Home NI629 Certification of offshore access systems This Guidance Note provides guidelines for the certification of offshore access systems (OAS), based on gangways, and used for the transfer of persons from ships to offshore facilities or from ship to ship. Reference Title Date NI629 R00 Certification of offshore access systems May 2016 check related documents: NR445 Rules for the classification of offshore units NR467 Rules for the classification of steel ships Check other Bureau Veritas rules and guidelines.