Temperature & Humidity Mapping

Temperature mapping,
done to survive inspection

Thermal mapping characterises how temperature and humidity actually behave across your storage space over time — so you can prove, with data, that every corner stays in range.

What it is

Find the hot spots
before a regulator does

A mapping study places calibrated sensors throughout a warehouse, cold room, fridge, freezer or chamber and records conditions during real operations — goods in, picking, door openings and all.

For pharmaceutical products this isn't optional. It's required under EU GDP Guidelines, GMP Annex 1 and WHO Technical Report Series No. 961, and it applies to warehouses, cold rooms, refrigerators, freezers and vehicles alike.

Pallet racking in a temperature-controlled pharmaceutical warehouse
Sensor density

How many sensors do you need?

The most common question in mapping. WHO guidance gives a starting framework based on room size and risk.

Small rooms < 50 m²
Minimum 9 sensors, distributed to capture vertical and horizontal variation — not just the middle.
Medium 50 – 300 m²
Minimum 15 sensors, with extra units near doors, air-handling units and any known problem areas.
Large > 300 m²
15 sensors + 1 per additional 100 m², plus dedicated units at loading docks, external walls, floor and ceiling.
Data logger positioned near a warehouse loading door
Placement & seasons

Map the extremes,
not a tidy grid

A uniform grid tells you about the middle of the room. Excursions happen at the edges. Instrument these first, regardless of room size:

  • Beside every door — the biggest fluctuations
  • At supply and return air-handling zones
  • Floor and ceiling level — temperature stratifies
  • Against external walls, especially south-facing
  • At loading docks and receiving areas
Seasonality is not optionalGDP expects mapping under worst-case conditions — a summer study (highest ambient) and a winter study (lowest ambient), each typically a minimum of 7 consecutive days covering normal operations.
From mapping to monitoring

Design the system that
watches it from now on

A mapping study is a snapshot. Continuous monitoring is the film. Once you know where your environment drifts, the next step is a monitoring system that catches it — sensors at the right positions, alarms that mean something, and data integrity that satisfies 21 CFR Part 11. We compare the options and match you to the right one.

Mapping → Monitoring handover
Sensor positions from studyCarried forward
Worst-case locationsPermanently monitored
Alarm set pointsRisk-based
Data integrity21 CFR Part 11
Requalification triggerDocumented

Get your mapping right first time

Whether you need a full study, a second opinion on an existing one, or help writing the protocol — let's talk.