All Things Shipping
May 1, 2020

Temperature-Controlled Shipping—and What Makes Dry Ice Cool

Shippo Snippets: 

  • The shipping journey may be unpredictable, but proper temperature controls and packaging can make for a more stable trip
  • Dry ice is considered a hazardous material and is subject to certain shipping regulations, by air and by sea
  • The best way to determine if you need dry ice or a gel pack is the temperature you will need when shipping
  • Some of the most desperately needed products right now require stable temperatures and special handling

The Story:

Due to lockdowns, quarantines, and the urgent need for pharmaceuticals, medical supplies and perishable food, temperature-controlled shipping and logistics have become a hot commodity. The pandemic has presented many challenges to the shipping industry, including the fact that not all items are created equal. Some of the most desperately needed products right now require stable temperatures and special handling. During normal times, frozen food often comes to mind when thinking of temperature control, but The International Air Transport Association (IATA) defines perishable items as:

Contents [that] will deteriorate over a period of time if exposed to severe environmental conditions like extreme temperatures or humidity. Examples include (but are not limited to): pharmaceuticals, seafood, dairy, plants, meat, fruits and vegetables.

The shipping journey may be unpredictable—especially in the uncertainty of our current situation—but proper temperature controls and packaging can help make for a stable trip.  

Innovative companies like HelloFresh have delivered on greener ways to ship temperature-controlled products, such as recyclable packaging. Goldbelly has built a business on helping other businesses—shipping them gourmet and regionally iconic foods. Their business model therefore depends on successful temperature-controlled shipping.  

The most popular shipping materials used for insulation: 

  • Dry ice
  • Gel coolants 

What Exactly is Dry Ice?

Dry ice is simply a solid form of carbon dioxide and universally used as a cooling agent. It’s easily manufactured, and used mostly to preserve and freeze food. 

Dry ice can be a miracle ingredient to your shipping, but keep in mind that, as a solid, it will naturally convert back to carbon dioxide. That means it doesn’t thaw; it just sort of gets gassy. This gaseous element needs to escape during the length of the journey, so make sure your packaging is ventilated so that the gas can escape. 

How Dry Ice Became Cool

Before dry ice became a thing in the late 1920s, salt was usually added to water and then frozen. The result of this process was called “brine ice.” Its main purpose was to keep ice cream frozen as it traveled from manufacturers to retail stores. However, it was not ideal; it was heavy and wet, and, because of the salt, corrosive. Yep, yuck. 

In 1925, The DryIce Corporation of America was producing dry ice, but no customers were yet biting. That is, until the Schraff’s Stores gave them a try, to keep their Eskimo Pies cold. As a result, customers could buy the pies cold at the store and bring them home to their iceboxes. By 1929, DryIce partnered with Liquid Carbonic and built 17 dry-ice manufacturing plants across the United States. Birdseye Frozen Foods came on board in 1931. By 1932, at the height of the Depression, more dry-ice manufacturers appeared and production topped 120 million pounds. 

Is Dry Ice Dangerous?

Not if it is stored and used correctly: 

  • Never eat it. It’s not edible, under any conditions. 
  • When handling it, use tongs or gloves. It will get extremely cold. 
  • Make sure the area around it is well ventilated. If the carbon dioxide is being released in an area that is not well ventilated, it can cause breathing issues.
  • Don’t seal dry ice in a locked cooler. The pressure from the carbon dioxide gas could cause rupturing or can destroy your product. 

Helpful hints from UPS

  • Never pack dry ice with live seafood or flowers. 
  • When shipping flowers, always place a layer of packing material between the secured coolant and the flowers so that they never touch. 

Don’t Forget the Dry Ice Label When Dry Ice Shipping

If you are going to ship with dry ice, you must use a proper shipping label. The United Nations and the UN Committee of Experts on the Transport of Dangerous Goods have assigned an identifying number to all shipments considered dangerous. For dry ice, that number is UN1845. All packages containing dry ice must include:

  • This number on the label, including the letters “UN.” 
  • Dry Ice” or “Carbon Dioxide Solid” clearly stated on the label
  • A class 9 HAZMAT label, since dry ice is a”miscellaneous dangerous good.” 
  • The net quantity of dry ice contained in the package. Example: “9 kilograms” or “9 kg.” 
  • The name and address of both the shipper and the receiver of the package. Use indelible ink to make sure the information does not wash away during transportation.

Gel Pacs: Alternatives to Dry Ice

The best way to determine if you need dry ice or a gel pack is the temperature you will need when shipping.  If you need your shipping package to be cold but not frozen, gel packs are often a good option. In fact, dry ice is best used for frozen shipping, such as ice cream. However, for shipping that only needs to stay cold-to-cool (32 to 60 degrees), gel packs are often used. 

Gel-packs are water based, so they normally freeze and thaw just like water would. Some pacs, though, are filled with refrigerant. Be sure to check the package before purchasing. Gel packs are often ideal for delicate goods like flowers. Always be sure to include lots of padding material (think bubble wrap or packing peanuts) to keep your products firmly in place during the journey. 

Benefits of a gel pac

  • It’s usually marketed as a single item, making it easier to use and store
  • It’s reusable. 
  • It’s portable. 
  • It will not contaminate your product. 

Keeping It legal

Remember that dry ice is considered a hazardous material. That means it is subject to certain shipping regulations, by sea and by air. Gel packs, on the other hand, have no restrictions on the amount you use when shipping by air.

For specific regulations, consult the FDA website and the International Air Transport Association’s publication on Perishable Cargo Regulations

Best Outer Packaging To Be Used With Temperature-Controlled Shipping

Choosing proper shipping materials for your product is a big deal. The basic rule of thumb: keep heat out and coolness in. 

Here’s how UPS advises your choice: 

  • Sturdy insulated foam containers work well for food and other items you want to remain frozen, whether you’re shipping ice cream or breast milk. They’re also a good option for shipping flowers in extreme heat, when you’ll want to include coolant.
  • The thicker the foam, the less coolant you’ll need. Start with walls that are at least 1.5 inches thick. For sturdy items that require less cooling, insulated foam planks or thermal bubble wrap may be sufficient. Pack all foam coolers and planks within a sturdy new corrugated box.
  • For healthcare shipments that must maintain a specific temperature range, use pre-qualified temperature-controlled packaging (TCP). Choose “active” TCP for especially sensitive shipments; these more complex systems consist of a thermostat-controlled refrigerated container powered by an internal power source.
  • Ship perishable food, flowers and other temperature-controlled goods quickly to minimize transit time. Overnight shipping with a maximum transit time of 30 hours is recommended via a service that provides specific delivery commitments.
  • Consider timing when shipping your temperature-sensitive goods. Avoid holidays and try to ship early in the week to avoid potential weekend warehouse stays.

Items you will probably need for your shipment: 

    • New corrugated box
    • Refrigerant (gel packs, dry ice)
    • Insulation (foam cooler, foam planks, thermal bubble wrap), 
    • Cushioning (bubble wrap, packing peanuts, foam)
    • Temperature-controlled packaging and a temperature-monitoring device.

Things to Keep in Mind

  • Remember that these are general shipping guidelines, and they may not be the right choice for every shipment 
  • Make sure that whatever outside packaging you are using will not be hazardous to your actual shipment 
  • Confirm that the packaging you are using is not going to be a contamination danger to edible products 
  • Be sure to thoroughly research product requirements to ensure the most proper packaging and to guarantee a safe shipping journey

Temperature-controlled shipping is nothing new, but advancements made over time have helped to make it much more effective, efficient and accessible, which will come in handy as we navigate the current situation.


Need a fast, efficient and cost-effective shipping solution? Check out Shippo today.

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Ron Sklar
is a business content writer based in New York. He writes for clients in a number of sectors, including real estate, healthcare, financial services, tech, and transportation/automotive.

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