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Why Should You Measure the Temperatures of Pharmaceuticals?

A growing trend in the pharmaceutical industry is the development of more complex and fragile products, like biologicals, chemical mixtures, and large molecules (COVID-19 vaccines are an example of this trend). 

These products generally require more stringent temperature controls to prevent them from degrading or deactivating during storage and shipment. Making the situation more complicated, different products require storage at different temperatures, from ‘ultra-cold’ (below -50 °C) to normal room temperature (20-25 °C). 

An integral part of safely handling these materials is having a temperature mapping protocol in place. Temperature mapping is also important for maintaining regulatory compliance, earning accreditations, and reducing or eliminating the loss of valuable products due to temperature excursions. 

In this article, we’ll cover the basics of temperature mapping, how it’s done, and some of the key elements to include in a temperature mapping protocol. 



What is Temperature Mapping?

Temperature mapping (or thermal mapping) involves placing a large number of sensors throughout a temperature-controlled space, to thoroughly measure how the temperature of the space varies in three dimensions. Mapping also tests how temperature varies during “stress conditions” like power outages, door openings, shift changes, and variations in outdoor temperature. Several organizations, including the US Pharmacopeia and the World Health Organization, provide detailed guidance on mapping. 

It’s important to distinguish between temperature mapping and routine temperature monitoring. Mapping is an exercise where a large number of sensors are placed for a temporary period, to fully characterize the behavior of a space. Monitoring, on the other hand, is conducted continuously, using a smaller number of strategically placed sensors. 

The main objectives of a temperature mapping protocol typically include:

  • Qualifying or validating a new or upgraded piece of equipment to ensure it is designed and working as intended
  • Determining the optimal placement of sensors for ongoing QA monitoring
  • Understanding the thermal behavior of a space as part of developing SOPs

The spaces that are mapped in this context include refrigerators, freezers, loading docks, holding rooms, or even entire warehouses. Essentially any part of the pharmaceutical cold chain- specifically, the temperature-controlled spaces used to maintain consistent refrigeration from the point of manufacture to the consumer- can be temperature mapped. Mapping is becoming even more critical as distribution chains become more complex, with many storage locations and the use of multimodal transportation. 


How is Mapping Conducted?

A temperature mapping protocol, particularly for highly regulated industries, is thorough and detail-oriented. It can be broken down into three phases: 

  1. Planning, including determining optimal sensor type and placement, and how the system will be stressed during mapping
  2. In execution, where sensors are placed temperature data is collected over a representative period of time
  3. Data review

Note that mapping, like most GxP processes, involves creating a full set of records at each step. 

Mapping can be carried out in-house, or by an external partner. Using a consultant for mapping is often the most economical option, since a large number of sensors are used (much more than would be needed for routine monitoring), and often the expertise needed to properly design and 

execute a mapping project aren’t available in-house. This is especially true for mapping conducted as part of a documented quality assurance program in highly regulated industries. 

Part of a comprehensive temperature mapping protocol is to repeat mapping regularly (the WHO recommends every 3 years, for example). Re-mapping can also be triggered by specific events, like installing a new HVAC system or storing new or different types of products. 


How Often Should Temperatures Be Recorded?

An important part of the temperature mapping protocol is setting the frequency of data collection, which is typically variable on modern digital data loggers.  During mapping, this frequency should be set to be able to accurately capture the temperature variations that take place during normal operation, like door openings, or temperature control equipment cycling on and off. 

For ongoing monitoring, data collection frequency is set based on a balance of operational conditions (like battery life or memory capacity, on loggers that don’t continuously upload to cloud storage), and how often data collection is needed to ensure the safety of the particular product in storage or to meet regulatory requirements. As an example, for vaccine storage areas, the CDC recommends collecting a temperature data point every 30 min using a digital data logger. 

Temperature mapping can also be used to determine the required data collection frequency since it provides a quantification of how quickly temperatures can change in space.  


Temperature Monitoring Protocols for Pharmacies and Warehouses

A temperature mapping protocol, as we’ve discussed here, is an important component of ensuring product safety and regulatory compliance in areas where pharmaceuticals are stored. 

Beyond temperature mapping, some other protocols or SOPs that should be considered are:

  • Initial qualification of temperature control equipment
  • Regular temperature sensor calibration (note that advanced monitoring solutions can provide automated tracking of calibration status) 
  • Preventative maintenance of refrigeration equipment, including sensors and loggers
  • Review of monitoring data to identify trends (here again, modern, cloud-based monitoring approaches greatly simplify aggregation and review of key monitoring data)
  • Response procedures for equipment failures, near misses, and temperature excursions


What Is Temperature Mapping Validation?

A temperature mapping protocol can also be part of a larger validation procedure. In the pharmaceutical industry, the term validation has a specific meaning, which is to demonstrate that a piece of equipment satisfies its intended purpose by collecting objective data. 

This is broken down into installation, operational, and performance qualifications (IQ, OQ, and PQ). Temperature mapping fits into the OQ and PQ steps. Specifically, mapping a space empty, just after installation, could be part of an OQ plan, while mapping while the space is loaded, simulating operating conditions, can be part of PQ. 



Temperature mapping is an important part of commissioning and maintaining temperature-controlled spaces for pharmaceuticals. Mapping is a thorough, detail-oriented process that has significant hardware demands and requires thoughtful planning. For this reason, it is not uncommon to engage an external expert for mapping exercises. 

Questions about temperature mapping, or temperature mapping for the pharmaceutical industry? Contact the experts at Dickson.