Proposal to amend Annex 16, para. 9.6. to clarify the endurance test procedure for pressure regulators and vaporizers by specifying that the outlet of the regulator shall be plugged during cycling of the inlet pressure from 100 per cent to 50 per cent of classification pressure at room temperature and at high and low temperatures. The regulator shall withstand 50,000 cycles without failure and remain leak proof after testing at temperatures of -20 °C, room temperature, and +120 °C.