Section 3 Installation
Clasification Society 2024 - Version 9.40
Clasifications Register Rules and Regulations - Rules and Regulations for the Classification of Offshore Units, July 2022 - Part 11 Production, Storage and Offloading of Liquefied Gases in Bulk - Chapter 5 Process Pressure Vessels and Liquids, Vapour and Pressure Piping Systems and Offshore Arrangements - Section 3 Installation

Section 3 Installation

Parent topic: Chapter 5 Process Pressure Vessels and Liquids, Vapour and Pressure Piping Systems and Offshore Arrangements

3.1 Installation design requirements

3.1.1  Design for expansion and contraction
  1. Provision shall be made to protect the piping, piping system and components and cargo tanks from excessive stresses due to thermal movement and from movements of the tank and hull structure. The preferred method outside the cargo tanks is by means of offsets, bends or loops, but multi-layer bellows may be used if offsets, bends or loops are not practicable.
3.1.2  Precautions against low temperature
  1. Low temperature piping shall be thermally isolated from the adjacent hull structure, where necessary, to prevent the temperature of the hull from falling below the design temperature of the hull material. Where liquid piping is dismantled regularly, or where liquid leakage may be anticipated, such as at cargo transfer connections and at pump seals, protection for the hull beneath shall be provided.
3.1.3  Protection of steelwork and personnel against uncontrolled cryogenic release
  1. Requirements are to be provided to minimize the risks associated with the uncontrolled release of low temperature liquids. Such a release could result in evaporation and dispersion of the product and, in cases, could cause brittle fracture of unprotected hull, deck and support structures. In locations where a release of low temperature liquid could occur, suitable mitigation methods are to be provided. The techniques selected need to consider; the inventory volume, maximum liquid pressure, minimum liquid temperature and the location of possible leakage.
  2. If drip trays and impoundment are used the material shall be selected to withstand exposure at the saturation temperature of the released liquid. The boundaries of the drip tray and impoundments are to be such to remain effective at the angles of inclination stated in Table 1.2.1 Inclination of ship units and other surface type units of the Rules and Regulations for the Classification of Offshore Units.
  3. The effect of drip trays and impoundments containing low temperature liquid is not to effect supporting or adjacent steelwork. The fitting of thermal breaks to drip tray supports and insulation between impoundments and supporting steelwork structure is to be considered.
  4. Where it is established that the liquid release may be substantial, the ability to drain drip trays and impoundments to be drained to an appropriate location or collection vessel is to be provided.
  5. Unless the material has been selected accordingly, a water distribution system shall be fitted in way of the hull under the discharge connections to provide a low pressure water curtain for additional protection of the hull steel and the side structure. This system is in addition to the requirements of Pt 11, Ch 11, 1.3 Water-spray system, and shall be operated when discharging is in progress.
  6. Personnel access ways, escape routes and refuge areas are to be protected against the possibility of uncontrolled release of low temperature liquids.
3.1.4  Bonding
  1. Where tanks or cargo piping and piping equipment are separated from the structure of the ship unit by thermal isolation, provision shall be made for electrically bonding both the piping and the tanks. All gasketed pipe joints and hose connections shall be electrically bonded. Except where bonding straps are used, it shall be demonstrated that the electrical resistance of each joint or connection is less than 1 MΩ.
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