ISO 21593:2019 pdf free
ISO 21593:2019 pdf free.Ships and marine technology – Technical requirements for dry-disconnect/ connect couplings for bunkering liquefied natural gas
An interlock function shall be included to ensure the coupling is sealed first under connection,before the internal valves are opened. When disconnecting, the internal valves shall be closed first, before it is possible to disconnect the coupling. This may be achieved by an internal interlock device (two-step action) or sequential in one single rotating manoeuvre (single-step action).
The volume between the two internal valves shall be as small as practical and reported by the manufacturer.
Once connected, the coupling shall remain liquid and gas tight under all operating conditions,and shall sustain:
1. The external loads applied at the connection between the bunkering system and the ship’s manifold(dynamic and static as well as ice accretion).
2. The internal loads due to the LNG transfer process, either pressure or thermal loads during transient and permanent phases.
The bending loads shall comply with the value specified in Table 5.
The design of the coupling shall allow the coupling to be manually connected and disconnected unaided and the maximum force to (dis )connect the nozzle from the receptacle shall not exceed 350 N.
Where this force exceeds 350 N, actuation shall be pneumatically or hydraulically assisted.
The nozzle shall be so designed as to be operated without the use of tools (e.g. extension bars) and excessive force for connecting and disconnecting.
The operation direction to open and close shall be indicated with an indelible mark. Connected condition shall be made with a positive indication that the mechanism action is fully made.
The design of the nozzle and receptacle shall allow for the removal of liquid and vapour before disconnection, avoiding vapour and liquid trapped in the dead space during purging operation.
The nozzle shall have an integrated swivel function. It shall allow free rotation, to prevent the application of torsional loads on the bunkering system.
The coupling shall have suitable fire resistance properties and shall be fire type tested in accordance with recognized standards (e.g. ISO 10497). ISO 21593 pdf free download.
