A mobile offshore unit is an offshore unit that is not intended to be placed permanently or long term on the field, but is designed to be moved from location to location whether or not it has a means of propulsion or of lowering legs to the seafloor (e.g. a unit used solely for exploration).
For example, floating units intended for production, such as FPSO’s (Floating Production, Storage and Offloading installations usually based on tanker designs) and FPP’s (Floating Production Platforms based on semi-submersible vessels), are not considered to be mobile.
Note:
Items of pressure equipment specifically intended for mobile offshore units are excluded from the PED. However, items of pressure equipment intended to be installed on both FPSO’s/FPP’s and mobile offshore units are not excluded from the PED.