Frozen, Refrigerated, or Protect-From-Freeze? Get the Spec Right

You booked a reefer, the driver showed up, and the load still arrived wrong. Maybe it froze when it shouldn’t have. Maybe it thawed. Maybe the driver ran the unit at a setpoint that was technically what you asked for but not what you meant. Most of the time, the problem isn’t the truck. It’s the temperature spec, and the three words shippers mix up the most.

Frozen, refrigerated, and protect-from-freeze are not interchangeable. They describe different jobs, and if you write the wrong one on your bill of lading, you can lose the product before the trailer leaves the dock. Here’s what each one actually means and how to tell your carrier what you need.

Frozen: keep it solid

Frozen freight has to stay below freezing for the whole trip. Think ice cream, frozen proteins, and anything that spoils the moment it softens. The reefer runs continuously at a low setpoint, and the load usually needs to be pre-frozen before it’s loaded. A reefer is built to hold a temperature, not to pull warm product down. If you hand the driver a pallet that’s already thawing, the unit will fight it the whole way and probably lose.

What to tell your carrier:

• The exact setpoint you need, in degrees, not “keep it frozen.”
• Whether continuous or cycle-sentry (start-stop) operation is acceptable. For most frozen loads, continuous is the safe answer.
• That the product will be pre-frozen at pickup.

Refrigerated: keep it cool, don’t freeze it

Refrigerated freight lives in a range above freezing, roughly the fresh-produce, dairy, and pharmaceutical world. The risk here runs in both directions. Too warm and it spoils. Too cold and you freeze product that was never supposed to freeze, which can be just as much of a loss. Lettuce, eggs, and many liquids are ruined by ice they were never meant to see.

This is where a vague spec bites hardest. “Refrigerated” without a number lets the driver guess, and a guess that’s a few degrees off can cross a line you cared about. Give the setpoint and, if it matters, the acceptable high and low.

Protect-from-freeze: not a reefer setpoint at all

This is the one that trips people up most. Protect-from-freeze doesn’t mean you want a cold trailer. It means the product just can’t be allowed to freeze, usually in winter. Paints, adhesives, certain chemicals, batteries, canned goods, and a lot of liquids fall here.

Sometimes protect-from-freeze rides in a reefer set to hold a floor temperature above freezing. Sometimes it rides in a heated or insulated trailer. Sometimes, on a short winter move, it’s a matter of not letting freight sit outside on a dock overnight. The point is that “protect from freeze” is a condition to avoid, not a temperature to run. Tell your carrier the lowest temperature the product can safely reach, and let them figure out the equipment.

Why the wrong word costs you

The difference between these specs isn’t wording, it’s equipment, handling, and liability. A frozen load handed off as “refrigerated” arrives soft. A refrigerated load run at a frozen setpoint arrives ruined by ice. A protect-from-freeze load treated like it needs no attention arrives cracked and leaking after one cold night on a dock.

And when a claim gets filed, the bill of lading is the document everyone reads. If the BOL says “keep cold” and nothing else, you’re arguing about intent after the fact. A clear spec protects the product and protects you.

Here’s how to get it right before pickup:

1. Write the exact setpoint, or the acceptable range, in degrees.
2. State continuous or cycle-sentry if your product is sensitive to swings.
3. Note whether product is pre-conditioned (pre-frozen or pre-chilled) at pickup.
4. Add handling instructions that matter, like “do not leave on dock” for protect-from-freeze.
5. Confirm the driver’s reefer download or temperature log is available if you need proof of the trip.

Match the spec to the shipment size

Temperature-controlled doesn’t have to mean a full truckload. Comet National handles dry and refrigerated freight at both LTL and truckload size, and moves frozen and refrigerated loads to all 48 states and Canada. If you’ve got a few pallets that need a specific setpoint, you don’t have to pay for a whole trailer to get the temperature right. And if your load needs to change modes on the way, our Atlanta transload facility keeps it staged and handled without breaking the cold chain along the way.

The main thing is this: tell us the number and the condition, not just the word. “Refrigerated” is a starting point. A setpoint, a range, and a handling note are what actually keep your product intact.

If you’ve got a temperature-sensitive load and you’re not sure how to spec it, call Comet and walk us through the product. We’ll help you get the setpoint and the equipment right before the truck ever shows up.