Section 12 Materials and fabrication

12.1.1 In general, the requirements of Ch 1, 1.6 Materials and fabrication, Ch 4, 2.25 Materials and Ch 11 Materials and Fabrication of the Code for Lifting Appliances in a Marine Environment, July 2022 are applicable to the materials and fabrication of OPTS and their components.

12.1.2 Manufacturers of OPTS and components shall have a suitable quality management (QM) system as per the requirements of ISO 9001 Quality management systems – Requirements in place. The manufacturer’s QM system shall be certified by an accredited certification body.

12.2.1 Classed OPTS shall be constructed of material which complies with LR’s Rules for the Manufacture, Testing and Certification of Materials, July 2022. Reference is made to Ch 1, 1.6 Materials and fabrication 1.6.1 of the Code for Lifting Appliances in a Marine Environment, July 2022 only.

12.2.2 Certified OPTS shall, as a minimum, be constructed of material which complies with a recognised National or International Standard provided the requirements are equivalent to LR’s Rules for the Manufacture, Testing and Certification of Materials, July 2022, but where the approval and survey requirements will not comply with the requirements of Ch 1 General Requirements and Section 1 of subsequent Chapters, of the Rules for the Manufacture, Testing and Certification of Materials, July 2022, materials may be subject to additional testing under LR survey prior to acceptance for any project at the discretion of the Surveyor. Reference is made to Ch 1, 1.6 Materials and fabrication 1.6.1 of the Code for Lifting Appliances in a Marine Environment, July 2022.

12.2.3 Material specifications that have no equivalent to LR’s Rules for the Manufacture, Testing and Certification of Materials, July 2022 will be subject to special consideration by LR. Reference is made to Ch 1, 1.6 Materials and fabrication 1.6.1 of the Code for Lifting Appliances in a Marine Environment, July 2022.

12.2.4 The materials shall be delivered in the hot finished condition and shall be of the fine grain steel type.

12.2.5 Carbon steel bolts are to be specified in accordance with ISO 898 Mechanical properties of fasteners made of carbon steel and alloy steel – Part 1: Bolts, screws and studs with specified property classes – Coarse thread and fine pitch thread. Bolts are to be selected within the range 8.8 to 10.9 (inclusive). Bolt materials in other materials such as stainless steels are to be specified in accordance with a recognised National or International Standard. The required level of certification for bolts is given in Ch 1, 12.8 Documentation.

12.2.6 LR shall be contacted in early design stages if material is proposed which is not defined in the Rules for the Manufacture, Testing and Certification of Materials, July 2022.

12.2.7 The application of aluminium or composite materials will be specially considered.

12.2.8 A suitable corrosion protection system is to be selected and applied by the designer/manufacturer depending on the expected corrosivity environment. If a protective paint system has been selected it shall comply with the requirements of the applicable parts of ISO 12944 Paints and varnishes – Corrosion protection of steel structures by protective paint systems. If there is no corrosivity category agreed between the Owner/Operator and the designer/manufacturer the corrosivity category ‘CX’ as defined in ISO 12944 Paints and varnishes – Corrosion protection of steel structures by protective paint systems shall be selected. All items and areas are to be sufficiently protected against corrosion for the agreed protection duration of the system. If there is no protection duration agreed between the Owner/Operator and the designer/manufacturer the durability range ‘H’ (as a minimum) as defined in ISO 12944 Paints and varnishes – Corrosion protection of steel structures by protective paint systems shall be selected. If the system is to be operated beyond the agreed protection duration or the duration of the durability range of ISO 12944 Paints and varnishes – Corrosion protection of steel structures by protective paint systems, additional maintenance inspections are to be carried out and appropriate defect criteria are to be defined in the maintenance section of the instruction for use.

12.3.1 All materials are required to provide adequate resistance against brittle fracture, and in general to comply with the requirements of:

1. Ch 4, 2.25 Materials 2.25.2 of the Code for Lifting Appliances in a Marine Environment, July 2022.

12.3.2 As an alternative to the requirements of Ch 1, 12.3 Brittle fracture 12.3.1, proposals to use engineering critical assessment approaches, to establish that fracture toughness requirements have been addressed, will be subject to special consideration. The designer shall contact LR in the early stages of the projects regarding acceptance of such proposals.

12.3.3 Proposals for resistance against brittle fracture for minimum design temperatures (MDT) below -40°C will be specially considered.

12.4.1 The use of ‘Z’ grade steel is recommended where the structural steel is subjected to tension stresses in the through thickness direction (e.g. cruciform or t-shape joints).

12.4.2 Where Z grade steel is specified the requirements of Ch 3, 8 Plates with specified through thickness properties of the Rules for the Manufacture, Testing and Certification of Materials, July 2022, shall be met and, if necessary, supplementary guidance on selection of Z25 or Z35 may be obtained from a recognised National or International Standard acceptable to LR to ensure structural integrity of the proposed design.

12.5.1 The minimum thicknesses are to be in compliance with Table 1.12.1 Minimum material thickness.

12.5.2 The minimum bolt size for critical and primary structural components shall be M12. The application of smaller bolt sizes will be specially considered.

12.6.1 The fabrication and inspection of classed OPTS are to be in compliance with Ch 11, 2 Fabrication of classed lifting appliances of the Code for Lifting Appliances in a Marine Environment, July 2022.

12.6.2 The fabrication and inspection of certified OPTS are to be in compliance with Ch 11, 3 Fabrication of certified lifting appliances of the Code for Lifting Appliances in a Marine Environment, July 2022.

12.6.3 OPTS are required to be built under survey of an LR Surveyor in case certification or classification is requested.

12.6.4 Before fabrication commences an Inspection and Test Plan (ITP) shall be prepared by the designer/manufacturer. This ITP shall be further discussed and agreed between the designer/manufacturer of the OPTS (or its components) and the attending Lloyd’s Register Surveyor. The ITP shall meet the requirements of this document.

12.6.5 Non-destructive examination is to be carried out by qualified Operators as per the minimum requirements given in Ch 12, 3.2 Initial Survey of new installations 3.2.4 of the Code for Lifting Appliances in a Marine Environment, July 2022 to the Surveyor’s satisfaction. 100 per cent visual examination is required in all cases for all welds. Reference is made to Ch 1, 13.3 Initial survey of new installations 13.3.2 for an OPTS specific definition of critical, primary and secondary welds.

12.6.6 Any classification and acceptance criteria of weld imperfections shall be in accordance with ISO 5817 Welding – Fusion-welded joints in steel, nickel, titanium and their alloys (beam welding excluded) – Quality levels for imperfections.

12.6.7 The quality level of critical, primary and secondary welds and weld connections between critical, primary and secondary components shall be in compliance with Table 1.12.2 Weld quality levels.

12.6.8 Concerning welds subject to fatigue, reference is made to Annex C of ISO 5817 Welding – Fusion-welded joints in steel, nickel, titanium and their alloys (beam welding excluded) – Quality levels for imperfections.

12.6.9 The designer/manufacturer should have a system of dimensional checks in place ensuring that the components and the system as a whole will be built in accordance with the approved plans.

12.6.10 The agreed corrosion protection system is to be applied in accordance with the agreed specification and manufacturer’s recommendations.

12.7.1 Repairs for classed OPTS shall be in compliance with LR’s Rules for the Manufacture, Testing and Certification of Materials, July 2022.

12.7.2 Repairs for certified OPTS shall be in compliance with Ch 11, 3 Fabrication of certified lifting appliances of the Code for Lifting Appliances in a Marine Environment, July 2022.

12.7.3 The following two types of repair shall be distinguished. Repairs necessary due to:

1. damages occurring during construction; and
2. in-service or out-of-service damages of completed OPTS.

12.7.4 In cases of damages occurring during construction the root cause of damage may be evaluated in order to avoid reoccurrence. LR shall be contacted to carry out a survey of the damage.

12.7.5 In cases of in-service or out-of-service damages the root cause of damage shall be evaluated in order to avoid reoccurrence. Reference is made to Ch 1, 13.7 Damage surveys and Ch 13, 2.3 Damage surveys of the Code for Lifting Appliances in a Marine Environment, July 2022.

12.7.6 In order to maintain the validity of the LR certification or classification, LR is to be contacted in case of in-service or out-of-service damages to carry out a survey as per the requirements of Ch 1, 13.7 Damage surveys and Ch 13, 2.3 Damage surveys of the Code for Lifting Appliances in a Marine Environment, July 2022.

12.7.7 The details of the repair and the repair procedure shall be discussed and agreed with the attending Surveyor before commencing the repair.

12.7.8 The materials used in the repair shall be the same as the original specification. Any deviations from the originally approved materials shall be agreed with LR and as a minimum provide equivalence with those of the original approved design and shall comply with the requirements of these Rules.

12.8.1 The designer/manufacturer of the OPTS shall have a system in place which ensures that all raw materials can be traced from purchasing to receipt at the manufacturer’s works until being used in the OPTS construction.

12.8.2 The required documentation for the materials used in classed OPTS applications is provided in Table 1.12.3 Material documentation for classed applications. See Ch 1, 1.6 Classification procedure.

12.8.3 The required documentation for the materials used in certified OPTS applications is provided in Table 1.12.4 Material documentation for certified applications. See Ch 1, 1.7 Certification procedure.

12.8.4 Any deviation from the above given documentation requirements shall be agreed with LR prior to any material being ordered for the actual project.