IQ, OQ, PQ and Temperature Mapping: How a Mapping Study Feeds Equipment Qualification

In a GMP or pharmaceutical quality system, Installation Qualification (IQ), Operational Qualification (OQ) and Performance Qualification (PQ) are the three documented stages that turn a chamber, cold room or warehouse from "installed" into "proven to do what it is meant to do", and a temperature mapping study is one of the primary sources of evidence for that proof, particularly for OQ and PQ, because it is the only exercise that actually characterises how temperature behaves across the real, three-dimensional space rather than at a single control point. This guide assumes you already know what a mapping study is; if you need the fundamentals first, our guide to what temperature mapping is covers that ground. This article focuses specifically on where mapping sits inside the IQ, OQ, PQ vocabulary and how the evidence should be structured.

A quick refresher on the qualification lifecycle

Equipment qualification in a GMP context typically runs through a defined sequence: a User Requirements Specification (URS) states what the equipment needs to achieve, Design Qualification (DQ) confirms the proposed design meets that specification, and then three stages of physical proof follow.

• Installation Qualification (IQ) confirms the equipment, chamber or room was installed correctly and matches its design documentation: the right model, the correct utilities connected, drawings and manuals on file, and critically, that the sensors and instruments to be used are correctly installed and carry current, traceable calibration.
• Operational Qualification (OQ) confirms the system operates as intended across its specified operating range. This typically means testing an empty chamber or room at its temperature extremes, verifying alarms, and checking recovery behaviour, before any product is introduced.
• Performance Qualification (PQ) confirms the system performs consistently under real, loaded, operational conditions over a representative period. This is where mapping with product or a representative load, run for the duration the space is actually used, becomes the evidence.

Where mapping fits: OQ versus PQ

The underlying mapping methodology, a calibrated grid of data loggers analysed against acceptance criteria, following WHO TRS 961 Annex 9 and its Supplement 8 on temperature mapping of storage areas, and for chamber performance confirmation, the methods of IEC 60068-3-5 and IEC 60068-3-11, is reused across both OQ and PQ. What changes is the load condition and the acceptance criteria tied to each stage's protocol.

An OQ mapping run is usually performed empty, at the extremes of the space's specified range, including deliberate stress conditions such as an open-door test and, where safe to do so, a power-interruption or recovery test. The question OQ asks is: does this space have the physical capability to hold its specified range and recover from a disturbance, independent of what is stored inside it?

A PQ mapping run is performed loaded, or with a representative load, over a period long enough to capture real operational variation, commonly a full 7-day cycle for a warehouse or several days for a chamber. The question PQ asks is: does this space, in actual day-to-day use with product inside it and staff moving through it, continue to hold its specified range? Because loaded storage changes airflow, and because normal operational door-opening and goods movement differ from a controlled test, PQ data can and sometimes does show different hot spots than an empty OQ run found.

What IQ needs before mapping can even start

A mapping study cannot count as valid OQ or PQ evidence if the instruments that generated the data cannot themselves be trusted. This is where IQ and mapping intersect directly: before a study begins, the IQ record should confirm that every data logger deployed carries a current calibration certificate, that its serial number and calibration due date are documented, and that the logger's placement position in the study is recorded against that identity. At Unitest, mapping loggers go through our temperature calibration service under our SAC-SINGLAS accreditation, LA-2023-0845-C, so the instrument-level traceability that IQ requires is already built into how the study is resourced. Skipping this step, or using loggers with expired or undocumented calibration, breaks the chain an auditor will trace from the mapping report back to the instrument that produced each data point.

Building the traceability matrix

A qualification package that will hold up to inspection needs a clear line from each URS requirement, through DQ, IQ, OQ and PQ, to the specific piece of mapping evidence that satisfies it. In practice this means the mapping protocol should state explicitly which qualification stage it is generating evidence for, what the acceptance criteria are for that stage, and how the resulting report will be filed against the equipment's qualification package. A single mapping study written without that framing can still produce good data, but it forces the quality team to reconstruct the traceability after the fact, which is exactly the kind of gap an experienced auditor probes for. Structuring the protocol against the qualification stage before the study runs is the difference between mapping data and mapping evidence.

The honest accreditation position, restated for a qualification context

The same accreditation boundary applies inside an IQ/OQ/PQ package as anywhere else: the calibration of the data loggers used in the mapping study is accredited under SAC-SINGLAS LA-2023-0845-C, and that accredited, traceable measurement chain is what feeds the OQ and PQ evidence. The mapping study itself, and by extension the OQ or PQ report built on it, is a documented exercise executed to WHO TRS 961 Annex 9, IEC 60068-3-5 and IEC 60068-3-11, and your facility's own qualification protocol. It is not, and should not be described as, an accredited activity in its own right. Stating that distinction accurately inside a qualification package protects the package under scrutiny; overstating it is exactly the kind of claim a GMP inspector will unpick.

Common gaps that fail an inspection

• Running an OQ empty-chamber map but never following it with a loaded PQ study, leaving the qualification without evidence of real operating conditions.
• Using different loggers, or loggers without documented calibration, between the OQ and PQ runs, breaking the instrument-level traceability an auditor expects across the qualification stages.
• Writing generic acceptance criteria that do not map back to the specific URS requirement or process parameter the equipment is meant to satisfy.
• Treating a single mapping study as covering both OQ and PQ without documenting why the empty and loaded conditions were, or were not, materially different for that specific space.
• Failing to trigger a PQ requalification after a layout, load pattern or cooling-system change, leaving the performance evidence out of date relative to how the space is actually run.

For the underlying mechanics of how a study itself is structured, protocol through report, our step-by-step mapping guide walks through each stage in detail, and it applies equally whether the study is being run for OQ or PQ purposes.

Get your IQ, OQ or PQ mapping study scoped

Whether you need an empty-chamber OQ run, a loaded PQ study, or both structured as a single coherent qualification package, the protocol should be written against your facility's actual URS and acceptance criteria. Our temperature mapping service in Singapore and temperature and humidity mapping service cover chambers, cold rooms and warehouses for GMP and GDP qualification. Contact our team to discuss your qualification stage and get a scoped protocol.