Collapsible plastic crate load capacity is quoted as a single number far more often than it should be. A catalogue figure such as “50 kg” is meaningless until you know whether it refers to static load, dynamic load or stacking load, at what temperature, at what stack height, and with what safety factor. Australian warehouse operators who buy on the single number routinely end up with crates that bow in the bottom layer, jam in an automated system, or fail a safety audit — not because the crate was below specification, but because the specification was never pinned down.
This is a short guide to reading load ratings properly and translating them into a purchase specification for a real distribution centre.
Every credible crate datasheet should separate three numbers, because they describe three different physical situations:
Confusing the three is the classic selection error. A crate rated 100 kg static may carry only 25 kg dynamic, and a five-high stack of that crate means the bottom unit is supporting four loaded crates above it, not 100 kg of product.
The calculation is simple, and it is worth doing on paper before ordering:
Required stacking load = (number of crates above) × (gross weight of one loaded crate) × safety factor
For example, a warehouse stacking five high on the floor, with each crate holding 18 kg of product and weighing 4 kg empty, puts 22 kg per crate on the layer below. The bottom crate supports four crates above it: 88 kg. With a safety factor of 1.5 — a reasonable minimum for a warm warehouse with imperfect load distribution — the crate needs a stacking rating of about 132 kg. A crate rated at 100 kg stacking will creep, bow and eventually split at the corners in that application.
Two practical adjustments to that formula:
| Application | Governing rating | Typical derating to apply | What fails if you get it wrong |
|---|---|---|---|
| Floor stacking, 3–5 high, ambient | Stacking load | 1.5 safety factor on gross stacked mass | Bottom crate bows, corners split, stack leans |
| Palletised, single layer | Dynamic load | 1.3 on gross content mass | Crate base cracks under forklift shock |
| Outdoor yard, full sun | Stacking load at 50 °C | 50% of the 23 °C rating | Permanent set, collapsed stack after weeks |
| Cold store at −25 °C | Dynamic / impact | Verify by drop test, not compression | Corners shatter on impact, hinge cracks |
| Automated conveyor or AS/RS | Dynamic plus dimensional tolerance | No derating, but tight ±2 mm tolerance | Jams, misreads, conveyor faults |
There is a second layer of arithmetic that catches importers of very large crate systems. Australia's heavy vehicle mass limits are enforced, and a pallet of loaded crates must fit within both the vehicle's payload and the axle group limits. A 40-foot container has a payload well below its internal volume, and a road train or B-double combination is limited by gross mass rather than by floor area. In practice this means very dense loads — metal parts, liquids, sand, aggregates — are usually mass-limited, while bulky light loads — packaging, plastics, insulation — are volume-limited.
The choice of crate capacity should follow that logic. There is no benefit in buying a 50 kg-rated crate to carry 8 kg of foam packaging, and there is a real cost in buying a 15 kg-rated crate to carry 22 kg of fasteners.
Capacity is one line item among several that determine whether a crate works in a warehouse:
For general warehouse and logistics duty, the 600×400×230 mm solid storage container covers the common 20–25 kg parts and goods application with a solid base and a stackable rim. For heavier industrial loads, the 500×500×415 mm heavy-duty collapsible crate uses a deeper, more heavily ribbed section, and the 565×365×215 mm PP stackable box suits dense, compact loads where stack height rather than footprint drives the requirement. The full foldable plastic crate range is specified with separate static, dynamic and stacking figures on request.
A load rating is only as good as the test behind it, and the tests are standard. The table below lists what to request for each of the three load figures, with the standard and the parameter that should be printed in the report.
| Rating | Test standard | Parameter in the report | Question to ask |
|---|---|---|---|
| Static load | ISO 12048 compression test, after ISO 2233 conditioning | Load–deflection curve, load at 10 mm and at failure | At what temperature, and over what duration? |
| Stacking load | ISO 12048 held for 24 h, or 30 days for creep | Deflection versus time at the rated load | Is this a short-term or a long-term number? |
| Dynamic load | ISO 2248 / ASTM D5276 drop, plus a transport vibration test to ISO 4180 | Drop height, orientation, pass/fail criterion | Was it tested loaded, and at what temperature? |
| Pallet unit load | ISO 8611-1 for the pallet; ISO 12048 for the crate stack | Rated load and the pallet pattern tested | Does the rating assume a specific 4-per-layer pattern? |
There is a subtlety worth understanding: a compression test measures the crate as a box, but a stacked crate in service is loaded through its rim, and rims are strong in compression and weak against point loads. A crate that passes a 500 kg compression test can still fail its first week in a warehouse if the layer above sits on a concentrated load with the crates slightly out of registration. This is why the passing criterion should include the load distribution, not only the total mass.
No. A higher rating usually means more material: thicker walls, more ribs, a heavier base. That costs money per unit, costs freight per container, and adds manual handling risk for staff. The right rating is the one that carries your actual load at your actual stack height with a sensible safety factor, and nothing more. Over-specification in a crate yard is a real, if quiet, cost.
A factor of 1.5 on the gross stacked mass above the crate is a reasonable minimum for warehouse use, covering uneven load distribution and a reasonable margin for damage. For high-value or fragile contents, or for stacks in a high-traffic aisle where impact is likely, use 2.0. The factor is applied to the mass above the crate in question, not to the crate's own load, which is the calculation error that most often leads to a crushed bottom layer.
Yes, and this is the most under-managed number in a warehouse. UV exposure, hinge fatigue and repeated impact all reduce the load a crate can safely carry, and a five-year-old crate in a sunny yard is not the asset the datasheet describes. Practical practice is to inspect annually and to reduce stack height by one layer for crates past mid-life or showing surface whitening.
Start from the static rating at 23 °C, apply the temperature derating for your worst-case season, divide by the safety factor, then confirm the result exceeds the stack load calculation. A crate rated 400 kg static, used at 50 °C (50% derating) with a 1.5 factor, gives a usable 133 kg — which is roughly one loaded crate of 22 kg per layer at five high with margin. That is the arithmetic that prevents a collapsed stack in February.
Ask for the three numbers, do the stack arithmetic once, apply the heat and time derating, and the crate you buy will hold the load you actually have — in the fifth layer, in February, six months after commissioning.
Collapsible plastic crate load capacity is quoted as a single number far more often than it should be. A catalogue figure such as “50 kg” is meaningless until you know whether it refers to static load, dynamic load or stacking load, at what temperature, at what stack height, and with what safety factor. Australian warehouse operators who buy on the single number routinely end up with crates that bow in the bottom layer, jam in an automated system, or fail a safety audit — not because the crate was below specification, but because the specification was never pinned down.
This is a short guide to reading load ratings properly and translating them into a purchase specification for a real distribution centre.
Every credible crate datasheet should separate three numbers, because they describe three different physical situations:
Confusing the three is the classic selection error. A crate rated 100 kg static may carry only 25 kg dynamic, and a five-high stack of that crate means the bottom unit is supporting four loaded crates above it, not 100 kg of product.
The calculation is simple, and it is worth doing on paper before ordering:
Required stacking load = (number of crates above) × (gross weight of one loaded crate) × safety factor
For example, a warehouse stacking five high on the floor, with each crate holding 18 kg of product and weighing 4 kg empty, puts 22 kg per crate on the layer below. The bottom crate supports four crates above it: 88 kg. With a safety factor of 1.5 — a reasonable minimum for a warm warehouse with imperfect load distribution — the crate needs a stacking rating of about 132 kg. A crate rated at 100 kg stacking will creep, bow and eventually split at the corners in that application.
Two practical adjustments to that formula:
| Application | Governing rating | Typical derating to apply | What fails if you get it wrong |
|---|---|---|---|
| Floor stacking, 3–5 high, ambient | Stacking load | 1.5 safety factor on gross stacked mass | Bottom crate bows, corners split, stack leans |
| Palletised, single layer | Dynamic load | 1.3 on gross content mass | Crate base cracks under forklift shock |
| Outdoor yard, full sun | Stacking load at 50 °C | 50% of the 23 °C rating | Permanent set, collapsed stack after weeks |
| Cold store at −25 °C | Dynamic / impact | Verify by drop test, not compression | Corners shatter on impact, hinge cracks |
| Automated conveyor or AS/RS | Dynamic plus dimensional tolerance | No derating, but tight ±2 mm tolerance | Jams, misreads, conveyor faults |
There is a second layer of arithmetic that catches importers of very large crate systems. Australia's heavy vehicle mass limits are enforced, and a pallet of loaded crates must fit within both the vehicle's payload and the axle group limits. A 40-foot container has a payload well below its internal volume, and a road train or B-double combination is limited by gross mass rather than by floor area. In practice this means very dense loads — metal parts, liquids, sand, aggregates — are usually mass-limited, while bulky light loads — packaging, plastics, insulation — are volume-limited.
The choice of crate capacity should follow that logic. There is no benefit in buying a 50 kg-rated crate to carry 8 kg of foam packaging, and there is a real cost in buying a 15 kg-rated crate to carry 22 kg of fasteners.
Capacity is one line item among several that determine whether a crate works in a warehouse:
For general warehouse and logistics duty, the 600×400×230 mm solid storage container covers the common 20–25 kg parts and goods application with a solid base and a stackable rim. For heavier industrial loads, the 500×500×415 mm heavy-duty collapsible crate uses a deeper, more heavily ribbed section, and the 565×365×215 mm PP stackable box suits dense, compact loads where stack height rather than footprint drives the requirement. The full foldable plastic crate range is specified with separate static, dynamic and stacking figures on request.
A load rating is only as good as the test behind it, and the tests are standard. The table below lists what to request for each of the three load figures, with the standard and the parameter that should be printed in the report.
| Rating | Test standard | Parameter in the report | Question to ask |
|---|---|---|---|
| Static load | ISO 12048 compression test, after ISO 2233 conditioning | Load–deflection curve, load at 10 mm and at failure | At what temperature, and over what duration? |
| Stacking load | ISO 12048 held for 24 h, or 30 days for creep | Deflection versus time at the rated load | Is this a short-term or a long-term number? |
| Dynamic load | ISO 2248 / ASTM D5276 drop, plus a transport vibration test to ISO 4180 | Drop height, orientation, pass/fail criterion | Was it tested loaded, and at what temperature? |
| Pallet unit load | ISO 8611-1 for the pallet; ISO 12048 for the crate stack | Rated load and the pallet pattern tested | Does the rating assume a specific 4-per-layer pattern? |
There is a subtlety worth understanding: a compression test measures the crate as a box, but a stacked crate in service is loaded through its rim, and rims are strong in compression and weak against point loads. A crate that passes a 500 kg compression test can still fail its first week in a warehouse if the layer above sits on a concentrated load with the crates slightly out of registration. This is why the passing criterion should include the load distribution, not only the total mass.
No. A higher rating usually means more material: thicker walls, more ribs, a heavier base. That costs money per unit, costs freight per container, and adds manual handling risk for staff. The right rating is the one that carries your actual load at your actual stack height with a sensible safety factor, and nothing more. Over-specification in a crate yard is a real, if quiet, cost.
A factor of 1.5 on the gross stacked mass above the crate is a reasonable minimum for warehouse use, covering uneven load distribution and a reasonable margin for damage. For high-value or fragile contents, or for stacks in a high-traffic aisle where impact is likely, use 2.0. The factor is applied to the mass above the crate in question, not to the crate's own load, which is the calculation error that most often leads to a crushed bottom layer.
Yes, and this is the most under-managed number in a warehouse. UV exposure, hinge fatigue and repeated impact all reduce the load a crate can safely carry, and a five-year-old crate in a sunny yard is not the asset the datasheet describes. Practical practice is to inspect annually and to reduce stack height by one layer for crates past mid-life or showing surface whitening.
Start from the static rating at 23 °C, apply the temperature derating for your worst-case season, divide by the safety factor, then confirm the result exceeds the stack load calculation. A crate rated 400 kg static, used at 50 °C (50% derating) with a 1.5 factor, gives a usable 133 kg — which is roughly one loaded crate of 22 kg per layer at five high with margin. That is the arithmetic that prevents a collapsed stack in February.
Ask for the three numbers, do the stack arithmetic once, apply the heat and time derating, and the crate you buy will hold the load you actually have — in the fifth layer, in February, six months after commissioning.
