Shipping and logistics
How a reefer container works.
A reefer container holds a temperature, it does not lower one. Cargo loaded warm stays warm, because the unit is sized to remove heat leaking through the walls rather than to chill a full load. Almost every reefer failure starts there.
What the machine actually does.
It circulates air at a set temperature through the load, entering under the floor and returning at the ceiling. The T-bar floor exists so air can move, and blocking it defeats the whole system.
It holds temperature rather than pulling it down. A pallet loaded at ambient temperature in Surabaya will still be warm in the middle when it reaches Rotterdam.
Frozen and chilled are different settings with different tolerances. Chilled cargo lives in a narrow band and frozen cargo mostly needs to stay below a line.
Controlled atmosphere and humidity control exist on some units and cost more. Do not assume a booking includes them.
The three ways it fails.
Loaded warm. The commonest failure, and it looks like a machine problem when the temperature trace never reaches the set point. It is a plant problem.
Loaded badly. Cargo stacked above the red load line, or packed against the doors, blocks the airflow and produces hot spots that only show on arrival.
Plugged out. A container that spent hours unplugged at a terminal or on a truck loses control. Gaps in the trace are what tell you.
What the temperature trace is for.
It is a record of what happened, and it becomes part of the goods commercially. A break in it decides who pays for a rejected load.
Download it rather than accepting a summary, and read it against the loading time. A trace that starts warm and takes two days to come down describes a loading failure precisely.
Independent recorders inside the load are worth the cost on high-value cargo, because the container's own probe measures return air rather than product temperature.
What to agree before booking.
The set point, in writing, and who sets it. A single digit error is a total loss on chilled cargo.
Pre-cooling of the container and pre-cooling of the cargo, which are two separate things.
Free time at destination, because a reefer accrues charges faster than a dry box and plug-in charges are their own line.
Who monitors the unit in transit, and what happens if an alarm fires mid-voyage.
Questions buyers ask.
Can a reefer freeze my product down?
No. It is sized to hold a temperature against heat leaking in, not to remove heat from a full load. Product has to be at temperature before it is loaded.
Why did the trace never reach the set point?
Almost always because the cargo was loaded warm. The unit works and it cannot overcome a container full of ambient-temperature product in the time available.
Do I need my own data logger?
On high-value or sensitive cargo, yes. The container probe reads return air rather than the product, so a logger in the load tells you what actually happened to the goods.
Read next.
Shipping chilled and frozen goods
A reefer is a machine with a recorder in it. What the trace proves, where the chain breaks, and who carries the risk.
Container loading and what actually fits
The cubic capacity figures in circulation disagree with each other. What really decides a load is weight, geometry and the carrier's own specification.
When the shipment is wrong
The first forty-eight hours decide what you can recover. What to do in order, and what destroys a claim.
Demurrage and detention
Two different charges buyers confuse, both on a clock that does not care whose fault the delay was.
Sourcing from Indonesia?
Tell us the product, the quantity and the destination. We come back with what it involves before anyone talks about money.