Systems, methods and apparatus for differential air pressure devices

A pressurizable chamber for a differential air pressure system, comprising:

• an inflatable enclosure having an inner surface and an outer surface;
• an user opening in the inflatable enclosure sized to accommodate a user;
• a releasable user seal having a skirt and a deformable rim wherein in use a portion of the deformable rim and a portion of the skirt are placed against the inner surface of the inflatable enclosure to form a sufficiently airtight junction allowing the inflatable enclosure to maintain its inflated state;
• an adjustable frame coupled to the outer surface of the inflatable enclosure wherein the adjustable frame controls at least one of a width and a height of the flexible inflatable enclosure in its inflated state to reduce interference of the inflated enclosure with arm or leg motion of a user wearing the releasable user seal within the user opening whose lower body is sealed into the pressurizable chamber and whose upper body is outside of the pressurizable chamber.