UR G1 Rev3 Corr1 CLN
UR G1 Cargo containment of gas tankers - Rev.3 Corr.1 May 2018 Underlined
UR G2 Rev1 CLN
UR G2 Liquefied gas cargo tanks and process pressure vessels - Rev.1 1979 Clean.
Note: UR G2 Rev.2 will come into force on 1 January 2020 and can be found in "Revision History"
UR G3 Rev6 CLN
UR G3 Liquefied gas cargo and process piping - Rev.6 Jan 2016
UR G4 Deleted
Re-categorised as UR Z16 - June 1999