Does a waterproof travel case have to be immersion tested?

Answer: Yes, at type stage and on the first batch. Routine lots use spray plus a feeler check; immersion destroys three samples.

How do I tell a waterproof zipper from a standard one?

Answer: Look for a continuous coating behind the chain and a flap behind the slider. The quicker test: five minutes of spray with dry paper.

Is more seal compression always better?

Answer: No. Past 1.2 mm the gasket takes a permanent set and stops sealing. The usable window is 0.8 to 1.0 mm.

Can a loose telescopic handle be reworked?

Answer: Rarely. Play comes from clearance between tube and sleeve, so a fix means new tubes at about the cost of a case.

How long are inspection records kept?

Answer: Three years, long enough to answer a complaint with the original weight gain.

Waterproof Travel Case Acceptance Standards: Items and Limits

Quick answer: A waterproof travel case is judged in the order water reaches it: lid seam and zipper, then spray and immersion, then handle and wheels. A 0.8 mm seal compression, 12.5 L/min spray for ten minutes and a 0.5 g gain after 30 minutes at 1 m decide it.

How Acceptance Items for a Waterproof Travel Case Are Graded
Lid Seams and Waterproof Zippers
Rain Spray and Immersion Values
Handle, Wheel and Telescopic Load Checks
Decision Rules and Inspection Records
FAQ

1. How Acceptance Items for a Waterproof Travel Case Are Graded

Spec sheets for a travel case are generous; the floor reduces them to three questions: load, roll, and whether rain reaches the packing inside. A waterproof travel case turns the third into numbers.

Grading follows the path water takes: lid seam, zipper teeth and tube collars, each with own checks, plus spray and immersion as class A. Appearance and hardware sit in class B, markings in class C.

Class	Items	Method	Disposition
A	Seam, zipper, spray, immersion	Gauge, spray rig, tank	Batch returned
B	Appearance, hardware, lining	Visual, feel, torque	Rework and re-check
C	Markings, tags, packaging	Against golden sample	Correct on site

Class A work is destructive, so those samples are moulded separately.

2. Lid Seams and Waterproof Zippers

The lid seam is where leakage concentrates. A double-lip TPU gasket at 65 Shore A joins lid and base at 0.8 mm compression, checked with a feeler gauge every 100 mm, and a 0.05 mm blade must not enter.

Waterproof travel case: an olive-green case open on a wooden table under a shelter, flat foam in the lid, empty compartments below, magazines beside it

A waterproof zipper is judged closed and after wear: 2000 cycles over a 300 mm stroke, then five minutes of spray, with no wet spot wider than 3 mm on the paper inside. Where a tube passes the shell, a rubber collar carries 0.3 mm of interference, or water runs inside the tube to the base.

3. Rain Spray and Immersion Values

Spray uses an oscillating tube of 400 mm radius at 12.5 L/min, case at 45 degrees, 2.5 minutes per side, ten minutes total. Dry paper inside is the pass condition, with no beading on latches.

Immersion is stricter: 1 m depth for 30 minutes, gaining no more than 0.5 g, then weighed again after 24 hours.

Test	Condition	Limit
Spray	12.5 L/min, 2.5 min per side	No wet spot inside
Immersion	1 m, 30 minutes	Gain ≤ 0.5 g
Second weighing	24 h later	Gain ≤ 0.2 g
Thermal cycling	−20 to 60 °C, 4 h, 2 cycles	No hardening

Thermal cycling runs first: two cycles of four hours at minus 20 °C and four at 60 °C will harden or craze a poor gasket, and a later spray result means nothing.

4. Handle, Wheel and Telescopic Load Checks

Sealing and load carrying must not fight each other. The telescopic handle runs 5000 cycles under 18 kg, and play may grow 1.5 mm; past that the case wobbles, the collar wears oval and water finds the gap.

Waterproof travel case: an olive-green case open on a bench, foam cut-outs holding a black meter, a coiled cable and a white battery pack

Wheels cover 32 km over 12 mm obstacles with tread wear inside 1.0 mm. The carry handle takes 40 kg for 30 minutes with residual set within 2 mm, and its four screws sit at 1.2 N·m.

Item	Condition	Limit
Telescopic handle	5000 cycles, 18 kg	Play ≤ 1.5 mm
Wheels	32 km, 12 mm obstacles	Wear ≤ 1.0 mm
Carry handle	40 kg, 30 min	Residual ≤ 2 mm

5. Decision Rules and Inspection Records

Batches run by day, compound and cavity. Three units go through every class A item and one failure returns the batch; class B is sampled at level II with AQL 2.5, class C in full.

Records keep sample number, conditions and inspector. Disputes over a waterproof travel case surface months later, when the weighing sheet is the only evidence.

Conclusion

Accepting a waterproof travel case means turning one rainstorm into a handful of numbers: a feeler blade that will not enter, ten minutes of spray with dry paper, half a gram after immersion, no wobble after five thousand cycles. Those numbers tell the supplier what to change and the buyer what to reject, which is how a waterproof travel case keeps a stable floor on quality.

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.