Section 1 General
Clasification Society 2024 - Version 9.40
Clasifications Register Rules and Regulations - Rules and Regulations for the Classification of Offshore Units, July 2022 - Part 3 Functional Unit Types and Special Features - Chapter 3 Production and Storage Units - Section 1 General

Section 1 General

Parent topic: Chapter 3 Production and Storage Units

1.1 Application

1.1.1 The requirements of this Chapter apply to units engaged in production and/or crude oil or liquefied gas bulk storage and offloading at offshore locations. Production units have specialised structures and plant installed on board for production and/or processing crude oil or gas.

In general, oil storage units have integral tanks for the storage of crude oil in bulk and the Rules are primarily intended for units which are to store flammable liquids having a flash point not exceeding 60°C (closed-cup test).

Ship units with bulk storage tanks for liquefied gases or liquid chemicals are to comply with Pt 3, Ch 3, 1.1 Application 1.1.4 and Pt 3, Ch 3, 1.1 Application 1.1.5 respectively. Other unit types with bulk storage tanks for liquefied gases or liquid chemicals will be specially considered on the basis of Pt 3, Ch 3, 1.1 Application 1.1.4 and Pt 3, Ch 3, 1.1 Application 1.1.5 as applicable.

1.1.2 Column-stabilised and self-elevating units which are intended to operate only at a fixed offshore location are to comply with this Chapter, but reference should be made to Pt 3, Ch 1, 1 Rule Application.

1.1.3 Ship units are to comply with this Chapter, in addition to Pt 10 Ship Units.

1.1.4 Ship units required for the storage of liquefied gases in bulk are to comply with Pt 11 Production, Storage and Offloading of Liquefied Gases in Bulk, in addition to Pt 3, Ch 3, 1.1 Application 1.1.3.

1.1.5 Ship units required for the storage of liquid chemicals in bulk are to comply with Pt 3, Ch 3, 1.1 Application 1.1.3, and in general with the International Code for the Construction and Equipment of Ships Carrying Dangerous Chemicals in Bulk (IBC Code), as interpreted by LR.

1.2 Class notations

1.2.1 The Regulations for classification and the assignment of class notations are given in Pt 1, Ch 2 Classification Regulations, to which reference should be made.

1.2.2 In general, units complying with the requirements of this Chapter and the relevant Parts of the Rules will be eligible for the assignment of one of the following class type notations:
  • Floating production unit.
  • Floating production and storage and offloading unit.
  • Floating storage offloading unit.

Other type notations may be assigned when considered appropriate by the Classification Committee.

1.2.3 Type class notations for units with bulk storage tanks for liquefied gases or liquid chemicals will be specially considered by the Classification Committee.

1.2.4 When a unit is to be verified in accordance with Regulations of a Coastal State Authority/National Administration, an additional class notation may be assigned in accordance with Pt 1, Ch 2 Classification Regulations.

1.2.5 Production units with an installed process plant facility, which comply with the requirements of Pt 3, Ch 8 Process Plant Facility, will be eligible for the assignment of the special features class notation PPF. For units with riser systems, see also Pt 3, Ch 12 Riser Systems.

1.2.6 When a PPF notation is not assigned to a unit with a process plant facility, classification of the unit will be subject to the process plant being certified by LR, or by another acceptable organisation.

1.2.7 Production units without an installed process plant facility are to comply with the general requirements of Pt 3, Ch 8 Process Plant Facility as applicable.

1.2.8 Units with an installed drilling plant facility, which comply with the requirements of Pt 3, Ch 7 Drilling Plant Facility, will be eligible for the assignment of the special features class notation DRILL.

1.2.9 When a DRILL notation is not assigned to a unit with a drilling plant facility, classification of the unit will be subject to the drilling plant being certified by LR, or by another acceptable organisation.

1.3 Scope

1.3.1 The following additional topics applicable to the class type notation are covered by this Chapter:
  • General arrangement.
  • Structural arrangement of the unit.
  • Supporting structures below production and process plant equipment, flare structures, and marine risers.
  • Deckhouses and modules related to production operations.
  • Loading of hot oils.
  • Structural arrangement of oil storage tanks, cofferdams and pump-rooms.
  • Access arrangements.
  • Compartment minimum thickness.
  • Hazardous areas and ventilation.
  • Pollution prevention.

1.3.2 Where the unit is fitted with drilling equipment, the requirements of Pt 3, Ch 2 Drilling Units are to be complied with.

1.4 Installation layout and safety

1.4.1 In principle, production units are to be divided into main functional areas to ensure that the following areas as applicable are separated and protected from each other:
  1. Production area:
    • Wellhead area.
    • Processing area.
  2. Drilling area:
    • Drill floor area.
    • Mud circulation and treatment area.
  3. Auxiliary equipment area.
  4. Living quarters’ area.

1.4.2 Attention is to be given to the relevant Statutory Regulations for fire safety of the National Administrations in the country of registration and/or in the area of operation as applicable, see Pt 1, Ch 2, 1 Conditions for classification and Pt 7, Ch 3 Fire Safety.

1.4.3 Additional requirements for safety systems and hazardous areas are given in Pt 7 Safety Systems, Hazardous Areas and Fire.

1.4.4 Living quarters, lifeboats and other evacuation equipment are to be located in non-hazardous areas and be protected and separated from production and wellhead areas.

1.4.5 In general, production units with crude oil bulk storage tanks are to be designed so that the arrangement and separation of living quarters, storage tanks, machinery rooms, etc., are arranged in accordance with the SOLAS - International Convention for the Safety of Life at Sea as amended, Regulations 11-2/56. Where this is not practicable owing to the unconventional design construction of the unit, special consideration will be given to other arrangements which provide equivalent separation and protection. See also Pt 1, Ch 2, 1.1 Application. For ship units and surface type units with crude oil bulk storage tanks, the general arrangement and separation of spaces are to comply with Pt 4, Ch 9 Double Hull Oil Tankers of the Rules for Ships, or equivalent arrangements provided.

1.4.6 The position of the process plant in relation to storage tanks for crude oil, gas or other products will be specially considered, and consideration will be given to the requirements with regard to the provision of effective separation, methods of storage, loading and discharging arrangements.

1.4.7 Provision is to be made for purging, gas freeing, inerting or otherwise rendering safe crude oil bulk storage tanks, process plant and process storage facilities before the unit moves to a new location.

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