23. The expert from Belgium introduced ECE/TRANS/WP.29/GRSG/2014/28 clarifying the provisions for the periodic inspection of pressure relief valves. The expert from OICA suggested to improve the proposal by adding further instructions on how to conduct the tests. The expert from France raised similar comments and suggested to indicate the exact test that should be conducted either visually or physically. The expert from IANGV argued the lack of empirical evidence for the proposal and suggested a five-year frequency of visual inspection frequency. The expert from Germany stated that the proposal addressed issues beyond of the scope of the type approval procedures. Finally, GRSG agreed to resume discussion on this matter at its May 2015 session.

33. The expert from Belgium presented GRSG-106-15 reflecting the current provisions of UN Regulation No. 110 on the periodic requalification of CNG gas cylinders (Annex 3A) and LNG tanks (Annex 3B). She questioned the differences in the periodicity for the inspection of such cylinders and tanks. Following the discussion, GRSG underlined the need to investigate this subject and agreed to keep GRSG-106-15 on the agenda.