Temperature Mapping Exercises in Temperature Controlled Environments

Learn the basics about temperature mapping. When you have read this article, you will have a good overall idea of how you can perform a professional temperature mapping of your equipment.

If you are looking for information on how to perform a temperature mapping on specific temperature controlled equipment and areas, go to one of these sections:

  • Cold room temperature mapping
  • Freezer temperature mapping
  • Fridge temperature mapping
  • Warehouse temperature mapping
  • Validating storage areas with temperature mapping
A Temperature mapping as seen on the website
Learn the basics of temperature mapping

Read our eBook – What is Temperature Mapping?​

Read our eBook and get introduced to the basics of temperature mapping. We will give you a good overall idea of how to perform a professional mapping of your equipment.

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Thermal mapping equipment

What is temperature mapping?

Temperature mapping of refrigeration equipment is the process that is carried out to prove that the equipment meets the criteria set by authorities and auditors for the equipment and to locate hot and cold zones.

In other words, a temperature mapping / thermal mapping study documents that the equipment maintains temperatures within defined limits at all times. This is especially important to test and document before new equipment is used for storing temperature sensitive goods in GxP-regulated industries.

Inside a fridge, the temperature can vary by several degrees. The temperature in your kitchen fridge can fluctuate by as much as 5 degrees from the top to the bottom. The same applies to industrial fridges and freezers, which is the main reason for performing a mapping study before using new equipment.

Using various temperature data loggers to make the temperature mapping, you will afterwards have a clear understanding of ​​how the equipment meets temperature requirements, and which zones can be used for storage and which cannot.

Last but not least, it will provide you with information on ​​where exactly to place your temperature monitoring equipment. Knowing where to place your data loggers, allows you to get a precise measurement of the temperature of the critical goods which will ensure that you receive an alarm the exact minute any temperature deviates from the required temperature range.

Mapping of refrigeration equipment with Eupry’s Mapping Kit

Save time by using Eupry’s easy-to-use Mapping Kit with accredited DANAK ISO17025 calibration and 21CFR PART11 compliance. Temperature mapping of cooling equipment is an important process when examining whether your equipment is working properly.

Mobile Box

Practical mobile box with the number of data loggers (temperature sensors) needed.

Temperate Mapping - Batteries

Base Station & Batteries

A wireless base station and extra batteries for the temperature data loggers.

Temperature Mapping - Calibration Icon


All temperature data loggers are START calibrated, and an END calibration is performed.

An example of a mapping report

Download a sample mapping report

Download a full sample mapping report for a refrigerator from a real life case. The report was conducted and delivered ultimo 2020.

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How is a temperature mapping performed?

Performing a temperature mapping of refrigeration equipment does not have to be complicated or time consuming. The most important thing is that the scope and complexity fit the equipment and what is stored in the equipment.

You, therefore, don’t need to overdo the temperature mapping if your processes do not require it.

The most important elements of mapping are:

  • Create a plan for the mapping study
  • Check the documentation of the measuring equipment
  • Set up your measuring equipment
  • Collect mapping data
  • Document and evaluate results
The basics of a temperature mapping

1. Create a plan

Before the mapping study, you must specify how to map. We prefer detailing a standard operating procedure (SOP) with focus on answering the following questions:

  • How many places do you want to measure?
  • Should the equipment contain goods during the mapping study?
  • What are the acceptance criteria i.e. what is the temperature range and the limits for the equipment?
  • What kind of temperature mapping equipment(data loggers) will you use?

The most important thing before you start the process is to find out what your limits are, so you have something to validate against, as well as how thoroughly you expect to carry out the mapping.

2. Check the documentation of the measuring equipment

You must check that the temperature data loggers you use for mapping are calibrated and comes with certificates documenting that the data loggers are calibrated within a reasonable limit and timespan. Typically, 0.5 °C precision and a maximum calibration interval of 1 year will be sufficient for a temperature controlled storage room or refrigeration unit.

Additionally, make sure you can extract data from the data loggers when you have completed the mapping e.g. by using a system where you can export reports within specific time periods. Eupry’s wireless data loggers automatically sends all data wirelessly, after which the data can be easily analyzed in our app or in a web browser.

3. Set up your measuring equipment

Typically, the mapping will take place in the areas of the refrigeration equipment where high temperature fluctuations are expected. This will usually be:

  • The front door far from the cooling element
  • Close to the compressor at the bottom
  • At the back panel where the cooling elements are located.

You can save time by assessing where the largest fluctuations will occur. You will never be able to find all extremes in the refrigeration equipment, so it is more important to choose locations that are representative.

Optimally, you have several pieces of measuring equipment(data loggers), that you can install at the same time. If you only have a few or a single temperature data logger, you can instead move it from place to place and thus create an overview of the temperature extremes in the equipment.

Typically, it will be enough to measure in a 24-hour time span. This ensures that you catch both hot periods, often in the middle of the day, as well as the normal cooling cycle that the cooling equipment goes through.

To get a good picture of how your equipment performs under normal conditions, you can fill the equipment with goods. The mapping can also run without goods, but it will not provide a precise picture of how your equipment behaves under normal conditions and where it is hot or cold.

During the mapping, it is important not to open the door(s) of the equipment as this may affect the precision of the temperature measurements.

4. Collect mapping data

Whether you use multiple pieces of equipment or few pieces that you move around, it is paramount to collect the temperature data, which can later be compared.

If the goal of the mapping is to provide a credible picture of how your equipment is performing, it is important that the entire measurement period is included.

The temperature data stored in the data loggers have to be exported in order to document the measured data. This is mostly done either by inserting the data logger into a computer’s USB port, and then using the associated software to download the data from the data logger, or by using a WiFi data logger that automatically transfer data on a regular basis wirelessly to an online system.

It is worth considering how easy it is to export temperature data from the sensor you are planning use. Eupry’s wireless data loggers automatically sends all data wirelessly, after which the data can be easily analyzed in our app or in a web browser.

5. Document and evaluate results

When you are done, it is time to draw some conclusions based on the data. Typically, the hottest and coldest areas of the equipment will be of interest since the risk of temperature deviations during normal use are high in these areas. If you have located areas unsuitable for temperature sensitive items, it may be a good idea to mark those with tape to notify staff members. At the same time, note which areas are within the temperature limits and thus can be used for storing critical goods.

The data from the thermal mapping study can also be visualized in 3D, which can help improve the understanding of where a potential issue is, or where it is safe or not safe to store valuable goods.

Sometimes the results of the mapping study can show that the cooling equipment have to be adjusted. A new thermal mapping study is thus needed afterwards.

The data gathered from the temperature mapping can also be used to locate where it is useful to place temperature monitoring devices during normal operation. If the cooling equipment has a zone where large fluctuations occur, this location can be used for temperature monitoring since it will provide an early warning if the equipment malfunctions.

It is especially advantageous to use a temperature monitoring system with an alarm function, that notifies you if the equipment fails or does not work properly. This way deviations can be discovered immediately, which will save valuable goods.

Lastly, it is critical that a consistent justification for decisions is established and that these are documented as part of the validation procedure. The reasoning should be scientifically based, applicable to facilities and products and suitable for the intended use of the area being mapped.

How is a temperature mapping planned?

Together with Eupry a temperature mapping is planned, executed and reported through 9 steps.

  1. Client will send information to Eupry about the equipment (refrigerator, freezer, cold storage etc.) that is supposed to temperature mapped, we will analyse the storage area and send back a proposal (temperature data loggers needed, estimated time until finished mapping report, conditions and price)
  2. The client has comments or accepts the proposal.
  3. Eupry create an exact plan and protocol for the mapping.
  4. The client QP sign the protocol (or has extra comments to protocol)
  5. The Wireless Data loggers are placed within the storage area as per defined in the protocol
  6. The mapping is being performed and several tests are made such as Pre-Qualification, Stability Study, Power failures and door openings
  7. The Wireless data loggers are taken down and shipped back to Eupry
  8.  Eupry exports the data from monitoring equipment and creates the Mapping report
  9. The mapping report and protocol is signed by both the client QP and Eupry
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Mapping process by Eupry

Temperature mapping on specific temperature controlled equipment and areas

Below you can see specific details for things to be aware of when you perform a temperature mapping study in cold rooms, freezers, fridges, warehouses and storage areas. As well as pointers on which zones that are most often non-compliant.

When mapping cold rooms, it is important to understand the implication loading of goods has on the temperature in different areas of the cold room.

Also distribution of air, or airflow, can have a big influence on the performance of the cold room. If there is no airflow, or if the airflow is obstructed, the risk of having areas with a lower or higher temperature is high. When air is not being circulated properly, areas which are in close proximity to a hot surface, e.g. an outer wall, will be at risk of becoming non-compliant.

Freezers are mostly used for storage of sensitive assets and tend to have some issues, that are important to be aware of.

Especially loading of goods has a large impact on the performance of freezers, which need to be considered when both temperature mapping and using the freezer. Since freezers often have little thermal mass, the temperature in the areas where goods are placed will often be drastically affected when hot or cold goods are loaded into the freezer.

It is therefore important to evaluate the effect larger loadings of goods has on especially small freezers and implement these findings into the standard operating procedures for using the freezer.

The place you decide to place the freezer can also impact the performance, since a freezer needs to be able to get rid of the heat generated when the freezer is going through cooling cycles. If the freezer is placed in an enclosed space, the heat cannot escape properly and thus it cannot perform as expected.

Furthermore, the room temperature must not exceed certain limits, which also will cause the freezer to perform badly. This can also affect the freezer temperature mapping since the mapping study has to reflect normal use of the freezer.

Temperature mapping in fridges is used in order to locate hot and cold zones and get a clear understanding of temperature variations during cooling cycles, or in other words to ensure that the fridge can actually maintain temperatures within limits. Otherwise stored goods will not be maintained at the specified temperatures either. Ensuring that your fridges are mapped, avoids downtime in business operations and performance interruption in equipment.

In the case of warehouse temperature mapping, the goals of the mapping are the same as if mapping smaller pieces of equipment, but in practice the mapping studies can vary.

When mapping a warehouse, one of the important things that the mapping should investigate is possible airflow issues. Especially at large warehouses there can be issues with airflows, which result in cold or hot zones, either due to high flow of cold air in some areas, or the lack of airflow in other areas. A temperature mapping should take possible airflow issues into account, and can provide guidance on where to place sensitive assets and where not to. Next to air vents, doors and packing areas, etc., temperature variations can be expected, and therefore these areas are often of special interest.

Another important factor is external influences. This could be from walls that are connected to areas of substantially different temperatures, or outer walls that will experience great temperature difference due to seasonal changes. Therefore, a temperature mapping of a warehouse is often performed at the coldest and hottest time of the year.

By conducting a proper mapping study, these variations can be measured, analyzed and adjusted throughout the entire system to ensure a more efficient and effective operation of managed warehouses.

Another point of interest is the amount of sensors used to perform the thermal mapping of a warehouse. When a large area is being mapped, a larger amount of sensors is often needed. Care should be given when choosing the amount and position of sensors, to properly allow the detecting of variations in temperature in different areas of the warehouse.

WHO has issued a guideline that can aid in determining the amount and positions of sensors, which can be downloaded here: https://www.who.int/medicines/areas/quality_safety/quality_assurance/TS-mapping-storage-areas-final-sign-off-a.pdf

When mapping warehouses, it is important to have information on the external conditions of the building in order to perform a successful temperature mapping or monitoring of temperature sensitive products.

To ensure that all external conditions are met, particularly for pharmaceutical products, it is necessary to map warehouses. Even a few degrees of variations may affect the quality of the product. Changes in temperature location, layout, cooling equipment, air circulation, product quality, and many other factors can be the cause of temperature fluctuations. Next to air vents, doors and packing areas, etc., temperature variations can be expected.


Temperature mapping can help understand the temperature dynamics of the warehouse and ensure that the most sensitive areas are controlled.

Storage areas can both be small rooms with medicine or huge storage buildings with robotic placement machinery. Validation and mapping could in theory follow the same protocol but that is not always the case. In both cases it is necessary to thoroughly consider where to place the sensors.

When storage areas are being thermally validated using a thermal mapping, airflow issues are one of the major points of interest. As there are often racks with goods stored on them in the storage area, the airflow can be obstructed, and thus creating large variations in temperature and humidity. Therefore, it is often required to perform mapping with and without goods on shelves, which can confirm that the storage area can still maintain temperatures or humidity levels within specifications, even though goods obstruct airflows.

FAQ About Temperature Mapping

We have gathered the most frequently asked questions and answers below. Click on a headline to see the answer.
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Eupry optimizes how organizations monitor and document temperatures. Using the Internet of Things (IoT), Eupry changes the way organizations approach compliance, quality, and efficiency. We have a wide variety of customers in many different sectors.

We offer an easy-to-use Mapping Kit with accredited DANAK ISO17025 calibration and 21CFR PART11 compliance that contains:

  • Practical mobile box with the number of data loggers (temperature sensors) needed.
  • A wireless base station and extra batteries
  • All data loggers are START calibrated, and an END calibration is performed

Contact us to get more information or if you have any questions.

This depends on multiple factors, one being the type of products that are stored. For pharmaceutical companies it is crucial to maintain temperatures at the right levels, which for medication in most cases are between 2° C and 8° C in refrigerators and between -50° C and -15° C in freezers dependent on use.

Another factor which should be accounted for is the uncertainty of the sensors or data loggers used for the mapping. The uncertainty of the measurement equipment should be taken into account by decreasing the span of acceptable temperature or humidity fluctuations.

The sensors for performing a mapping of any kind of equipment or facility should be chosen based on the task at hand.

Some specifications to look for are:

  • Resolution: The resolution should normally be at least 0.05°C so that even small temperature variations can be detected.
  • Accuracy: Dependent on the acceptable span for different mapping exercises, the required accuracy can vary from ±0.1°C to ±0.5°C for either small acceptable spans to larger spans. For humidity a normal acceptable accuracy is ±3%.

Furthermore, it can be beneficial to look at how data is handled, both during and after mapping, as time used for gathering data can be higher than expected if wired systems are used rather than wireless systems.

If you use software requiring tools to collect and download data or produce reports, you will need to document that the software has been tested and complies with qualification requirements.

When mapping cooling equipment such as freezers, refrigerators and fridges we recommend using between 8-12 sensors per unit as a rule of thumb. Size differences of the equipment can affect the number of sensors needed though. Look in the sections above on temperature mapping of specific equipment for information on where to place the sensors.

When mapping storage rooms you must analyze the room and classify possible causes of humidity and temperature variations such as doors and windows. Include these observations in your reasoning so that reviewers of the thermal validation can understand and assess your choices. These are called the rationals and are an important part of the mapping exercise.

All sensors used for a mapping exercise must be calibrated, either traceable or accredited based on quality requirements.

Based on quality requirements, it should be decided whether the sensors should also be calibrated after the mapping exercise. In less regulated areas, a start calibration is sufficient, while more rigorous standards of quality require an end calibration to be performed to ensure that the sensor is also accurate at the end of the mapping exercises.

The duration of your mapping study should be long enough to ensure that you have accurately captured the environmental dynamics of the area being mapped. The larger the area or the more activity is ongoing during the study, the longer the estimated time of the mapping study.

It is worth considering seasonal changes. It can therefore be necessary to perform a mapping study in the hottest and the coldest time of the year to get the most accurate picture of the temperature fluctuations in your equipment or warehouse.

FAQ about temperature mapping