A tank that may be used in combination with an actuating means such as a pneumatic door actuator includes a first, inner, enclosure positioned and enclosed within a second, outer, enclosure, to provide an enclosed chamber between the inner enclosure and outer enclosure. The pressure in the chamber may be measured with a gauge that does not extend into the inner enclosure. The measured pressure may then be monitored and compared in order to detect a change in pressure and thereby also detect a leak through a wall from the inner enclosure. The tank may also be used to inflate and/or deploy an emergency evacuation slide in an aircraft.