Packaging, Palletizing, Staging and Pre-cooling
It may sound simple, but shipping refrigerated cargo successfully starts with proper packaging, palletizing, and loading of the product. Many claims relating to spoiled or damaged temperature-controlled cargo begin with poorly executed pre-loading procedures.
These topics and others will be the focus of our upcoming webinar, "Refrigerated Shipping: Myths versus Facts." In the meantime, read on to learn some of the most important things shippers can do to keep their perishable freight safe.
Most cold products must be in sealed packaging to provide stability for temperature protection unless it is fresh produce or nursery freight. While some freight is packed to retain the cold, others are packed to keep it from freezing. If you are concerned about keeping the product maintained within a specific temperature range, make sure before loading that is already within those designated temperatures or insulated at the required temps. When accidental freezing is a concern, pallets can be wrapped with thermal protective pallet covers or shipping blankets. These wraps keep the external temperatures from penetrating the freight’s packaging and helps keep the product inside at a consistent temperature.
Just like any other kind of freight, refrigerated cargo needs to be correctly palletized. Stacking boxes or bags neatly on pallets and then optimally loading them into a trailer is critical to the safety of perishable freight. Automation and robotics have entered the picture in recent years, making the process more of an exact science for preparing shipments. For companies and distribution centers using them, these robotic palletizers (both case palletizers and bag palletizers) have helped eliminate human error and the need to spend hours laboring in cold warehouses in sub-zero temperatures preparing shipments. Read more about robotic palletizers.
If you are manually putting your product on pallets, be sure to follow best practices.
- Never allow any overhang on pallets
- Shrink wrap and/or strap all cargo to every pallet
- If varying box weights, heaviest boxes go on bottom
- Do not stack in a pyramid
- Leave no voids or spaces between products
- Use slip sheets every 3-4 layers to distribute weight
Download the Palletizing Guide
Staging Your Shipment
Products should be ready to go when the truck arrives. Freight with temperature requirements of less than 40 degrees Fahrenheit should be documented before going on the truck. Make sure to properly stage your shipments so that loading time can be kept to a minimum. For multi-stop LTL shipments, freight that delivers first should be put into the trailer last. Have the pallets lined up in the order in which they get loaded on the trailer. Timing is especially important during summer months and at cross-docking facilities where exposure to the heat is greater.
If you are unsure how to optimize your cargo’s pallet space inside a trailer, there are software programs that can do it for you. If you are working with a freight broker, they usually provide this valuable information as part of the service. Choptank Transport’s ORBIT TI, the company’s custom-built transportation management system, not only provides its customers with this service, they also provide analytics on capacity utilization metrics. This information gives shippers a record of how much of the available cargo space has been used during each trip.
Making sure there is adequate air circulation around the product by using spacers is another key factor in keeping the product within a specified temperature range. Cool air must be able to move over, under, around, and preferably up through the pallets. If you don’t have proper airflow, goods in the center of the shipment can become warmer. This practice is called center loading, and it means that the product should never be pushed up against the sides of the trailer, directly on the floor, or against the back of the trailer doors as these areas can conduct heat from external temperatures.
Pre-cooling the Trailer
Before the shipment is ready to be loaded, the trailer must be pre-cooled. Reaching the required stable temperature can take an hour or sometimes longer. If a trailer has real-time telematics on board, the shipper may be alerted when the trailer is ready for loading. If not, the dock manager must check the trailer manually before it is ready to be loaded. Be sure to clarify and document if the shipment needs to run “continuous” or if it can run “start/stop.” The set temperature should be to the coolest requirement since there will be some loss when the doors open for loading. The reefer unit should be turned OFF when loading.
Why? Keeping the unit off when loading does a couple of things. It prevents:
- Ice accumulation on the coil
- Any blockage of cold air movement
- Accumulation of moisture on the evaporator
- Poor performance of the refrigeration unit
There is a lot to know about shipping temperature-controlled freight. With emerging technology in the cold supply chain, old practices may no longer be the most efficient. Join us for our upcoming webinar, “Refrigerated Shipping: Myths versus Facts” to learn what’s new from the experts. (August 20, 2020 at 2 pm EDT.) Sign up today!