As defined by the International Maritime Organization, an offshore container is a "portable unit specially designed for repeated use in the transport of goods or equipment between fixed and/or floating offshore installations and ships. Known in the offshore oil and gas community as "slippery rails "as they are often used to transport large assemblies to drilling and production rigs.
DNV's certification standards 2.7-1, 2 and 3 are a globally recognized set of certification standards for offshore containers and marine service modules. The certification standards relate to the certification of all types of marine containers as transport units. The three typical stages of transportation are: shore-based residency (eg, forklifts), supply vessels, and loading and unloading offshore facilities. The certification standards include design requirements related to all three phases.
There are five basic steps for DNV approval and certification:
1. Certification of our (or our client's designation) written welding procedures, laboratory tests and welder qualifications
2. Evaluate and approve our primary device/skid/frame designs
3. Audit/Survey during initial welding start-up
4. Production：Audits/investigations during equipment manufacturing
5. Prototype testing：For "type" approval (type approval means a series of identical units are manufactured over a period)