A dry shipper is a cryogenic transport vessel that maintains sample temperatures without containing any free liquid nitrogen. This single characteristic is what makes it suitable for transporting biological samples by road, air and courier where a standard liquid nitrogen dewar is not.
A standard liquid nitrogen dewar holds free liquid nitrogen that the sample sits in or above. If that vessel is tilted, dropped or inverted during transit, the liquid nitrogen moves. On an aircraft, liquid nitrogen classified as a free liquid is subject to IATA dangerous goods restrictions that make air freight of standard dewars impractical for routine clinical use.
A dry shipper works differently. The inner absorption matrix of the vessel is charged with liquid nitrogen before use, retaining the cold mass within the material itself rather than as a free liquid. Once correctly charged, the vessel can be tilted, inverted and handled without liquid nitrogen moving or spilling. This is what allows all CryoStork models to travel as not restricted under IATA Special Provision A152, rather than under the dangerous goods restrictions that apply to liquid-phase nitrogen containers. Packing Instruction 650 is a separate requirement covering the biological samples inside where those are classified as UN 3373 Category B, not the nitrogen holding them cold.
The dry shipper does not hold liquid nitrogen. It holds the cold stored within an absorption matrix. That distinction is the reason embryos and gametes can travel on commercial flights as non-hazardous goods.
The temperature inside a correctly charged dry shipper is maintained by slow vapour release from the absorption matrix rather than by active refrigeration or free liquid. This means the vessel has a defined hold time after charging, determined by its capacity and the quality of its vacuum insulation. All CryoStork models carry UKCA and CE markings and come with a three-year vacuum warranty. For advice on which CryoStork model is right for your transfer requirements, contact the Cryolab team or use CryoGPT. Browse the full CryoStork dry shipper range here.
