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Frigo 101: Answers to 10 Essential Refrigerated Truckload Questions

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The refrigerated truckload market follows most of the same patterns as the wider truckload market — most of which is dry van capacity — but there are a few differences that make temperature-controlled shipping a little more complex.

Whether you’re a dry van carrier looking to get into the frigo market, or a truckload shipper trying to boost your knowledge, every industry professional should have an understanding of this important mode.

This guide answers core refrigerated truckload questions to get you familiar with refrigerated the basics.

 

What is a frigo trailer?

Refrigerated truckload trailers — commonly referred to as frigos— are just as the name promises: insulated, full truckload trailers with a refrigeration unit in the front (nose).

 

What’s the difference between a dry van and a frigo trailer?

Refrigerated trailers are similar to standard 13.6-meter dry van trailers, but there are a few important differences:

  • The walls, ceiling and floors are made of metal or fiberglass, never wood. This not only improves insulation, but it prevents the floors and walls from absorbing odors from product.
  • Between the heavier construction materials and refrigeration unit, refrigerated trailers are heavier. The maximum loadable weight for a 13.6-meter refrigerated trailer is 22,5 tons.
  • Trailers are typically newer. Refrigeration units burn out after a few years of continuous work, and carriers typically have to replace trailers every three to five years.

 

What type of freight ships in refrigerated trailers?

Any product that can be damaged by high or low temperatures is shipped in refrigerated trailers.

While perishable foods are always shipped in refrigerated trailers, many products that you won’t find in your refrigerator require temperature control — to name a few:

  • Pharmaceuticals
  • Hazardous materials
  • Bulk liquids
  • Candles
  • Flowers
  • Chewing gum
  • Paint

Though frigos are often used to maintain cooler temperatures, they are also used to heat air. In the winter, shippers use frigos to protect temperature-sensitive products from freezing.

 

How does a refrigerated trailer work?

Refrigerated trailers are actually not intended to cool product, but to maintain the specific temperature of a product.

The three main components of a refrigeration unit are the:
  1. Evaporator coil
  2. Compressor (which powers the evaporator coil)
  3. Small diesel engine (which powers the compressor)

The process of refrigeration is actually not the addition of cold air, but the removal of heat from the air inside the trailer.

Variations in air pressure create air flow. As air from inside the trailer passes over the evaporator coil, it removes heat and redistributes the now colder air back throughout the trailer.

 

What is cycle vs. continuous air in a refrigerated trailer?

There are two different ways to run the refrigeration unit — cycle or continuous. Running the refrigeration unit in cycles reduces diesel consumption, but also creates more temperature variance.

Many products require continuous cooling. Ripening produce, for instance, generates heat, and requires a steady stream of cool air to maintain a consistent temperature.

Some frozen loads are less temperature sensitive and can withstand slight temperature variances — in these scenarios, cycling may be okay.

Understanding the commodity specifications is extremely important for carriers since they are responsible for the product from the moment it is loaded onto their trailer until it is unloaded.

Ripening produce generates heat and requires a continuous stream of cool air.”

 

What is an air chute in a frigo trailer and why does it matter?

Air chutes in a frigo trailer (aka trailer chutes or a chuted trailer) are flexible air ducts connected to the refrigeration unit that run along the top of the trailer. Chutes act as a ventilation system to evenly distribute chilled air throughout the trailer.

Trailer chutes lay flat against the trailer ceiling and inflate when in use. They are easy to install, made of highly durable material, protect against temperature variance and create more efficiency, which reduces diesel consumption.

By providing a uniform temperature throughout the trailer, chutes reduce the chance of product damage due to:

  • Top-freezing: occurs when temperature-sensitive products are damaged by frost because they are placed too close to the airflow source.
  • Hot spots: occur when pockets within the trailer heat up and are cut off from the temperature-controlled airflow, actively cooling the rest of the load.
  • Short-cycling: occurs when the airflow does not travel throughout the entire trailer — due to poor loading practices and back pressure in the trailer — resulting in uneven temperatures throughout the load.

 

Do different commodities have different shipping requirements?

With dry van freight, the loading, shipping and unloading process is pretty similar across most products. That is not the same with temperature-controlled freight — different commodities can have very different refrigerated shipping requirements (particularly produce).

For instance: sweet corn needs to be immediately cooled after harvest to prevent sugar from turning to starch (reducing quality). To do that, corn shippers often dump ice on top of the corn after harvest, then again once it is loaded in the trailer, where it will slowly melt during transit.

Another example: ice cream comes off the production line at a higher temperature than it ships at. If the shipper does not already have the ice cream pre-cooled to the appropriate temperature, it doesn’t matter if the driver has their trailer pre-cooled to a -30 degrees Celcius deep-freeze — there is a chance the product will be rejected upon arrival.

To ensure a chain of product integrity and to avoid costly shipping mistakes, both shippers and carriers need to:

  • Understand the commodity
  • Know exactly how it needs to be cooled, loaded, transported and delivered
  • Ask lots of questions
  • Over-communicate and document the specific product requirements

 

How does produce season impact the frigo market?

Whether or not you’re are a produce shipper, produce season can still impact your supply chain.

Every summer, it kicks off in southern Europe as fresh fruits and vegetables become ready for harvest. Produce volumes continue to increase and spread across the countries throughout the spring and summer.

As soon as produce comes out of the ground (or off the tree), the clock starts ticking. These products must be delivered by a certain date or the food will spoil and the shipper won’t make any money.

Since timeliness is so critical, produce shippers are generally very knowledgeable about how to move their freight from the farm to the store, and use pricing strategies to ensure capacity.

Once produce season kicks off, many frigo carriers will move some — or all — of their capacity to service these high-paying, seasonal produce shippers.

This includes carriers local to produce regions, as well as those migrating from other capacity markets. The net impact is spot rate inflation and capacity shortages for refrigerated truckload services.

While the hottest produce shipping regions will experience these more intensely (e.g. Spain in June), there is a ripple effect across the market.

Furthermore, the refrigerated truckload market is comparatively smaller than the dry van market. Less supply and higher seasonal demand make rate and capacity swings even more volatile.

 

What is a frigo trailer download?

A “downloadable frigo” just means that the carrier has the ability to download the temperature data from the trailer.

Think of it as an ELD for the refrigerated trailer, only instead of recording Hours of Service activity, it measures temperature activity over time.

It is also a great way to help determine if a product was damaged in transit or not. This can help fairly settle claims and help protect compliant drivers and carriers against liability.

 

Key Takeaways: What shippers & carriers need to know when shipping temp-controlled freight

If you’re a carrier:

The frigo truckload market can be a great way to expand your business and access new opportunities, but before you buy a trailer and “ride the wave” of produce season, here are a few things to remember:

  • Carry a thermo gun.
    A handheld, infrared thermometer (thermo gun) will allow you to check if the freight is at the correct temperature before it gets onto your truck.
  • Know what you’re hauling.
    Ask lots of questions and make sure you understand the shipping requirements for that specific commodity.
  • Work with a provider that knows what they’re doing.
    Whether you’re sourcing refrigerated shipments directly from a shipper or through a logistics provider/broker, this will help protect you against bad experiences.
  • Be prepared for market volatility.
    While frigo freight can offer high-margin opportunities, rates and capacity can be more volatile compared to truckload shipping.

Looking for frigo freight? You can find and book available loads from over 1,000 shippers in CoyoteGO, our free digital freight marketplace. 

 

If you’re a shipper:

Whether you’re new to refrigerated shipping, or just brushing up on the basics, keep these basic ideas in mind:

  • Trust who is on your loads.
    Work with a provider who has experience moving refrigerated freight and understands its complexities.
  • Know how produce season affects your region.
    Create a capacity plan with your providers to make sure you aren’t left hanging out to dry in the spring and summer.
  • Overcommunicate with your providers.
    If you have sensitive products or specific requirements, make sure you clearly communicate and document what you need from your carriers.

Want quotes for your refrigerated shipments? Get on-demand quotes and capacity from carriers with your free CoyoteGO account.

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