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Date：2026-10-14How is lighting fixture mould kept out of an export shipment, and why does the packing come before the container? Because what goes damp first is not the fixture but the carton and the foam liner. Assembly holds relative humidity below 60% and keeps liners dry, the carton is sealed with iHeir-D gas-phase antimicrobial and mould inhibitor made into anti-mould paper or sachets at 0.1-0.2 g per sheet, and the container carries T-1000 container desiccant sticks. This article covers the doses and checks at each of the four stages.
1. Why the packing comes first: cartons and foam absorb moisture fastest
The usual route into a fixture shipment is not the fixture itself but the packing, from where moisture travels on to the product. Corrugated cartons and foam liners are porous and have a large surface area, so they take up and give off moisture far faster than metal or plastic parts. When store humidity rises they absorb first, and when the air dries they release slowly, leaving the carton air humid for long stretches.
Foam liners bring a second problem: the closer a liner fits the product, the less the gap ventilates, so condensation stays on the contact face and mould starts where nobody can see it until the carton is opened.
That is why the order runs from packing to container: handle the container only and damp cartons still go on board, handle the carton only and condensation inside the container runs down the walls onto the boxes. Both together are set out in the guide to mould prevention for exported lighting fixtures.
2. Four stages and the dosing at a glance
The table lines up the stage, what it controls, the main measures, the figure and the points to watch, as a first draft of an export damp-control instruction.
| Stage | What it controls | Main measures | Figure or criterion | Points to watch |
|---|---|---|---|---|
| Assembly and packing shop | Shop air, cartons and liners | Dehumidification, separate storage for liners, humidity held at the storage position | Relative humidity below 60% | Foam and EPE liners that have taken on moisture carry it to the line; never store them in the open |
| Finished-goods store | Cartons and liners in storage | Dehumidifiers, off-wall and off-floor stacking, first-in first-out | Relative humidity below 60% | No carton against a wall or on the floor; more frequent checks in the wet season |
| Inside the carton, paper and sachets | Carton air and liners | iHeir-D coated or printed onto paper as anti-mould paper or sachets, sealed with the product | 0.1-0.2 g of active ingredient per sheet | Sized to the carton and its free space; solids content 70%±5, packed 25 kg per drum |
| Inside the container | Container air and wall condensation | T-1000 container desiccant sticks hung in position | 8-10 sticks for a 20ft container, adjusted to container type | Chloride-free and pH neutral; dosed by container type, not by carton count |
The first two rows dose no product and rely on equipment and discipline, while the last two dose product and look after two sealed spaces, the carton and the container. Miss any one and the problem only shows at the destination port.
3. In the carton: how the paper and sachets are made up and how many go in
The carton stage uses iHeir-D gas-phase antimicrobial and mould inhibitor. It is combined with an ink system, coated or printed onto paper, dried, and made up as anti-mould wrapping paper or sachets sealed with the product. The usual loading is 0.1-0.2 g of active ingredient per sheet or sachet, adjusted to the surroundings and the free space in the carton. Solids content is 70%±5, packed 25 kg per drum, stored sealed and dry with a shelf life of one year.
Three uses are common in fixture packing: paper in the bottom and under the lid, where it becomes part of the liner and adds no volume; a sachet with the manual or the accessory bag, small enough to fit a foam recess; and paper built into the liner or divider itself. The three differ in process and cost, not in principle.
There is no single number for how many sheets a carton takes: it follows carton size, free space, packing material and transit time. Once set, run a sealed-carton trial and open it at the 15-day and 30-day marks, then adjust the next batch from what you find.
4. In the container: desiccant sticks are dosed by container type, not by carton count
The container stage uses T-1000 container desiccant sticks. The carrier is natural plant fibre and the product degrades completely; it contains no additives, no corrosive substances and no chlorides, and its pH is neutral. That matters for fixtures with plated holders and metal brackets: the desiccant must not be what rusts the hardware.
Dosing is quoted by container type: a 20ft container takes 8-10 sticks, adjusted for loading density, packing material and the route season. Why by container type rather than carton count? Because what has to be handled is the air in the whole container and the condensation on its walls, and a fuller container leaves less air rather than needing fewer sticks. Hang them along both side walls, clear of the door end, with the lower ends not trailing onto the cartons.
Condensation at sea is the larger part of the problem: the day-night swing inside a container is far wider than in any warehouse, so moisture condenses on the walls and on the goods. The sticks take that out before it forms, so they go up once loading is finished and before the doors close, as covered in the note on container moisture and mould in shipping.
5. Checks before dispatch, and resealing after an inspection
Three checks are worth running before an export lot ships: carton and liner moisture content on sampled boxes; a configuration check, with the paper and stick quantities written onto the shipping documents against the carton and container types; and a pre-closing check, with sticks in position and photographed before the doors close.
After an inspection at the destination or by the customer, the carton has to be resealed: opening it disperses the gas phase that had built up inside, so close it again immediately, with the paper and sachet quantities adjusted to the inspection frequency, and keep records to GB/T 4768 for anti-mould packaging.
6. Questions that come up: sticks alone, and what to do after an inspection
Is it enough to hang desiccant sticks in the container and leave the cartons untreated? No. The sticks work on the container air and on wall condensation, not on the sealed volume inside each carton, so a carton that has already taken up moisture in a damp warehouse simply carries that water on board. In-container protection is a second layer above the packing, not a substitute.
Can the anti-mould paper replace the desiccant sticks, or the other way round? No, they cover different volumes: the paper works inside the carton on a small sealed space, the sticks work on the whole load. Without the carton stage, product surfaces face the container air directly; without the container stage, condensation travels into the cartons.
Four points carry the work. Assembly and the packing shop hold relative humidity below 60% and store liners separately, and the finished-goods store stacks off the wall and off the floor, dehumidifies and ships first-in first-out. The carton takes iHeir-D gas-phase antimicrobial and mould inhibitor at 0.1-0.2 g of active ingredient per sheet, and the container carries T-1000 container desiccant sticks at 8-10 per 20ft box, chloride-free and pH neutral, hung before the doors close. Samples and TDS are available for a configuration check against your carton sizes and container types.
