In the absence of complete harmonization with ISO 11439, this proposal recommends that Table 6.4 of UN R110 should be amended by the following for CNG-1 designs:

1. Delete A.17, A.25, and A.7 since they do not match the tests specified in paragraph 7.5 on Cylinder design qualification tests
2. Add A.15 and A.6 since they do match the tests specified in paragraph 7.5 on Cylinder design qualification tests
3. Add A.24 because paragraph 6.9 on Fire protection requires all PRDs on all cylinder types to comply with A.24.

Proposal to clarify visibility requirements for CNG cylinders, LNG tanks, and their accessories to facilitate external inspections (e.g. for periodic technical inspection).