Due to settlement and voids, it may be necessary to inspect cryogenic storage tanks for any development of cold spots.

 

The presence of cold spots can be identified, before they become a major problem, by Thermal imaging.

 

Thermal imaging will identify major anomalous areas that may be visible due to temperature differences between the inner and outer shells of the tanks. These images will indicate increased cold transfer between the inner and outer shells of the tank.

 

This cold transfer shows initially as a cooling of the outer shell corresponding to the reduced level of the Perlite inside. The cooler 
areas show up initially as condensation patches often with areas of 
algae and, as the Perlite level reduces, these patches form an ice layer.

 

Both the condensation/ice and the algae eventually cause a breakdown of the tank coating/paint to the point that corrosion takes place on the tank outer shell. Ice coatings will then occur; these can develop such 
that the ice in itself can be quite thick and in the worst case becomes detached with obvious and subsequent danger. The condensation also makes it more difficult to repair the coating.

 

In turn, this will increase boil off and the subsequent pressure build up will result in the excess pressure, in some cases, being released to the atmosphere. This is clearly not acceptable environmentally.

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