A positive pressure gradient is maintained across an open access port of an interface chamber such as a load lock chamber which provides an interface between a low pressure chamber such as a transfer or buffer chamber, and a high pressure area such as a staging area or factory interface area. When the access port of the interface chamber is open to the high-pressure area, the positive pressure gradient may be used in some applications to inhibit the flow of gasses from the high-pressure area into the interior of the interface chamber.