Why qualification exists
A datasheet tells you how a cabinet performed in the maker's test room. Qualification produces documented evidence that this particular unit, installed in your building and loaded your way, does what you need. WHO's supplement on qualifying temperature-controlled storage says all temperature-controlled equipment used to store such products should be qualified — and its scope explicitly includes refrigerators and freezers as well as cold rooms.
The stages in plain language
| Stage | Question it answers | Typical checks |
|---|---|---|
| DQ — design qualification | Was the right thing specified? | Design reviewed against a user requirements specification |
| IQ — installation qualification | Was it installed as specified? | Model and serial numbers, clearances, power supply, documentation, maintenance plan in place |
| OQ — operational qualification | Does it work as designed when empty? | Controller and sensor calibration, alarms, temperature distribution, door-open recovery, power-failure behaviour |
| PQ — performance qualification | Does it work in real use, loaded? | Temperature distribution and door-open recovery with product loaded and normal operations running |
What temperature mapping is
Mapping places several calibrated data loggers through a storage space and records them together for a set period. The result shows the temperature profile of the whole space: where the hot and cold spots are, how much the temperature varies, how quickly it recovers after a door opening and how long it holds after a power failure.
WHO's mapping supplement says new storage areas should be mapped before use, empty and in a normal loaded condition, and that the study should identify zones not to be used for product — for example near cooling coils or cold air streams.
How a basic mapping study runs
- Write a protocol first: the space, the acceptance range, logger positions, duration, recording interval and what counts as a pass.
- Use loggers with valid calibration. WHO's mapping supplement calls for a traceable three-point calibration with an error of no more than ±0.5 °C at each point.
- Set every logger to the same interval and start time. WHO's supplement suggests intervals of 1 to 15 minutes.
- Place loggers in a three-dimensional pattern — corners, centre, near the door, near the air outlet and return, top and bottom — and record their exact positions.
- Run the study long enough to capture normal cycles. For cold rooms and freezer rooms WHO suggests 24 to 72 hours; spaces affected by outdoor conditions need longer.
- Analyse minimum, maximum, average and hot and cold spots, then write a report with the raw data and calibration certificates attached.
Mapping refrigerators and small freezers
WHO's mapping supplement is written for rooms and notes that small-scale equipment such as refrigerators and freezers is generally tested independently, for example through prequalification. In practice many quality systems still map individual cabinets, with fewer loggers spread across shelves, corners and the door zone.
The goal is the same at any size: find out where product can safely go and where it cannot, and put the routine monitoring probe where it represents the stock.
Seasons and re-mapping in India
Where outside conditions affect a store, WHO's supplement suggests mapping in both the warmest and coldest seasons. In much of India that means a May–June study, when non-AC rooms push cabinets hardest, and a winter study where nights get cold.
Re-map after significant changes — a new set point, a moved cabinet, a different loading pattern or refrigeration repairs — and when monitoring records show unexplained variation. WHO suggests periodic re-mapping, for example every three years, depending on how continuously the space is monitored.
What to ask an equipment supplier
- Can you supply IQ and OQ documentation for this model, or support a third party who does?
- What uniformity and recovery data exists, at what room temperature and load?
- Where do you recommend placing the monitoring probe?
- Are spare logger ports or probe entry points provided for mapping without leaving the door ajar?
Frequently asked questions
- Is mapping the same as calibration?
- No. Calibration checks that a sensor reads correctly. Mapping uses calibrated sensors to find out how temperature varies across a whole storage space.
- Does a small clinic fridge need IQ/OQ/PQ?
- That depends on your regulator, your customers and your quality system. Distributors and manufacturers usually qualify all cold storage; small clinics often rely on supplier data and independent monitoring. Ask the authority or customer whose requirements apply to you.
- Who can carry out qualification?
- It can be done in-house or by a third party. WHO's supplement says the protocols and reports should be approved within your quality system either way.
