Temperature Mapping Locations

Industry guidance instructs us that when determining mapping locations, the potential storage location should be considered, along with; probe locations; worst place locations, number of probes, distance between probes, usable space, and direct path of air flow.

Many temperature mapping protocols we come across may just tell us to place probes or measurement sensors in the chamber to be mapped, but how many know where they should go and why?

Why am I placing all these probes?

The goal of temperature mapping is to determine the differences between each probe or measurement sensor, or fluctuation within your chamber over a period of time. This is what I would call determining the temperature uniformity of a chamber.

Uniformity or Temperature uniformity is the measurement of temperature consistency across all usable locations in the chamber.

Performing a temperature mapping also known as a temperature uniformity study, is to ensures that every point within the chamber confidently meets a specified acceptance criteria typically provided with a plus/minus value. That activity will show you exactly what's going on inside your chamber and you will use the data to determine whether or not the equipment passes the requirements you need for your required product storage.

Where do I place my probes?

For the typical controlled temperature chamber we perform mapping studies on a daily basis, the sensors would be placed in each of the eight corners, with one in the geometric center of the space.

This would be a good configuration for most refrigerators, freezers, and incubators. This layout of course is dependent on the size of the unit you are mapping (e.g. counter height units vs. upright or double door units).

For larger units, you could place 5 sensors on the middle shelf or even lay out an alternate pattern on the middle shelves (ex. 5 on shelf 1, shelf 2 back left and front right, shelf 3 in middle, shelf 4 front left and back right, and 5 on shelf 5).

See sensor placement examples below.

You’ll need to place sensors in a uniform pattern in all three dimensions of your space.

• Top to bottom
• Left to right
• Front to back.

All sensors, other than the one in the center, should be placed away from the nearest wall at a distance that will define the actual volume of the space used for storage. 

Don't forget additional sensor(s) should be placed adjacent to the display, control, and monitoring probe(s), if applicable.

By following the basic principles listed above, you will be on your way to successfully completing a temperature mapping study and well prepared for your next qualification.

Here to Help

If you would like more information on Temperature Mapping Locations, recording intervals, pre/post calibration, protocol generation or would like help with your general validation needs please contact us at [email protected]