Kelvin Hours
It is important to understand the difference between ordinary and high-tech TempChain shippers. With Kelvin Hours you will know the actual performance of your high-efficiency thermal packaging and get better planning security.
ISTA 7D for 72 hours
This graph shows the performance of the box under standardized conditions, but it does not reflect the kind of individual loads that it can be subjected to during transport (e.g. longer transport times, more extreme peaks, longer peaks).
How can you tell if the graph presented to you reflects the actual real-world challenges?
To get the actual performance you need to calculate the Kelvin Hours.
Look up the number of hours that your selected box promises at the required temperature load and check that the box has sufficient Kelvin Hours available.
Kelvin Hour Calculator
Example
This medicine needs to get from Berlin to Brisbane
Using the normal graph shown above we only get a standardized indication that does not account for individual factors.
Finding the thermal packaging that can maintain the medicine bottle at a temperature between 2°C to 8°C for a period of three days – at the expected external temperatures is now possible.
Use the Kelvin Hours calculator above and learn that all three shippers are able to perform for 72 hours. But only the green shipper is able to withstand the required temperature load. It is the only one with sufficient Kelvin Hours.
Only knowing the actual performance will give you 100% planning security.
FAQs
What are Kelvin Hours?
Kelvin Hours are a statement about the degree of temperature stability that a transport solution can realistically attain.
Why Kelvin Hours?
A simple comparison of qualification data under different temperature profiles does not generally provide a reliable statement. Different temperature scenarios impact thermal packaging in different ways. To allow for a reliable comparison to be made, these differences are taken into account in the calculation of Kelvin Hours.
Why are Kelvin Hours useful?
Kelvin Hours represent the best means of obtaining an objective comparison of different thermal packaging solutions.
How do I calculate Kelvin Hours?
To determine the number of Kelvin Hours, you need two variables: the expected transport time and the expected average temperature difference to which the packaging solution will be subjected. The product of these two variables represents the number of Kelvin Hours.
Why is the number of Kelvin Hours not given for all boxes?
Kelvin Hours represent an objective means of comparing thermal transport solutions. If you do not know a product’s Kelvin Hours, then please contact the manufacturer, who should be able to provide you with the necessary data.
How can I determine the Kelvin Hours of my current box?
The easiest way is to contact your supplier. If this does not help, you can determine the Kelvin Hours from the qualification data or live-shipment data. If you wish, we will be happy to assist you with this. Please contact us at: [email protected]
Why can boxes have the same performance with different numbers of Kelvin Hours?
The impact of different temperature profiles on different types of thermal packaging can vary. The result of this can be that a box with fewer Kelvin-hours in combination with a weaker profile can attain the same performance as a box with more Kelvin Hours in combination with a stronger profile. By using Kelvin Hours, this difference is eliminated, with the result that a simple comparison of Kelvin Hours shows which box fulfills your requirements.
When does it make sense to consider Kelvin Hours?
Whenever it is necessary to conduct an objective comparison of the performance of different thermal packaging units.
How do I determine the average external temperature?
If it is not possible to calculate the average external temperature exactly, it should still be possible using a simple graphical method. Plot the horizontal line in your temperature graphs so that the area above the line is as large as the area below the line. The point at which the line crosses the temperature axis denotes the average temperature.
How many Kelvin Hours does my temperature profile need?
First you need to determine the average temperature of your external profile. Then subtract from this the desired internal temperature. This will lie in the middle of the desired temperature range (i.e. for 2-8°C it is 5°C, and for 15-25°C it is 20°C, etc.). Finally, multiply this value with the required transport time. The resulting value is the minimum number of Kelvin Hours that you need for a transport within your temperature profile.
My external temperature is in the range of my permitted internal temperature – how do I calculate the Kelvin Hours in such cases?
In this case, the outside temperature profile does not constitute a load on the thermal packaging, and therefore no Kelvin Hours are required. They thus equal zero.
