What is the pressure difference required to open the valve on the MBU-12/P oxygen mask?

The pressure difference required to open the valve on the MBU-12/P oxygen mask is 1 mm Hg greater. This specific measurement is critical for ensuring proper operation of the mask in oxygen delivery systems. When the pressure inside the mask reaches a level that is 1 mm Hg greater than the external atmospheric pressure, it allows the valve to open, facilitating the flow of oxygen to the user. This functionality is particularly important for maintaining safe and effective breathing support for pilots and aircrew at varying altitudes and environmental pressures. Proper understanding of this pressure requirement helps ensure that the oxygen delivery system operates efficiently, thus supporting the critical safety of aircrew in flight operations.