A container fleet needs a rule that says when a container stops being serviceable, and the rule has to be applicable by whoever happens to be inspecting – which usually means quickly, without tools, and without much training. Rules based on judgement fail on all three counts. Rules based on a measurement anyone can make work, and they make the fleet’s condition consistent.
Why judgement fails
Two people looking at the same cracked corner will disagree, and the same person will decide differently at the start of a shift than at the end. Where containers are in short supply, everything looks serviceable; where they are plentiful, everything looks worn. A judgement-based rule produces a fleet whose condition depends on circumstances rather than on the containers.
Measurements that work
A crack longer than a stated length, measured against a finger or a marked gauge. A base worn through to a second layer, which is visible as a colour change. A deformation greater than a stated gap, checked with a straight edge across the base. A stacking feature that no longer seats. And an identification mark that can no longer be read. Five checks, all visual or by hand, none needing tools.
Making them fast
An inspection that takes more than about fifteen seconds per container will not be done on every container. The way to achieve that is to give the inspector a small number of things to look at and a clear pass or fail for each – a gauge with a marked limit, or a go/no-go straight edge, rather than a list to think about.
Separating structure from appearance
A stained container can be structurally sound; a clean one can be cracked. The rule has to say explicitly that staining is not a retirement reason except where cleanliness is a requirement – otherwise a fleet gets retired for looking old, which is expensive and achieves nothing. The distinction is set out in rust stains on a plastic container.
Different standards for different duties
A container that is unfit for an automated slot may be perfectly good on a manual lane. A single fleet-wide criterion therefore either scraps containers that could still work or keeps ones that should not be in service. Two criteria – one for automated duty with tight tolerance, one for general duty – cost nothing to write and prevent both errors.
Where the rule lives
On the wall where inspection happens, with the measurement shown rather than described. A photograph of each failure type next to the criterion is more effective than words, and it survives staff changes. Where the rule is in a document that nobody opens, it does not exist in practice.
Reviewing it
Once a year, look at what is being retired and ask whether the criterion is catching the right things. Where containers are failing in service that were passed on inspection, the criterion is too loose. Where containers are being scrapped with obvious life left, it is too tight. Both show up in the retirement data within a year of the criterion being introduced.
What it enables
A consistent criterion turns retirement from a series of individual decisions into a rate. Once it is a rate, the replacement budget can be forecast, the fleet’s condition can be tracked, and the failure pattern can be used to specify the next order – which is where the money actually is.