The US Coast Guard Office of Design and Engineering Standards has released the Policy Letter “Implementation of IMO Resolution A.673(16), Guidelines for the Transport and Handling of Limited Amounts of Hazardous and Noxious Liquid Substances in Bulk on Offshore Support Vessels, For New and Existing U.S. Offshore Supply Vessels.”
IMO resolutions MEPC.318(74) and MSC.460(101) adopted amendments to the IBC Code updating carriage requirements for a significant number of products. These amendments became effective on January 1, 2021 and affected several cargoes. On 16 May, 2022, 03-12 CH-1 was published, which includes a second enclosure with changes in carriage requirements for affected cargoes.
Vessel companies have been granted extensions to their certificates of fitness in the interim between the effective date of the amendments and the publishing of the updated policy letter. As of now, those extensions have been granted until December 31, 2022.
Before the expiration of vessel COFs, a plan must be proposed to CG-ENG-5 to meet the updated requirements for affected products, or with proposed equivalencies to specific requirements. Once a plan is approved, the modifications will be required by the vessel’s next drydock date.
Survey and certification
Following a satisfactory initial survey of an offshore support vessel, the Administration or its duly authorized organization should issue a certificate, suitably endorsed to certify compliance with the provisions of the Guidelines.
If the language used is not English, French, or Spanish, the text should include the translation into one of these languages. The certificate should indicate the cargoes regulated by these Guidelines that the vessel is permitted to carry with any relevant carriage conditions and should have a period of validity not to exceed five years.
Stability
Offshore support vessels built in accordance with these Guidelines should be designed to meet the requirements for intact stability and for subdivision and damage stability contained in the Guidelines for the Design and Construction of Offshore Supply Vessels 2006.
Well-stimulation vessels which are permitted to carry more than the maximum amounts should be designed to meet the requirements for intact stability and for subdivision and damage stability contained in the Guidelines for the Design and Construction of Offshore Supply Vessel.
Special requirements for the carriage of liquefied gases
Each enclosed space used for handling or storage of a liquefied gas should be fitted with a sensor continuously monitoring the oxygen content of the space and an alarm indicating low oxygen concentration. For semi-enclosed spaces portable equipment may also be acceptable.
Drip trays resistant to cryogenic temperatures should be provided at manifolds transferring liquefied gases or at other flanged connections in the liquefied gas system.
For the carriage of liquid nitrogen the requirements of 17.19 of the International Gas Carrier Code should apply.
The construction of cargo tanks and cargo piping systems for liquefied nitrogen and liquid carbon dioxide should be to the satisfaction of the Administration.
Emergency shutoff valves should be provided in liquid outlet lines from each liquefied gas tank. The controls for the emergency shutoff valves should meet the requirements given in for remote shutdown devices.
Download the guidelines: USCG Implementation of IMO Resolution
