Test agencies expressed concern about knowing the material and fitting configuration of adapters in advance of testing. One agency suggested adapter material should match the original valve material strength. Agencies agreed small diameter supply lines present no pressure and temperature issues but suggested mandating a one to two second hold at maximum pressure during cycles. Test agencies questioned whether adapters and TPRD plugs are considered part of the test and whether leakage constitutes failure. Components not covered by UN R134 should be tested per ISO 19887-1.