilation ducts are located within those areas liable to be damaged and serve more than one compartment, they are to be provided with a valve in each compartment served, and non watertight ventilation ducts are to be provided with a watertight valve at each penetration of a watertight boundary.

Where valves are provided at watertight boundaries to maintain watertight integrity, these valves are to be capable of being operated from a pump-room or other normally manned space, a weather deck, or a deck which is above the final waterline after flooding. In the case of a semi-submersible unit this will be the central ballast control station. Valve position indicators are to be provided at the remote control station. For self elevating units the ventilation system valves required to maintain watertight integrity are to be kept closed when the unit is afloat. Necessary ventilation in this case is to be arranged by alternative approved methods. 4.4.2.2 SCUPPERS, INLETS AND SANITARY DISCHARGES

Scuppers, inlets and discharges are to satisfy the following requirements:

a) Scuppers and discharges leading through the shell from buoyant spaces are to have an automatic non return valve with a positive means for closing from an accessible position above the final damage waterline, or two automatic non return valves, the upper of which is always to be accessible in service.

b) In manned machinery spaces sea inlets and discharges in connection with the operation of machinery may be controlled by locally operated valves situated in a readily accessible position.

c) Indicators showing whether the valves mentioned in a) or b) above are closed or open are to be provided.

d) Scuppers leading from non buoyant space are to be led overboard.

4.4.2.3 OVERFLOWS

Overflow pipes are to be located giving due regard to damage stability and to the location of the worst damage waterline. Overflow pipes which could cause progressive flooding are to be avoided unless special consideration has been taken in the damage stability review.

In cases where overflow pipes terminate externally or in spaces assumed flooded, the corresponding tanks are also to be considered flooded. In cases where tanks are considered damaged, the spaces in which their overflows terminate are also to be considered flooded.

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Overflows from tanks not considered flooded as a result of damage and located above the final immersion line may require to be fitted with automatic means of closing.

Where overflows from tanks intended to contain the same liquid or different ones are connected to a common main, provision is to be made to prevent any risk of inter-communication between the various tanks in the course of movements of liquid when emptying or filling.

The openings of overflow pipes discharging overboard are generally to be placed above the load waterline; they are to be fitted where necessary with non-return valves on the plating, or any other device of similar efficiency.

4.4.2.4 INTERNAL OPENINGS

The means to ensure the watertight integrity of internal openings are to comply with the following:

a) Doors and hatch covers which are used during the operation of the unit while afloat are to be remotely controlled from the central ballast control station and are also to be operable from each side. Open/shut indicators are to be provided at the control station.

b) Doors and hatch covers which are normally closed while the unit is afloat, are to be provided with an alarm system (e.g. light signals) showing personnel both locally and at the central ballast control station whether the doors or hatch covers in question are open or closed. A notice is to be affixed to each such door or hatch cover stating that it is not to be left open while the unit is afloat.

The means to ensure the watertight integrity of internal openings which are kept permanently closed during the operation of the unit, while afloat, are to comply with the following:

a) A notice is to be affixed to each closing appliance stating that it is to be kept closed while the unit is afloat.

Note: the present requirement is not applicable to manholes fitted with watertight bolted covers.

b) On self-elevating units, an entry is to be made in the official log-book or tour report, as applicable, stating that all such openings have been witnessed closed before the unit becomes waterborne.

4.4.2.5 EXTERNAL OPENINGS

All downflooding openings the lower edge of which is submerged when the unit is inclined to the first intercept between the righting moment and wind heeling moment curves in any intact or damaged condition are to be fitted with a suitable watertight closing appliance, such as closely spaced bolted covers.

Where flooding of chain lockers or other buoyant volumes may occur, the openings to these spaces are to be considered as downflooding points. 4.4.3 WEATHERTIGHTNESS (FLOATING AND FIXED UNITS) 4.4.3.1 SCOPE

The conditions given in [4.4.3.2] are applicable to floating units liable to operate in waters other than sheltered waters. Alternative requirements will be given for units intended to be used in sheltered waters only after examination of each particular case.

The attention of the Owners and/or the party applying for classification is directed to the applicable requirements of the MODU Code and of the ILLC 1966. The conditions given in [4.4.3.3] are applicable to fixed units.

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4.4.3.2 ASSIGNMENT CONDITIONS FOR FLOATING UNITS

1) The assignment conditions are applicable to openings leading to spaces considered buoyant in the

intact stability computation, to weathertight closing appliances and to weathertight enclosures.

Where buoyancy in the damage conditions is required, the applicable requirements of [4.4.2] are

to be satisfied.

2) In accordance with [4.4.1.2], weathertight boundaries and closing appliances fitted to exposed

decks and bulkheads of a space or enclosure mentioned in the previous paragraph are to comply

with the strength requirements of Part B Ch 9 and/or of the "Rules and Regulations for the

Classification of Ships".

Note: the present requirement concerns particularly the doors, hatchways covers, machinery casings

and ventilators coamings.

3) All access openings in exposed bulkheads of weathertight enclosures are to be fitted with doors of

steel or other equivalent material so arranged that they can be operated from both sides of the

bulkhead. The means of securing these doors weathertight are to consist of gaskets and clamping

devices or other equivalent means permanently attached to the bulkhead or to the doors

themselves. Unless otherwise specified the height of the sills of access openings in exposed

bulkheads is not to be less than 380 mm above the deck.

4) Hatchways and other openings in exposed decks of a space or enclosure mentioned in 1), here

above, are to be provided with coamings and weathertight steel covers or other equivalent material

fitted with gaskets and clamping devices. The height of coamings is generally required to be not

less than 600 mm but may be reduced, or the coamings omitted entirely, subject to the approval of

the Society, in each particular case, taking into consideration the structural type and stability

characteristics of the unit, the space to which the opening leads, its size and location.

5) Manholes and flush scuttles located on exposed decks or within enclosures not considered

weathertight are to be closed by substantial covers capable of being made watertight. Unless

secured by closely spaced bolts, the covers are to be permanently attached.

Ventilators leading to spaces or enclosures mentioned in 1) here above are to comply with the following:

a) Coamings of steel or other equivalent material having adequate strength are to be provided and efficiently connected to the deck. The coaming of a ventilator passing through non weathertight enclosures is to be fitted at the exposed deck of the buoyant space.

b) Coamings are to have a height of at least 900 mm above the deck of a buoyant space and 760 mm above the deck of a weathertight enclosure. For self propelled surface units ventilators coamings are to be at least 900 mm in height if located upon exposed freeboard and raised quarter decks, and upon enclosed superstructures decks situated forward of a point located a quarter of the unit's length from the forward perpendicular.

c) Ventilator openings are to be provided with weathertight closing appliances permanently attached or, subject to the approval of the Society, conveniently stowed near the ventilators to which they are to be fitted. The weathertight closing appliance may however not be required where the ventilator coaming exceeds 2,3 m above the deck and where the intact stability calculations show that the ventilator opening is not submerged before the heeling angle at which the required area ratio is achieved.

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Any exposed portion of air pipes to ballast or other tanks considered buoyant in the intact stability calculation is to be of substantial construction and is to be provided with permanently attached weathertight closing appliances. Their height from the exposed deck to the point where water may have access below is to be at least 760 mm on the deck of a buoyant space and 450 mm on the deck of a weathertight enclosure. Lower heights may be accepted by the Society after examination in each case taking into consideration the stability calculations.

Openings to machinery spaces are to be protected by weathertight enclosures or steel casings of equivalent strength and weathertightness. The prescription 3) , under [4.3.2.1] is applicable to machinery spaces with emergency equipment.

4.4.3.3 ASSIGNMENT CONDITIONS FOR FIXED UNITS In case of fixed units, special attention is to be given to watertightness and weathertightness protection of certain areas of the installation, such as:

• The lower deck: air gap is to be duly considered to take into account the maximum wave height and freak waves occurrence, when relevant.

• The control rooms openings.

• The power generation spaces.

• Ventilator areas.

• And emergency equipment , as well.

Some specific requirements related to the above listed items are presented here after, as follows:

1) Weathertight boundaries and closing appliances fitted to exposed decks and bulkheads of a space

or enclosure are to comply with the relevant strength requirements of Part B Ch 9 of the "Rules

and Regulations for the Classification of Ships".

Note: the present requirement concerns particularly the doors, hatchways covers, machinery casings

and ventilators coamings.

2) All access openings in exposed bulkheads of weathertight enclosures are to be fitted with doors of

steel or other equivalent material so arranged that they can be operated from both sides of the

bulkhead. The means of securing these doors weathertight are to consist of gaskets and clamping

devices or other equivalent means permanently attached to the bulkhead or to the doors

themselves. Unless otherwise specified the height of the sills of access openings in exposed

bulkheads is not to be less than 380 mm above the deck.

3) Hatchways and other openings in exposed decks of a space or enclosure are to be provided with

coamings and weathertight steel covers or other equivalent material fitted with gaskets and

clamping devices. The height of coamings is generally required to be not less than 600 mm but

may be reduced, or the coamings omitted entirely, subject to the approval of the Society, in each

particular case, taking into consideration the structural type and stability characteristics of the unit,

the space to which the opening leads, its size and location.

4) Manholes and flush scuttles located on exposed decks or within enclosures not considered

weathertight are to be closed by substantial covers capable of being made watertight. Unless

secured by closely spaced bolts, the covers are to be permanently attached.

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Ventilators leading to spaces or enclosures are to comply with the following:

a) Coamings of steel or other equivalent material having adequate strength are to be provided and efficiently connected to the deck. The coaming of a ventilator passing through non weathertight enclosures is to be fitted at the exposed.

b) Coamings are to have a height of at least 760 mm above the deck of a weathertight enclosure.

c) Ventilator openings are to be provided with weathertight closing appliances permanently attached or, subject to the approval of the Society, conveniently stowed near the ventilators to which they are to be fitted. The weathertight closing appliance may however not be required where the ventilator coaming exceeds 2,3 m above the deck.

Openings to machinery spaces are to be protected by weathertight enclosures or steel casings of equivalent strength and weathertightness.

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5 MAIN STRUCTURE OF THE TERMINAL 5.1 GENERAL 5.1.1 INTRODUCTION The main structure of the terminal, named the platform, is the main structural part of the installation, designed to accommodate the majority of main components of the LNG terminal, such as, the main containment system, the gas pre-treating facilities, the liquefaction production installations, piping and loading/offloading systems, power generation units, electrical and safety equipment and topsides. In case of gravity based structures the main containment structure is in general to be considered as an integral part of the main structure of the terminal. 5.1.2 TYPES OF PLATFORMS Reference is made to API RP 2A – WSD, “Recommended Practice for Planning, Designing and Constructing Fixed Offshore Platforms – Working Stress Design”. Three general types of platforms are given, as follows:

1. Fixed Platforms, including amongst others: • Jacket or template • Tower • Gravity structures

2. Floating structures, including amongst others: • Surface units (ship and barge shaped platforms) • Tension Leg Platforms • Spars, • Semisubmersibles

3. Related structures: • Include underwater oil storage tanks, bridges connecting platforms, flare

booms, etc. The present guidance note is referring to gravity structures (GB LNG) and floating structures (F LNG), as the primary structure of offshore LNG terminals. However, for the purposes of LNG transfer from the platform to shuttle carriers (or vice-versa), intermediate structures, such as, jackets, column stabilized structures, could also be considered, either to support rigid mechanical arms or to connect flexible systems, used for loading/offloading operations of the cryogenic product. 5.1.3 PLATFORM EXPOSURE CATEGORIES The two classification groups, according to API RP 2A – WSD, based on the life-safety and consequences of failure levels, are considered as follows:

1. Categories for life-safety: • L-1 = manned-nonevacuated • L-2 = manned-evacuated • L-3 = unmanned

2. Categories for consequences of failure:

• L-1 = high consequence of failure • L-2 = medium consequence of failure • L-3 = low consequence of failure

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According to this standard, the level to be used for platform categorization is the more restrictive level for either life-safety or consequence of failure. Platform categorization should be revised over the life of the structure as a result of changes in factors affecting life-safety or consequence of failure.

5.2 DESIGN APPROACH 5.2.1 BASIS OF DESIGN

The limit state approach is recommended for the design of all elements of the main structure. They have to be designed for the following limit states:

• The ultimate limit states (ULS) that correspond, in general, to the maximum resistance to applied actions;

• The serviceability limit states (SLS) that correspond to the criteria governing normal functional use;

• Fatigue limit states (FLS) that correspond to the accumulated effect of cyclic actions; • The accidental limit states (ALS) that correspond to the situation where damage to

components has occurred due to an accidental event. Structural design with respect to the ALS shall involve consideration of resistance of the structure to a relevant accidental event, and resistance in the structural condition resulting from the accidental event. 5.2.2 DESIGN LOADING CONDITIONS For ship-shaped and barge-shaped hulls reference is made to BV Rule note NR 497 DTM R00 E October 2004: “Hull structure of Production, Storage and Offloading Surface Units”. For platforms other than ship-shaped and barge-shaped hulls reference is made to API RP 2A WSD. Amongst others, this standard is stating that: the loading conditions should include environmental conditions combined with appropriate dead and live loads in the following manner:

1. Operating environmental conditions combined with dead loads and maximum live loads appropriate to normal operations of the platform.

2. Operating environmental conditions combined with dead loads and minimum live loads appropriate to the normal operations of the platform.

3. Design environmental conditions with dead loads and maximum live loads appropriate for combining with extreme conditions.

4. Design environmental conditions with dead loads and minimum live loads appropriate for combining with extreme conditions.

Environmental loads, with exception of earthquake load, should be combined in a manner consistent with the probability of their simultaneous occurrence during the loading conditions being considered. Earthquake load, where applicable, should be imposed on the platform as a separate environmental loading condition. 5.2.3 GENERAL ENVIRONMENTAL CONSIDERATIONS Experienced specialists should be consulted when defining the relevant meteorological and oceanographic conditions affecting a platform site. Reference is made to chapter 3 of this guidance note: “Environmental Conditions – Loadings”.

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5.2.4 ACTIVE GEOLOGIC PROCESS Reference is made to API RP 2A – WSD. … The nature, magnitude, and return intervals of potential seafloor movements should be evaluated by site investigations and judicious analytical modeling to provide input for the determination of the resulting effects on structures and foundations. Seismic forces should be considered in platform design for areas that are determined to be seismically active. Areas are considered seismically active on the basis of previous records of earthquake activity, both in frequency of occurrence and in magnitude. 5.3 DESIGN REVIEW BY THE SOCIETY 5.3.1 GENERAL The design review concerns relevant drawings, calculations notes and other documents covering naval architecture and main structural components of the terminal, developed by the Designer and submitted to the Society for approval, appraisal and information. 5.3.2 NAVAL ARCHITECTURE & STRUCTURE An independent evaluation is made by the Society with respect to the safety of the unit on the naval architecture and structural aspects. This evaluation is made in the following fields :

• Buoyancy and stability integrity • Structural integrity for steel and concrete structure(s) • Strength of production plant, topsides structures and other secondary structures (helideck,

living quarters, ..., if requested by the owner). • Corrosion protection of structures • Mooring system

At the satisfactory conclusion of evaluations, a Certificate of Design Approval is issued, which expresses the opinion of the Society as regards the compliance with the present Guidance Note and the applicable requirements of the reference documents as defined in [5.3.4]. 5.3.3 ANALYSIS EXTENT

This analysis is performed to the extent deemed necessary for the assessment of Unit design. However, by no way, independent analysis is due to replace Designer's calculations.

This analysis is performed for : • Intact and damage stability • Motions of floating units or during transportation of fixed components • Mooring - Positioning • Overall strength and fatigue

Additional analysis may be performed upon special request at the Classification contract definition.

The analysis of Offshore Units may be performed by using the programs developed by Bureau Veritas : - HYDROSTAB - Stability - HYDROSTAR - Motions - 3D Diffraction Radiation - ARIANE - Mooring and Positioning - BV-STRUDL - Structural Analyses, including fatigue analysis - STNT - Sloshing Analyses

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5.3.4 REFERENCE DOCUMENTS The design review of structures is made in view of the following Regulations, Rules and Standards, editions in force at the unit design contract signature date : • National Regulations for Continental Shelf (if any) • Bureau Veritas Rules for the Classification of Offshore Units – NR 445 • International Regulations, and recognized standards as applicable to subject unit :

- API RP 2A --WSD - MODU code - SOLAS - MARPOL - ILLC - Tonnage - ILO

• Bureau Veritas Rule Note "Construction survey of steel structures of offshore units and installations" - NR 426

• Bureau Veritas Rules and Regulations for the classification of steel ships – Part D Materials • Recommended Practice "Corrosion Protection of Steel Offshore Units and Installations" – NR 423 • Other Bureau Veritas Rules and guidance notes, as applicable to a specific subject (e.g. Rules for

Steel Ships, for Lifting Appliances,...) • Other recognised Standards, where suitable for design of concrete and steel structures in a marine

environment, as agreed between parties and the Society for specific aspects of the project A detailed non exhaustive list of relevant rules and standards is given in [12] for reference. 5.3.5 DOCUMENTS TO BE SUBMITTED The documents to be provided to the Society include:

• The LNG terminal’s specifications

• Basic engineering documents, specifications of the installation, and other Owner’s documents including General Arrangement.

• Specific technical documents (for example, soil report and metocean report)

• Detailed engineering documents

• Drawings

• Specifications for loads and other relevant parameters

• Supporting calculations as necessary to fully demonstrate the adequacy of proposed design for the relevant conditions.

Documents to be received are to be identified prior to starting the design review, from supplied lists defined in agreement with the Society on the basis of [5.3.4]. In any case, the Owner shall submit himself, or make submit, any other documents relevant to the scope of classification/certification. Besides, the Society may request any document found relevant, should the need arise along the course of the Design Review.

Drawings are reviewed with particular attention to: • primary structure: the sizing, the design of connection, the selection of materials, and the

welding standard details. • secondary structure and appurtenance: their impact on primary structure, such as applied loads

and methods of attachment.

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5.3.6 MAIN ITEMS TO BE COVERED BY THE REVIEW The review of the Unit Naval Architecture and Structural Design is made with attention to the items as outlined in [5.3.6.1] to [5.3.6.10]. These items are indicative of the various aspects to be addressed in usual project and is not meant to be exhaustive. Particulars of the project are to be duly considered. 5.3.6.1 METOCEAN

Reports of environmental conditions are examined for appraisal as to the availability of all data which are necessary to perform unit design, including :

• Extreme conditions • Long term distribution, for fatigue evaluation

Background reports and studies for information are examined for their support of proposed design data.

5.3.6.2 SOIL DATA

The methods and results of soil investigation, are examined for appraisal.

A review is made of the soil parameters proposed for foundation design, and the methods by which they were derived from results of investigations.

5.3.6.3 DESIGN PREMISES

Design premises proposed by the designer for each activity (naval architecture, mooring, structural design) are reviewed for information for their suitability to generate an acceptable design, with respect to : • Site data • Design conditions resulting from Owner’s operating requirements (e.g. limit condition for a

given situation of the unit) • Output of safety assessment study (e.g. requirements for integrity under fire and blast

conditions) and other design activities.

However, it is understood that amendments or complements may arise with the progress of design.

5.3.6.4 NAVAL ARCHITECTURE

The following items are reviewed: • Floating stability, intact and damaged. • Arrangement of vessel with respect to requirements of

- Stability - MARPOL Regulations, as applicable to subject vessel (storage units) - Segregation of storage spaces and other safety requirements impacting on arrangement of

structure - Inspection requirements taking into account non-docking

• Watertightness, weathertightness and related provisions • Hull and topsides strength with respect to design hydrodynamic loads, and specifically for

the assessment of : - slamming and green waters (ship-shaped units) - sloshing in storage tanks

• Design of station keeping system(s), and specification of components (design of specific components - e.g. anchors - is to be addressed separately, as equipment

design)

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5.3.6.5 FLOATING STRUCTURES

Floating structures other than ship-shaped and barge-shaped hulls are considered in a case by case basis.

For ship-shaped and barge-shaped hulls the following items are reviewed for approval: • Longitudinal hull strength in still water, taking into account anticipated loading conditions

(loading manual), and on wave. • Overall and local strength of hull structure, including fatigue strength, in the central storage /

ballast / void space areas • Structural and mechanical strength of turret, turret area or connection structure, or equivalent

structures • Strength, overall and local, of fore and aft structures, and other specific areas of the unit

For this specific type of floating installation, reference is made to BV Rule note NR 497 DTM R00 E October 2004: “Hull Structure of Production, Storage and Offloading Surface Units”.

5.3.6.6 CONCRETE FIXED STRUCTURES

The following items are reviewed for approval: • Strength of primary structure under gravity, operational and environmental loads, • Strength of local structure, • Fatigue strength, • Details about materials and workmanship, arrangements and details of reinforcement, typical

details of concrete cover, location and detail of construction joints, water stops, etc.. • Deformation loads due to prestress, creep, shrinkage and expansion. • Foundation design.

5.3.6.7 JACKET STRUCTURES, TOPSIDES STRUCTURES AND OTHER SUPERSTRUCTURES

The following items are reviewed for approval: • Strength of primary framing of structures under gravity loads and operational loads, and

under environmental loads (motions, wind) • Design of connections in primary framing : tubular connection, stiffened nodes, connections

between sections, or tubular and sections. • Design of decks for local superimposed loads, concentrated loads induced by heavy

equipment, and test loads (large vessels, cranes, life-boat davits). • Strength under fire and/or blast loading cases, where applicable • Strength of slender booms or towers (vent, flare, telecom) foundations in hull under body

motions, wind loads, gravity loads and design of foundations in primary framing or hull • Capability to withstand loads arising from temporary conditions such as load out,

transportation of items on barge, or lifting where relevant • Review of temporary conditions during fabrication, if needed, are made within the scope of

the survey of fabrication. • Foundation design

5.3.6.8 CORROSION PROTECTION

The corrosion protection design of main structure, is reviewed for approval, including : • selection of the protection methods (cathodic, paint, etc...) versus location (underwater,

splash and atmospheric zone, storage, ballast, enclosed spaces) • design parameters and design calculations of cathodic protection • arrangement of anodes and/or impressed current electrodes • specific protection for concrete structure relative to chemical deterioration & corrosion of

reinforcement • specific protection for concrete-steel hybrid structure interaction • monitoring system (if applicable).

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5.3.6.9 MOORING

The design of mooring systems is reviewed for approval, including: • design procedures, wind tunnel test data, and model basin test (specification and report. • design calculations of mooring system • arrangement • strength of anchors and other particular components

5.3.6.10 MATERIAL SPECIFICATIONS

Specifications for structural materials or components are reviewed for approval. • For structural concrete, attention is given to:

- suitability of proposed concrete grades and qualities to cover the range of proposed application, - materials, concrete mix proportions, construction procedures and quality control, - resistance to abrasion, cavitations, freeze-thaw durability and strength retention, chemical deterioration, - serviceability relative to cracking.

• For structural steels, attention is given to : - suitability of proposed steel grades and qualities to cover the range of proposed application, - notch toughness and through thickness requirements, in relation with design temperature of structure, thickness of item, and application, - method of identification of the steel grades.

• Specifications for other structural components (e.g. components of mooring system) will be reviewed with respect to : - performance requirements as identified by the design - suitability of reference standards for subject application

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6 PROCESS, TRANSFER AND STORAGE SYSTEMS

6.1 INLET AND GAS TREATING FACILITIES 6.1.1 GAS QUALITY The natural gas obtained from the production well will be, in general, a mixture of light hydrocarbons in which the main product is methane. In addition, it contains indesirable components such as water, methanol, carbon oxide, mercury and sulphur, that have to be removed before liquefaction. 6.1.2 METERING Flow metering can be required for fiscal, custody transfer or material balance purposes. The accuracy of the metering systems have to be demonstrated as being sufficient for the purpose. 6.1.3 GAS PROCESSING Pre-treatment operations have to be performed to remove undesirable components of the natural gas, such as water, methanol, carbon dioxide and sulphur compounds, as they solidify during the liquefaction process, causing blockages of the main circuits. Mercury will seriously attack aluminium parts, for example those from heat exchangers, causing their failure, and consequently it has to be removed from the system. 6.2 LIQUEFACTION UNIT 6.2.1 GENERAL The purpose of liquefaction process is to extract sensible and latent heat from natural gas to transform it from gaseous state at high temperature to liquid phase under a cryogenic temperature of about -162 °C, and under a pressure close to the atmospheric pressure. The selection of the most suitable liquefaction cycle for an offshore installation will be mainly depending on factors such as:

• Machinery configuration and available drivers • Power requirements • Heat exchanger type and surface area • Ease of operation/start-up/shutdown • Space and weight requirements • In case of floating units, the process sensitivity to motions and accelerations

Among a variety of liquefaction process, three main types of refrigeration cycle could be mentioned for LNG offshore units:

• Cascade refrigerant cycle: the natural gas is cooled, condensed and sub-cooled in three discrete stages, by using a combined propane, ethylene, methane refrigerant system.

• Mixed refrigerant cycle (MRC): uses a single mixed refrigerant, comprising nitrogen and hydrocarbons.

• Expander cycle: combines compression and work-expansion of gas to provide refrigeration in a closed cycle. It uses either nitrogen or methane as the refrigerant cycle gas.

The liquefaction plant, cold box, cooling fluids and insulation materials are to be duly selected and designed to make sure produced LNG quantities will be stored and maintained within the acceptable range of pressure and temperature.

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Special attention is to be drawn to offshore terminal motions, in case of floating units, to make sure allowable operating conditions are respected to motion sensitive process equipment. Whenever it is possible, these sensitive equipment should be located close to the centre of gravity of the floating structure. 6.2.2 COLD BOXES For certain items of cold equipment, including the intercooler and cargo heat exchangers, and turbo expander, a designed cold box can be used to house these items together, providing them with a common heat insulation casing. The principle consists of enclosing these equipment items within a metal box, made of steel-framed panels which will be completely filled with powdery or another kind of heat insulation material. Inside of cold boxes, duly access for inspection, maintainance and repair works are to be provided. 6.2.3 COOLING FLUIDS STORAGE Hydrocarbon refrigerants are generally stored inside of pressure vessels at ambient temperature, excepted for Ethylene, which is stored at a cryogenic temperature. The design, installation and operation of such storage vessels shall be in conformity with local regulation. If no specific regulation is prescribed for such kind of equipment, it is recommended to design, manufacture and test it according to ASME Code or the European Pressure Equipment Directive. 6.3 LNG STORAGE TANKS 6.3.1 GENERAL The following prescriptions will apply for both categories of storage tanks previously mentioned under [1.8.3.2]. However, these general principles are to be adapted under a case-by-case basis for each of these 2 categories of storage tank. 6.3.2 DESIGN PRINCIPLES The storage tanks have to be designed to properly ensure the following functions:

• Safely contain the liquefied gas at cryogenic temperature, as well as its gaseous phase corresponding to the boil-off

• Allow the safe in/out transfer of the gas • Allow the safe removal of the boil-off • Prevent any ingress of air and moisture • Minimise the rate of thermal transfer • Withstand the effects of detrimental external accidental factors, as defined by engineering

specifications 6.3.3 LOADS The following categories of loads acting on the storage vessel are to be considered and provided for information:

• Permanent actions: corresponding to time independent actions resulting from nominal use of the tank and from permanent interactions of tanks with their surrounding. Permanent actions are including:

o Weights (own weight, weight of connected items) o Gaseous pressure o Pre-stress, if any o Pressure from insulation material (example, from perlite) o Permanent differential settlements o Permanent temperature gradients o Mechanical and thermal reactions from connected pipes

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• Transient actions: corresponding to time dependent actions such as:

o Loading during construction phase o Hydrostatic action from stored LNG o Variable actions due to loading/unloading operations, that could result in fatigue o Variable actions during commissioning/decommissiong o Any test load o Climatic actions (wind, snow, ice, waves, daily and seasonal atmospheric changes) o Seismic action corresponding to OBE

Both permanent and transient actions as defined hereabove are considered as ‘’normal actions’’, and will be referred to as such in the following.

• Accidental actions: corresponding to low probability transient actions caused either by abnormal operating conditions or upsets, or by extreme external conditions. They are including:

o Overpressures, for example, caused by a roll-over o Underpressure o Overfilling o Leakage of primary containment, if relevant o Extreme seismic action (SSE) o Missile impact o Radiation produced by an external fire o External blast o Pump drop during maintenance operations

Some mandatory remarks are formulated here below:

• Lists of loads(actions) presented hereabove are not exhaustive. The exact definition of the actions to be considered during the design is to be submitted to BV for consideration. Whenever possible, these actions should match results from hazard/risk analyses.

• Actions are to be combined according to their likelihood of occurrence. Unless otherwise specified, combination as defined by EN 1473 is applicable.

• It is acknowledge that detailed safety objectives and acceptance criteria are dependent upon the design codes selected. However the following principles are to be applied in any case:

o Occurrence of normal actions must not result in safety nor operability impairment o In case of accidental actions, it is acceptable that operability could be temporary altered,

provided that safety is maintained. • Non-conventional design principles such as, for example, Leak before Break concept, can be

considered provided that suitable justification is given. 6.3.4 PRIMARY CONTAINMENT (SELF SUPPORTING TANK) Primary containment is usually made of 9% Ni steel, aluminium or stainless steel. Design is covered by well known codes such as API 620, NFPA 59a, EN 1473, which shall be adapted to also consider the specific marine environment conditions. Reference is also made to BV Rules for the Classification of Steel Ships, Part D, Ch 9 and to IGC Code as well. The choice of the Code will depend on the specific shape of containment to be considered (for example, circular, or prismatic, or spherical tanks). Special issue, such as seismic analysis usually requires specific modelling.

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6.3.5 MEMBRANE TANKS (INTEGRATED TANK) Structural strength of membrane tanks has to be checked under the effects of static and dynamic loads, to demonstrate the suitability of the membrane and of the associated insulation to withstand plastic deformation and fatigue. Primary and secondary barriers, including corners and joints, are to be designed to support the expected combined strains due to static, dynamic and thermal loads. Membranes are to be designed against buckling, by paying special attention on the effects of overpressure in the interbarrier space, possible vaccum in the cargo tank, sloshing stresses and vibration of the hull. Metallic membranes are usually made of SS 304 austenitic stainless steel, or INVAR, as well. The methodology used for the design of membrane tanks shall be submitted to the Society for approval. Non metallic secondary membranes are usually made of Triplex. The methodology used for the design of these tanks shall be submitted to the Society for approval. 6.3.6 THERMAL INSULATION Materials used for insulation should, as a rule, comply with identified standards. As an example, EN 1160 is an acceptable one. Selected material has to show suitable thermal characteristic, that are determined by the specific constraints of the project, mainly related to the rate of boil-off. Moreover, insulation materials have to present a mechanical resistance compatible with the loads they are intended to carry, according to design condition. Other material properties are also to be considered, such as, their resistance to corrosion, or to moisture limited creep behavior, and possibly non-combustibility.(non-flammability) 6.3.7 TANK CONNECTIONS 6.3.7.1 NOZZLES

a) Loads to be considered for design purposes shall be consistent with the constraints of the engineering specification. In particular they must include: • Pressure (steady and transient) • Movements due to changes in temperature of the tank • Pipe thermal expansion • Wind, waves (if applicable) • Earthquakes (if applicable) • Differential movements due to eventual settling of tank or pipes supporting systems

b) Each tank pipe shall be provided with at least one remote-controlling closing device located as

near the tank as possible. Moreover, the closing system shall also to be provided with local hand control system

c) Connection of safety valves, high level alarms and lines normally fitted with blind flanges shall be

given special consideration.

d) Pipes fitted on tank with service temperature below –100 °C should preferably be located above the tank’s maximum filling level

e) Pipes fitted below the tank’s maximum filling level shall be provided with remote-controlled or

automatic valve (e.g. check valve) fitted inside the primary tank. This arrangement shall be designed so that any defects liable to develop in way of tank wall penetrations, caused by stresses resulting from pipe distortions or thermal gradient, occur outside the inner tank.

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6.3.7.2 INTERNAL PIPING SYSTEMS

a) Piping systems situated in annular space between inner and outer tanks, which are connected to inner tank, shall be designed for a pressure at least equal to that of the tank.

b) Suitable devices shall be provided to compensate thermal shrinkage. (the use of expansion

bellows or slip joints is not acceptable inside of the annular space)

c) Piping systems penetrating insulation space, but not connected to it, shall preferably be welded.

6.3.8 TANK MONITORING DEVICES Each storage tank shall be provided with suitable instrumentation system to enable safe and reliable operation, during commissioning, in service conditions and decommissioning situations. At least, the following aspects are to be considered:

• Liquid level: it is recommended to use high accuracy and independent measurement level devices allowing for a continuous measurement, and for a high level detection to initiating ESD.

• Pressure: each tank shall be fitted with pressure gauges, suitably located, enabling to:

o Perform continuously measurements of the pressure o Detect excessive pressures o Detect too low pressures (up to vacuum) o Detect differential pressure in case where insulated space is not in communication with

internal tank • Temperature: each tank has to be fitted with properly located temperature sensors allowing to

measure: o Temperature at different depths (every two meters, as a minimum) o Gaseous phase temperature o Primary and secondary tank wall and bottom temperature

• Density: LNG density should be monitored throughout the whole liquid depth (unless otherwise

specified) Limited reliability of measuring devices are to be managed by the use of appropriate redundancy system. All measurements shall be transmitted to control room and/or to ESD, whenever an emergency action is to be automatically taken. Alarms are to be transmitted directly to the designated operator.

6.3.9 SAFETY DEVICES 6.3.9.1 GENERAL Protection for overpressurisation shall be insured by safety valves and/or rupture disks. Each tank shall be fitted with, at least, two overpressure valves directly relieving to the atmosphere. The maximum flow rate to be discharged at the maximum operating pressure is either gas flow due to the heat input in the event of a fire or likely combination of the following flow due to:

• Evaporation produced by heat input • Displacement caused by filling • Flash at filling • Variations in atmospheric pressure • Recirculation from submerged pump • Control valve failure • Possibly, roll-over

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6.3.9.2 GAS INJECTION SYSTEM Each tank shall be fitted with an injection system able to inject gas under automatic control, upon receipt of a signal indicating a too low pressure of the system. 6.3.9.3 BOIL-OFF EVACUATION/RECOVERY Independing on the means provided for the recovery of the boil-of gas which might exist elsewhere, the vapour space of the tank shall be connected to a flare/vent, safety valve, or rupture disk being capable of discharging flow rate from any combination of the following:

• Evaporation caused by heat input • Displacement caused by filling • Flash at filling • Variation in atmospheric pressure • Recirculation from a submerged pump

6.3.9.4 PURGING SYSTEM Each tank should be provided with a purging system. 6.3.9.5 ANTI ROLL-OVER SYSTEM Measures shall be taken to prevent liquid stratification to occur. Amongst possible provisions, the following is recommended:

• For bottom filling, at least one of the features here below shall be provided: o Jet nozzles placed at the bottom of the tank and oriented toward the surface o Vertical pipe perforated for part or for its whole length o Jet breaker located at the extremity of a pipe for spray filling.

• A recirculation system • A boil-off monitoring system • A temperature/density measurement system.

6.3.9.6 ANTI LIGHTNING SYSTEM Tankers and their accessories are to be duly protected against lightning. 6.3.9.7 DELUGE SYSTEM / WATER CURTAINS Water deluge system is frequently used for cooling purposes, to avoid any risk of a fire escalation. Water supply should be determined by using results from risk analysis, if available. It is to be assessed that deluge system is designed in such a way that it will evenly distribute water flow onto the exposed surface. Water curtains systems are designed to rapidly decrease the gas concentration of an LNG vapour cloud to values below the Lower Flammability Limit of the gas in air. This system will transfer heat to the cold natural gas cloud through the contact between LNG vapours and water droplets. In addition, water curtains will facilitate LNG cloud dispersion. Water curtains design is to be assessed by using models validated by experimental results. 6.3.9.8 DIFFERENTIAL SETTING MEASUREMENT DEVICES Each tank shall be provided with a differential setting measurement device enabling continuous differential setting of the various parts of the tank.

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6.3.9.9 PRIMARY (OR THROUGH MEMBRANE) GAS LEAK DETECTION Storage tanks for which the insulation space is not in communication with the primary containment shall be fitted with a monitoring primary containment tightness system based on nitrogen and hydrocarbon continuous detection. 6.3.9.10 LEAK DETECTION (GENERAL) Two types of leak detectors can be used, as follows:

• Low temperature thermal detector of the straight-line type. Within hazardous areas such as those of, manifold and valves at lower tank, it is recommended to provide a TV-monitoring system.

• Gas detector for locations presenting a particularly high risk of leakage, like areas of manifolds.

Such detectors shall always be placed under cone-shaped collectors. 6.4 PIPING SYSTEMS 6.4.1 GENERAL Prescriptions given under this chapter will be applying to piping items of:

• the main process system, • the auxiliary system, • utilities • and fire protection systems

Design of pipes, fabrication and installations should comply with specific recognised codes/standards. Pipes are to be arranged either on piperacks or pipeways. 6.4.2 CONSTRUCTION MATERIALS Construction materials are to be selected according to the conditions of use of the pipes. Two cases have to be taken into consideration:

• Material in permanent contact with LNG: in this case, materials are to be suitable for cryogenic use.

• Material in accidental contact with LNG: in this case, the pipe will be provided with suitable insulation or with any equivalent protective measure.

6.4.3 SUPPORTS Supports are to be designed in such a way that stresses induced by pipe displacements caused by thermal expansion or contraction remain within acceptable limits. Moreover, special attention is to be drawn with respect to design of the supports, to allow a proper behavior of the pipes under earthquake, wind and wave loads, is applicable. 6.4.4 CORROSION Pipes will be designed so as to prevent any leak due to corrosion or pitting during the lifetime of the plant. The material selection and corrosion allowances will be made according to the operating and environmental conditions. Whenever necessary, special measures, such as cathodic protection or special coating, are to be enforced.

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6.4.5 PIPE CONNECTIONS Pipe connections will be normally of welded type, and the number of flange connections will be limited as far as practicable. Bolted connections should be limited to diameters up to 50 mm. If used, gaskets should be of a fire resistant type, compatible with conveyed products. 6.5 LOADING/OFFLOADING SYSTEMS 6.5.1 GENERAL The LNG transfer system is to be duly designed to ensure safe and reliable transfer of LNG offshore to and from LNG carriers, taking into consideration the combination of containment integrity requirements and site environmental conditions, maximum significant wave heights, and subsequent range of relative motions between the terminal and the shuttle. Several relative positions of terminal and shuttle tanker have to be considered, to cover different waterdepth and environmental conditions, and always keeping in mind the need of high availability of the system, and also the suitability to receive a variety of shuttle vessels. Depending on the site conditions, either the concept of a side-by-side LNG transfer or a tandem mode should be considered, the latter being adapted to more severe site weather conditions. 6.5.2 SYSTEM DESCRIPTION The loading/offloading system will consist of any marine transfer systems, designed to compensate and balance mechanical efforts existing on the transfer system, accentuated by relative motions between the terminal and shuttle vessels. Depending on the site characteristics, structural parts could include, one or various of the items listed here below:

1. a jacket structure with turntable, anchored to the seabed, or directly fixed on the LNG offshore terminal

2. a submerged or a suspended rigid arm, hinged at one end to the jacket turntable, and

terminating at its other end either with a buoyant column, or with mechanical articulated structures

3. the LNG loading and transfer structure 4. berthing structural floating structure, able to receive LNG carriers, connected to a Single Point

Mooring (SPM) system, and also fitted with a simple Dynamic Positioning (DP) system

5. fluid transfer lines 6.5.3 MAIN CHARACTERISTICS The transfer system is to demonstrate its ability to:

1. ensure reliable fluid containment,

2. cover the range of operating conditions specified for site, sea states, and the variety of shuttles it is intended to work with

3. be rapidely connected and/or disconnected in different sea states, and designed configurations

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4. to control, based on real time measurements and computer devices, relative motions between shuttle and terminal (PMS: Position Monitoring System)

5. to follow the low frequency motions caused by horizontal relative motions of the LNG carrier

6. stop important LNG leakages in case of accidents during the transfer operations (levels 1 and 2

ESD systems(*), with both options, for automatic and manual control)

7. allow easy access to all system parts for inspection and maintenance, provide adapted means for efficient repairs or replacements

(*) NOTA: ESD1 is the emergency shut down system which stops transfer operation when initiated from ship or terminal, whereas the ESD2 is the one which disconnects transfer lines by both: 1) closing valves (limiting liquid spills) and 2) powering the coupling apart. The fluid transfer lines operating parameters are generally, considering:

1. cryogenic temperatures around –162 °C

2. working pressure inside of the range –0.3 bar to +30 bar 3. thermal insulation requirements, suitable diameter to ensure LNG flow rates of up to 10 000

m3/hr, and dedicated line for the vapour return. In general, standard fluid transfer systems consist of 3 transfer lines, two intended for LNG transfer, and the third for the vapour return. (All the three transfer lines are in general designed under the same basis, in such way they are fully interchangeable).

Structural parts in the neighbourhood of cryogenic transfer lines are to be duly protected of any eventual product leakage that could cause their brittle fracture. Among others, they are to be provided with suitable low temperature material barriers, fire detection equipment, especially in areas close to manifolds, and appropriate electrical insulation to prevent any electrical current flow through components of the transfer system. (also refer to SIGTTO ‘’Gas Transfer Guide’’ and ‘’Gas Handling Procedures’’, EN 1474, and OCIMF, as well) 6.6 PUMPS, COMPRESSORS AND VALVES Every pump and compressor shall be provided with a local or remote control system. Explosion-proof light signals showing whether the component is in service shall be provided locally or transmitted to control room. Every pump and compressor shall be provided with the following:

• Isolating valves aimed at facilitating maintenance operations • Check valves at discharge lines (two items in parallel) • Suitable protection against overpressure • Whenever necessary, cooling down system aimed at preventing thermal shocks

Fluid transfer piping systems are to be designed so as to incorporate a sufficient number of valves to prevent huge fluid spillage in case of a rupture. Such valves are to be provided with both local and remote control devices. Valves shall be designed to operate at minimum service temperature and shall be provided with suitable protection against possible icing during unloading phases.

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6.7 VAPORIZATION UNITS (RE-GASIFICATION) 6.7.1 GENERAL Several categories* of vaporizers are currently used:

• Heated Vaporizers in which heat is provided by the combustion of fuel, electric power, exhaust gas from boiler or waste heat from internal combustion engines

• Integral Heat Vaporizers for which the heat source is integral to the actual vaporizing exchanger. This type includes the so-called submerged combustion vaporizers.

• Remote Heated Vaporizers corresponding to cases where the heat source is separated from the actual vaporizing exchanger and an intermediate fluid (water, steam, iso-pentane, glycol) is used as the heat transport medium.

• Ambient Vaporizers using natural sources such as the atmosphere, seawater, or geothermal waters.

• Process Vaporizers in which heat is provided from another thermodynamic or chemical process or in such a way to conserve or to utilize the refrigeration from the LNG.

* this classification is the one adopted by the NFPA A59, ch 5 § 5-1. 6.7.2 DESIGN AND CONSTRUCTION MATERIALS Vaporizers shall be designed, fabricated and inspected in accordance to a recognized pressure vessel code. As vaporizers usually operate at temperatures comprised between –163 °C and 40 °C, special consideration should be given to selection and welding of materials. It is recommended that design pressure of vaporizers be at least equal to the maximum discharge pressure of the LNG pump of pressurized container system supplying them, whichever is greater. Design values to be specified for vaporizers should comply with EN 1473, Annex E, Table E.1. 6.7.3 STORAGE OF INTERMEDIATE VAPORIZER FLUIDS Manifolds of vaporizers shall have both inlet and discharge block valves at each vaporizer. Automatic equipment shall be provided to prevent the discharge of either LNG or vaporized gas into a distribution system at a temperature either above or below the design temperature of the send-out system. Isolation of an idle manifolded vaporizer shall be accomplished with two inlet valves. If flammable intermediate fluid is used with a remote heated vaporizer, shut-off valves shall be provided on both the cold and hot lines of the intermediate fluid system. 6.7.4 SAFETY AND RELIEF VALVES Safety shut-off valve shall be fitted on liquid line of heated vaporizer at a location at least 15 meters from the vaporizer, except when vaporizer is located at less than 15 meters from the liquefied gas supply tank. For a vaporizer located inside a building, safety shut-off valve shall be at least 15 meters from the structure. In addition to the above remote control system, safety shut-off valve shall be provided with local control system.

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6.7.5 COMBUSTION AIR SUPPLY Heated vaporizers with internal heating system or heat sources for heating vaporizers with external heating system shall not use the air contained in a closed space. Air intake shall be provided with suitable flammable vapour detector. When such heated vaporizers are located inside buildings precautions shall be taken to prevent the accumulation of combustion products. 6.8 BOIL-OFF RECOVERY SYSTEM 6.8.1 GENERAL Each plant shall be provided with a boil-off recovery system in such a way to collect boil-off product, to reliquefy, recompress, to flare or to release it to the atmosphere in a controlled way. These systems generally comprise:

• Boil-off collection system (pipework) • Systems of gas transfer to/from the tanker • Boil-off gas compressors • Flares and vents

6.8.2 COLLECTING SYSTEM Collecting system should be designed in such a way as no direct emission of cold gas into the atmosphere can arise during normal operation. It has to be designed, at least for the following items:

• Tanks and LNG receivers, and • Degassing system of pipes and equipment containing LNG

The principles underlying the design, fabrication and control of collecting systems shall be the same as those applicable to pipework. 6.8.3 GAS RETURN SYSTEM This system is aimed at compensating the volume of liquid shifted during loading/unloading operations as well as at collecting boil-off of the tanker while at berth or during the inerting of the tank. Material constitutive to this system shall comply with the same requirements as applied to collecting system. 6.8.4 BOIL-OFF GAS RECOVERY Boil-off can be processed in different ways according to the nature of the storage as well as its particular economic constraints and objectives. As a matter of fact, boil-off can be:

• Re-liquefied* • Recondensed in the LNG send out prior to vaporization (especially for receiving terminals) • Sent to flare/vent • Used as fuel gas • Recompressed and sent to gas network

In any case, boil-off gas recovery system design and material shall comply with the same requirements as applied to cryogenic systems. 6.8.5 COMPRESSORS Compressors shall be fitted with devices suitable to limit downstream pressure to the Maximum Allowable Working Pressure (MAWP) of equipment installed downstream. They shall be equipped with a shut down system capable to isolate them in case of an emergency. Compressors handling flammable gas shall be provided with collected vents.

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6.8.6 FLARE/VENTS Flare/vents shall be designed according to the maximum flow rate they are intended to convey. This flow rate can result of the following working circumstances:

• Unloading of an LNG carrier without gas return • Stop of boil-off recovery compressor(s) • Operation of a submerged pump in full recycle • Cool down of LNG carrier tanks (for exporting terminals)

Usually, several types of flow rates are defined:

• Nominal flow rate, and • Accidental flow rate,

These flow rates should be considered separately. Flare lay out shall be chosen as to account for site specific wind direction distribution to minimize the risk of a fammable gas cloud reaching a source of ignition. Snuffing and cooling devices can be used as last resort. 6.9 MODULARIZATION CONCEPTS When the design of the terminal is based upon the assemblage of several dedicated modules, constructed apart, by one or several constructors, particular attention is to be given to:

• Eventual interface problems, to ensure a safe, reliable and maintenable connection between modules

• The respect of minimum required distance between equipment. The final layout of the

installation is to consider a detailed disposition of equipment inside of modules, and their arrangement on the terminal itself.

• Accessibility into modules for inspection, maintenance and repair after installation.

• Ability to isolate a module, in case of failure.

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7 ELECTRICAL EQUIPMENT 7.1 GENERAL 7.1.1 APPLICATION The requirements in this chapter apply, in addition to those contained in Bureau Veritas Rules for the Classification of Steel Ships Part C, Ch 2, to gas carriers, more specifically:

• Section 12, [7.15] • Section 11, [5] • Section 3, [10]

Requirements in this chapter, which are given immediately after a reference to the IGC code are to be understood as being complementary requirements to the IGC code. 7.1.2 DOCUMENTATION TO BE SUBMITTED In addition to the documentation requested in Bureau Veritas Rules for the Classification of Steel Ships Part C, Ch 2, Sec 1, Tab 1, the following are to be submitted for approval:

a) plan of hazardous areas

b) document giving details of types of cables and safety characteristics of the equipment installed in hazardous areas

c) diagrams of tank level indicator systems, high level alarm systems and overflow control systems where requested.

7.1.3 SYSTEM OF SUPPLY 7.1.3.1 ACCEPTABLE SYSTEMS OF SUPPLY

IGC CODE REFERENCE : Ch 10, 10.1.1

The following systems of generation and distribution of electrical energy are acceptable:

a) direct current:

• two-wire insulated b) alternating current:

• single-phase, two-wire insulated • three-phase, three-wire insulated.

In insulated distribution systems, no current carrying part is to be earthed, other than:

a) through an insulation level monitoring device

b) through components used for the suppression of interference in radio circuits.

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7.1.3.2 EARTHED SYSTEM WITH HULL RETURN IGC CODE REFERENCE : Ch 10, 10.1.1 Earthed systems with hull return are not permitted, with the following exceptions to the satisfaction of the Society:

a) impressed current cathodic protective systems b) limited and locally earthed systems, such as starting and ignition systems of internal

combustion engines, provided that any possible resulting current does not flow directly through any hazardous area

c) insulation level monitoring devices, provided that the circulation current of the device does not exceed 30 mA under the most unfavourable conditions.

7.1.3.3 EARTHED SYSTEMS WITHOUT HULL RETURN IGC CODE REFERENCE : Ch 10, 10.1.1 Earthed systems without hull return are not permitted, with the following exceptions:

a) earthed intrinsically safe circuits and the following other systems to the satisfaction of the Society

b) power supplies, control circuits and instrumentation circuits in non-hazardous areas where technical or safety reasons preclude the use of a system with no connection to earth, provided the current in the hull is limited to not more than 5 A in both normal and fault conditions; or

c) limited and locally earthed systems, such as power distribution systems in galleys and laundries to be fed through isolating transformers with the secondary windings earthed, provided that any possible resulting hull current does not flow directly through any hazardous area; or

d) alternating current power networks of 1,000 V root mean square (line to line) and over, provided that any possible resulting current does not flow directly through any hazardous area; to this end, if the distribution system is extended to areas remote from the machinery space, isolating transformers or other adequate means are to be provided.

7.1.4 EARTH DETECTION

7.1.4.1 MONITORING OF CIRCUITS IN HAZARDOUS AREAS IGC CODE REFERENCE : Ch 10, 10.1.1 The devices intended to continuously monitor the insulation level of all distribution systems are also to monitor all circuits, other than intrinsically safe circuits, connected to apparatus in hazardous areas or passing through such areas. An audible and visual alarm is to be given, at a manned position, in the event of an abnormally low level of insulation.

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7.1.5 ELECTRICAL INSTALLATION PRECAUTIONS 7.1.5.1 PRECAUTIONS AGAINST INLET OF GASES OR VAPOURS

IGC CODE REFERENCE : Ch 10, 10.1.2

Suitable arrangements are to be provided, to the satisfaction of the Society, so as to prevent the possibility of gases or vapours passing from a gas-dangerous space to another space through runs of cables or their conduits.

7.2 HAZARDOUS LOCATIONS AND TYPES OF EQUIPMENT

7.2.1 ELECTRICAL EQUIPMENT PERMITTED IN GAS- DANGEROUS SPACES AND ZONES

a) IGC CODE REFERENCE : Ch 10, 10.2

The electrical equipment specified in Tab 1 may be installed in the gas-dangerous spaces and zones indicated therein.

b) IGC CODE REFERENCE: Ch 10, 10.2.5.3

Enclosed or semi-enclosed spaces (not containing a source of hazard) having a direct opening, including those for ventilation, into any hazardous area are to be designated as the same hazardous zone as the area in which the opening is located.

Electrical installations are to comply with the requirements for the space or area into which the opening leads.

c) IGC CODE REFERENCE: Ch 10, 10.2.5.4

Electrical installations in spaces protected by air-locks are to be of a certified safe type unless arranged to be de-energised upon loss of overpressure in the space.

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Table 1 : Electrical equipment permitted in gas-dangerous spaces and zones

Hazardous area

Spaces Electrical equipment

N° Description

Zone 0 1 IGC CODE REFERENCE: Ch. 10, 10.2.2 Cargo containment systems

a) IGC CODE REFERENCE: Ch. 10, 10.2.1 certified intrinsically safe apparatus Ex(ia);

b) simple electrical apparatus and components (e.g. thermocouples, photocells, strain gauges, switching devices), included in intrinsically safe circuits of category “ia” not capable of storing or generating electrical power or energy in excess of limits stated in the relevant rules, and acceptable to the appropriate authority;

c) equipment specifically designed and certified by the appropriate authority for use in Zone 0;

d) IGC CODE REFERENCE: Ch. 10, 10.2.2

submerged cargo pump motors and their supply cables may be fitted in cargo containment systems.

Zone 0 2 IGC CODE REFERENCE: Ch. 10, 10.2.3.1 Hold spaces where cargo is carried in a cargo containment system requiring a secondary barrier

a) IGC CODE REFERENCE: Ch. 10, 10.2.1 certified intrinsically safe apparatus Ex(ia);

b) simple electrical apparatus and components (e.g. thermocouples, photocells, strain gauges, switching devices), included in intrinsically safe circuits of category “ia” not capable of storing or generating electrical power or energy in excess of limits stated in the relevant rules, and acceptable to the appropriate authority;

c) equipment specifically designed and certified by the appropriate authority for use in Zone 0;

d) IGC CODE REFERENCE: Ch. 10, 10.2.3.1 supply cables for submerged cargo pump motors.

Zone 1 3 IGC CODE REFERENCE: Ch. 10, 10.2.3.2 Hold spaces where cargo is carried in a cargo containment system not requiring a secondary barrier

a) IGC CODE REFERENCE: Ch. 10, 10.2.1 any type considered for Zone 0;

b) IGC CODE REFERENCE: Ch. 10, 10.2.1 certified intrinsically safe apparatus Ex(ib);

c) simple electrical apparatus and components (e.g. thermocouples, photocells, strain gauges, switching devices), included in intrinsically safe circuits of category “ib” not capable of storing or generating electrical power or energy in excess of limits stated in the relevant rules, and acceptable to the appropriate authority;

d) based on IGC CODE 10.2.3.2.1 electrical cables passing through the spaces;

e) IGC CODE REFERENCE: Ch. 10, 10.2.3.2.2 lighting fittings are to have pressurised enclosures Ex(p) or to be of the flameproof type Ex(d). The lighting system is to be divided between at least two branch circuits. All switches and protective devices are to interrupt all poles or phases and are to be located in a gas-safe space;

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Hazardous area


N° Description

f) based on IGC CODE 10.2.3.2.3 hull fittings containing

the terminals or shell plating penetrations for anodes or electrodes of an impressed current cathodic protection system, or transducers such as those for depth sounding or log systems, provided that such fittings are of gas-tight construction or housed within a gas-tight enclosure, and are not located adjacent to a cargo tank bulkhead. The design of such fittings or their enclosures and the means by which cables enter, and any testing to establish their gas-tightness, are to be to the satisfaction of the Society.

Zone 1 4 IGC CODE REFERENCE: Ch. 10, 10.2.3.2 Spaces separated from a hold space where cargo is carried in a cargo containment system requiring a secondary barrier by a single gas-tight steel boundary

IGC CODE REFERENCE: Ch. 10, 10.2.1 any type considered for spaces under item 3; IGC CODE REFERENCE: Ch. 10, 10.2.3.2.4 flameproof motors for valve operation for cargo or ballast systems; and IGC CODE REFERENCE: Ch. 10, 10.2.3.2.5 flameproof general alarm audible indicators.

Zone 1 5 IGC CODE REFERENCE: Ch. 10, 10.2.4 Cargo pump and cargo compressor rooms Enclosed spaces in Turret Re-gasification installations




d) IGC CODE REFERENCE: Ch. 10, 10.2.4.1 lighting fittings are to have pressurised enclosures Ex(p) or to be of the flameproof type Ex(d). The lighting system is to be divided between at least two branch circuits. All switches and protective devices are to interrupt all poles or phases and are to be located in a gas-safe space;

e) IGC CODE REFERENCE: Ch. 10, 10.2.4.2 electric motors for driving cargo pumps or cargo compressors are to be separated from these spaces by a gas-tight bulkhead or deck. Flexible couplings or other means of maintaining alignment are to be fitted to the shafts between the driven equipment and its motors, and in addition, suitable glands are to be provided where the shafts pass through the bulkhead or deck. Such electric motors and associated equipment are to be located in a compartment complying with Chapter 12 of the IGC Code;

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Hazardous area


N° Description

f) IGC CODE REFERENCE: Ch. 10, 10.2.4.3 where

operational or structural requirements are such as to make it impossible to comply with the method described in e), motors of the following certified safe types may be installed: • IGC CODE REFERENCE: Ch. 10, 10.2.4.3.1

increased safety type with flameproof enclosure Ex(de); and

• IGC CODE REFERENCE: Ch. 10, 10.2.4.3.2 pressurised type;

g) based on IGC CODE 10.2.4.4 certified safe type visual and/or acoustic indicators (e.g. for general alarm, fire-extinguishing media alarm, etc.);

h) certified safe type sensors for gas detection systems.

Zone 1 6 IGC CODE REFERENCE: Ch. 10, 10.2.5.1 Zones on open deck or non- enclosed spaces on the open deck, within 3 m of any cargo tank outlet, gas or vapour outlet, cargo pipe flange, cargo valve or entrances and ventilation openings to cargo pump rooms and cargo compressor rooms. It also includes:

• Non-enclosed spaces in Turret

• Loading/offloading system




d) based on IGC CODE 10.2.5.1.1 certified flameproof Ex(d);

e) based on IGC CODE 10.2.5.1.1 certified pressurised Ex(p);

f) based on IGC CODE 10.2.5.1.1 certified increased safety Ex(e);

g) based on IGC CODE 10.2.5.1.1 certified encapsulated Ex(m);

h) based on IGC CODE 10.2.5.1.1 certified sand filled Ex(q);

i) based on IGC CODE 10.2.5.1.1 certified specially Ex(s);

j) based on IGC CODE 10.2.5.1.2 electrical cables passing through the spaces.

Zone 1 7 IGC CODE REFERENCE: Ch. 10, 10.2.5.1 Zones on the open deck over the cargo area and 3 m forward and aft of the cargo area on the open deck and up to a height of 2,4 m above the deck

As allowed for spaces under item 6.

Zone 1 8 IGC CODE REFERENCE: Ch. 10, 10.2.5.1


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Hazardous area


N° Description

Zones within 2,4 m of the outer surface of a cargo containment system where such surface is exposed to the weather

Zone 1 9 Areas on open deck, or semi- enclosed spaces on open deck, within 3 m of any cargo tank pressure relief valve vent exits


Zone 1 1 0 IGC CODE REFERENCE: Ch. 10, 10.2.5.2 Compartments for cargo hoses




d) IGC CODE REFERENCE: Ch. 10, 10.2.5.2.1 lighting fittings are to have pressurised enclosures Ex(p) or to be of the flameproof type Ex(d). The lighting system is to be divided between at least two branch circuits. All switches and protective devices are to interrupt all poles or phases and are to be located in a gas-safe space;

e) based on IGC CODE 10.2.5.2.2 electrical cables passing through the spaces.

Zone 1 1 1 IGC CODE REFERENCE: Ch. 10, 10.2.5.2 Enclosed or semi-enclosed spaces in which pipes containing cargoes are located


Zone 2 1 2 Areas of 1,5 m surrounding the Zone 1 spaces defined in item 9

a) any type considered for Zone 1; b) electrical equipment of a type which ensures the

absence of sparks, arcs and "hot spots" during its normal operation;

c) electrical equipment tested specially for Zone 2 (e.g. type "n" protection);

d) electrical equipment encapsulated and acceptable to the Society.

Zone 2 1 3 Spaces 22 m or (B − 3) m, whichever is the lesser, beyond the Zone 1 spaces defined in item 9


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7.2.2 SUBMERGED CARGO PUMPS 7.2.2.1 EXCEPTIONS IGC CODE REFERENCE: Ch 10, 10.2.2 Submerged cargo pumps are not permitted in connection with the following cargoes:

• diethyl ether • vinyl ethyl ether • ethylene oxide • propylene oxide • mixtures of ethylene oxide and propylene oxide.

7.2.2.2 SUBMERGED ELECTRIC MOTORS

IGC CODE REFERENCE: Ch 10, 10.2.2

a) Where submerged electric motors are employed, means are to be provided, e.g. by the arrangements specified in paragraph 17.6 of the IGC Code, to avoid the formation of explosive mixtures during loading, cargo transfer and unloading.

b) Arrangements are to be made to automatically shut down the motors in the event of low liquid level. This may be accomplished by sensing low pump discharge pressure, low motor current, or low liquid level. This shutdown is to be alarmed at the cargo control station. Cargo pump motors are to be capable of being isolated from their electrical supply during gas-freeing operations.

7.3 PRODUCT CLASSIFICATION 7.3.1 TEMPERATURE CLASS AND EXPLOSION GROUP

IGC CODE REFERENCE: Ch 10 and Ch 19

Temperature class and explosion group data, are given for the case of methane, only:

Product name Temperature class Explosion group

Methane T2 II A

In case of any other product, reference is made to BV Rules for the Classification of Steel Ships, Part D, Ch 9, Sec 10, [Tab 2] .

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8 UTILITIES

8.1 NITROGEN SUPPLY Nitrogen is mainly used for gas treatment (adjustment of calorific value), pressurization, LNG tank insulation space and piping purging , drying and inerting, rapid extinction of flares, vents and furnaces, cooling, refrigerant cycle make up. Nitrogen should be of cryogenic quality. It can be produced on site or delivered by ship under pressure or liquefied. Liquified nitrogen pipework shall use cryogenic materials selected in accordance with specific standards (for example, EN 1160). 8.2 COMPRESSED AIR CIRCUITS Compressed air circuits generally include air instrument, air service and air breathing. As far as air instrument is concerned, it is recommended that:

• The air be dried before delivery • A minimum redundancy of two compressors be provided, each being able to supply the total

demand. 8.3 WASTE TREATMENTS Special care should be given for secure storage and recycling of toxic wastes, in particular those containing mercury. 8.4 LIVING AND TECHNICAL QUARTERS Living and technical quarters shall be designed and built according to recognized standards, complying with the local regulations concerning safety for the public, based on environmental conditions, including earthquake analysis, if applicable. When no local regulations exist, API RP-2A will be applied. 8.5 ESCAPE ROUTE & LIFESAVING Special attention is to be drawn on the following aspecs:

1) Access arrangements are to be carefully designed to ensure ease of access for escape and rescue teams, taking into account the required first aid equipment, including the transportation of injured persons. Entrance points need probably to be provided with both watertight and airtight doors, support devices to the escape routes must ensure adequate ventilation, even during an incident.

2) The general requirements for means of escape, and lifesaving are to comply with the SOLAS Reg. II-2/13.

3) Safety and protective equipment is to be provided in accordance with relevant requirements of the Part D, Ch 9, of “the Rules for the Classification of Steel Ships”.

4) The existence of regulations by the National Authorities, with additional requirements for such installations operating in their territorial waters.

8.6 SECURITY The operator of the facility shall provide a security system aimed at restricting the access to some specific reserved areas of site to authorised persons, only. Access (arrivals and derpartures) should be strictly controlled at access gates to the terminal.

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9 FIRE PROTECTION 9.1 GENERALITIES The fire hazard remains the major risk for this kind of installations. The main objective of the safety code is then to reduce the probability of occurrence of any accident of this type, keeping in mind the huge confined quantity of LNG to be stored, processed, loaded and/or offloaded in offshore LNG terminals. The probability that a person in or adjacent to the terminal will be exposed to an unacceptable safety hazard as a result of the design and construction of the terminal, has to be reduced to very low levels, to be decided in agreement with the Administration. The implementation of the fire safety system must take into account this major objective of reducing the probability of injury of any person in the terminal or in adjacent areas, caused by any fire accident. These risks of injury due to fire are addressed here after, as being those caused by:

1) fire or explosion occurring 2) fire or explosion impacting areas beyond its point of origin 3) collapse of physical elements due to a fire or explosion 4) fire safety systems failing to function as expected 5) persons being delayed in or impeded from moving to a safe place during a fire emergency

The fire safety functional requirements are:

1) To minimize the risk of accidental ignition. 2) To limit the severity and effects of fire or explosions. 3) To retard the effects of fire on areas beyond its point of origin. 4) To retard failure or collapse due to the effects of fire. 5) To protect emergency egress facilities from the effects of fire. 6) To protect facilities for notification, suppression and emergency response from the

effects of fire. 7) To facilitate the timely movement of persons to a safe place in an emergency. 8) To notify persons, in a timely manner, of the need to take action in an emergency. 9) To facilitate emergency response. 10) To notify emergency responders, in a timely manner, of the need to take action in an

emergency. In case of floating structures, reference is made in general to Part D, Ch 9, Section 11, of the Rules for the Classification of Steel Ships. 9.2 PASSIVE PROTECTION 9.2.1 GENERAL While in a confined area, the rise in LNG temperature will result in the rise of vapour tension. In open air, a considerable amount of gas (600 liters of gas for 1 liter of liquid) is released, which is liable to quickly form an explosive gas/air mixture. To prevent major accidents, four passive protection measures are therefore recommended, as follows:

1. Prevention and detection of liquid leaks of gas 2. Limitation of evaporated amount of LNG, in case of a leak, by confining the leak within bonds

(compartmented areas, and liquefied gas recovery system). 3. Removal of ignition sources from possible leakage areas, to locate them at minimum safe

distances from these sites 4. Passive fire protection structures

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The concept of safety distance shall be duly observed, specially between LNG storage tanks, and others hydrocarbon storage tanks, as well. This safety distance concept is aimed at preventing fire to escalate from one tank to another. The determination of suitable distances are subject to specific justification , including regulatory requirements, codes and standard recommendations, as well as, results from risk / hazard analysis. 9.3 FIRE DETECTION AND LIQUEFIED GAS RECOVERY SYSTEM 9.3.1 LIQUEFIED GAS LEAK-DETECTION Two types of leak detectors can be used:

1. low temperature thermal detectors. In harzadous areas (manifolds, valves at lower tank), it is recommended to provide a TV-monitoring system.

2. Gas detectors for locations presenting a particularly high risk of leakage, such as, areas around manifolds. These detectors shall always be placed under cone-shaped collectors.

9.3.2 FLAME DETECTION Flame detectors shall normally be used only in case of processing areas associated with the storage plant. 9.3.3 LIQUEFIED GAS RECOVERY SYSTEM Pumps provided for the liquefied gas recovery system shall be of low suction height (maximum of 50 cm) and capable of sucking a diaphasic mixture, without presenting any cavitation problem. A safety wall able to withstand a gas fire for one hour shall be provided to suitably protect recovery lines and control rooms. 9.4 FIRE PROTECTION 9.4.1 WATER SUPPLY AND FIRE MAINS Water pressure in fire mains shall be suitable for the proper operation of drencher nozzles (pressure will depend on type of drencher nozzle fitted and on effective rate of water jet, but it will never be under 4 bars of effective pressure) and of fire water hoses (7 bars of effective pressure). Five to six bars of effective pressure shall be maintained in fire mains when not in use. Fire-mains shall include:

• Anti-hammering devices (water hammering being prejudicial to drencher nozzles) • Isolating valves, to isolate any defective pipe sections. Valve locations are to be lit and

suitably protected against thermal radiation. Constituent materials of mains and pumps shall be corrosion resistant, in particular to seawater corrosion. 9.4.2 DRENCHER NOZZLE SYSTEM Open type drencher nozzles shall be supplied through control stations, including:

• One direct-passage gate valve with position indicator (position displayed at control station) and locking device (valve locked in open position while in normal service)

• One automatic quick-opening valve able to be operated locally or from control room. Valve hand control device shall remain easily accessible in the event of a disaster. Lighting above 20 LUX shall be provided to illuminate the device (considered as vital power consumer).

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9.4.3 FOAM FIRE-EXTINGUISHING SYSTEM Foam systems shall be provided with sufficient capacity to cover the largest primary drainage area and the associated vessels. Attention is to be drawn with respect to the selection of the foam expansion rate and foam discharge rate, as well.

Foam systems shall be provided with remote control from the control station or through low temperature detection (with alarm signal displayed in control room).

Sufficient reserve of foam forming liquid available to cover ten times the surface of all concerned items is to be provided, as well (about 0.8 liters per square meter of surface to be covered).

To the fixed foam fire-extinguishing systems, it can be advantageously to add monitor or foam-making branch pipes controlled from control room and coupled to a TV-monitoring system.

9.4.4 TESTING OF FIRE-EXTINGUISHING SYSTEMS Periodical tests of fire-fighting systems shall be made to check that:

• No line or drencher nozzle is clogged • Water discharge rate is as required and correctly distributed to all drencher nozzles, at the

designed pressure • Water pressure at drencher nozzles and hydrants is as required • Fire detectors and remote measuring, detection and control systems operate normally

9.4.5 POWDER FIRE-EXTINGUISHING SYSTEMS Every storage area shall be provided with fire-extinguishing powder system. Fire-extinguishing powder shall be compatible with the foam used. Moreover, hand vent masts of release valves shall be suitably protected by a powder system of sufficient capacity. 9.5 INSTRUMENTATION The following information on fire-extinguishing systems shall be displayed at control room:

• Position of check valves • Operation of automatic valves • Failure in electric power supply • Failure in fire-detection circuits

In addition to this, it shall be possible to open automatic valves from control room. Continuous monitoring system shall be provided for all cable connections, depending on their importance, and cables shall be of flame-resisting or incombustible type. 9.6 PROTECTION OF PERSONNEL In addition to protective isotherm clothing, personnel shall be protected against radiant heat by means of screesns fitted in suitable locations, especially in the axis of pathways located in the vicinity of storage tanks.

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10 SAFETY EQUIPMENT & SYSTEMS

10.1 SCOPE The design review concerns safety equipment & systems regarding the offshore LNG terminal as described in [1.2], the plans, the drawings and other documents covering structures, equipment and systems developed by the Designer and submitted to the Society for approval, appraisal and information.

10.2 EQUIPMENT & SYSTEMS 10.2.1 SCOPE OF WORK An independent evaluation is made by the Society with respect to the safety of the proposed installation.

Relevant data are to be submitted to the Society, for assessment, on the following items: - Passive safety systems - Mechanical equipment - Equipment, machinery & electrical installations in hazardous areas, including:

- Ignition sources - Explosion prevention

- Process and utilities, including: - Design philosophy specification P.F.D’S & P & ID’s - Emergency shutdown & gas relieving systems - Process/utilities systems corrosion control

10.2.2 REFERENCE DOCUMENTS The design review of installations is made in view of the following Regulations, Rules and Standards :

• Rules for the Construction and Classification of Offshore units, NR 445 to 456 • Rules for the classification of steel ships (where applicable)

A list of applicable Rules and Standards is given for reference in [12 ].

10.2.3 DOCUMENTS TO BE SUBMITTED The documents to be reviewed for approval, for appraisal or for information will be fixed by the Society from a list of documents intended to be issued for the Project and prepared by the Contractor Engineering Department. The Society may require other documents not mentioned in the provided list when deemed necessary for classification issues. In addition to this list, the Safety Analysis Report and relevant Studies are to be made available for information.

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10.2.4 DESIGN REVIEW The contents of design review of Equipment & Process covered the fields detailed hereafter in [10.2.4.1 to 10.2.4.4]: 10.2.4.1 PASSIVE SAFETY SYSTEMS The assessment will cover the following topics:

• the general arrangement & layout of the passive safety systems including, but not be limited to: − marine environment − risk segregation − safety equipment.

• the classification of the units areas versus: − sources of hazards − extent of hazardous areas

• the passive fire protection with respect to: − structural integrity − fire partitions − materials fire resisting characteristics − locations of fire divisions − fire protection of living quarters

• the liquefied natural gas storage systems with respect to, but not be limited to: − the capacity of systems to ensure the safe containment of LNG − the safe internal and offloading transfer − the prevention of the formation of flammable mixtures as well as the presence of ignition

sources − the suitability of mechanical and electrical equipment − the safety control systems

• the ship piping systems with respect to: − bilge & ballast − venting and sounding

• the escape routes • the active safety systems • the ventilation with respect to:

− the general arrangement − the natural ventilation (particularly applicable to open modules concept) − the mechanical ventilation systems − the segregation

• the fire & gas detection systems with respect to: − the design review objectives − the detection philosophy − the voting system(s) − the activation of alarm & safety functions − the power supplies

• the active fire protection with respect to: − the general arrangement − the fire water systems − the total flooding systems − the other systems

• the life saving appliances (lsa) for appraisal of the adequacy to meet applicable requirements with respect to: − the unit life saving crafts − the unit individual life saving appliances − the safety plan

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• the alarm & intercommunication system with respect to: − the alarm system − the internal communication system

• the navigation aids for appraisal 10.2.4.2 MECHANICAL EQUIPMENT The design review will give emphasis to the following :

• design arrangement and materials specification of pressure piping and more generally shells under pressure (see process design review),

• protection and segregation of pipes carrying hazardous or toxic substances, • checking of utilities directly in connection with plant safety systems (instrument air), • capacity of drain system and segregation between hazardous and safe drains, • relief system of pressurised piping and capacity.

The design of lifting appliances is reviewed for approval and is performed as part of the process of verification/classification of appliances onboard an offshore installation, following the provisions of Bureau Veritas Rules for lifting appliances NI 184, or other agreed standard. Consideration will be given to type approval already obtained by Suppliers. 10.2.4.3 EQUIPMENT, MACHINERY, & ELECTRICAL INSTALLATIONS IN HAZARDOUS

AREAS The design review will give emphasis to the items as defined in [10.2.4.3.1 to 10.2.4.3.2] hereunder. 10.2.4.3.1 IGNITION SOURCES The review for appraisal aims at ascertaining that all equipment, either continuously or intermittently operating (hot work for instance), liable to produce ignition sources are either located outside hazardous areas or adequately protected (enclosures). Equipment considered as ignition sources placed in safe areas will also be subject to review as regards their isolation (shut down, hot surface protection etc ...) in the event of upset or emergency conditions. 10.2.4.3.2 EXPLOSION PREVENTION To ascertain that due care has been exercised to reduce explosion risks, consideration will be given to equipment as defined hereafter:

• Electrical equipment 1. Operating temperatures with respect to the ignition temperature of gases or vapours

which may be released at a given location. 2. Safety type of protection, according to agreed standards. 3. Lighting fixtures 4. Wiring design to ascertain compliance with the following :

− protection against damage, − suitability for use under emergency/upset conditions (geographical) segregation of

network), − suitability for use hazardous areas.

• Other equipment 1. Gas turbines including :

− turbine room classification accounting for air renewal, differential pressure under operating conditions with adjacent hazardous areas or with turbines acoustic hood, alarms

− location and protection of auxiliary equipment : valves, piping branches, piping, gas supply etc...

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2. Diesel engines including: − air intakes and exhaust outlets location − exhaust spark arrestors and cooling arrangements including alarm for loss of

circulation − protection of fuel injection piping − over speed protection coupled to gas detection at intake − protection of hot surfaces

3. Gas boilers 4. Heaters (including electrical and naked flame if applicable) 5. Piping thermal insulation according to hydrocarbon fluids ignition temperature, grouping

and applicable standards. 6. Equipment used for maintenance (hot work etc ...)

10.2.4.4 PROCESS AND UTILITIES The review will cover the following areas as defined in [10.2.4.4.1 to 10.2.4.4.3]. 10.2.4.4.1 DESIGN PHILOSOPHY SPECIFICATION P.F.D'S & P & ID'S The design review will consider for appraisal the following points:

• Piping mechanical

Layout of piping with regard to areas segregation, mechanical damages possibly sustained, fire, flow, condition, etc... Check of design computation in accordance with applicable Codes/Standard. Verification that stresses induced by hammer effects, if applicable, have been accounted for. Verification of adequacy of materials, conformity with applicable codes fabrication testing procedures. Check of corrosion protection design.

• Process and Utilities vessels & mechanical equipment

Process, utilities vessels and equipment according to applicable (retained) Codes & Standards. Pressure vessels, etc.. including review of specifications detailing :

− design parameters (temperatures, pressures, environmental loads, etc...), − design criteria (calculation basis and calculation notes with reference to Codes and

Standards retained), − material, fabrication and control procedures.

10.2.4.4.2 EMERGENCY SHUTDOWN & GAS RELIEVING SYSTEMS

Design review will be conducted to ascertain that control engineering is adequate to prevent the release of hydrocarbons from the process and, if they occur, to minimise their adverse consequences. The two objectives are respectively to be reached by the review of plant safety system (P.S.S.) an emergency support systems (E.S.S.)

The review will be conducted to ascertain that abnormal conditions within the process equipment are detected by Process Shutdown System (PSD) and that the process or part of the process are adequately shutdown to safeguard against casually situations.

The review of the Emergency support systems will be conducted to ascertain that the systems are designed to quickly and safely sectionalise or shutdown all plant activities and to minimise the consequences of hydrocarbons release.

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The review will include :

• pressure relieving, venting and flaring system adequacy,

• gas and fire detection/protection systems as well as emergency power system already dealt with in the preceding sections,

• liquid containing systems to collect and safely dispose of released liquid hydrocarbons, to initiate alarms and shutdowns,

• emergency shutdown (E.S.D.) systems to enable partial or total shut-down, either manually or automatically, of the plant activities,

• subsurface safety valves and their control system.

and will concern the following items:

• Platform safety

Review of the platform safety analysis performed for each process component under worst input/output conditions to be later integrated in the entire process flow stream.

Review of the two (primary and secondary) levels of protection : independence of control devices (for birth monitoring and shut-down unless otherwise accepted), functional difference between the two levels of protection, total coverage by each level of protection of possible configurations and consequences of a given failure, etc...

Review of logic diagram and cause and effect chart.

Review of the choice of protection systems and devices : − fail safe design, − continuous operation (not by-passing), − automatic operation of detecting devices, − automatic and manual shut-down devices − activation signals at control centre(s) − Review of testing possibilities in service − Review of valves arrangements and securing

• Process shutdown (PSD)

Review of P.S.D. will be made of : − Shut-down time after detection − Shut-down location (individual shut-downs, cascading shutdown, shut-down of

primary energy source, etc...) − Shut-down energy (capacity and reliability) and associated equipment (accumulators,

piping/bleed port sizing, actuating mechanism, etc...) − Suitability for use in hazardous areas for electrical components.

• Emergency shutdown systems

In addition to the same topics as given under P.S.D. the review will also include − Location of manual activation stations, − Shut-down levels : in a given area ; process activities ; all plant activities (process

and utilities) except essential emergency services, total platform shut-down.

• Shutdown valves

The review will bear upon : − check of location in relation to process flow schematics and operating parameters, − check of isolating valves location with regards to fire protection system, − check of valves design, particularly of fire resisting properties.

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• Pressure relieving systems

The review will include the following : − Sizing of all PSV’s and rupture discs under all process upsets and emergency

conditions. Check of valve types, materials in relation to gas outlet temperature, etc... − Header and piping : check of pressure drop and back pressure computation under

different upset/emergency conditions (several PSV and depressurising valves simultaneously operating).

− Check of possible slug (hydrates) formation − Check of scrubbing capacity of K.O. drum − Check of flare radiation computation and radiation levels with regards to safety

requirements − Check of gas dispersion calculations under upset conditions (emergency blowdown),

flare blow out. 10.2.4.4.3 PROCESS/UTILITIES SYSTEMS CORROSION CONTROL Certification review will be conducted of methods of protection against corrosion. 10.3 MONITORING / CONTROL SYSTEM 10.3.1 GENERAL LNG terminal shall include monitoring and control room. All the information from control systems shall be displayed at control room. All remote control devices and emergency shut-off devices shall be capable of activation from control room 10.3.2 SPECIAL ARRANGEMENTS

a) Control room shall be located in such a way to remain operational even in the event of failure in any system of the terminal

b) Qualified personnel shall attend the control station at all times c) If the terminal includes several control stations, they shall be interconnected by several

communication systems d) Control station shall be capable of transmitting possible alarms to any part of the terminal liable

to be attended by watch personnel 10.3.3 OPERATING MANUAL Attention is drawn on that LNG terminals shall be provided with the Operating Manual, listing all necessary instructions for loading/unloading operations, emergency shut-off, etc. The Operating Manual shall be kept at control station and be readily available to the personnel in charge. It shall be submitted to the relevant Authorities. 10.3.4 CONTROL DEVICES 10.3.4.1 GENERAL Control devices shall fulfil their function under any normal conditions of service and shall be arranged so as to permit their monitoring and maintenance.

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10.3.4.2 CONTROL DEVICES FAIL-SAFE SYSTEM Control devices for main components of the terminal system shall be designed to automatically switch over to fail-safe system in the event of power failure (fail-safe design). Control devices with electric power supply shall be supplied by two independent sources of power. Whenever auxiliary generators are provided as the emergency power source, their location shall be such that they can operate in the event of major damage to any part of the system. 10.3.4.3 EMERGENCY SHUT-DOWN SYSTEMS (ESD) 10.3.4.3.1 CONCERNED EQUIPMENT Following equipment shall be provided with emergency shut-off systems:

a) Liquefying units b) Tanks c) Vaporizers d) Transfer systems

10.3.4.3.2 EMERGENCY SHUT-OFF AUTOMATIC ACTIVATION Emergency shut-off system shall be, as a rule, automatically activated, and especially in the following cases/

a) Service temperature beyond the fixed limits b) Service pressure beyond the fixed limits c) High level of the liquid d) Gas concentration near the equipment being over 40 % of the Lower Explosive Limit e) Outbreaks of fire near the equipment

10.3.4.3.3 EMERGENCY SHUT-OFF PROCEDURE Emergency shut-off system, when released , shall stop the concerned equipment. If applicable, it shall also include the depressurization of the equipment. Whenever emergency shut-off is liable to cause serious damage to the equipment or represent additional hazards, no automatic shut-off shall be provided for this specific situation. Necessary arrangements shall, nevertheless, be made to limit the escape of gas or the outflow of liquid. 10.3.4.3.4 EMERGENCY SHUT-OFF CONTROL SYSTEM For the equipment under the continuous watch of qualified personnel, it can be accepted that the events listed in § 10.3.4.3.2 above, trigger off only one alarm of the emergency shut-off system being hand-operated. Hand-operated emergency shut-off devices shall be easily accessible and located at a reasonable distance from the equipment they serve, with relevant protection of personnel from any injury. 10.3.4.3.5 STORAGE SYSTEMS EMERGENCY SHUT-DOWN LNG storage unit shall be provided with emergency shut-off for the whole installations on the site. Emergency shut-down systems shall be activated from control room. 10.3.4.4 CONTROL AND ALARM DEVICES 10.3.4.4.1 DETECTION DEVICES Detection devices shall be provided for the following:

• Control of parameters, which represent a potential danger for the equipment during its operation, being liable to cause a dangerous situation.

• Fire or fammable gas detection (in areas where a fire is liable to break out) • Continuous gas detection in buildings with equipment liable to contain flammable fluids

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Alarm device shall be provided at control station and inside of the concerned building. It shall be triggered off when the gas concentration reaches 25 % of the Lower Limit of Flammability. 10.3.4.4.2 VAPOUR CLOUD DETECTION SYSTEM LNG terminal shall be provided with continuous flammable gas detection system. Such systems shall trigger off an alarm at control station when gas concentration reaches 25 % of the Lower Limit of Flammability. Gas sensors shall be fitted next to possible sources. Storage site shall be provided with, at least, two sets of portable gas detectors, able to measure the flammable gas content. Detecting instruments shall be periodically calibrated and checking entered in the Fire record. 10.3.4.4.3 FIRE DETECTION SYSTEM Continuous fire detection system shall be provided in locations where outbreaks of fire are liable to be a hazard to persons or property. Fire detection system shall trigger off an alarm locally and at control station. 10.3.4.4.4 ALARM SYSTEMS Sensors required in this chapter should trigger off alarms when critical levels are reached. Such alarms include, in particular, light and sound signals displayed at control room. Morever, the nature and location of potential danger, pointed out by alarms, shall be clearly indicated.

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11 CONSTRUCTION SURVEY & COMMISSIONING

11.1 GENERAL 11.1.1 SCOPE OF THE WORK During the fabrication, building, installation and commissioning of the terminal the following activities are to be covered under the supervision of the Society:

• before the construction starts, review of the fabrication documents,

• organization of the Surveyor Program (witness, hold points, …)

• at the beginning of the construction, appraisal of the procedure defining the content of the manufacturing record book,

• during construction, inspection of the significant main phases of the construction, survey of testing of equipment and systems,

• commissioning witness. 11.1.2 REFERENCE DOCUMENTS The applicable technical documents are selected amongst the following documents which define the technical requirements for the performance of the Classification or Certification activities on the construction survey :

• Bureau Veritas approved design documentation (design drawings, material specifications, fabrication specifications, data sheets, ...)

• Bureau Veritas Rule Note "Construction Survey of Steel Structures of Offshore Units and Installations" ( NR 426)

• Guidance Note "Inspections at works for the classification of steel ships & offshore units" (NR 266)

• Bureau Veritas Rules and Regulations for the Classification of Offshore Units, NR 445 to 456 • Bureau Veritas Rules for the Classification of Steel Ships – Part D, Materials. • Other recognised Standards, where suitable for design of concrete and steel structures in a

marine environment, as agreed between parties for specific aspects of the project

11.2 REVIEW OF FABRICATION DOCUMENTS FOR STRUCTURES The following fabrication documents (to be issued by the Contractor) are to be submitted to the Society for appraisal, before the construction starts :

• Contractor QA/QC manual

• Quality Control plans

• Structural, equipment and systems drawings, as per rules

• Fabrication procedures

• Welding procedure specifications and supporting qualifications

• Qualifications of steel welders and welding operators

• Concrete fabrication

• Qualifications of NDT operators

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• Equipment and systems testing procedures

• Coordination procedure(s) and Planning

• List of Subcontractors and Vendors

• Fabrication standards

• Records of testing equipment calibration

11.3 SURVEY OF FABRICATION OF STRUCTURES AND SUB-ASSEMBLIES A surveillance program is to be set according to the capabilities shown by the Contractor with regard to its quality organization. 11.3.1 PRELIMINARY A quality audit is performed by the Society to check the QA system of the Contractor and to demonstrate that the procedures needed to obtain the required quality are existing. The way these procedures are implemented is also checked. 11.3.2 SURVEY EXTENT A random inspection of the significant main phases of the construction is to be performed, mainly to check the implementation of the mentioned procedures in [4.3.1], during the progress of the construction. The whole responsibility of the Quality Control operations is left to the Q.C. department of the Contractor, The role of the Society is to monitor the compliance of the construction with the applicable rules by random verification covering the following fields:

• Materials

• Material traceability

• Cuttings and welding preparations

• Main fit-ups

• Preheating

• Welding consumables

• Welding parameters

• Visual random checks on weld aspects and fillet weld throats dimensions.

• Identification of NDT operators in relation with the approved list.

• Non destructive testing

• Heat treatments and other fabrication operations (forming, straightening,...)

• Final visual examination of the sub-assemblies to verify the absence of distortions or damages, and the correct removal of temporary attachments.

• Contractor's Site queries

• Contractor's Non conformity reports

• Contractor's Modifications / changes

• Contractor's release notes

• Closing out the relevant Contractor's punch-list.

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11.4 SURVEY OF EQUIPMENT & SYSTEMS INSTALLATION AND TESTING 11.4.1 GENERAL This section defines the installation, equipment & systems which will be surveyed and should be submitted to testing. The following activities on the construction site are concerned:

• mechanical equipment & piping installation

• electrical equipment installation

• structural fire protection

• cathodic protection installations

as defined in [11.4.2 to 11.4.5] hereafter.

11.4.2 MECHANICAL EQUIPMENT & PIPING INSTALLATION The survey and testing of the mechanical equipment & piping installation will cover the following items:

• Pressure Vessels/Exchangers, storage tanks.

• Pumps, Compressors, which are covered by the rules.

• Fired heaters and boilers

• Gas turbines/Diesel engines.

• Piping systems

• Lifting equipment, at special request of the owner.

• H.V.A.C.

11.4.3 ELECTRICAL EQUIPMENT INSTALLATION The survey and testing of the electrical equipment installation will cover the following items:

• Generators/Motors

• Switchboards

• Transformers

• Batteries

• Cables

• Lighting and small power sub-circuit socket outlets

• Grounding

• Electrical instrumentation

• Fire and Gas detection and protection (Alarms and public address, Navigation aids)

• Emergency Supplies

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11.4.4 STRUCTURAL FIRE PROTECTION For Classification purpose the involvement of the Society will be limited to the Inspection of the passive fire protection installations and blast protection arrangements.

The following activities are concerned :

• Review of certificates of passive fire protection materials (wall/ceiling panels, fire bats, doors, windows, deck insulation, surface lining, paint systems, floor covering, etc. ...)

• Check installation of passive fire protection materials in accordance with approved drawings and specifications.

11.4.5 CATHODIC PROTECTION INSTALLATIONS

In particular, it will be verified:

• the certificate of inspection at works of the anodes and the storage conditions.

• that the electrical continuity with the protected structures is ensured if the anodes are clamped and not welded (resistivity tests should have been done by the builder).

• that the number and location of the anodes are in accordance with the approved design. 11.5 MANUFACTURING RECORDS BOOK REVIEW At the beginning of the construction a procedure defining the content of the manufacturing record book is to be established by the Contractor and submitted to the Surveyor for appraisal.

During the construction, the quality control records, selected by the Surveyor, are reviewed by him. These records are to be checked and signed by the Contractor's QC engineer before submittal to the Surveyor.

NDT tasks and records in the process of fabrication are to be carried out according to the acceptable procedures and methodologies.

Periodically the Surveyor checks specific NDT or testing operations (from the beginning to the reporting) and verifies the correct implementation of the approved procedures and the operators qualifications.

The quality control records are to be listed for each structure /system on registers such as material registers and weld registers, according to a previously agreed procedure. These registers are to be provided by the Contractor.

At the end of the fabrication the quality control registers/records are compiled by the Contractor in a manufacturing record book.

11.6 COMMISSIONING ACTIVITIES The Surveyor will witness the terminal commissioning, as required by the Rules and will issue the corresponding contractual documents.

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11.6.1 SCOPE As the commissioning of systems or parts of systems will be completed at the construction site, a reduced commissioning programme limited to the outstanding items will be carried out offshore.

The commissioning is associated with operating the plants and includes:

• where possible, the checking of the protection devices (the adjustment being made previously to the commissioning period),

• checking of the remote control devices including the alarm system running,

• witness the endurance tests and examination of results of tests.

11.6.2 ORGANISATION OF THE SURVEY

The Bureau Veritas Surveyor is to be provided with all commissioning procedures and programmes enough time before commissioning commences, so that he may indicate which checks/tests he wishes to attend.

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12 APPENDIX 1: RULES & STANDARDS

12.1 BASIC RULES The basic rules will be the following:

Bureau Veritas Rules & Rule-Related Documents

Title Ref. N° Rules for the Classification of Offshore Units NR 445 DTO

Introduction NR 446 DTO Chap. 1 Classification NR 447 DTO Chap 2 Maintenance of class NR 448 DTO Chap 3 Stability, subdivision and freeboard NR 449 DTO Chap 4 Environmental conditions- loadings NR 450 DTO Chap 5 Steel structures NR 451 DTO Chap 7 Equipment & safety NR 453 DTO Chap 8 Control systems and automation NR 454 DTO Chap 10 Floating storage, production and offloading units NR 456 DTO

Towage at sea of vessel of floating units NR 183 DNC Rules for the classification and certification of lifting appliances of ships and offshore units

NR 184 DNC

Procedure for review of loading instruments and load master NI 189 DNC Rules and Regulations for the classification of steel ships and offshore installations - Materials

NR 216 DNC

Inspections at works for the classification of steel ships and offshore units

NR 266 DNC

Model procedure on inclining experiment NI 299 DNC Fatigue Strength of Welded Ship Structures NI 393 DSM Guidelines for corrosion protection of sea water ballast tanks and hold spaces

NI 409 DNC

Corrosion protection of offshore units and installations. Recommended practice

NR 423 DTO

Approval of computerised equipment NR 424 DNC Recommendations on the quality of software onboard NI 425 DNC Construction survey of offshore units and installations Rule Note NR 426 DTO Electrical systems on board offshore units and installations NR 428 DTO Certification of synthetic fibre ropes for mooring systems NI 432 DTO Piping systems on board offshore units and installations NR 458 DTO Process systems on board offshore units and installations NR 459 DTO Safety features of offshore units and installations NR 460 DTO Classification of Mooring Systems for Permanent Offshore Units NI 493 DTM

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IMO Regulations SOLAS MARPOL ILCC MODU CODE COLREG

12.2 OTHER RELEVANT CODES, STANDARDS AND RECOMMENDED PRACTICES The following rules or standards are given as guidance. Other codes and standards recognised as equivalent are acceptable

GENERAL ARRANGEMENT & LAYOUT

API RP 2A -- WSD API RP 2G API RP 14 J

AREAS CLASSIFICATION API RP 500 or 505 IP part 15

VENTILATION API RP 500 or 505

GAS & FIRE DETECTION SYSTEMS API RP 2G API RP 14G API RP 14C API RP 14 J

FIRE PROTECTION SYSTEMS SOLAS API RP 14 G NFPA 11, 11B, 12A, 17, 13, 14, 15, 20

HYDROCARBON STORAGE SYSTEMS MARPOL SOLAS

SHIP PIPING SYSTEMS SOLAS IMO MODU

SECONDARY & EMERGENCY POWER SUPPLY, DISTRIBUTION & LOAD SHEDDING IEC 79 and relevant IEC publications API RP 14F

EQUIPMENT, MACHINERY & ELECTRICAL INSTALLATIONS IN HAZARDOUS AREAS IMO MODU and as complement : OCMA MEC-1 IEC 79 electrical apparatus for explosive gas atmosphere or as equivalent : NFPA - NEC CENELEC Electrical apparatuses for potentially explosive atmosphere EN 500 14, 15, 16, 17, 18, 19, 20

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LIFE SAVING APPLIANCES & ESCAPE ROUTES

IMO MODU SOLAS

HELIDECK FACILITIES

IMO MODU

ALARM & INTERCOMMUNICATION SYSTEMS

MODU CODE NFPA

LIFTING APPLIANCES

International and other regulations quoted in BV Rules

MOORING

API 2 SK

PROCESS DESIGN PHILOSOPHY AND PIPING SPECIFICATIONS PFD'S AND P & ID'S

API RP 14E (piping) ANSI B 31-3 ASME section VIII div. 1 and 2 or equivalent as :

BS 5500 BV Rules CODAP

TEMA class R API STD 660 - 661 API 650 atmospheric vessels ASME section I and IV - fired units API std 610, 615, 616, 617, 618, 619 API 7B - 11c - 7C - 11F API 12J, separators, API 12L, treaters

UTILITY SYSTEMS, UFD'S AND PHILOSOPHY Refer to previous §.

PROCESS SAFETY SYSTEMS, EMERGENCY SHUTDOWN & GAS RELIEVING SYSTEMS API RP 14E, RP 14C, RP 14J API RP 520, RP 521 API RP 6D, RP 6F

PROCESS/UTILITIES SYSTEM CORROSION CONTROL API RP 14E NACE MR 01 75

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CONCRETE Euro Code 2 Unified Code on Concrete Euro Code 8 Code on Earthquake Engineering ISO CD 19903 Fixed Concrete Structures BS-8110 Structural Use of Concrete NS3473 Concrete Structures, 4th Edition Norwegian Council for Building Standardisation, Nov

1992 CSA S474-94 Concrete Structures, ‘Part IV of the Code for the Design, Construction and Installation of Fixed Offshore Structures, 1994 ACI 213R Guide for Structural Lightweight Aggregate Concrete ACI 301 Specifications for Structural Concrete ACI 311.4R Guide for Concrete Inspection Programs ACI 318 Building Code Requirement for Structural Concrete ACI 357R-84 Guide for the Design and Construction of Fixed Offshore Concrete Structures ACI 357.2R-88 State-of-the-Art Report on Barge-like Concrete Structures ASTM C330 Specification for Lightweight Aggregates for Structural Concrete ACMC-ICCMC Asian Concrete Model Code 2001

LNG

NFPA 59A Standard for the production, storage and handling of Liquefied Natural Gas (LNG) 2001

edition NFPA 59 Standard for the storage and handling of Liquefied Petroleum Gases at utility gas plants, 1995 edition BS-7777 Flat-bottomed, vertical, cylindrical storage tanks for low temperature service EN 1473 Installation and equipment for liquefied natural gas – Design of onshore installations

LIGHTING AND AIDS TO NAVIGATION

IALA Regulations LOADING/OFFLOADING SYSTEMS

OCIMF Design and Construction Specification for Marine Loading Arms, 1987 EN 1474 Installation and equipment for liquefied natural gas - Design and testing of loading/unloading arms SIGITTO Gas transfer guide and Gas handling procedures

NI518 - Offshore LNG Terminals - VeriSTAR Practice 2A – WSD - for the Planning, Designing and...

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