What is Temperature Mapping?

by Nathan Roman

Temperature mapping is a study or analysis performed on controlled temperature chambers (CTC). Equipment such as a freezer, refrigerator, incubator, stability chamber, oven, warehouse, cold room, or autoclave that maintains and controls temperature or humidity and must be temperature mapped. This means that we record the temperature or humidity readings of multiple locations inside of the equipment over a specified period of time.

Storage temperature is very important in maintaining critical quality attributes because drug products or samples are temperature dependent and must be well sustained and controlled.

Current Good Manufacturing Practices (cGMP) are requirements to maintain the products’ safety, quality, and efficacy.

Food and drug products must be stored and transported according to predetermined conditions (for example, 2°C – 8°C). The distribution of products must be transported, handled, and stored in a manner that mitigates the risk of exposure to temperature excursions.

In order to record the temperature or humidity, you will place data loggers in a uniform pattern in all three dimensions of your space – top to bottom, left to right, front to back. You will leave these sensors positioned in their location without being disturbed for a period of time (typically 24 hours for a freezer, refrigerator, or incubator).

That study will provide you a representative view of what’s going on inside of your controlled temperature chamber at that time, and you will evaluate the data to determine whether or not that controlled temperature chamber data conforms with the necessary tolerances or precise conditions you require for the samples, reagents, or drug product you want to store.

Temperature Mapping is a part of the overall equipment qualification process for companies that are involved in regulated environments and apply Good Manufacturing Practices (GMP) and or Good Laboratory Practices (GLP) to their processes.

The qualification of controlled temperature chambers presents a contradictory challenge to the validation technician: while each chamber qualification follows a relatively simple framework, the nuances of different chambers, manufacturers, temperature set points, alarms, automation systems, refrigeration, and heating systems, and various other peripheral components often require highly individualized methodologies, thus revealing a deceptive level of complexity in the task. Although in the most general terms, a chamber is only required to maintain uniform environmental conditions within given process limits, few owners require so little of their equipment, particularly in highly regulated workspaces.

Even when the control is limited to temperature regulation, the individual nature of each chamber becomes apparent through qualification studies. Temperature stabilization and recovery periods vary widely across different refrigeration and heating systems, which can present a multitude of problems during mandatory temperature uniformity studies. Defrost cycles occurring automatically within a cold chamber can often cause unpredictable temperature spikes outside of the process range, negatively impacting product stability within the chamber. Certain control systems allow for several hours of temperature fluctuation after the chamber is opened before returning to process levels, and others will overcompensate for large changes in temperature, requiring careful observation before a qualification study can be started. Further, control systems that behave in one way at a specified set point may behave in an entirely separate way if the set point is adjusted, even if no changes are made to the control system itself. With such variation between chambers, it is impossible at the onset of qualification for the technician to predict everything that might occur during temperature mapping. Beyond the mechanical controls of the chamber, the safety features equipped with each unit require further analysis to ensure that, in the event of equipment failure, the chamber will respond properly to the emergency condition and resume operation as normal once the fault is cleared. Building automation systems present a second level of convolution on top of the local alarm system, requiring a full test of all relays to ensure that each signal is transmitted properly to the monitoring software. Even further, when the local and remote alarm systems are independent of one another, any additional temperature probes must be individually calibrated and proven to function as required. Like temperature uniformity testing, there is no hard-and-fast blueprint for the technician to prove the functionality of chamber alarm systems, only guidelines and general knowledge of how to meet certain requirements placed on the chamber. Understanding the diverse nature of controlled temperature chambers, it is my firm belief that the value of our industry technicians lies in their ability to quickly adapt to the individual operation of each chamber, effectively identifying and avoiding roadblocks in the qualification process while meeting both regulations and the highest quality standards. Our technicians are at their best when they apply their knowledge of chamber qualification procedures to the specifics of the chamber qualification at hand, and not the other way around, ensuring that your qualification package will only be considered complete when it rises to all of your expectations.

Nathan Roman is Director of Validation at Genesis AEC, responsible for Qualification and Validation consulting services. He has over 22 years of experience in commissioning, qualification, and regulatory compliance services. He is an expert in CQV and CGMP, and GLP compliance.

His passion is and always has been ‘to help’. He helps people implement proven processes for temperature mapping studies and equipment qualifications (IQ/OQ/PQ). In the area of temperature mapping, his goal is to better inform and guide those who aim to meet regulatory requirements.

He does this by providing you simple, practical tools for compliant mapping & qualification. Over two decades of experience working hand-in-hand with customers like you.

Nathan has supported over 55 companies and 120+ Customers and executed over 2000 equipment qualifications.

He has found success in what he does through experience and learning from others.

To learn more about Temperature Mapping and Validation Services, please contact Nathan Roman directly at nroman@genesisaec.com or Follow Nathan Roman on LinkedIn

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