Is there an industry average for Transit Damage?

Answer: A range, not a number: consumer electronics run 1% to 2% per unit, industrial goods 0.5% to 1%.

Which figure goes to the customer?

Answer: The per-unit rate, with the basis written next to it. A claim-based figure looks better until the customer recounts.

Is five layers always safe?

Answer: Depends on storage time and humidity: five layers holds 30 days at a factor of 3.2, but six months of creep drops it to 2.6 and needs a divider.

Is ISTA 3A mandatory?

Answer: Depends on the lane: parcel networks and overseas warehouses ask for 3A, domestic pallet freight is fine with 2A.

Can a claim be filed after 21 days?

Answer: Rarely. The carrier closes the window, and the insurance route needs proof the damage happened in transit.

Protective Case Transit Damage: Packing and Stacking

Quick answer: Transit Damage reads 1.8% per unit, 6.2% per lot and 0.9% per claim; none substitutes for another, and all three fall when stacking drops to five layers.

Counting Transit Damage: Per Unit, Per Lot, Per Claim
Stack Height and the Load on the Bottom Case
ISTA 3A and ISTA 2A: What Each Test Covers
Attribution: Shell Cracks, Load Shift, Corner Collapse
Claims and Payout Timeline
Six Moves That Cut Transit Damage to 0.4%
FAQ

1. Counting Transit Damage: Per Unit, Per Lot, Per Claim

One order of 1200 units to three warehouses came back with 22 scuffed cases, which per unit is 22 ÷ 1200, or 1.83%.

Per lot reads differently: two of the five lots carried damage, so the lot rate is 40% on the same 22 units.

Per claim is money: 27,000 yuan paid against 3 million of value, 0.9%. It counts only claims that succeed, so it always sits under the unit rate.

The three differ in the denominator, not the arithmetic: unit rate tracks process stability, lot rate batch control, claim rate cash. Quote and appraise on the same one, or a single shipment reads three ways.

Basis	Numerator	Denominator	This order	What it hides
Per unit	Damaged units	Units shipped	1.83%	Batch defects
Per lot	Lots with damage	Lots shipped	40%	Small lot sizes
Per claim	Payout	Cargo value	0.9%	Unreported damage

2. Stack Height and the Load on the Bottom Case

Stacking starts at the bottom. A 22 kg case under five layers carries four cases, 88 kg; under seven layers it carries 132 kg.

Transit Damage check at the latch, black case in close-up, one steel latch closed with scuff marks, rubber grab bar showing wear

Carton compression is 5200 N, about 530 kg, but that is a short-term figure. Thirty days of creep takes 0.75 and 90% humidity another 0.7, leaving 278 kg, so a factor of 3 allows 92 kg — exactly five layers.

Seven layers breaks the line: 132 kg against 278 kg is a factor of 2.1. Nothing shows for 60 days, then the bottom cartons crush.

Layers	Bottom load	Effective strength	Factor	Outcome
3	44 kg	278 kg	6.3	Too much margin
5	88 kg	278 kg	3.2	Holds long term
7	132 kg	278 kg	2.1	Crushes within 90 days

3. ISTA 3A and ISTA 2A: What Each Test Covers

ISTA 2A tests one package: ten drops across six faces, three edges and one corner, 30 minutes of fixed-frequency vibration, and 24 hours of compression. Drop height follows weight, 76 cm below 20 kg and 61 cm from 21 to 45 kg.

ISTA 3A follows a parcel journey and adds 60 minutes of random vibration at 0.5 Grms after conditioning. It passes on three points: no through-crack in the wall, corner collapse under 5 mm, latches that still close three times.

Neither replaces the other: a case that fails 2A fails 3A, while one that passes 2A can still shift its liner in the 3A vibration block. Overseas batches take 3A and domestic pallet freight takes 2A.

Test	ISTA 2A	ISTA 3A	Pass mark
Drop	10 drops from 76 cm	Weight-banded	Corner collapse under 5 mm
Vibration	Fixed, 30 minutes	Random, 60 minutes	Liner stays put
Compression	24 hours	With conditioning	No through-crack

4. Attribution: Shell Cracks, Load Shift, Corner Collapse

Attribution has to reach a part, not a leg of the journey. Of 46 damaged units, 21 were corner collapse at 46%, 14 were load shift at 31% and 11 were shell cracks at 23%.

Transit Damage inspection outdoors, olive case corner in close-up, moulded bumper with ribs and a black pin, mud specks on the shell

Collapse clusters at pallet corners. A 20 mm corner board leaves the four corners carrying 2.4 times the load of the panel centre at five layers, and the fold starts at the 8 mm radius.

Load shift comes from liner clearance. At 3 mm, a 1.2 m drop at 15 g moves the load 6 mm; at 8 mm it moves 17 mm and the impact passes into the wall.

Cracks belong to the cold. At −18 °C HDPE keeps 40% of its room-temperature impact strength, and the crack rate at the same drop height rises from 3% to 19%.

5. Claims and Payout Timeline

The claims clock runs tight: inspect on collection, file within 3 days, and after that the carrier accepts outer damage only.

Six photographs go with the filing: case number, seal, damaged face, liner state, packing list and the full pallet. One missing shot rebooks the survey and turns 7 days into 14.

The window is 21 days from delivery. Excess runs 800 yuan per filing and insured claims pay 80%; uninsured ones fall to the carrier limit, often 20 yuan per kg, so a 22 kg case returns 440 yuan.

6. Six Moves That Cut Transit Damage to 0.4%

Six moves, ordered by return; the first three carry half the result.

Drop stacking from seven layers to five and the bottom load falls from 132 kg to 88 kg, back to a factor of 3. That change alone takes the rate from 1.8% to 1.1%.

Add 30 mm corner blocks and pull liner clearance from 8 mm to 3 mm, and the rate falls to 0.7%. A block costs 1.2 yuan, four per case, so 4.8 yuan a unit buys most of the gain.

Foam pads on the pallet corners, three cases dropped at 76 cm before loading, and seals tied to case numbers finish the set at 0.4%. Below that, the wall must change: 18 yuan more per case buys 0.1 of a point.

Conclusion

Read the Transit Damage figure for its basis first. Three checks settle the plan: quote per unit, appraise per lot, negotiate claims per claim; divide effective carton strength by 3 to set stack height, which puts a 22 kg case at five layers; hold corners at 30 mm, liner clearance at 3 mm, and drop three cases at 76 cm before loading. That set takes 1.8% to 0.4%, and going lower means changing the wall, where the arithmetic stops paying.