monitoring spaces 231 221 and 211 are defined by inner wall 202 and outer wall 204 as indicated in fig2 in this embodiment since monitoring spaces 231 221 and 211 are in fluid communication they are collectively known as the integrated monitoring space 203 as shown in fig2 integrated monitoring space 203 is filled with fluid 242 reservoir 240 is in fluid communication with integrated monitoring space 203 between walls 202 and 204 if a leak were to occur in containment enclosure 200 fluid 242 would gradually leak out causing the level to drop in reservoir 240 if the level were to drop too low a sensor placed at location 241 would indicate that containment enclosure 200 is leaking any known sensor may be placed at location 241 for example a float sensor may be used preferably reservoir 240 includes one or more openings 244 246 and 248 preferably one or more of these openings are closable and leak resistant each opening may serve a different purposes for example in the exemplary embodiment shown in fig2 opening 244 can be used to fill reservoir 240 with fluid 242 opening 248 may be used to drain fluid 242 out of reservoir 240 opening 246 may be used as a vent to facilitate movement of fluid 242 in reservoir 240 and within integrated monitoring space 203 and to limit the fluid level in reservoir 240 when filling reservoir 240 space with fluid 242 0066 fig4 is a partial view of another exemplary containment enclosure of the invention showing a.