ISO/TC 67/SC 7 - Offshore structures

This document specifies requirements for managing and controlling the weight and centre of gravity (CoG) of offshore facilities by means of mass management during all lifecycle phases including; conceptual design, front end engineering design (FEED), detail engineering, construction and operations. These can be new facilities (greenfield) or modifications to existing facilities (brownfield). Weight management is necessary throughout operations, decommissioning and removal to facilitate structural integrity management (SIM). The provisions of this document are applicable to fixed and floating facilities of all types. Weight management only includes items with static mass. Snow and ice loads are excluded as they are not considered to be part of the facility. Dynamic loads are addressed in ISO 19904-1, ISO 19901-6 and ISO 19901-7. This document specifies: a) requirements for managing and controlling weights and CoGs of assemblies and entire facilities; b) requirements for managing weight and CoG interfaces; c) standardized terminology for weight and CoG estimating and reporting; d) requirements for determining not-to-exceed (NTE) weights and budget weights; e) requirements for weighing and determination of weight and centre of gravity (CoG) of tagged equipment, assemblies, modules and facilities; This document can be used: f) as a basis for costing, scheduling or determining suitable construction method(s) or location(s) and installation strategy; g) as a basis for planning, evaluating and preparing a weight management plan and reporting system; h) as a contract reference; i) as a means of refining the structural analysis or model.

This document provides requirements and guidelines for marine geophysical investigations. It is applicable to operators/end users, contractors and public and regulatory authorities concerned with marine site investigations for offshore structures for petroleum and natural gas industries. This document provides requirements, specifications, and guidance for: a) objectives, planning, and quality management; b) positioning; c) seafloor mapping, including instrumentation and acquisition parameters, acquisition methods, and deliverables; d) sub-seafloor mapping, including seismic instrumentation and acquisition parameters, and non-seismic-reflection methods; e) reporting; f) data integration, interpretation, and investigation of geohazards. This document is applicable to investigation of the seafloor and the sub-seafloor, from shallow coastal waters to water depths of 3 000 m and more. It provides guidance for the integration of the results from marine soil investigations and marine geophysical investigations with other relevant datasets. NOTE 1 The depth of interest for sub-seafloor mapping depends on the objectives of the investigation. For offshore construction, the depths of investigation are typically in the range 1 m below seafloor to 200 m below seafloor. Some methods for sub-seafloor mapping can also achieve much greater investigation depths, for example for assessing geohazards for hydrocarbon well drilling. There is a fundamental difference between seafloor mapping and sub-seafloor mapping: seafloor signal resolution can be specified, while sub-seafloor signal resolution and penetration cannot. This document therefore contains requirements for the use of certain techniques for certain types of seafloor mapping and sub-seafloor mapping (similarly, requirements are given for certain aspects of data processing). If other techniques can be shown to obtain the same information, with the same or better resolution and accuracy, then those techniques may be used. Mapping of pre-drilling well-site geohazards beneath the seafloor is part of the scope of this document. NOTE 2 This implies depths of investigation that are typically 200 m below the first pressure-containment casing string or 1 000 m below the seafloor, whichever is greatest. Mapping of pre-drilling well-site geohazards is therefore the deepest type of investigation covered by this document. In this document, positioning information relates only to the positioning of survey platforms, sources and receivers. The processes used to determine positions of seafloor and sub-seafloor data points are not covered in this document. Guidance only is given in this document for the use of marine shear waves (A.8.3.3), marine surface waves (A.8.3.4), electrical resistivity imaging (A.8.3.5) and electromagnetic imaging (A.8.3.6).

This document specifies requirements and recommendations for the site-specific assessment of mobile floating units for use in the petroleum and natural gas industries. It addresses the installed phase, at a specific site, of manned non-evacuated, manned evacuated and unmanned mobile floating units. This document addresses mobile floating units that are monohull (e.g. ship-shaped vessels or barges); column-stabilized, commonly referred to as semi-submersibles; or other hull forms (e.g. cylindrical/conical shaped). It is not applicable to tension leg platforms. Stationkeeping can be provided by a mooring system, a thruster assisted mooring system, or dynamic positioning. The function of the unit can be broad, including drilling, floatel, tender assist, etc. In situations where hydrocarbons are being produced, there can be additional requirements. This document does not address all site considerations, and certain specific locations can require additional assessment. This document is applicable only to mobile floating units that are structurally sound and adequately maintained, which is normally demonstrated through holding a valid RCS classification certificate. This document does not address design, transportation to and from site, or installation and removal from site. This document sets out the requirements for site-specific assessments, but generally relies on other documents to supply the details of how the assessments are to be undertaken. In general: — ISO 19901‑7 is referenced for the assessment of the stationkeeping system; — ISO 19904‑1 is referenced to determine the effects of the metocean actions on the unit; — ISO 19906 is referenced for arctic and cold regions; — the hull structure and air gap are assessed by use of a comparison between the site-specific metocean conditions and its design conditions, as set out in the RCS approved operations manual; — ISO 13624‑1 and ISO/TR 13624‑2[1] are referenced for the assessment of the marine drilling riser of mobile floating drilling units. Equivalent alternative methodologies can be used; — IMCA M 220 is referenced for developing an activity specific operating guidelines. Agreed alternative methodologies can be used. NOTE RCS rules and the IMO MODU code[13] provide guidance for design and general operation of mobile floating units.

This document specifies requirements and provides recommendations applicable to the following types of fixed steel offshore structures for the petroleum and natural gas industries: ? caissons, free-standing and braced; ? jackets; ? monotowers; ? towers. In addition, it is applicable to compliant bottom founded structures, steel gravity structures, jack-ups, other bottom founded structures and other structures related to offshore structures (such as underwater oil storage tanks, bridges and connecting structures). This document contains requirements for planning and engineering of the design, fabrication, transportation and installation of new structures as well as, if relevant, their future removal. NOTE 1 Specific requirements for the design of fixed steel offshore structures in arctic environments are presented in ISO 19906. NOTE 2 Requirements for topsides structures are presented in ISO 19901-3; for marine operations in, ISO 19901‑6; for structural integrity management, in ISO 19901-9 and for the site-specific assessment of jack-ups, in ISO 19905‑1.

This document specifies requirements and provides recommendations applicable to fixed, floating and grounded concrete offshore structures for the petroleum and natural gas industries and for structures supporting nationally-important power generation, transmission or distribution facility. This document specifically addresses — the design, construction, transportation and installation of new structures, including requirements for in-service inspection and possible removal of structures, — the assessment of structures in service, and — the assessment of structures for reuse at other locations. This document is intended to cover the engineering processes needed for the major engineering disciplines to establish a facility for offshore operation.

This document specifies principles for the structural integrity management (SIM) of offshore structures subjected to known or foreseeable types of actions. This document specifies requirements and provides recommendations applicable to the following types of fixed steel offshore structures for the petroleum and natural gas industries: — caissons, free-standing and braced; — jackets; — monotowers; — towers. This document is applicable to topsides, including but not limited to the main decks, deck legs, topsides modules, crane pedestals, helideck, drilling derrick, skid beams, flare booms, exhaust towers, radio tower, conductor support frames, and lifeboat davits. In addition, it is applicable to compliant bottom founded structures, steel gravity structures, jack-ups, other bottom founded structures and other structures related to offshore structures (e.g. underwater oil storage tanks, bridges and connecting structures), to the extent to which its requirements are relevant. This document contains requirements for planning and engineering of the following tasks: a) integrity management data requirements; b) in-service inspection and integrity management of both new and existing structures; c) assessment of existing structures; d) evaluation of structures for reuse at different locations; e) evaluation of structures for their future removal.

This document specifies requirements and provides recommendations and guidance for the design, construction, transportation, installation and decommissioning of offshore structures related to the activities of the petroleum and natural gas industries in arctic and cold regions. Reference to arctic and cold regions in this document is deemed to include both the Arctic and other locations characterized by low ambient temperatures and the presence or possibility of sea ice, icebergs, icing conditions, persistent snow cover, and/or permafrost. The objective of this document is to ensure that complete structures, including substructures, topsides structures, floating production vessel hulls, foundations and mooring systems, in arctic and cold regions provide an appropriate level of reliability with respect to personnel safety, environmental protection and asset value. Value includes value to the owner, to the industry and to society in general. This document does not contain requirements for the operation, maintenance, service-life inspection or repair of arctic and cold region offshore structures, unless the design strategy imposes specific requirements such as ice management (IM) to reduce ice actions. Provisions for the operation, maintenance, service‐life inspection and repair of mobile units are given in ISO 19905-1 and ISO 19905-3, supplemented by the provisions relating to ice actions and IM in this document. This document does not apply to mechanical, process and electrical equipment or any specialized process equipment associated with arctic and cold region offshore operations except in so far as it is necessary for the structure to sustain safely the actions imposed by the installation, housing and operation of such equipment. This document applies to equipment used for the positioning and disconnection of floating structures (see Clause 13).

This document specifies general requirements and recommendations for the design and assessment of bottom-founded (fixed) and buoyant (floating) offshore structures. This document is applicable for all phases of the life of the structure, including: — successive stages of construction (i.e. fabrication, transportation, and installation), — service in-place, both during design life and during any life extensions, and — decommissioning, and removal. This document contains general requirements and recommendations for both the design of new build structures and for the structural integrity management and assessment of existing structures. This document does not apply to subsea and riser systems or pipeline systems.

This document provides requirements and guidance for the structural design and/or assessment of floating offshore platforms used by the petroleum and natural gas industries to support the following functions: — production; — storage and/or offloading; — drilling and production; — production, storage and offloading; — drilling, production, storage and offloading. NOTE 1 Floating offshore platforms are often referred to using a variety of abbreviations, e.g. FPS, FSU, FPSO (see Clauses 3 and 4), in accordance with their intended mission. NOTE 2 In this document, the term "floating structure", sometimes shortened to "structure", is used as a generic term to indicate the structural systems of any member of the classes of platforms defined above. NOTE 3 In some cases, floating platforms are designated as "early production platforms". This term relates merely to an asset development strategy. For the purposes of this document, the term "production" includes "early production". This document is not applicable to the structural systems of mobile offshore units (MOUs). These include, among others, the following: — floating structures intended primarily to perform drilling and/or well intervention operations (often referred to as MODUs), even when used for extended well test operations; — floating structures used for offshore construction operations (e.g. crane barges or pipelay barges), for temporary or permanent offshore living quarters (floatels), or for transport of equipment or products (e.g. transportation barges, cargo barges), for which structures reference is made to relevant recognized classification society (RCS) rules. This document is applicable to all possible life-cycle stages of the structures defined above, such as: — design, construction and installation of new structures, including requirements for inspection, integrity management and future removal, — structural integrity management covering inspection and assessment of structures in-service, and — conversion of structures for different use (e.g. a tanker converted to a production platform) or re‑use at different locations. The following types of floating structure are explicitly considered within the context of this document: a) ship-shaped structures and barges; b) semi-submersibles; c) spars; d) shallow-draught cylindrical structures. In addition to the structural types listed above, this document covers other floating platforms intended to perform the above functions, consisting of partially submerged buoyant hulls made up of any combination of plated and space frame components. These other structures can have a great range of variability in geometry and structural forms (e.g. tension leg platforms) and, therefore, can be only partly covered by the requirements of this document. In other cases, specific requirements stated in this document can be found not to apply to all or part of a structure under consideration. NOTE 4 Requirements for topsides structures are presented in ISO 19901-3. In the above cases, conformity with this document requires the design to be based upon its underpinning principles and to achieve a level of safety equivalent, or superior, to the level implicit in it. NOTE 5 The speed of evolution of offshore technology often far exceeds the pace at which the industry achieves substantial agreement on innovation in structural concepts, structural shapes or forms, structural components and associated analysis and design practices, which are continuously refined and enhanced. On the other hand, International Standards can only capture explicit industry consensus, which requires maturation and acceptance of new ideas. Consequently, advanced structural concepts can, in some cases, only be partly covered by the requirements of this document. This document is applicable to steel floating structures. The principles documented herein are, however, considered to be generally applicable to structures fabricated in materials other

This document specifies requirements for lifting sets for use with containers in offshore service, including technical requirements, marking and statements of conformity for single and multi-leg slings, including chain slings and wire rope slings.

This document specifies requirements for the periodic inspection, examination and testing of offshore freight and service containers, built in accordance with ISO 10855‑1, with maximum a gross mass not exceeding 25 000 kg and their associated lifting sets, intended for repeated use to, from and between offshore installations and ships. Inspection requirements following damage and repair of offshore containers are also included. Recommended knowledge and experience of staff responsible for inspection of offshore containers is given in Annex B. Recommended knowledge and experience of staff responsible for inspection of lifting sets intended for use with offshore containers is given in Annex C.

This document specifies requirements for the design, manufacture and marking of offshore containers with a maximum gross mass not exceeding 25 000 kg, intended for repeated use to, from and between offshore installations and ships. This document specifies only transport-related requirements.

ISO 19901-2:2017 contains requirements for defining the seismic design procedures and criteria for offshore structures; guidance on the requirements is included in Annex A. The requirements focus on fixed steel offshore structures and fixed concrete offshore structures. The effects of seismic events on floating structures and partially buoyant structures are briefly discussed. The site-specific assessment of jack-ups in elevated condition is only covered in ISO 19901-2:2017 to the extent that the requirements are applicable. Only earthquake-induced ground motions are addressed in detail. Other geologically induced hazards such as liquefaction, slope instability, faults, tsunamis, mud volcanoes and shock waves are mentioned and briefly discussed. The requirements are intended to reduce risks to persons, the environment, and assets to the lowest levels that are reasonably practicable. This intent is achieved by using: a) seismic design procedures which are dependent on the exposure level of the offshore structure and the expected intensity of seismic events; b) a two-level seismic design check in which the structure is designed to the ultimate limit state (ULS) for strength and stiffness and then checked to abnormal environmental events or the abnormal limit state (ALS) to ensure that it meets reserve strength and energy dissipation requirements. Procedures and requirements for a site-specific probabilistic seismic hazard analysis (PSHA) are addressed for offshore structures in high seismic areas and/or with high exposure levels. However, a thorough explanation of PSHA procedures is not included. Where a simplified design approach is allowed, worldwide offshore maps, which are included in Annex B, show the intensity of ground shaking corresponding to a return period of 1 000 years. In such cases, these maps may be used with corresponding scale factors to determine appropriate seismic actions for the design of a structure. For design of fixed steel offshore structures, further specific requirements and recommended values of design parameters (e.g. partial action and resistance factors) are included in ISO 19902, while those for fixed concrete offshore structures are contained in ISO 19903. Seismic requirements for floating structures are contained in ISO 19904, for site-specific assessment of jack-ups and other MOUs in ISO 19905 (all parts), for arctic structures in ISO 19906 and for topsides structures in ISO 19901‑3.

ISO 19901-4:2016 contains provisions for those aspects of geoscience and foundation engineering that are applicable to a broad range of offshore structures, rather than to a particular structure type. Such aspects are: - site and soil characterization; - identification of hazards; - design and installation of shallow foundations supported by the seabed; - design and installation of pile foundations; - soil-structure interaction for auxiliary structures, e.g. subsea production systems, risers and flowlines (guidance given in A.10); - design of anchors for the stationkeeping systems of floating structures (guidance given in A.11). Particular requirements for marine soil investigations are detailed in ISO 19901‑8. Aspects of soil mechanics and foundation engineering that apply equally to offshore and onshore structures are not addressed. The user of this part of ISO 19901 is expected to be familiar with such aspects. ISO 19901‑4 outlines methods developed primarily for the design of shallow foundations with an embedded length (L) to diameter (D) ratio L/D 10 (Clause 8). This part of ISO 19901 does not apply to intermediate foundations with 1

ISO 19905-1:2016 specifies requirements and guidance for the site-specific assessment of independent leg jack‑up units for use in the petroleum and natural gas industries. It addresses: manned non-evacuated, manned evacuated and unmanned jack‑ups; the installed phase at a specific site. To ensure acceptable reliability, the provisions of this part of ISO 19905 form an integrated approach, which is used in its entirety for the site-specific assessment of a jack‑up. This part of ISO 19905 does not apply specifically to mobile offshore drilling units operating in regions subject to sea ice and icebergs. When assessing a jack-up operating in such areas, it is intended that the assessor supplement the provisions of this part of ISO 19905 with the provisions relating to ice actions and procedures for ice management contained in ISO 19906. This part of ISO 19905 does not address design, transportation to and from site, or installation and removal from site. However, it is advisable that the assumptions used in the assessment be checked against the as‑installed configuration. To ensure that the design of the jack‑up is sound and the structure is adequately maintained, this part of ISO 19905 is applicable only to independent leg jack‑ups that either: - hold a valid classification society certification from a recognized classification society (RCS) throughout the duration of the operation at the specific site subject to assessment; or - have been verified by an independent competent body to be structurally fit for purpose for elevated situations and are subject to periodic inspection, both to the standards of an RCS. NOTE 1 An RCS is an International Association of Classification Societies (IACS) member body, meeting the RCS definition given in 3.52. Jack‑ups that do not comply with this requirement are assessed according to the provisions of ISO 19902, supplemented by methodologies from this part of ISO 19905, where applicable. NOTE 2 Future revisions of this part of ISO 19905 can be expanded to cover mat-supported jack‑ups. NOTE 3 Well conductors are a safety-critical element for jack‑up operations. However, the integrity of well conductors is not part of the site-specific assessment process for jack‑ups and is, therefore, not addressed in this part of ISO 19905. Annex A provides references to other publications addressing this topic. Note 4 RCS rules and the IMO MODU code provide guidance for the design of jack-ups.

ISO 19901-1:2015 gives general requirements for the determination and use of meteorological and oceanographic (metocean) conditions for the design, construction and operation of offshore structures of all types used in the petroleum and natural gas industries. The requirements are divided into two broad types: - those that relate to the determination of environmental conditions in general, together with the metocean parameters that are required to adequately describe them; - those that relate to the characterization and use of metocean parameters for the design, the construction activities or the operation of offshore structures. The environmental conditions and metocean parameters discussed are: - extreme and abnormal values of metocean parameters that recur with given return periods that are considerably longer than the design service life of the structure, - long-term distributions of metocean parameters, in the form of cumulative, conditional, marginal or joint statistics of metocean parameters, and - normal environmental conditions that are expected to occur frequently during the design service life of the structure. Metocean parameters are applicable to: - the determination of actions for the design of new structures, - the determination of actions for the assessment of existing structures, - the site-specific assessment of mobile offshore units, - the determination of limiting environmental conditions, weather windows, actions and action effects for pre-service and post-service situations (i.e. fabrication, transportation and installation or decommissioning and removal of a structure), and - the operation of the platform, where appropriate. NOTE Specific metocean requirements for site-specific assessment of jack-ups are contained in ISO 19905‑1, for arctic offshore structures in ISO 19906 and for topside structures in ISO 19901‑3.

ISO 19901-3:2014 gives requirements for the design, fabrication, installation, modification and structural integrity management for the topsides structure for an oil and gas platform. It complements ISO 19902, ISO 19903, ISO 19904‑1, ISO 19905‑1 and ISO 19906, which give requirements for various forms of support structure. Requirements in this part of ISO 19901 concerning modifications and maintenance relate only to those aspects that are of direct relevance to the structural integrity of the topsides structure. ISO 19901-3:2014 is applicable to the topsides of offshore structures for the petroleum and natural gas industries, as follows: topsides of fixed offshore structures; discrete structural units placed on the hull structures of floating offshore structures and mobile offshore units; certain aspects of the topsides of arctic structures. ISO 19901-3:2014 contains requirements for, and guidance and information on, the following aspects of topsides structures: design, fabrication, installation and modification; in-service inspection and structural integrity management; assessment of existing topsides structures; reuse; decommissioning, removal and disposal; prevention, control and assessment of fire, explosions and other accidental events. ISO 19901-3:2014 applies to structural components including the following: primary and secondary structure in decks, module support frames and modules; flare structures; crane pedestal and other crane support arrangements; helicopter landing decks (helidecks); permanent bridges between separate offshore structures; masts, towers and booms on offshore structures.

ISO 19901-8:2014 specifies requirements, and provides recommendations and guidelines for marine soil investigations regarding: a) objectives, planning and execution of marine soil investigations; b) deployment of investigation equipment; c) drilling and logging; d) in situ testing; e) sampling; f) laboratory testing; and g) reporting. Rock materials are only covered by ISO 19901-8:2014 to the extent that ordinary marine soil investigation tools can be used, e.g. for chalk, calcareous soils, cemented soils or similar soft rock. ISO 19901-8:2014 is intended for clients, soil investigation contractors, designers, installation contractors, geotechnical laboratories and public and regulatory authorities concerned with marine soil investigations for any type of offshore and nearshore structures, or geohazard assessment studies, for petroleum and natural gas industries.

ISO 19901-7:2013 specifies methodologies for - the design, analysis and evaluation of stationkeeping systems for floating structures used by the oil and gas industries to support production, storage, drilling, well intervention and production, production and storage, drilling, well intervention, production and storage, and - the assessment of stationkeeping systems for site-specific applications of mobile offshore units (e.g. mobile offshore drilling units, construction units, and pipelay units). ISO 19901-7:2013 is applicable to the following types of stationkeeping systems, which are either covered directly in ISO 19901-7:2013 or through reference to other guidelines: - spread moorings (catenary, taut-line and semi-taut-line moorings); - single point moorings, anchored by spread mooring arrangements; - dynamic positioning systems; - thruster-assisted moorings. Descriptions of the characteristics and of typical components of these systems are given in an informative annex. The requirements of ISO 19901-7:2013 mainly address spread mooring systems and single point mooring systems with mooring lines composed of steel chain and wire rope. ISO 19901-7:2013 also provides guidance on the application of the methodology to synthetic fibre rope mooring systems, and includes additional requirements related to the unique properties of synthetic fibre ropes. ISO 19901-7:2013 is applicable to single anchor leg moorings (SALMs) and other single point mooring systems (e.g. tower soft yoke systems) only to the extent to which the requirements are relevant. ISO 19901-7:2013 is not applicable to the vertical moorings of tension leg platforms (TLPs).

ISO/TR 19905-2:2012 provides a commentary to some clauses of ISO 19905-1 including background information, supporting documentation, and additional or alternative calculation methods as applicable and also provides a detailed sample 'go-by' calculation. ISO 19905-1 specifies requirements and guidance for the site-specific assessment of independent leg jack‑up units for use in the petroleum and natural gas industries.

ISO 19901-6:2009 provides requirements and guidance for the planning and engineering of marine operations, encompassing the design and analysis of the components, systems, equipment and procedures required to perform marine operations, as well as the methods or procedures developed to carry them out safely. This part of ISO 19901 is applicable to marine operations for offshore structures, including steel and concrete gravity-base structures (GBS); piled steel structures and compliant towers; tension leg platforms (TLP); deep-draught floaters (DDF), including spars or deep-draught caisson vessels (DDCV); floating production semi-submersibles (FPSS); floating production, storage and offloading vessels (FPSO); other types of floating production systems (FPS); mobile offshore units (MOU); topsides and components of any of the above; subsea templates and similar structures; gravity, piled, drag-embedded and suction or other anchors; tendon foundations; and associated mooring systems. This document is also applicable to modifications of existing structures, e.g. installation of additional topsides modules. This part of ISO 19901 is not applicable to the following marine operations: — construction activities, e.g. in a fabrication yard onshore, where there is no exposure to the marine — environment; — drilling, processing and petrochemical activities; — routine marine activities during the service life of the structure; — drilling from mobile offshore drilling units (MODU); — installation of pipelines, flowlines, risers and umbilicals; — diving.

ISO 19905-3 specifies requirements and gives guidance for the site-specific assessment of mobile floating units for use in the petroleum and natural gas industries. It addresses the installed phase, at a specific site, of manned non-evacuated, manned evacuated and unmanned mobile floating units. ISO 19905-3 addresses mobile floating units that are monohull (e.g. ship-shaped vessels or barges); column-stabilized, commonly referred to as semi-submersibles; or other hull forms (e.g. cylindrical/conical shaped). It is not applicable to tension leg platforms. Stationkeeping can be provided by a mooring system, a thruster assisted mooring system, or dynamic positioning. The function of the unit can be broad, including drilling, floatel, tender assist, etc. In situations where hydrocarbons are being produced, there can be additional requirements. The requirements of ISO 19905-3 apply to the hull and stationkeeping system for all types of mobile units. The activity specific operating guideline document requirements can be modified to be appropriate to the situation being assessed. ISO 19905-3 does not address all site considerations, and certain specific locations can require additional assessment. ISO 19905-3 is applicable only to mobile floating units that are structurally sound and adequately maintained, which is normally demonstrated through holding a valid RCS classification certificate. ISO 19905-3 does not address design, transportation to and from site, or installation and removal from site. ISO 19905-3 sets out the requirements for site-specific assessments, but generally relies on other documents to supply the details of how the assessments are to be undertaken. In general: - ISO 19901‑7 is referenced for the assessment of the stationkeeping system; - ISO 19904‑1 is referenced to determine the metocean actions on the unit; - ISO 19906 is referenced for arctic and cold regions; - the hull structure and airgap are assessed by use of a comparison between the site-specific metocean conditions and its design conditions, as set out in the RCS approved operations manual; - ISO 13624‑1 and ISO/TR 13624‑2[1] are referenced for the assessment of the marine drilling riser of mobile floating drilling units. Equivalent alternative methodologies can be used; - IMCA M 220[5] is referenced for developing an activity specific operating guidelines. Agreed alternative methodologies can be used. NOTE 1 The scope of ISO 19904‑1 specifically states that its requirements do not apply to mobile units, but the methodologies given for assessing metocean actions can be used. NOTE 2 RCS rules and the IMO MODU code[4] provide guidance for design and general operation of mobile floating units.

ISO 19901:2016 specifies requirements for controlling the weight and centre of gravity (CoG) by means of mass management during the engineering and construction of structures for the offshore environment. The provisions are applicable to offshore projects that include structures of all types (fixed and floating) and materials. These structures can be complete new installations or the modifications to existing installations. Maintaining the weight control of existing installations is not part of the main body of this part of ISO 19901, but some guidance on this is included in the Annex G. ISO 19901:2016: - specifies quality requirements for reporting of weights and centres of gravity; - specifies requirements for weight reporting; - provides a basis for overall project weight reports or management reports for all weight control classes; - specifies requirements for weight and load budgets; - specifies the methods and requirements for the weighing and the determination of weight and CoG of major assemblies; - specifies requirements for weight information from suppliers, including weighing of equipment and bulk materials for offshore installations. It can be used: - as a basis for planning, evaluating and presenting the client's, contractor's or fabricator's weight management and reporting system; - as a means of refining the structural analysis or model; - as a contract reference between client, contractor and suppliers; - as a basis for costing, scheduling or determining suitable fabrication method(s) or location(s).

ISO 19900:2013 specifies general principles for the design and assessment of offshore structures subjected to known or foreseeable types of actions. These general principles are applicable worldwide to all types of offshore structures, including, bottom-founded structures as well as floating structures, and to all types of materials used including steel, concrete and aluminium. ISO 19900:2013 specifies design principles that are applicable to: the successive stages in the construction of the structure (i.e. fabrication, transportation and installation); use during its intended life; and its decommissioning. The principles are also generally applicable to the assessment or modification of existing structures. Aspects related to quality control are also addressed. ISO 19900:2013 is applicable to the design of complete structures, including substructures, topsides structures, vessel hulls, foundations and mooring systems.

ISO 19905-1:2012 specifies requirements and guidance for the site-specific assessment of independent leg jack‑up units for use in the petroleum and natural gas industries. It addresses manned non-evacuated, manned evacuated and unmanned jack‑ups; the installed phase at a specific site. To ensure acceptable reliability, the provisions of ISO 19905-1:2012 form an integrated approach, which is used in its entirety for the site-specific assessment of a jack‑up. ISO 19905-1:2012 does not apply specifically to mobile offshore drilling units operating in regions subject to sea ice and icebergs. When assessing a jack-up operating in such areas, it is intended that the assessor supplement the provisions of ISO 19905-1:2012 with the provisions relating to ice actions and procedures for ice management contained in ISO 19906. ISO 19905-1:2012 does not address design, transportation to and from site, or installation and removal from site. However, it is advisable that the assumptions used in the assessment be checked against the as-installed configuration. To ensure that the design of the jack‑up is sound and the structure is adequately maintained, ISO 19905-1:2012 is applicable only to independent leg jack‑ups that either: hold a valid classification society certification from a recognized classification society (RCS) throughout the duration of the operation at the specific site subject to assessment, or have been verified by an independent competent body to be structurally fit for purpose for elevated situations and are subject to periodic inspection, both to the standards of an RCS. Jack‑ups that do not comply with this requirement are assessed according to the provisions of ISO 19902, supplemented by methodologies from ISO 19905-1:2012, where applicable.

ISO 19906:2010 specifies requirements and provides recommendations and guidance for the design, construction, transportation, installation and removal of offshore structures, related to the activities of the petroleum and natural gas industries in arctic and cold regions. Reference to arctic and cold regions in ISO 19906:2010 is deemed to include both the Arctic and other cold regions that are subject to similar sea ice, iceberg and icing conditions. The objective of ISO 19906:2010 is to ensure that offshore structures in arctic and cold regions provide an appropriate level of reliability with respect to personnel safety, environmental protection and asset value to the owner, to the industry and to society in general. ISO 19906:2010 does not contain requirements for the operation, maintenance, service-life inspection or repair of arctic and cold region offshore structures, except where the design strategy imposes specific requirements. While ISO 19906:2010 does not apply specifically to mobile offshore drilling units (see ISO 19905‑1), the procedures relating to ice actions and ice management contained herein are applicable to the assessment of such units. ISO 19906:2010 does not apply to mechanical, process and electrical equipment or any specialized process equipment associated with arctic and cold region offshore operations except in so far as it is necessary for the structure to sustain safely the actions imposed by the installation, housing and operation of such equipment.

ISO 19901-3:2010 gives requirements for the design, fabrication, installation, modification and structural integrity management for the topsides structure for an oil and gas platform. It complements ISO 19902, ISO 19903, ISO 19904‑1, ISO 19905‑1 and ISO 19906, which give requirements for various forms of support structure. Requirements in ISO 19901-3:2010 concerning modifications and maintenance relate only to those aspects that are of direct relevance to the structural integrity of the topsides structure. The actions on (structural components of) the topsides structure are derived from ISO 19901-3:2010, where necessary in combination with other International Standards in the ISO 19901 series. The resistances of structural components of the topsides structure can be determined by the use of international or national building codes, as specified in ISO 19901-3:2010. If any part of the topsides structure forms a primary structural component of the overall structural system of the whole platform, the requirements of ISO 19901-3:2010 are supplemented with applicable requirements in ISO 19902, ISO 19903, ISO 19904‑1, ISO 19905‑1 and ISO 19906. ISO 19901-3:2010 is applicable to the topsides of offshore structures for the petroleum and natural gas industries, as follows: topsides of fixed offshore structures; discrete structural units placed on the hull structures of floating offshore structures and mobile offshore units; certain aspects of the topsides of arctic structures. ISO 19901-3:2010 is not applicable to those parts of the superstructure of floating structures that form part of the overall structural system of the floating structure; these parts come under the provisions of ISO 19904‑1. ISO 19901-3:2010 only applies to the structure of modules on a floating structure that do not contribute to the overall integrity of the floating structural system. ISO 19901-3:2010 is not applicable to the structure of hulls of mobile offshore units. ISO 19901-3:2010 does not apply to those parts of floating offshore structures and mobile offshore units that are governed by the rules of a recognized certifying authority and which are wholly within the class rules. Some aspects of ISO 19901-3:2010 are also applicable to those parts of the hulls of floating offshore structures and mobile offshore units that contain hydrocarbon processing, piping or storage. ISO 19901-3:2010 contains requirements for, and guidance and information on, the following aspects of topsides structures: design, fabrication, installation and modification; in-service inspection and structural integrity management; assessment of existing topsides structures; reuse; decommissioning, removal and disposal; prevention, control and assessment of fire, explosions and other accidental events. ISO 19901-3:2010 applies to structural components including the following: primary and secondary structure in decks, module support frames and modules; flare structures; crane pedestal and other crane support arrangements; helicopter landing decks (helidecks); permanent bridges between separate offshore structures; masts, towers and booms on offshore structures.

ISO 19902:2007 specifies requirements and provides recommendations applicable to the following types of fixed steel offshore structures for the petroleum and natural gas industries: caissons, free-standing and braced; jackets; monotowers; towers. In addition, it is applicable to compliant bottom founded structures, steel gravity structures, jack-ups, other bottom founded structures and other structures related to offshore structures (such as underwater oil storage tanks, bridges and connecting structures), to the extent to which its requirements are relevant. It contains requirements for planning and engineering of the following tasks: design, fabrication, transportation and installation of new structures as well as their future removal; in-service inspection and integrity management of both new and existing structures; assessment of existing structures; evaluation of structures for reuse at different locations.

ISO 19903:2006 specifies requirements and provides recommendations applicable to fixed concrete offshore structures for the petroleum and natural gas industries, and specifically addresses the design, construction, transportation and installation of new structures, including requirements for in-service inspection and possible removal of structures, the assessment of structures in service, and the assessment of structures for reuse at other locations.

ISO 19904-1:2006 provides requirements and guidance for the structural design and/or assessment of floating offshore platforms used by the petroleum and natural gas industries to support production, storage and/or offloading, drilling and production, production, storage and offloading, and drilling, production, storage and offloading.

ISO 19901-7:2005 specifies methodologies for a) the design, analysis and evaluation of stationkeeping systems for floating structures used by the oil and gas industries to support production, storage, drilling, well intervention and production, production and storage, drilling, well intervention, production and storage, and b) the assessment of stationkeeping systems for site-specific applications of mobile offshore units (e.g. mobile offshore drilling units, construction units, and pipelay units).

ISO 19901-1:2005 gives general requirements for the determination and use of meteorological and oceanographic (metocean) conditions for the design, construction and operation of offshore structures of all types used in the petroleum and natural gas industries.

ISO 19901-2:2004 contains requirements for defining the seismic design procedures and criteria for offshore structures; guidance on the requirements is included. The requirements are applicable to fixed steel structures and fixed concrete structures. The effects of seismic events on floating structures and partially buoyant structures are also briefly discussed. The site-specific assessment of jack-ups in elevated condition is only covered in ISO 19901-2:2004 to the extent that the requirements are applicable. Only earthquake-induced ground motions are addressed in detail. Other geologically-induced hazards such as liquefaction, slope instability, faults, tsunamis, mud volcanoes and shock waves are mentioned and briefly discussed. The requirements are intended to reduce risks to persons, the environment, and assets to the lowest levels that are reasonably practicable. This intent is achieved by using seismic design procedures which are dependent on the platform's exposure level and the expected intensity of seismic events and a two-level seismic design check in which the structure is designed to the ultimate limit state (ULS) for strength and stiffness and then checked to abnormal environmental events or the accidental limit state (ALS) to ensure that it meets reserve strength and energy dissipation requirements. For high seismic areas and/or high exposure level fixed structures, a site-specific seismic hazard assessment is required; for such cases, the procedures and requirements for a site-specific probabilistic seismic hazard analysis (PSHA) are addressed. However, a thorough explanation of PSHA procedures is not included. Where a simplified design approach is allowed, worldwide offshore maps are included that show the intensity of ground shaking corresponding to a return period of 1 000 years. In such cases, these maps may be used with corresponding scale factors to determine appropriate seismic actions for the design of a structure.

ISO 19901-4:2003 contains requirements and recommendations for those aspects of geoscience and foundation engineering that are applicable to a broad range of offshore structures, rather than to a particular structure type. Such aspects are site characterization, soil and rock characterization, and design and installation of foundations supported by the seabed (shallow foundations) and the identification of hazards. Aspects of soil mechanics and foundation engineering that apply equally to offshore and onshore structures are not addressed. The user of this part of ISO 19901-4:2003 is expected to be familiar with such aspects.

ISO 19901-5:2003 specifies requirements for controlling the weight and centre of gravity (CoG) by means of mass management during the engineering and construction of structures for the offshore environment. The provisions are applicable to offshore projects that include structures of all types and materials. ISO 19901-5:2003 differentiates between projects where considerations with regard to weight and CoG have a high priority as a result of weight and/or CoG sensitivity, and projects where weight and CoG are of little consequence. This differentiation has been made by the introduction of three different classes of structure (Class A, Class B and Class C). Depending on the degree of control necessary, different clauses of ISO 19901 will apply; clause 4 provides guidelines for assigning one of these classes. ISO 19901-5:2003 specifies quality requirements for reporting of weights and centres of gravity, specifies requirements for weight reporting, provides a basis for overall project status reports or management reports for all classes, specifies requirements for weight and load budgets for offshore installations, specifies the methods and requirements for the weighing of major assemblies and the determination of weight and centre of gravity, specifies requirements for weight information from suppliers, including weighing of equipment and bulk materials for offshore installations. It may be used as a basis for planning and presentation of the contractor's weight-reporting system; as a basis for evaluation of the contractor's weight-reporting system; as a means of refining the structural analysis/model; as a contract reference between the ordering client and the contractor; and as a basis for costing.

ISO 19900:2002 specifies general principles for the design and assessment of structures subjected to known or foreseeable types of actions. These general principles are applicable worldwide to all types of offshore structures including bottom-founded structures as well as floating structures and to all types of materials used including steel, concrete and aluminium. ISO 19900:2002 specifies design principles that are applicable to the successive stages in construction (namely fabrication, transportation and installation), to the use of the structure during its intended life and to its decommissioning. Generally, the principles are also applicable to the assessment or modification of existing structures. Aspects related to quality control are also addressed. ISO 19900:2002 is applicable to the design of complete structures including substructures, topsides structures, vessel hulls, foundations and mooring systems.

Contains guidelines for the design of steel, fixed offshore platforms and contains provisions for specific regional areas. Applicable to the design of complete platform structures including substructures, topside structures and foundations. Specifies design principles that are also applicable to the successive stages in construction (fabrication, transportation and installation).

Specifies general principles for the design and assessment of structures subjected to known or foreseeable types of actions. The principles specified are applicable worldwide and are applicable to all types of materials used including steel, concrete, aluminium etc..