Dry Ice Alternatives for Frozen Parcel Shipping
The conversation usually happens late. A frozen range is ready, the boxes are specified, and then someone reads the carrier’s prohibited items list properly and finds dry ice on it.
Dry ice is UN1845, a Class 9 dangerous good. It brings marking, paperwork, workplace safety duties under COSHH and, depending on the carrier, restrictions or an outright refusal. None of that has anything to do with how well it keeps a product frozen.
That is the problem our HydroFreeze Technology was developed to solve. HydroFreeze is a phase change coolant formulated for the frozen band, made from food approved ingredients at our facility in High Wycombe, and it is not classified as a dangerous good. Frozen consignments cooled with it need no HAZMAT labelling and no specialist dangerous goods courier. Unlike dry ice it does not sublime away in transit, so the coolant you pack is the coolant still in the box at delivery.
What follows is a short account of what makes dry ice difficult, and then what a switch to HydroFreeze actually involves.
Hydropac offers every customer a customized solution for chilled and conditioned shipping. For example, we help a customer with limited freezing capacity to deliver gel packs frozen and ready to use, and we can manufacture almost all shapes and sizes of cooling elements. As a customer, you come first: we are here to help you.
What Makes Dry Ice Difficult
By road: one short section of ADR
In Great Britain, ADR is given effect by the Carriage of Dangerous Goods and Use of Transportable Pressure Equipment Regulations 2009, as amended. For UN1845 only section 5.5.3 of ADR applies. Packages are marked CARBON DIOXIDE, SOLID, AS COOLANT, the transport document carries the same wording with UN 1845 and the total number of packages, and the vehicle must be marked where there is a real risk of asphyxiation and it is not adequately ventilated. There are no orange plates and no ADR driver certificate, but general health and safety duties and training still apply.
By air: a declared dangerous good
Under IATA Packing Instruction 954 the limit is 200 kg per package. Each package carries a Class 9 label, UN1845, the name Dry ice or Carbon dioxide, solid, and the net weight of dry ice, and it must be able to vent. The air waybill shows the same details. A full Shipper’s Declaration is not needed where dry ice is the only dangerous good, but it is as soon as the dry ice is cooling other dangerous goods.
At work: a COSHH substance
Carbon dioxide is a substance hazardous to health under COSHH, with EH40 workplace exposure limits of 5,000 ppm over eight hours and 15,000 ppm over fifteen minutes. It is colourless, odourless and heavier than air, so it gathers in vans, cold rooms and enclosed packing areas, and HSE records fatalities where it has displaced oxygen in confined spaces. Contact with dry ice causes severe cold burns. Whether gas monitoring is needed is decided by the COSHH risk assessment.
In the network: the carrier decides
Carriers set their own rules, and they are stricter than the law. Royal Mail prohibits dry ice on inland and international services. Other carriers vary by service, and the express networks that do accept it usually require an approved dangerous goods account first. Dry ice also sublimes continuously: FAA testing of small EPS shippers in a simulated flight measured a loss of around 2 per cent of its mass every hour. That makes a stated hold time difficult to promise across a real courier network.
Making the Switch to HydroFreeze
Replacing dry ice is not a like for like swap. The pack-out is rebuilt around three decisions, and each one is something we specify with customers rather than leave to a catalogue.
The right phase change point
A frozen payload has to stay below freezing, so the coolant has to change phase below the product temperature. A water based pack stabilises around 0 degrees C as it melts, which suits chilled distribution but cannot hold a frozen product. HydroFreeze is formulated for the frozen band, which is what allows Frozen Ice Packs to maintain frozen conditions inside a suitable insulated container rather than simply slow the thaw.
Enough coolant, properly conditioned
Once the phase change point is right, coolant quantity sets how long the parcel holds, and it follows from payload mass, route duration and the conditions on the lane. The packs also need conditioning in a freezer cold enough to take them fully through their phase change. A pack that has spent a night in a domestic-grade freezer is not ready, whatever it feels like in the hand. Where freezing capacity is the constraint, we can supply packs already frozen and ready to use.
An insulation envelope that does more work
Without the extreme cold of dry ice in the box, wall thickness, closure and void fill matter more. Frozen Shipping Boxes and Polystyrene Boxes become part of the thermal calculation rather than a container for it, and the seasonal side of that decision is covered in Seasonal Pack-Outs.
How we approach it
Our Cold Chain Optimisation process runs the same way whatever prompted the review: assessment of the current pack-out, thermal testing and operational mapping against the real route, refinement of coolant and format, then validation and scalable manufacturing. The test that matters is the worst realistic journey, the Thursday despatch before a bank holiday, not the average one. Carrier acceptance of the frozen product itself still varies by service, so it belongs in the same review.
Dry ice still has its place in deep frozen pharmaceutical logistics at minus 70 degrees C and below, and in specialist air freight where dangerous goods handling is already in place. For frozen parcels that simply need to arrive frozen, a coolant that is not a dangerous good is usually the simpler route. Courier Safe Frozen Packaging and Long Lasting Ice Packs are good places to start.