Cleanroom Cleaning Procedure: Cleaning, Disinfecting and Sterilizing
Published by Harmony Lab & Safety Supplies on Mar 13, 2025
Updated October 2026 · Harmony Lab & Safety Supplies
A cleanroom cleaning procedure removes particles and residues, then disinfects surfaces, in a set order: from the cleanest area to the dirtiest, from top to bottom, using low-lint tools and a disinfectant left wet for its full contact time. Done consistently, it keeps the room within its ISO classification. Done badly, cleaning itself becomes a source of lint, residue and cross-contamination. This guide covers the terms, the supplies, the step-by-step procedure and how often to clean.
Cleaning vs disinfecting vs sterilizing
The three words are often used interchangeably, but they mean different things, and a cleanroom program needs all three.
| Term | What it does | Notes |
|---|---|---|
| Cleaning | Removes dirt, residues and particles from a surface, usually with a detergent and a low-lint wipe or mop. | Always comes first. Disinfectants work poorly on a dirty surface. |
| Disinfecting | Kills most microorganisms on a surface with a chemical agent such as 70% isopropyl alcohol or a quaternary ammonium product. | Most disinfectants, including alcohol, do not reliably kill bacterial spores. |
| Sterilizing | Destroys all microbial life, including spores, by a validated process such as steam (autoclave), irradiation or a sterilant chemical. | Applied to items and supplies before they enter aseptic areas, not to the room itself. |
Where cleanroom contamination comes from
- People: skin flakes, hair, droplets and fibers from clothing. Gowning and behavior control most of this.
- Materials and equipment: cardboard, paper, tools and packaging carried in from outside. Remove outer packaging in the airlock and wipe items down before entry.
- The facility: particles that settle on surfaces, and anything that gets past or builds up around the HEPA filtration and air handling.
- The cleaning itself: linting wipes and mops, dirty mop water, and disinfectant residues left to build up.
Cleanroom cleaning supplies
| Task | What to use |
|---|---|
| Wiping work surfaces and equipment | Cleanroom wipes: polyester knit for ISO 5 and cleaner, poly-cellulose for ISO 6 to 8 |
| Disinfecting small surfaces and tools | Pre-saturated IPA wipes |
| Aseptic (sterile) areas | Sterile wipes and sterile disinfectants |
| Detergent cleaning of floors, walls and surfaces | Cleanroom cleaners and detergents |
| Floors and walls | Cleanroom mops with a multi-bucket system |
| Crevices, fixtures and small parts | Cleanroom swabs |
| Waste | Cleanroom trash bags |
| Checking results | Environmental surface testing |
Every tool that goes into the room should be rated for it. Ordinary cotton rags, sponges and household mops shed fibers. For help choosing wipes, see how to choose cleanroom wipes.
Cleanroom cleaning procedure, step by step
- Gown before you clean. Cleaning staff follow the same gowning procedure as everyone else in the room. Bring in only cleanroom-grade tools, and wipe buckets and handles down on entry.
- Work from the cleanest area to the dirtiest. Start in the cleanest room or zone and move toward the exit and the less clean areas, so you never carry contamination back into a cleaner space.
- Work from top to bottom. Ceilings and high surfaces first, then walls, equipment and work surfaces, and floors last. Particles that fall while you clean land on surfaces you have not cleaned yet.
- Clean, then disinfect. Remove residues and soil with a detergent first. EU GMP Annex 1 notes that prior cleaning is needed for disinfection to be effective.
- Respect the contact time. Apply the disinfectant and leave the surface wet for the full contact time on the product label. Wiping it dry early cuts the kill.
- Wipe in straight, overlapping strokes. Fold the wipe in quarters. Wipe in one direction with parallel, slightly overlapping strokes, and turn to a fresh face of the wipe for each stroke. Don’t scrub in circles, which spreads contamination around. Discard the wipe when its faces are used.
- Mop floors with a multi-bucket system. Keep the clean solution and the dirty rinse water separate, mop in unidirectional strokes toward the exit, and change solution at the interval your SOP sets. See our multi-bucket mopping guide.
- Remove disinfectant residue when your SOP calls for it. Some disinfectants leave a film that builds up over time. Many sites periodically wipe surfaces with sterile water or IPA to remove it.
- Bag waste and document the clean. Bag used wipes and mop heads in cleanroom trash bags and remove them from the room. Record what was cleaned, with what, and by whom.
Choosing a disinfectant
Isopropyl alcohol (IPA). 70% IPA is the most common cleanroom disinfectant for surfaces, tools and gloves. It evaporates quickly without residue. The CDC gives the optimum bactericidal concentration of alcohol as 60% to 90% in water. Alcohol is not sporicidal, so it is not used as a sterilant.
Detergents and other disinfectants. Neutral detergents remove soil before disinfection. Other disinfectant chemistries cover organisms that alcohol does not, and a sporicide handles spores. Follow the label for dilution, contact time and compatible surfaces.
Pharmaceutical sites. EU GMP Annex 1 expects more than one type of disinfectant, with periodic use of a sporicidal agent. Disinfectants and detergents used in Grade A and B areas must be sterile before use, and the disinfection process must be shown to work as it is actually applied.
Shop cleanroom cleaners, pre-saturated IPA wipes and the full range of cleanroom cleaning supplies.
How often to clean a cleanroom
Frequency depends on the class, the work done in the room and your environmental monitoring results. IEST-RP-CC018 covers how to set and monitor cleaning frequencies. A common starting schedule for a working cleanroom looks like this:
| Area | Typical frequency |
|---|---|
| Work surfaces, benches and frequently touched equipment | Every shift, or before and after each operation |
| Floors | Daily or every shift |
| Walls, doors and windows | Weekly |
| Ceilings, light fixtures and storage areas | Monthly |
| Sporicide application (pharmaceutical sites) | Periodically, at a frequency set from monitoring data |
Tighten the schedule for cleaner classes and higher-risk work, and adjust it when monitoring shows rising particle or microbial counts. Your SOP sets the actual frequencies.
Sterilizing supplies for aseptic areas
Rooms are cleaned and disinfected, while items going into aseptic areas are sterilized before entry. Many consumables come pre-sterilized by irradiation and double-bagged, so the outer bag can be removed in the airlock. Look for the sterility method and dose on the product’s spec sheet. Reusable tools and garments are sterilized by a validated process, such as autoclaving or irradiation, according to your procedures.
Frequently asked questions
Why is 70% IPA used instead of 99%?
Alcohol needs water to kill microorganisms effectively, and the CDC gives the optimum range as 60% to 90%. 70% also evaporates more slowly than 99%, which helps it stay wet for its contact time.
What is the correct order for cleaning a cleanroom?
Cleanest area to dirtiest, top to bottom, and clean before you disinfect. Floors are always last.
Can you use regular cleaning supplies in a cleanroom?
No. Household wipes, rags and mops shed fibers, and many household cleaners leave residues. Use low-lint, cleanroom-rated wipes, mops and cleaners.
How do you reduce contamination in a cleanroom?
Control the people (gowning and behavior), the materials coming in (wipe-down and packaging removal), and the room (filtration, pressure and a consistent cleaning program), and use environmental monitoring to check that it is working.
Related guides
- Cleanroom classifications: ISO classes, FS 209E and EU GMP grades
- Cleanroom gowning procedure: donning and doffing steps
- A guide to mopping cleanrooms with the multi-bucket system
- How to choose cleanroom wipes
- What is a cleanroom?
Sources
- CDC, Guideline for Disinfection and Sterilization in Healthcare Facilities: Chemical Disinfectants
- EU GMP Annex 1, Manufacture of Sterile Medicinal Products (2022), section 4 (Premises)
- IEST-RP-CC018, Cleanroom Cleaning and Sanitization: Operating and Monitoring Procedures
- IEST-RP-CC004, Evaluating Wiping Materials Used in Cleanrooms and Other Controlled Environments