Basics of Reefer Container and Reefer Cargoes
A REEFER CONTAINER is a short form for REFRIGERATED CONTAINER.
Simply put, reefer containers are big fridges that are used to transport temperature-controlled cargoes
such as fruits, meat, fish, seafood, vegetables, dairy and also non-food products such as flowers,
pharmaceuticals and film across many miles and oceans.
Some cargoes may need to be shipped chilled or frozen or in controlled temperatures.
Reefer containers have the ability to maintain the cargo at the required temperatures for the duration
of the transit.
How does a reefer container work?
Reefer containers are bottom air-delivery units designed to distribute chilled air from the floor, via
specific T-shaped decking, with the advantage of producing a consistent and uniform flow of air across
the entire shipment, powerful enough to ensure a perfect air exchange with the goods.
Reefer containers can maintain or lower the temperature of your shipment, even in the most difficult
conditions.
Reefer containers can also be equipped to ‘warm up’ the goods for those shipments where required,
with the ability to maintain temperatures up to 30°C when required, regardless of outside temperatures.
Important point to note is that,
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A reefer unit is NOT DESIGNED to reduce the temperature of the cargo.
Its MAIN JOB is simply to maintain the pre-cooled cargo temperature.
Air-Flow or Ventilation Requirements
The airflow requirements of each commodity varies and there is no one size fits all in reefer cargo
movement.
Example:
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in the case of chilled cargo, air has to flow through the cargo at all times so that heat and gases
are removed, therefore the cartons used should have ventilation
in the case of frozen cargo, air has to flow around the cargo so there should be no gaps
between the cargo and the walls and the cargo itself, so the cargo has to be block stowed.
Cold Treatment
Due to some fruit types carrying potential pathogens,
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Some importing countries like China, Japan, Nigeria, require cold treatment of the fruit
This type of shipment is also called as – Steri Shipment
For these kinds of shipments,
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Fruit will be pre-cooled to a lower temperature than a commercial market
In order to monitor this pre-cooling temperature, steri probes (about 3 per shipment) are
inserted into the pulp of the fruit, within the carton.
There is a minimal tolerance allowed in temperature variance.
Should the tolerance be exceeded, then either additional hours or days will be required to bring it to the
required temperature.
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Should one of the probes drift above the tolerance, the cargo will be rejected at country of
destination, due to the potential of the fruit still retaining pathogens.
All in all, cold-treatment cargoes follow the normal pattern of shipping with one or two additional
requirements.
Should the units be packed correctly and cargo post-harvest process followed, barring the unit failing,
cargo can be received by the customer on a ready to eat basis or even for further storage.
Checklist for stowage of reefer cargo
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Cargo should not be stuffed beyond the end of the T-floor
Cargo should not be stuffed above the red load line
Cargo must be stable on the floor and tightly wedged so it doesn’t shift during passage
Unit must always be set at the proper carrying temperature and this set temperature will vary
according to the cargo being loaded
Dehumidification controls must be checked
If pre-cooling is required, it must be the cargo that is pre-cooled and not the container, unless
the container is loaded in an airlocked cold tunnel in the cold storage
Ventilation setting is of utmost importance and must be set at the correct level
As air will follow the path of least resistance, there should not be any restrictions for air flow
and any gaps between the pallets and the doors must be closed using cardboard or even wood.
This will then force the air to circulate correctly and reduce the potential for heat sinks (warm
air continuously circulating) near the doors
Stowage Principles
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Refrigeration unit
Boxes do not extend beyond pallet
Deck board spacing allows vertical airflow
Boxes vented for vertical airflow
Pallet load is secured
Rear doors
Air space above cargo
Airflow
Box vents aligned