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How to make a temperature mapping of your refrigerators and freezers

Easily map your refrigeration equipment using this temperature mapping template.

When new equipment is being put into use or temperature monitoring is implemented it is important to know how the equipment is performing. All refrigeration equipment will have hot and cold zones which are important to be aware of when placing temperature sensitive goods in the cooling equipment. It is therefore necessary to produce a ‘temperature mapping report’.

This guide covers a simple method temperature mapping smaller equipment; refrigerators etc.https://www.vaisala.com/sites/default/files/documents/CEN-LSC-AMER-5-Rules-of-Sensor-Placement-B211369EN-A.pdf

What is mapping?

Mapping of refrigeration equipment is the process that is carried out to prove that the equipment meets the criteria set for the equipment and to find any hot and cold zones.

Inside a refrigerator the temperature can vary from point to point. A regular consumer refrigerator in your kitchen will in many cases show that temperature in the top of the fridge is 5 degrees higher than in the bottom. This is the reason that performing a mapping study is an important part before using a specific cooling equipment.

Mapping is typically part of the installation process for new equipment but can also be used to find out which zones can be used and which cannot.

After you have mapped the equipment, you will have a clear idea of ​​how the equipment meets temperature requirements, and which zones in the equipment can be used for storage and which cannot. Last but not least, it will give you a good idea of ​​where to place your temperature monitoring to give the best picture of the temperature of the critical goods.

How is it performed?

Mapping 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 the frame in which the equipment is included. You there do not need to overdo the mapping if your processes does not require it.

The most important elements of mapping are:

  • Make a plan
  • Check the documentation of the measuring equipment
  • Setup your measuring equipment
  • Collect data
  • Document and evaluate results

1. Create a plan

Before mapping takes place, you must specify how to map, for example by making a temperature mapping SOP:

  • How many places do you want to measure?
  • Should the equipment contain goods during the mapping?
  • What are your acceptance criteria – i.e. what are the external limits for temperatures in the equipment?
  • What temperature mapping equipment 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 do the mapping.

2. Check the documentation of the measuring equipment

You must check that the measurement equipment you use for mapping is calibrated and comes with a certificate showing that the equipment is calibrated within a reasonable limit and timespan. Typically, 0.5C precision and a maximum calibration interval of 1 year will be enough.

Additionally, make sure you can extract data when you have completed the mapping, e.g. by using a system where you can export reports within specific time periods.

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:

  • In the front door far from the cooling element
  • Close to 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 capture all extremes in the refrigeration equipment so it is more important to choose locations that are representative.

Optimally you have several measuring equipments, that you can put up at the same time. If you have only have a few or a single piece you can instead move it around

and thus creating an overview of the temperature extremes in the equipment.

Typically it will be enough to measure for 24 hours. This ensures that you catch both hot times 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, it is worth filling up the equipment as normal. The mapping can also run without items, but it will not provide a precise picture of how your equipment behaves under normal circumstances. It is possible to use empty boxes to replace real items.

During the mapping it is important not to open and close the doors of the equipment as this may affect the measurements.

4. Collect data

Whether you use multiple pieces of equipment or few that you move around, data must be collected and 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.

5. Document and evaluate results

When you’re done, it’s time to draw some conclusions based on the data.

Typically, the hottest and coldest areas will be of interest since the risk of deviations during normal use are high at these areas. If there are areas that are found to be unsuitable for temperature sensitive items, it may be a good idea to mark these with tape so the staff knows they cannot use them. At the same time note which areas are within the limits and thus can be used for storing critical goods.

Sometimes it may be apparent that the cooling equipment must be adjusted after which you have to perform a new mapping study.

The data gathered from the mapping can also be used to show where it is advantageous to place temperature monitoring in normal operation. If the cooling equipment turns out to have a zone where there are large fluctuations, this location can be used for temperature monitoring as this will give 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 captured in time which will save valuable goods.

Mapping should be used as a tool to give you an overview of your equipment and to prove to authorities and auditors that your equipment is working properly in those areas where critical goods are placed.

Need help?

Eupry optimises how organisations monitor, and document temperatures. Using the Internet of Things (IoT), Eupry changes the way organisations approach compliance, quality, and efficiency. We have a wide variety of customers in several sectors. If you have any questions regarding how to secure temperature sensitive goods, you are welcome to contact us.