Many portable units intended for offshore use are not containers as defined in this standard. However, there is often a need for verification and certification of such units. DNV GL has therefore prepared standard DNVGL-ST-E273 2.7-3 Portable offshore units with requirements for design, manufacture, testing etc. for units normally up to 100000 kg. Portable offshore units are not intended to carry goods (general cargo) as their primary function but may be used for equipment that is not possible/impractical or too heavy to transport in offshore containers. Portable offshore units may be designed for subsea use and for single transport events. All portable offshore units are evaluated for safe handling and transport and assigned to an Operational Class for the offshore handling. Additional operational procedures may be required. There are three Operational Classes with limiting significant wave height: — Class R60 - Lift from/to vessel in max Hs = 6.0 m — Class R45 - Lift from/to vessel in max Hs = 4.5 m — Class R30 - Lift from/to vessel in max Hs = 3.0 m