Should Your Laboratory Own a Dry Shipper or Hire One?

Dry shipper enquiries almost always arrive as a specification question. Which size, which hold time, which model. The prior question is whether you should own one at all, because a vessel used four times a year and a vessel used four times a month are different commercial decisions entirely.

Start with what the vessel is

A dry shipper holds liquid nitrogen absorbed into a porous inner matrix rather than as free liquid. Samples travel in the vapour phase, the vessel can be inverted without spilling, and there is no free liquid available to escape.

That construction is why the shipper itself travels as not restricted under Special Provision A152 of the IATA Dangerous Goods Regulations, provided the packaging cannot build pressure or release nitrogen in any orientation and the air waybill carries the words not restricted together with the special provision number. Packing Instruction 650 of the same regulations governs the samples inside where those are classified as UN 3373 Category B. It applies to the samples, not to the nitrogen holding them cold. The two are constantly conflated.

Four arguments for hiring

Infrequent shipments, first. A purchased shipper used a few times a year spends most of its life empty in a corner, and an empty shipper still needs storage space, periodic inspection and charging before use.

Unusual sizes, second. A one off shipment needing more capacity than your own unit holds is a hire, not a reason to buy a second vessel.

Capital constraints, third. Hire moves the cost out of capital expenditure and into the shipment, which is usually easier to approve and considerably easier to recharge to whoever the shipment is for.

Peak cover, fourth. A regular pattern with occasional surges is better served hiring for the surge than owning for the peak.

Three arguments for owning

Frequency, obviously, and the crossover point sits lower than most people expect once staff handling time is counted properly.

Control, which is the stronger argument. With your own vessel you know its history, whether it has been dropped, and how it performed on the last shipment. With a hired unit you rely entirely on somebody else's inspection regime, and a dry shipper that has taken a knock can carry a degrading vacuum with no external sign whatsoever.

Readiness, third. Charging is not instant, so owning means preparing on your own timetable rather than a hire company's, which matters when a transfer date moves.

Two things that decide whether the shipment works

Hold time first. Published figures are measured upright, unopened, at moderate ambient temperature. Real shipments meet none of those conditions reliably, and every opening costs hold time that cannot be recovered. Treat the published number as an upper bound and build margin for the delay you have not planned for. A hold time quoted without its measurement conditions is not usable for planning.

Charging second, and this is where shipments actually fail. The absorbent matrix has to be fully saturated, which takes appreciably longer than most protocols allow, and the vessel must then be inverted and drained so no free liquid remains. Weigh the unit before and after charging and record both figures, because weight is the only practical measure of how much cold mass is genuinely in the vessel.

Full article: Dry Shipper Hire or Purchase.