Abstract: A respirator mask for positive pressure respirator equipment comprises several peripheral seal edges around the face of the mask wearer. It must be assured that in case of possible leaks of the seal edges no respiratory gas, in particular respiratory gas with increased oxygen concentration, escapes into the open. To check that there are no leaks of respiratory gas past the seal edges, one of the sealing cavities defined by the seal edges in the mask is connected to a connecting line. This cavity defines a control chamber. A flow indicating device is connected to the connecting line and is placed so that it is visible to the wearer. A valve is positioned in a part of the mask bounding the interior of the control chamber. The valve can be actuated to permit the flow of gas, for example exhaled gas, into the control chamber and out through the connecting line and flow indicating device.