Home NR459 Process Systems Onboard Offshore Units and Installations This Rule Note provides particular provisions applicable to offshore units, including hydrocarbon processing facilities, intended to receive additional class notation PROC. Reference Title Date NR459 R01 Process systems onboard offshore units and installations Jul 2015 Check related documents: NI524 Classification and certification of high integrity protection system (HIPS) NR445 Rules for the classification of offshore units NR542 Classification of floating gas units Check other Bureau Veritas rules and guidelines.