How much does a pallet cover reduce temperature? Reading four data sets
Temperature results depend on sensor position, ambient conditions and duration. This guide reproduces readings from the company material and compares how the tests were arranged. Some derived differences in the source table do not match its temperature rows; those rows are identified below and should be checked against the original report before procurement.
What each of the four tests measured
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| Test | Sample | Environment | Duration | Location | Key reading |
|---|---|---|---|---|---|
| Direct sunlight | Double-sided MPET bubble pallet cover | Outdoor, direct sun | 48 hours | Suzhou, China | Max 39.2℃ between ambient and carton inside-bottom |
| Cold | Same cover | Ambient -10℃ | 8 hours | Suzhou, China | Two internal sensor records; derived differences require verification |
| Direct sunlight (control) | Woven pallet cover | Outdoor, direct sun | 48 hours | Suzhou, China | Source summary and table differences require verification |
| SGS insulation | Rack cover, sample 1235×1030×1910mm | Chamber set to 50℃ | 6 hours | Third party | Average inside-outside 41.5℃, max 49.9℃ |
Sensor naming differs between tests, so align “measured where” before comparing.
Direct sunlight: the gap peaks at noon and closes at dawn and dusk
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Full temperature record for the bubble cover under direct sunlight (℃):
| Time | 6:00 | 8:00 | 10:00 | 12:00 | 14:00 | 16:00 | 18:00 | 20:00 |
|---|---|---|---|---|---|---|---|---|
| A Ambient (sun) | 31.0 | 46.0 | 62.0 | 70.0 | 68.0 | 58.0 | 39.0 | 27.0 |
| C Inside cover, carton top | 28.8 | 33.5 | 40.0 | 47.0 | 45.0 | 38.5 | 31.0 | 28.2 |
| D Inside carton, bottom | 26.9 | 27.8 | 29.2 | 30.8 | 30.7 | 29.5 | 28.0 | 27.2 |
| Difference A-C | 2.2 | 12.5 | 22.0 | 23.0 | 23.0 | 19.5 | 8.0 | -1.2 |
| Difference A-D | 4.1 | 18.2 | 32.8 | 39.2 | 37.3 | 28.5 | 11.0 | -0.2 |
Three points stand out:
- The gap tracks sunlight intensity, peaking at 12:00 and closing around 20:00 — at night the cover no longer cools and shows a slight lag.
- Position inside the cover matters: at 12:00 the carton top (47.0℃) is nearly 16℃ above the carton bottom (30.8℃). Reporting “inside temperature” without a position makes comparison meaningless.
- At an ambient peak of 70.0℃ the carton bottom is only 30.8℃. The carton and stacking voids resist heat too; the cover is not the only variable.
Cold exposure: check sensor labels and calculated differences
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The source gives the following temperature readings for an eight-hour cold test. Its difference rows and accompanying sensor interpretation are inconsistent with these readings, so they are not reproduced as verified results.
| Hour | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 |
|---|---|---|---|---|---|---|---|---|---|
| A Ambient (°C) | -9.5 | -10 | -10 | -10 | -10 | -10 | -10 | -10 | -10 |
| B Carton outside-top (°C) | 20 | 16.2 | 13.2 | 10.6 | 8.6 | 7 | 5.6 | 4.2 | 3.5 |
| C Carton inside-bottom (°C) | 18 | 5 | 2.5 | 1 | 0 | -1 | -2 | -3 | -3.5 |
Keep the time, sensor positions and temperature readings together. Obtain the original report to resolve the sensor interpretation before using a temperature difference in a specification or comparing it with another test.
The woven cover as control: a different order of magnitude, or not
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The woven cover also underwent the 48-hour sunlight test; key interval (℃):
| Time | 4:00 | 6:00 | 8:00 | 10:00 | 12:00 | 14:00 | 16:00 | 18:00 |
|---|---|---|---|---|---|---|---|---|
| Ambient (sun) | 23.0 | 31.0 | 46.0 | 62.0 | 70.0 | 68.0 | 58.0 | 39.0 |
| Cover inside, carton top | 30.0 | 36.0 | 45.0 | 54.0 | 52.0 | 44.0 | 34.0 | 29.5 |
| Cover inside, carton bottom | 27.6 | 28.9 | 30.8 | 33.5 | 33.1 | 31.3 | 29.0 | 27.8 |
The source summary reports a maximum difference of 36.5°C, but its difference rows do not consistently follow the temperatures above. Check the original timestamps and sensor records before quoting a maximum or ranking the two covers.
The SGS insulation test: different method, different number
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Conditions and results of the SGS insulation test on the rack cover:
| Item | Detail |
|---|---|
| Sample size | 1235×1030×1910mm |
| Method | Initial cargo 5℃, test temperature 50℃ |
| Duration | 6 hours |
| Average external | 54.4℃ |
| Average internal | 12.9℃ |
| Average inside-outside difference | 41.5℃ |
| Maximum difference | 49.9℃ |
| Minimum difference | 31.2℃ |
| Cargo temperature range | 4.8℃ - 21.2℃ |
| Appearance | No abnormality before or after |
The 41.5℃ here cannot be compared directly with the bubble cover's 39.2℃ under sunlight: one is a controlled chamber over 6 hours reported as an average, the other is real outdoor sunlight over 48 hours reported as a maximum. Different reporting conventions make the figures incomparable.
The records illustrate why an outdoor peak and a chamber average cannot be compared as one insulation rating. They do not establish a guaranteed temperature difference or holdover time for another load or route.
·Selection steps·
Step-by-Step Guide
- 01
Align the measurement position first
Confirm whether the figure compares ambient to cover, cover to carton, or ambient to carton bottom. Positions are not interchangeable.
- 02
Check the reporting convention
Average, maximum or a single instant — record duration and ambient conditions alongside.
- 03
Validate against your own route
Record with your own loading pattern, route temperature profile and duration rather than converting someone else's figures.
·Frequently asked questions·
Frequently Asked Questions
01 What is the maximum temperature difference under direct sunlight?
In the 48-hour Suzhou outdoor test on the bubble pallet cover, the maximum difference between ambient and the carton inside-bottom was 39.2℃ (at 12:00: ambient 70.0℃, inside-bottom 30.8℃). This is a peak under specific conditions, not a guarantee for another route or duration.
02 Why is the difference smaller in the -10℃ test?
The cargo and sensors change temperature during exposure. The source table also contains inconsistent difference rows, so obtain the original report before quoting a numerical comparison.
03 Why are there two different “inside” temperatures?
Because the sensor positions differ. At the same moment the carton top and carton bottom inside the cover can differ by about 16℃, so any temperature figure must state where it was measured.
04 Can these figures estimate my transit duration?
No. Neither material data nor a single test equals a guaranteed insulation duration for a route. Run a validation record with your real loading pattern, temperature profile and duration.
References and scope
- ASTM C518 — Standard Test Method for Steady-State Thermal Transmission Properties
- ISTA — Test Procedures for transport packaging and thermal performance
- ASTM E96 — Standard Test Methods for Water Vapor Transmission of Materials
References explain selection principles and test methods; they do not certify any product. Temperature figures come from measured records in the Aspirature insulation product manual, with test location and duration stated in the text. Actual performance varies with loading, conditions and route; final specifications are subject to the confirmed datasheet, test reports and order.
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