This standard covers all types of manually operated high pressure oxygen, cylinder shut off valves for use in commercial aircraft. It is intended that the valve shall be attached to a pressure cylinder storing oxygen under a nominal pressure of 12.76 MPa (1850 psig) at 21 °C (70 °F). Upon opening the valve, oxygen will be permitted to discharge from the storage cylinder to the valve outlet and to other downstream components of the oxygen system. It shall also be possible to recharge the cylinder through the valve.