In short
- Mapping is a one-time study of the whole space; monitoring is continuous follow-uping at fixed points.
- The EU GDP guidelines require monitoring equipment to be placed according to the mapping results, at the points with the greatest fluctuations.
- A single monitoring point without mapping is not demonstrably the right place.
- After changes to the space or with seasonal influence, a new mapping may be needed.
What is temperature mapping?
Temperature mapping is the documented measurement of how temperature is distributed across a controlled space, in order to find where it gets warmest and coldest. You place a number of calibrated data loggers throughout the space and measure over a representative period under conditions that match the purpose of the study. Depending on the phase, this may be empty, loaded or simulated loaded; the load affects airflow and therefore the temperature distribution. The result is a picture of the hot and cold spots, and so of where continuous monitoring belongs.
What is temperature monitoring?
Temperature monitoring is the ongoing watch with fixed sensors during day-to-day operation. It continuously records whether conditions at those points stay within the permitted range and raises an alarm when they do not. Monitoring therefore looks at a fixed point, throughout the entire time the space is in use.
What is the difference? An overview
| Temperature mapping | Temperature monitoring | |
|---|---|---|
| Goal | Characterise the temperature distribution across the whole space | Watch whether conditions at fixed points stay within range |
| When | One-time (and repeated after changes) | Continuous, during operation |
| Setup | Many loggers, under representative conditions for the study purpose | A few fixed sensors at the critical locations |
| Result | Insight into hot and cold spots and the right monitoring location | Ongoing recording and alarming |
Why monitoring follows from mapping
The dependency is set out in the regulation itself. The EU GDP guidelines state that monitoring equipment should be located according to the results of the temperature mapping, at the points that experience the greatest fluctuations (EU GDP guidelines 2013/C 343/01, §3.2.1). Mapping comes first, and monitoring follows from it.
Regulators describe it the same way: the mapping reveals where the permanent loggers for continuous monitoring should be placed. Only once mapping has shown where the critical location is can you know whether your monitoring sensor is in the right place.
View the central guidelines page
Is temperature monitoring enough without mapping?
No. "We already monitor our fridge, so we don't need mapping" is the most common misconception in temperature control, and exactly what an inspection picks up on.
A single monitoring point tells you about one location. If that location has never been substantiated with a mapping, your daily readings can look flawless while a warm spot at the top of the racking, near the lighting or the evaporator, drifts out of range unseen. The fixed sensor simply does not see it, because it sits somewhere else.
An example we often see in practice: a cold room with one fixed probe in the centre whose daily readings stayed neatly within 2-8 °C for years. A full mapping then revealed a warm zone at the top, near the evaporator outlet, that was structurally above the limit. The measurement point was fine, it just was not in the place that mattered.
When should you re-map (requalification)?
Repeating the mapping may be determined on a risk basis. A new mapping is in any case needed after significant changes: a refurbishment or extension, a new or replaced cooling installation, a different layout or loading pattern, or recurring deviations. Seasonal influence also plays a part, because spaces sensitive to outside temperature may need both a summer and a winter mapping.
Whenever the space changes, the same question returns: are we still monitoring the right place? Read when requalification is needed.
How many measurement points, and where?
The number of measurement points depends on volume, layout, airflow, loading and risk. There is no universal legal number. The logic is always the worst case: corners, near the door, near heat sources, and at different heights. Read how many measurement points are sensible.
Is your sensor in the right place?
A quick check to gauge whether your monitoring is substantiated:
- Is there a mapping report showing where the hot and cold spots are?
- Is the location of your fixed sensor based on it?
- Has the space been re-mapped after the last refurbishment, relocation or installation change?
- Were both a summer and a winter situation included?
Unsure about any of these?
Send us your situation and we will think along about a sensible, defensible approach.
Request a checkWho can carry out a temperature mapping?
A defensible mapping calls for a protocol defined in advance, calibrated loggers with traceable certificates, a justified measurement setup and a report that records the hot and cold spots and the right monitoring location. We carry this out for pharmacies, laboratories, clinics, GDP distributors and SMEs, and deliver an audit-ready report with raw data, graphs, hot- and cold-spot analysis, calibration certificates and monitoring sensor advice.
View our fridge and freezer mapping service
Sources used
- EU GDP 2013/C 343/01, chapter 3.2 (in particular 3.2.1) on premises and temperature control.
- IGJ FAQ on the EU GDP guideline, version 9.
- WHO TRS 961 Annex 9 Supplement 8, Temperature mapping of storage areas.
- ISPE Good Practice Guide: Controlled Temperature Chambers, 2nd edition.