Should case export africa shipments size desiccant for 30 or 45 days?

Answer: Size for the longest leg: 10.2 kg for a 40GP at 45 days costs about 40 USD, less than one carton rework.

Is 30 g of silica per case enough for 45 days?

Answer: Yes, with a fivefold margin: 1.2 g of interior water plus 1.1 g of gasket permeance against 6 g of capacity.

Why keep pallets 100 mm off the floor?

Answer: The floor can hold 5 mm of water, so 100 mm stops capillary rise reaching the deckboards.

Can the case layer be dropped when the hold layer is generous?

Answer: No. The hold layer pulls humidity to 60%, but each case is still a closed cell.

Is one logger per box enough?

Answer: No. Roof and floor can differ by 15 K, so one reading misses where condensation forms.

Case Export Africa: Container Moisture

Quick answer: Case export africa means 30–45 days at sea, so moisture control needs two layers: 1 kg/10 m³ in the hold and 30 g inside each case.

Where the moisture comes from
Hold-level desiccant at 1 kg/10 m³
Case-level desiccant and gasket permeance
Pallet clearance and three logger points
The first 30 minutes after opening
Writing both layers into the loading sheet
FAQ

1. Where the moisture comes from

Shanghai to Lagos is 32 days, Shenzhen to Mombasa 28, so case export africa lands at 30–45 days. The roof panel reaches 60 ℃ by day and 20 ℃ at night, and air at 30 ℃ and 85% RH holds 25.8 g/m³, of which 21.8 g survives a drop to 24 ℃.

Interior condition	Dew point	Water released per m³ at 20 ℃
32 ℃ / 85%	29.1 ℃	11.5 g
30 ℃ / 85%	27.2 ℃	8.5 g
28 ℃ / 80%	24.2 ℃	4.5 g
26 ℃ / 75%	21.2 ℃	1.0 g

A 40GP holds 68 m³ of air and sheds 306 g a night at 28 ℃ and 80%, or 12 kg over 40 days, the capacity of 24 bags of 500 g calcium chloride. Rain leaves a sharp line on the door side; condensation starts at the roof.

2. Hold-level desiccant at 1 kg/10 m³

The baseline is 1 kg per 10 m³ for 30 days: a 20GP at 33 m³ takes 3.3 kg, a 40GP at 68 m³ takes 6.8 kg. On a 45 day lane multiply by 1.5, so the 40GP needs 10.2 kg or 21 bags of 500 g.

Case export africa case closed on a steel bench, olive green shell, two black latches and one folding handle, grey racking behind

Size	Interior volume	30 day base	45 day case	500 g bags
20GP	33 m³	3.3 kg	5.0 kg	10
40GP	68 m³	6.8 kg	10.2 kg	21

At 25 ℃ and 80% RH calcium chloride absorbs 120% of its weight against 20% for clay, so 10 kg captures 12 kg. Hang one bag every 2 m on the ceiling, two per door leaf, four on 50 mm risers.

A 2 mm nick in the door gasket doubles air exchange, so replace any seal below 25% compression. Below 40% RH corrugated strength also falls from 4800 N to 3600 N.

3. Case-level desiccant and gasket permeance

Each case carries 30 g of silica gel in a non-woven bag, pressed above the foam cells so it shows the moment the lid opens. The 45 L interior holds 1.2 g of water at 30 ℃ and 85%, and 30 g of silica absorbs 6 g, a fivefold margin.

The variable is the gasket: a 60 Shore A silicone profile compressed 25% to 30% permeates 0.02 g per metre per day, so a 1.2 m perimeter passes 1.1 g in 45 days. At 15% compression permeance quadruples to 4.4 g. Run a 30 min check before loading: 85% down to below 55% means the latches and groove work.

Blue turning pink means the silica is half spent, so sample three cases and replace the lot when two have changed. The hinge leaks next: 0.3 mm bore clearance lifts daily permeance from 0.024 g to 0.09 g, the white bloom on older case export africa lots.

4. Pallet clearance and three logger points

Hold the pallet face 100 mm off the floor with plastic blocks. The floor panel swings through the widest range and can carry 5 mm of standing water, so a pallet set flat sits in water.

Case export africa tan case open on a steel table, grey foam dividers, tan desiccant packs and foil pouches either side

Three loggers answer three questions: roof marks condensation onset, middle reads the air around cases, floor shows standing water.

Point	Position	Height	Reads	Trigger
A roof	1 m inside the door	2.2 m	condensation onset	15 K above point B
B middle	mid length, above stack	1.0 m	air around cases	75% for 6 h
C floor	rear, on the floor panel	0.3 m	water and wicking	under 5 K below A

Use one model: −30 to 70 ℃, ±0.5 ℃ and ±3% RH, 30 min interval. Only above a 15 K spread between A and B is the box really breathing.

5. The first 30 minutes after opening

One wrong step undoes 45 days. Outside air rushes in within 90 s of cracking the door, the case surface sits below dew point, and water lands on the lid where the foam takes it.

Six steps in fixed order: read the logger, open 300 mm and hold 15 min, confirm the lid is 2 ℃ above dew point with an infrared gun, take the top tier out with each lid open under 30 s, reach a store below 60% RH within 30 min, photograph the silica. Three in ten case export africa rework claims start on opening day.

6. Writing both layers into the loading sheet

Six fields are mandatory: desiccant lot and bag count, logger serials with three positions, closing time and ETA, the two opening thresholds, block height, two signatures.

The field most often dropped is the logger serial: without it a curve handed over 45 days later cannot be tied to a box or a tier. Write thresholds, not adjectives.

Conclusion

The moisture budget for case export africa ends on two lists: the hold layer manages 68 m³ of air, the case layer manages 45 L per unit, and 100 mm of pallet clearance separates them. Judge with three numbers: interior humidity above 75%, roof to floor spread beyond 15 K, a lid within 2 ℃ of dew point at opening. Inside those limits a 30 day configuration holds; cross any one and move to 45 days at 10.2 kg plus 30 g per case.

Layer	Covers	Configuration	45 day quantity	Pass mark
Hold	68 m³ of air	calcium chloride 500 g, 6 roof, 2 door, 4 floor	10.2 kg	interior RH ≤60%
Case	45 L per unit	silica gel 30 g above the foam	one bag each	lid-open RH ≤55%
Interface	floor water	100 mm blocks on the bearers	4 per pallet	pallet face at 100 mm
Monitor	three point logging	3 loggers at 30 min	3 per box	roof to floor ≤15 K

This article discusses container-side specifications and design implications only, and does not cover any handling, loading or use of the contents.