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 11 Production, Storage and Offloading of Liquefied Gases in Bulk - Chapter 16 Use of Cargo as Fuel - Section 1 General

Section 1 General

Parent topic: Chapter 16 Use of Cargo as Fuel

1.1 Application

1.1.1 Except as provided for in Pt 11, Ch 16, 5 Alternative fuels and technologies, Methane (LNG) is the only cargo whose vapour or boil off gas may be utilised in machinery spaces of category A, and in these spaces it may be utilised only in systems such as boilers, inert gas generators, internal combustion engines, gas combustion units (GCU) and gas turbines.

1.1.2  In addition to the requirements of this Chapter in respect of using LNG as a fuel, the requirements of Pt 5, Ch 15 are also to be complied with.

1.1.3  The following plans are to be submitted for consideration:
  • General arrangement of plan.
  • Gas piping systems, together with details of interlocking and safety devices.
  • Gas heaters.
  • Gas compressors and their prime movers.
  • Gas storage pressure vessels.
  • Gas and fuel oil burning arrangements.

1.2 Use of cargo vapour as fuel

1.2.1 This section addresses the use of cargo vapour as fuel in systems such as boilers, inert gas generators, internal combustion engines, GCUs and gas turbines.

1.2.2 For vaporised LNG, the fuel supply system shall comply with the requirements of Pt 11, Ch 16, 2.1 Supply requirements 2.1.1, Pt 11, Ch 16, 2.1 Supply requirements 2.1.2 and Pt 11, Ch 16, 2.1 Supply requirements 2.1.3.

1.2.3 For vaporised LNG, gas consumers shall exhibit no visible flame and shall maintain the uptake exhaust temperature below 535°C.

1.3 Arrangement of spaces containing gas consumers

1.3.1 Spaces in which gas consumers are located shall be fitted with a mechanical ventilation system that is arranged to avoid areas where gas may accumulate, taking into account the density of the vapour and potential ignition sources. The ventilation system shall be separated from those serving other spaces.

1.3.2 Gas detectors shall be fitted in these spaces, particularly where air circulation is reduced. The gas detection system shall comply with the requirements of Pt 11, Ch 13 Instrumentation and Automation Systems.

1.3.3 Electrical equipment located in the double wall pipe or duct specified in Pt 11, Ch 16, 2.1 Supply requirements 2.1.3 shall comply with the requirements of Pt 11, Ch 10 Electrical Installations.

1.3.4 All vents and bleed lines that may contain or be contaminated by gas fuel shall be routed to a safe location external to the machinery space and be fitted with a flame screen.

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