A flow regulation vent (10, 110, 150, 250) for regulating flow from a pressurized gas supply, comprising: a fixed portion (14, 114, 154, 276) adapted to engage a gas supply conduit, wherein the fixed portion has a gas flow orifice (20, 120, 160, 262); and a movable portion (12, 112, 158, 278) adapted to be flowingly connected to the pressurized gas supply, the movable portion being biased against a spring force to reduce an outflow area of the vent with increasing pressure; wherein the movable portion (12, 112, 158, 278) is movable between a relaxed position, whereby at a specified minimum operating pressure, the movable portion (12, 112, 158, 278) is moved by the spring force to a position away from the fixed portion (14, 114, 154, 276) to establish a first gas flow area between the movable portion (12, 112, 158, 278) and the gas flow orifice (20, 120, 160, 262), and a fully pressurized position, whereby, at a specified operating pressure, the pressurized gas offsets the spring force to move the movable portion (12, 112, 158, 278) to a position adjacent the fixed portion (14, 114, 154, 276) to establish a minimum gas flow area between the movable portion (12, 112, 158, 278) and the gas flow orifice (20, 120, 160, 262); and wherein a hinge (16, 116, 280) pivotally con nects the movable portion (12, 112, 278) to the fixed portion (14, 114, 276) and the movable portion (12, 112, 278) is pivotably movable between the relaxed position and the fully pressurized position, or wherein the movable portion is provided by a resiliently bendable cantilevered flap and the movable portion is bendable between the relaxed position and the fully pressurized position; characterised in that the flow regulation vent (10, 110, 150, 250) further comprises a strain gauge for measuring the position of the movable portion (12, 112, 158, 278) and for providing an indicator of flow through the vent, wherein the strain gauge is mounted between the fixed portion (14, 114, 154, 276) and the movable portion (12, 112, 158, 278). a fixed portion (14, 114, 154, 276) adapted to engage a gas supply conduit, wherein the fixed portion has a gas flow orifice (20, 120, 160, 262); and a movable portion (12, 112, 158, 278) adapted to be flowingly connected to the pressurized gas supply, the movable portion being biased against a spring force to reduce an outflow area of the vent with increasing pressure; wherein the movable portion (12, 112, 158, 278) is movable between a relaxed position, whereby at a specified minimum operating pressure, the movable portion (12, 112, 158, 278) is moved by the spring force to a position away from the fixed portion (14, 114, 154, 276) to establish a first gas flow area between the movable portion (12, 112, 158, 278) and the gas flow orifice (20, 120, 160, 262), and a fully pressurized position, whereby, at a specified operating pressure, the pressurized gas offsets the spring force to move the movable portion (12, 112, 158, 278) to a position adjacent the fixed portion (14, 114, 154, 276) to establish a minimum gas flow area between the movable portion (12, 112, 158, 278) and the gas flow orifice (20, 120, 160, 262); and wherein a hinge (16, 116, 280) pivotally con nects the movable portion (12, 112, 278) to the fixed portion (14, 114, 276) and the movable portion (12, 112, 278) is pivotably movable between the relaxed position and the fully pressurized position, or wherein the movable portion is provided by a resiliently bendable cantilevered flap and the movable portion is bendable between the relaxed position and the fully pressurized position; characterised in that the flow regulation vent (10, 110, 150, 250) further comprises a strain gauge for measuring the position of the movable portion (12, 112, 158, 278) and for providing an indicator of flow through the vent, wherein the strain gauge is mounted between the fixed portion (14, 114, 154, 276) and the movable portion (12, 112, 158, 278).