IQ, OQ, and PQ stand for Installation Qualification, Operational Qualification, and Performance Qualification — the three sequential stages of equipment qualification used to prove a system was installed correctly, operates as intended across its full range, and performs consistently under real production conditions. They form the core of equipment validation under cGMP (21 CFR Part 211) and the FDA process validation framework, and are performed in order after Design Qualification (DQ). Each stage produces documented, signed evidence that the equipment is fit for its intended use.
What IQ, OQ, and PQ mean
Equipment qualification is the documented process of demonstrating that a piece of equipment or a system does what it is supposed to do. Rather than a single test, it is broken into stages so that each foundation is verified before the next is built on top of it. This staged approach is why the three qualifications are always referenced together and always performed in the same order.
Installation Qualification (IQ) verifies that the equipment is received and installed correctly and matches its approved specifications. IQ checks the physical build: correct model and serial numbers, materials of construction, utility connections, calibration status of instruments, slope and support of sanitary piping, and that installation follows the manufacturer’s requirements. Deliverables include the completed IQ protocol, as-built drawings, material and calibration certificates, and a signed summary confirming the installation is correct before any power-on testing begins.
Operational Qualification (OQ) verifies that the installed equipment operates as intended across its full specified operating range. OQ challenges the system at its limits — temperatures, pressures, flow rates, speeds, alarms, interlocks, and control functions — to confirm it behaves correctly not just at a nominal setpoint but throughout the range it will actually be run. Deliverables include the executed OQ protocol, functional and alarm test records, and documentation of any deviations and their resolution.
Performance Qualification (PQ) verifies that the equipment performs consistently and reproducibly under real, routine production conditions, typically using actual product or a representative surrogate. Where OQ proves the machine can do the job across its range, PQ proves it reliably does the job as part of the intended process, usually across multiple runs to demonstrate reproducibility. Deliverables include the executed PQ protocol, run data, and a summary establishing that the system is ready for routine use.
Where DQ fits and the order of the stages
Design Qualification (DQ) comes before IQ. DQ documents that the proposed design of the equipment or system is suitable for its intended purpose and meets user requirements and cGMP expectations — it is completed during design and procurement, before the equipment is built or delivered. The full lifecycle sequence is therefore DQ → IQ → OQ → PQ.
The order matters because each stage depends on the one before it. There is no point challenging operating limits (OQ) if the equipment was not installed and calibrated correctly (IQ), and no point running production loads (PQ) if the controls and alarms have not been proven across their range (OQ). A deviation found late is far more expensive to resolve, so completing each stage and approving it before starting the next is both a regulatory expectation and sound engineering practice.
IQ vs OQ vs PQ compared
| IQ | OQ | PQ | |
|---|---|---|---|
| What it verifies | Correct installation against specifications | Correct operation across the full operating range | Consistent performance under routine production conditions |
| Example checks | Model/serial, materials of construction, utility hookups, instrument calibration, piping slope | Operating limits, flow/pressure/temperature ranges, alarms, interlocks, control functions | Multiple production runs with product or surrogate, reproducibility of results |
| Key question | Was it installed correctly? | Does it operate as intended? | Does it perform consistently? |
| Deliverable | Signed IQ protocol, as-builts, calibration & material certs | Executed OQ protocol, functional & alarm test records | Executed PQ protocol, run data, readiness summary |
How IQ/OQ/PQ fit into cGMP validation
Under current Good Manufacturing Practice, a manufacturer must demonstrate with documented evidence that equipment and processes are capable of consistently producing product that meets its predetermined quality attributes. Equipment qualification (IQ/OQ/PQ) provides the equipment-level foundation for that evidence, and it feeds into the broader process validation lifecycle described in FDA guidance — process design, process qualification, and continued process verification.
Qualification is not a one-time event. Significant changes to equipment, controls, or use, as well as periodic review, can trigger requalification. Throughout, protocols are written and approved before execution, results are recorded contemporaneously, deviations are investigated, and a final report is signed — because in a cGMP environment, if it is not documented, it is not done.
Standards & references
- cGMP / 21 CFR Part 211
- The FDA’s Current Good Manufacturing Practice regulations for finished pharmaceuticals. They require that equipment be suitably designed, of adequate capacity, and appropriately qualified for its intended use — the legal basis for performing IQ, OQ, and PQ.
- FDA Process Validation guidance
- The FDA’s guidance on process validation frames validation as a lifecycle: process design, process qualification, and continued process verification. Equipment qualification supports the process qualification stage by proving the equipment is fit for use.
- GAMP 5 (ISPE)
- A Good Automated Manufacturing Practice framework from ISPE that provides a risk-based, scalable approach to qualifying and validating automated and computerized systems, widely used to structure IQ/OQ/PQ deliverables.
Frequently asked questions
What does IQ OQ PQ actually mean?
What is Installation Qualification (IQ)?
What is Operational Qualification (OQ)?
What is Performance Qualification (PQ)?
Why must IQ, OQ, and PQ be done in that order?
Is IQ OQ PQ required by the FDA?
What is the difference between qualification and validation?
Who writes IQ OQ PQ protocols?
What documents make up an IQ OQ PQ package?
What happens if a qualification test fails?
How long does IQ OQ PQ take?
Does IQ OQ PQ apply to more than water systems?
Yes, to essentially every piece of GxP equipment and to software. Autoclaves, bioreactors, CIP skids, cleanrooms, freeze dryers, filling lines, laboratory instruments and computerized systems all follow the same three-stage logic, though what constitutes performance qualification differs sharply. For a water system it is three phase sampling; for an autoclave it is thermal mapping of each load pattern; for a cleaning system it is recovery studies and worst-case sampling; for software it is testing against user requirements.
What is a DQ and how does it relate to IQ OQ PQ?
Can you requalify existing equipment we already own?
What are acceptance criteria in a qualification protocol?
Who is accountable when one firm handles the whole IQ OQ PQ?
What does IQ, OQ, PQ stand for?
Installation, operational and performance qualification. Installation qualification documents that what was installed matches what was specified. Operational qualification demonstrates the equipment performs across its full operating range rather than at a single design point. Performance qualification proves it performs consistently in routine use with actual materials and loads. The distinction that matters commercially is that a supplier factory or site acceptance test is none of these; it is a commercial confirmation against a purchase order.
What is the difference between IQ, OQ, and PQ?
What order are IQ, OQ, and PQ done in?
In that order, and the sequence is not administrative. Each stage assumes the previous one passed, so running operational qualification on equipment whose installation was never verified means testing performance against an unknown baseline. The practical argument is cost: a wrong heat number, an uncalibrated instrument or a section that does not drain is cheap to fix while access is open and crews are on site, and expensive once the system is closed, passivated and sampled.
What is DQ (Design Qualification)?
Who performs IQ, OQ, and PQ?
Need equipment installed and qualified?
Paul Industries designs, installs, and validates process-equipment and sanitary-piping systems for manufacturers nationwide.
Request a Project Quote or call 201-450-8280What is the regulatory basis for IQ, OQ and PQ?
Qualification is not a stand-alone practice; it is how a facility demonstrates compliance with specific, citable regulatory requirements. The sections below are the ones inspectors actually reference, and naming them in your protocols makes the link explicit.
| Citation | What it requires | Stage it drives |
|---|---|---|
| 21 CFR 211.63 | Equipment of appropriate design, adequate size and suitably located for its intended use, and to facilitate cleaning and maintenance | DQ and IQ |
| 21 CFR 211.65 | Equipment surfaces must not be reactive, additive or absorptive so as to alter product quality | IQ — materials of construction verification |
| 21 CFR 211.67 | Equipment cleaned and maintained at appropriate intervals to prevent contamination altering product quality | OQ and cleaning validation |
| 21 CFR 211.68 | Automatic, mechanical and electronic equipment must be routinely calibrated, inspected and checked according to a written program | IQ and OQ — calibration and control systems |
| 21 CFR 211.100(a) | Written procedures for production and process control, designed to assure the drug products have the identity, strength, quality and purity they purport to possess | PQ |
| 21 CFR 211.110 | Control procedures to monitor output and validate performance of manufacturing processes that may cause variability | PQ and continued process verification |
| 21 CFR 211.113(b) | Validation of any sterilization process | PQ for sterilizers, SIP and depyrogenation |
| 21 CFR 211.160(b) | Scientifically sound and appropriate laboratory controls, specifications and test procedures | Analytical and utility qualification |
| 21 CFR 211.182 | Equipment cleaning and use log | Post-qualification lifecycle |
| 21 CFR Part 11 | Controls for electronic records and electronic signatures | All stages where data is captured electronically |
| FD&C Act 501(a)(2)(B) | Statutory basis: a drug is adulterated if not manufactured in conformity with cGMP | Underpins the entire program |
Outside the United States the equivalent framework is EU GMP Annex 15 (Qualification and Validation), EU GMP Annex 11 (Computerized Systems), ICH Q8, Q9 and Q10, WHO Technical Report Series 1019, and PIC/S PI 046. Risk-based commissioning and qualification is addressed by ASTM E2500, and computerized systems by GAMP 5, Second Edition.
DQ vs IQ vs OQ vs PQ — what does each stage verify?
Four stages, four different questions. Confusing them is the most common protocol error we see.
| Stage | Question it answers | When | Typical evidence |
|---|---|---|---|
| DQ — Design Qualification | Is the proposed design capable of meeting the user requirements? | Before purchase or fabrication | URS to design traceability, design review records, materials of construction |
| IQ — Installation Qualification | Was it installed as designed and specified? | After installation, before operation | P&ID walkdown, weld and material certs, calibration certificates, utility connections, software version records |
| OQ — Operational Qualification | Does it operate as intended across the full operating range? | After IQ, before product | Alarm and interlock testing, range and setpoint challenges, failure and recovery testing, sequence verification |
| PQ — Performance Qualification | Does it perform consistently under real production conditions? | After OQ, using production materials | Consecutive successful runs, worst-case challenges, sampling against acceptance criteria |
Who performs IQ, OQ and PQ, and who signs them off?
Execution is usually shared. The equipment vendor or installing contractor typically executes IQ and much of OQ, because they hold the design detail and the installation records. The owner’s engineering or validation function executes or witnesses PQ, because PQ uses production materials and production procedures.
Approval is not shared. Quality Assurance owns final approval of every protocol and every report. Under 21 CFR 211.22 the quality control unit has the authority to approve or reject procedures and specifications, and a qualification package that has not been approved by QA is not a completed qualification regardless of how thoroughly it was executed.
How many PQ runs are required?
There is no regulatory number. The frequently cited “three consecutive batches” convention appears nowhere in 21 CFR 211 and the FDA has explicitly moved away from it in its process validation guidance, which asks instead for a number justified by risk, process understanding and variability.
In practice, three successful consecutive runs remains common for well-understood processes because it is the minimum that demonstrates reproducibility rather than a single success. Processes with higher variability, novel technology, or limited prior knowledge routinely require more, and the justification for whatever number you choose belongs in the validation master plan and the PQ protocol — not in a footnote.
What must an IQ protocol contain to be compliant?
An IQ that survives inspection is specific and traceable. At minimum it should carry:
- A stated purpose, scope and system boundary, with the equipment identified by asset number
- Traceability from the user requirement specification through to each verification
- Equipment identification: manufacturer, model, serial number, and software and firmware versions where applicable
- Materials of construction verification with mill certifications, addressing 21 CFR 211.65
- Utility connection verification — clean steam, purified water, WFI, compressed air, power
- Instrument list with current calibration certificates, addressing 21 CFR 211.68
- P&ID and drawing walkdown records, red-lined to as-built where required
- Weld documentation for hygienic piping: weld map, weld log, welder and procedure qualification records
- Slope, drainability and pressure test records where applicable
- Passivation and surface finish records for product-contact surfaces
- Safety and environmental verification, including interlocks
- Documented acceptance criteria for every test, with pass or fail recorded against each
- Deviation records with impact assessment and disposition
- QA approval signature and date on both protocol and report
Two of these are where projects most often fall short at turnover: the weld documentation package, and per-test acceptance criteria written before execution rather than assessed afterwards.
More questions we are asked
What are the differences between IQ, OQ, and PQ qualifications in equipment validation?
They test different questions in sequence. Installation qualification verifies the equipment was delivered and installed as specified: correct model and materials, utilities connected properly, instruments calibrated, drawings and manuals present, and for fabricated systems the weld records, material certificates and passivation certification. Operational qualification challenges each critical operating parameter across its full range rather than at setpoint alone, demonstrating the system does what it is supposed to do under all intended conditions, including alarms and interlocks. Performance qualification demonstrates sustained performance in actual use with real or simulated product, over enough runs or enough time to show consistency. The frequent error is treating PQ as a longer OQ; PQ is about the process, not the machine.
What is the purpose of IQ OQ PQ in regulated industries?
The purpose is to convert an assumption into documented evidence. Without qualification, a plant asserts that equipment works; with it, the plant can show a regulator how that was demonstrated and under what conditions. That matters legally because cGMP requires it, but the practical value is different: qualification establishes the baseline against which every future deviation is judged. When a system drifts three years later, the qualification package is what tells you how it performed when it was known good. It also forces the engineering questions to be asked before production starts rather than during an investigation. A plant with weak qualification is not just non-compliant; it has no reference point for troubleshooting.
Best practices for creating an IQ OQ PQ master plan
Start from a user requirement specification, because every test should trace to a stated requirement and untraceable tests are wasted effort. Apply risk to scale the work, in the spirit of ASTM E2500, so that critical aspects affecting product quality are tested thoroughly and non-critical features are documented lightly rather than tested to the same depth. Define acceptance criteria that are specific and measurable before execution, not after seeing results. State explicitly how vendor factory and site acceptance testing will be leveraged so supplier testing is not repeated needlessly. Define the deviation process and who may close deviations. And schedule realistically, since PQ on a compendial water system is calendar time that cannot be compressed by adding people.
How do IQ, OQ, and PQ qualifications impact FDA compliance in the pharmaceutical industry?
They are the evidence an inspector examines, and the way they fail inspection is rarely that they were absent. The common findings are qualification performed against vague requirements so the tests prove little; acceptance criteria written loosely enough that anything passes; deviations raised during execution and closed without genuine resolution; and, most often, a validated state that was not maintained, meaning the system was qualified years ago and has since accumulated undocumented changes, overdue calibrations and unexplained excursions. Inspectors probe the maintenance of the validated state more than the original package, because that is where the real risk sits. Change control, calibration, preventive maintenance and periodic review are what keep qualification meaningful.