How long does a waterproof safety case type test stay valid?

Answer: Twenty-four months; book the retest a month before expiry.

Our lot is 300 units. Do we still sample 80?

Answer: No. Under 500 units the sample is 50; critical items still allow zero.

Can we sort a lot with a critical defect?

Answer: No. Sorting suits appearance; sealing and latches send the lot back.

How is a reworked batch judged?

Answer: A fresh 80 at zero acceptance, one rework pass only.

What if the customer wants a looser AQL?

Answer: Loosen minor items only; critical stays fixed and any loosening sits in a dated deviation.

Waterproof safety case acceptance standards and verdict rules

Quick answer: Acceptance of a waterproof safety case has two levels. Twelve samples carry the type test through immersion, drop, ageing and handle load; each delivery then samples 80 units with zero acceptance on critical items. Mixing the levels is the usual mistake.

Two levels of waterproof safety case acceptance
Six type tests and the order they run in
Sampling plan and acceptance numbers
Critical defects and disposition
Retest, rework and release records
FAQ

1. Two levels of waterproof safety case acceptance

A type test asks whether the design survives: frame, gasket, latches and handle under extreme conditions, decided once and kept as the baseline. Batch inspection asks whether this delivery is the same object, or whether material, cavity count or injection settings drifted.

Draw the boundary in the contract. Any change of structure, wall thickness, gasket supplier or cavity count triggers a new type test; a colour or print change does not. A waterproof safety case type test takes twelve samples, four from each of three cavities.

Level	Trigger	Samples
Type test	New part or structural change	12
Batch inspection	Every delivery	80

2. Six type tests and the order they run in

The order cannot be shuffled: pre-conditioning, immersion, drop, handle load, salt spray, cold opening. Ageing before immersion follows the real failure path; the reverse leaves the gasket saturated and the ageing result optimistic.

Waterproof safety case: a dozen slim black cases stacked in two piles on a bench, several leaning in a fan, rounded rims with a groove

Pre-conditioning runs 72 hours at 80 °C. Immersion follows at 1 m above the lid for 30 minutes, then 15 minutes drying before opening. The drop is 1.8 m on one corner, and immersion repeats after it, where a shifted flange shows. Handle load is four times the payload, salt spray 480 hours with pitting capped at 0.1 mm, and cold opening runs three closures at minus 30 °C.

Test	Condition	Verdict
Immersion	Lid 1 m under, 30 minutes	No ingress
Drop	1.8 m, corner and faces	No crack
Salt spray	480 hours	Pitting 0.1 mm or less
Cold opening	Minus 30 °C, 3 cycles	Latch intact

3. Sampling plan and acceptance numbers

Fix a waterproof safety case sampling plan in writing and the verdict becomes repeatable. Under GB/T 2828.1 at inspection level II, a lot of 501 to 1200 units samples 80; below 500 it samples 50. Acceptance quality limits run at 0.65 for critical items with acceptance 0 and rejection 1, 1.5 for major, 4.0 for minor.

Only three items are critical: sealing, latches, handle, and one failure stops the lot. Major items are wall and cavity size, tolerating two failures; minor items are appearance, print and packing. Draw from the top, middle and bottom of the pallet, never from the row one cavity filled.

Class	Items	AQL	Accept
Critical	Sealing, latches, handle	0.65	0
Major	Wall, cavity size	1.5	2
Minor	Appearance, print, packing	4.0	5

4. Critical defects and disposition

A critical defect is never accepted by concession. Sealing, latches and handle decide how the body behaves in an incident, so a concession simply moves the risk to the user. Put that line in the contract.

Waterproof safety case: grey body filling the right of the frame, two latches closed, a thin seam along the rim, warehouse racks beyond

Disposition runs in four steps: segregate, label, review, rework. Segregation within 24 hours, labels carrying batch and cavity, review signed by quality, process and purchasing, one rework pass, then a fresh sample of 80 at zero. Major items may take a concession on a written deviation naming quantity, defect and use limit.

Defect class	Disposition	Signature
Critical	Return the lot	Quality manager
Major	Concession with deviation	User and quality
Minor	Rework or sort	Line supervisor

5. Retest, rework and release records

A waterproof safety case gets one retest only. A failed 80 doubles to 160 at zero acceptance; a single critical failure inside those 160 scraps the lot, which stops testing until a batch passes.

Release needs four papers: declaration of conformity, sampling record, a type test report inside its 24 months, and any deviation. A gasket change repeats immersion and salt spray; a structural change repeats everything. Every change gets a date and report number in the log.

Conclusion

The point of a standard is not severity but levels: the type test fixes the baseline, batch inspection guards consistency, critical items allow nothing. Write sample size, AQL and disposition into the contract and the argument ends. Do that and acceptance of a waterproof safety case becomes a rule anyone can repeat.

This article discusses only the container (case body) side of specifications and design intent, and does not cover any handling, loading or use of the contents.