BS EN ISO 20257-1:2020

What is ISO 20257-1 - Design of floating LNG installations about?

ISO 20257-1 provides requirements and guidance for the design and operation of floating liquefied natural gas (LNG) installations, including installations for the liquefaction, storage, vaporisation, transfer and handling of LNG, in order to have a safe and environmentally acceptable design and operation of floating LNG installations.

ISO 20257-1 is applicable to:

• Floating LNG liquefaction installations (plant) — FLNG
• Floating LNG regasification installations (plant) — FSRU
• Floating storage units — FSU

ISO 20257-1 is applicable to offshore, near-shore or docked floating LNG installations.

ISO 20257-1 includes any jetty in the scope in case of docked floating LNG installations with regards to the mooring. ISO 20257-1 briefly describes floating LNG mooring concepts.

ISO 20257-1 is applicable to both newbuilt and converted floating LNG installations, and addresses specific requirements.

Note 1: ISO 20257-1 is not applicable to:

• Onshore LNG storage, liquefaction and/or regasification installations/plants, except for docked FSRU and/or FLNG installations
• Offshore LNG plants based on non-floating structure (such as gravity-based structure [GBS] principle
• Support onshore based facilities (such as support vessels, tugs, etc.)

Note 2: ISO 20257-1 is not intended for design floating power generation facilities though relevant parts of ISO 20257-1 can be used.

Note 3: ISO 20257-1 is not intended to cover LNG as fuel bunkering applications.

Who is ISO 20257-1 - Design of floating LNG installations for?

ISO 20257-1 on design of floating LNG installations is beneficial for:

• Shipbuilding companies
• Installers of liquefied natural gas (LNG)
• Onshore and offshore plants
• Cryogenic engineers
• Marine petroleum (Gas) engineers
• Offshore engineers
• Naval architects

Why should you use ISO 20257-1 - Design of floating LNG installations?

ISO 20257-1 provides a non-exhaustive list of potential concepts. When a novel concept is proposed, the general principles in ISO 20257-1 can be applied as far as applicable.

ISO 20257-1 assumes that a floating LNG installation is also designed to meet IMO and classification society requirements. It is not intended to preclude the use of a 'barge' solution. ISO 20257-1 neither specifies the shape of the installation nor specifies the need for propulsion or an installation to fall within a particular regulatory regime. A barge can either be subject to exactly the same considerations as a unit designed as a non-propelled ship or not. This will depend on aspects such as whether a barge is located offshore or at shore, how it is transported, whether it stores LNG or not, the level of manning, the regulatory regime imposed on it. In this respect, the user of ISO 20257-1 is expected to take hull structure design, means of external communications, and evacuation, escape and rescue arrangements, etc. into consideration. Additional requirements by the Flag process, Shelf or Coastal Regulations can be applicable, that will vary depending on the type of floating LNG installation.

The loads applicable to the LNG storage can be derived from various scenarios, including:

• Construction, installation and tests
• Onsite operations (e.g., floating unit operations, LNG transfer operations, inspection and maintenance operations, and accidental situations)
• Transit conditions (i.e., LNG storage not in operation)

Overall, ISO 20257-1 is helpful as it is about the safety management system process which defines and monitors the organizational structure, responsibilities, procedures, processes and resources for determining and implementing the major accident prevention policy. The floating LNG installations are designed for a longer lifetime than the project duration to enable

future use. The project for which the floating LNG installation is originally planned can change during its life, for example an FLNG or FSRU can be redeployed to a different location or converted into a trading ship.