Heat pipe is a heat-transfer device which works on thermal conductivity and phase transition to manage the transfer of heat between two solid interfaces.
Heat pipes have various uses in the industry such as electronic cooling, radar electronics, waste heat recovery, satellite thermal control etc. Certain Heat pipes contains Propylene (UN 1077), Toluene (UN1294) and Anhydrous Ammonia (UN1005).
Experts from Spain submitted proposal at the Forty-first session of Sub-Committee of Experts on the Transport of Dangerous Goods to assign new UN Number for transport of heat pipes since this type of devise is not fitting into any currently available proper shipping names.
Proposal is to assign a new UN 3XXX with proper shipping name “Dangerous goods in heat pipes”
Read more about heat pipes on European Space Agency‘s website