Temperature Mapping | Cold Chambers

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Temperature Mapping in Pharmaceuticals: Complete Guide

What Is Temperature Mapping in Pharma?

Temperature mapping (thermal mapping) is the study of temperature distribution within a temperature-controlled area such as warehouses, cold rooms, freezers, refrigerators, stability chambers and temperature-controlled vehicles. The goal is to demonstrate that the area can consistently maintain products within their labelled storage range and to identify hot and cold spots.

Typical mapped areas:

Finished goods and raw material warehouses
Cold rooms (2–8 °C), freezers (–20 °C, –80 °C)
Quarantine / sampling rooms
Stability chambers and incubators
Reefer containers, reefer trucks and other temperature-controlled vehicles

Regulatory Expectations

WHO Guidance

WHO TRS 961, Annex 9, Supplement 8 – Temperature Mapping of Storage Areas describes a systematic approach for mapping any cold room, freezer room or other temperature-controlled store. It outlines four stages: mapping protocol, mapping execution, mapping report and implementation of recommendations. World Health Organization+2World Health Organization+2

EU GDP Guidelines

EU GDP guidelines require an initial temperature-mapping exercise for storage areas before use, under representative conditions. Mapping should:

Consider seasonal variations
Be repeated based on risk assessment and after significant modifications
Be used to locate permanent temperature monitoring probes at identified worst-case points (hot and cold spots) GMP Compliance+2EUR-Lex+2

Other References

WHO technical supplement on qualification of temperature-controlled storage areas links mapping to overall qualification / validation. World Health Organization
USP <1079.4> provides guidance specifically for temperature mapping of controlled temperature chambers and storage areas. usp.org

Objectives

A compliant mapping study should:

Demonstrate that the defined temperature range (e.g., 2–8 °C, 15–25 °C) is maintained throughout the storage period
Identify hot spots and cold spots and areas not suitable for storage
Support decisions on placement of continuous monitoring probes and alarms
Provide evidence for qualification / validation of warehouses, cold rooms and vehicles
Feed into risk assessments and remedial actions (HVAC improvement, air distribution changes, racking adjustments, load patterns) World Health Organization

Step-by-Step mapping Process

1. Risk Assessment and Study Design

Define products stored (e.g., 2–8 °C biologics, room-temperature tablets).
Review layout, HVAC, racking height, doors, windows, loading bays.
Identify potential risk areas: near doors, ceilings, corners, skylights, vents, and densely packed racks.
Decide whether to include humidity mapping where RH is critical.

Deliverable: Mapping Protocol (scope, acceptance criteria, number and location of loggers, sampling interval, duration, loading pattern, seasonal considerations). World Health Organization+1

2. Data Logger Selection and Placement

Use calibrated data loggers with appropriate accuracy (e.g., ±0.5 °C) and traceable calibration certificates.
Place loggers in a 3-D grid, typically at:
- Corners, centre, and mid-points of the room
- Top, middle, bottom of racking
- Near doors and air inlets/returns
- Identified risk points from the risk assessment
Ensure each logger has a unique ID and documented location diagram.

3. Execution Under Representative Conditions

Run mapping during worst-case conditions, e.g., hottest or coldest season and maximum or typical load.
Define study duration (often 24–72 hours for small rooms, up to several days for large warehouses).
Record operational events: door openings, defrost cycles, power interruptions, loading/unloading activities.

4. Data Analysis and Acceptance Criteria

Download and secure raw data.
Confirm that all logger readings remain within specified range plus any allowed excursion limits.
Identify:
- Maximum and minimum temperatures per location
- Time out of specification (if any)
- Worst-case hot and cold spots
Investigate OOS events; decide on corrective and preventive actions (CAPA).

5. Mapping Report and Follow-Up

A GMP-compliant mapping report typically includes: objective, scope, description of area, equipment details, logger layout, raw data summary, deviations, conclusions and recommendations.

Use findings to:

Relocate or add HVAC outlets / returns
Modify storage practices (e.g., no storage near doors)
Define permanent monitoring probe locations at identified worst-case points
Set alarm set-points and response procedures

How Often Should Temperature Mapping Be Repeated?

The frequency is risk-based and should consider:

Change of use (new product type or temperature range)
Significant modifications (HVAC changes, new racking, wall/door changes)
Temperature-related deviations or trend issues
Time since last mapping and criticality of products

Many companies remap warehouses every 1–3 years or when triggered by change control, in line with EU GDP and WHO risk-based guidance.

Common Pitfalls in Mapping

Inadequate number of loggers or poor placement
Mapping under non-representative conditions (e.g., empty warehouse used fully loaded)
Ignoring seasonal extremes
Not linking mapping results to permanent monitoring probe placement
Missing CAPA or change control when issues are identified

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FAQs on Temperature Mapping in Pharma

Q1. Is temperature mapping mandatory?
Regulations don’t always use the word “mandatory”, but WHO, EU GDP and USP guidance all expect temperature-controlled storage areas to be qualified via mapping and for monitoring probe locations to be justified by mapping data. For licensed pharma sites, mapping is effectively a regulatory expectation.

Q2. Do we need to map room-temperature warehouses?
Yes, if they store medicinal products. Ambient warehouses must also demonstrate that 15–25 °C (or other defined range) is maintained and that monitoring probes are in the correct locations.

Q3. How many loggers are required?
There is no fixed number in guidelines. The quantity should be justified by room volume, complexity, risk areas and criticality of products. A 3-D grid plus additional loggers at high-risk points is common practice.

Q4. Can we combine temperature and humidity mapping?
Where relative humidity is critical (e.g., hygroscopic APIs, capsules, some biologics), combined temperature/RH mapping is recommended so that both parameters are understood across the room. World Health Organization+1

Q5. What is the difference between mapping and routine monitoring?

Mapping = short-term, intensive study using many loggers to characterize the environment.
Monitoring = continuous measurement at selected points (usually worst-case) justified by mapping results.

Chemical SOP

Microbiology SOP

Warehouse SOP

Manufacturing SOP

Information technology SOP

TEMPERATURE MAPPING STUDY OF COLD CHAMBERS, INCUBATORS, WAREHOUSES, TRANSPORT VALIDATION, STABILITY CHAMBERS & REFRIGERATORS FOR PHARMACEUTICAL INDUSTRY