Explain equipment qualification (IQ, OQ, PQ), process validation, cleanroom grades and why gowning is done in a fixed order.
Why it matters
GMP does not trust equipment or processes because they look right. It requires documented evidence that they work as intended, every time: this is validation. And for products that cannot be terminally sterilised, such as many biologics, the room itself is part of product protection: cleanrooms control particles and microbes, and people, the biggest source of contamination, enter them only after gowning in a fixed sequence. Technicians execute qualification protocols, perform environmental monitoring and gown many times a day.
Equipment qualification: IQ, OQ, PQ
Before a new bioreactor, incubator, autoclave or HPLC is used for GMP work, it is qualified against its user requirements specification (URS):
| Stage | Question | Examples |
|---|---|---|
| DQ design qualification | Is the design suitable for the URS? | Review of specifications and drawings |
| IQ installation qualification | Is it installed correctly, as specified? | Correct model and parts, utilities connected, calibration certificates, manuals and drawings filed, software version recorded |
| OQ operational qualification | Does it operate across its intended ranges? | Temperature control at low, mid and high set points; alarms trigger; door interlocks work |
| PQ performance qualification | Does it perform consistently under real conditions? | Temperature mapping of a loaded incubator over days; a sterilisation cycle with a real load and biological indicators |
Each stage has an approved protocol written before testing, with acceptance criteria. Results go in a report; any failure is a deviation that must be resolved. After qualification, equipment stays in a validated state through calibration, preventive maintenance, periodic review and change control: a change (new software version, moved equipment) is assessed and may need requalification.
Process validation
Qualified equipment is necessary but not enough: the process must be shown to make product of the required quality consistently. FDA's process validation guidance describes three stages: process design (development defines critical parameters), process qualification (including process performance qualification batches at commercial scale) and continued process verification (ongoing monitoring of every batch). Cleaning procedures, analytical methods and computerised systems are validated too.
Cleanrooms
Cleanrooms are classified by airborne particle counts. ISO 14644-1 defines classes such as ISO 5, 7 and 8. EU GMP Annex 1 (in EudraLex Volume 4: https://health.ec.europa.eu/medicinal-products/eudralex/eudralex-volume-4_en, checked on 2026-10-23) uses grades A to D for sterile manufacturing:
- Grade A: the critical zone where sterile product or open containers are exposed (inside a unidirectional airflow hood or isolator).
- Grade B: the background room around Grade A for aseptic work.
- Grades C and D: less critical steps, such as preparing solutions.
Key design features: HEPA-filtered air supply, many air changes per hour, a pressure cascade (cleaner rooms at higher pressure, so air flows outward toward dirtier areas), airlocks between grades, smooth cleanable surfaces, and controlled flows of people and materials.
Environmental monitoring checks that the room stays in control: particle counts, settle plates and air samples for microbes, contact plates on surfaces and on operators' gloves and gowns. Results are trended, and excursions are investigated. Aseptic process simulations (media fills) run the aseptic process with growth medium instead of product to show that operators and process do not introduce contamination.
Gowning
People shed skin cells and microbes constantly, so gowning procedures are strict and sequential, moving from "dirty" to "clean":
- Remove outdoor clothing and jewellery; wash hands.
- Put on shoe covers or dedicated shoes, crossing a step-over bench.
- Put on a hood or hair cover and face mask (and goggles as required).
- Put on the sterile coverall without letting it touch the floor, then sterile boots over it.
- Put on sterile gloves, often two pairs, sanitised regularly.
- Check yourself in a mirror for gaps.
The order matters: you cover the head before the coverall, so hair and skin particles fall onto clothing you will cover, not onto the clean suit. Operators are gowning qualified (with contact plates taken from the gown) before entering Grade A/B areas, and requalified periodically. Inside, they move slowly and deliberately and never touch critical surfaces.
Common mistakes
- Running OQ before IQ is approved, or testing without an approved protocol.
- Moving or modifying qualified equipment without change control.
- Letting the coverall touch the floor during gowning.
- Fast movements and talking over open product in Grade A.
- Treating environmental monitoring excursions as noise instead of trends to investigate.
Quick recap
- IQ: installed correctly; OQ: operates across ranges; PQ: performs consistently in real use. Protocol first, report after.
- Validation covers processes, cleaning, methods and computerised systems; change control keeps the validated state.
- Cleanrooms: HEPA air, pressure cascade, airlocks; EU grades A to D; environmental monitoring and media fills.
- Gowning follows a fixed dirty-to-clean order; operators are gowning qualified.
Try it
The Do tab has a quiz on qualification stages and gowning.