ISO 14644 Classification System
ISO 14644-1 classifies cleanrooms by maximum allowable airborne particulate concentration. BSCs need to understand what class their client operates before specifying any procedure or product.
| ISO Class | Max Particles ≥0.1μm /m³ | FED 209E Equivalent | Typical Application | Gowning Level |
|---|---|---|---|---|
| ISO 1 | 10 | N/A | Advanced semiconductor R&D | Full bunny suit + PAPR |
| ISO 3 | 1,000 | Class 1 | Semiconductor lithography | Full bunny suit + gloves + mask |
| ISO 5 | 100,000 | Class 100 | Semiconductor, biotech | Full bunny suit + double gloves |
| ISO 6 | 1,000,000 | Class 1,000 | Pharmaceutical mfg, medical devices | Bunny suit or coverall + face mask |
| ISO 7 | 10,000,000 | Class 10,000 | Medical device assembly, pharma | Coverall, hair cover, gloves, mask |
| ISO 8 | 100,000,000 | Class 100,000 | Electronics assembly, packaging | Smock/coat, hair cover, gloves |
Gowning Requirements for Cleaning Personnel
Cleaning technicians are among the highest contamination-generating individuals in a cleanroom environment. A standing human generates approximately 100,000 particles per minute; a moving, working human generates 5–10 million particles per minute. Proper gowning is the primary contamination control measure.
ISO 5–6 Gowning Protocol
- Gown room entry: Remove street shoes; put on cleanroom-approved booties or dedicated cleanroom shoes
- Tacky mat: Step onto tacky mat to remove residual sole particulate
- Coverall/bunny suit: Don full-body cleanroom coverall with integrated hood; verify no exposed hair, skin, or street clothing
- Gloves: Nitrile or latex cleanroom gloves; double-gloving for ISO 5 environments
- Face mask / respirator: Surgical mask minimum for ISO 6; full-face respirator or PAPR for ISO 5
- Gown inspection: Supervisor visual inspection before entry clearance
- Gown room exit: Never re-enter cleanroom after exiting gown room without re-gowning
ISO 7–8 Gowning Protocol
Less stringent but still critical:
- Cleanroom smock or coverall over street clothing
- Hair/beard cover
- Clean gloves
- Appropriate footwear; tacky mat at entry
Cleaning Materials and Chemicals
Material Selection Criteria
Only materials specifically validated for use in the cleanroom classification are acceptable. Standard commercial cleaning products generate particle and chemical contamination that can fail particle count verification.
Key material properties:
- Low-linting: All cloths, mops, and wipes must be tested and certified for particle shed — non-woven polyester or microfiber materials validated for specific ISO class use
- Non-shedding: No open-cell foam, paper towels, or cotton materials in ISO 5–7 environments
- Low VOC/outgassing: Solvents and cleaning chemicals used in semiconductor cleanrooms must not outgas compounds that contaminate process chemistry — IPA (isopropyl alcohol, semiconductor grade) is the most commonly used cleanroom cleaner
- Particle-free water: Deionized (DI) water, not tap water, is used as the diluent for all cleanroom cleaning solutions — mineral deposits from tap water are a particulate contamination source
Approved Cleanroom Chemicals
| Chemical | Application | ISO Class |
|---|---|---|
| IPA (semiconductor grade, 70% in DI water) | General surface wipe | ISO 5–8 |
| Deionized water | Rinse; mopping dilutant | ISO 5–8 |
| Cleanroom-grade quaternary | Surface disinfection (biotech, pharma) | ISO 6–8 |
| Hydrogen peroxide vapor (HPV) | Terminal decontamination (biotech) | ISO 5–7 (specialist only) |
| Cleanroom-grade glass cleaner | Window and viewport surfaces | ISO 6–8 |
| Category | Value |
|---|---|
| ISO 8 | 100% |
| ISO 7 | 200% |
| ISO 6 | 300% |
| ISO 5 | 500% |
| ISO 3 | 700%+ |
IEST-RP-CC018 Cleanroom Housekeeping Standard
The Institute of Environmental Sciences and Technology (IEST) publishes Recommended Practice CC018, which is the industry reference standard for cleanroom housekeeping operations. Key protocols from CC018:
Movement protocol: Always move in the direction of airflow — from cleanest zone to less clean zone. In a unidirectional flow (laminar) cleanroom, always work in the direction of the airflow stream.
Wiping technique: Use overlapping S-pattern wipe technique — never circular wiping, which redistributes contamination. Each wipe stroke uses a fresh, clean surface of the cloth; fold and rotate to expose new surface.
Mop technique: Use a wrung-out, damp mop; overlap each pass by 25%; change mop head when soiled; never dry-mop.
Waste management: All cleaning materials (used wipes, mop heads, spent supplies) exit the cleanroom in sealed bags; never shake out mops or wipes inside the cleanroom.
$2.50–$8.00
Per-square-foot annual cleaning cost range for ISO 6–8 cleanroom facilities — with ISO 5 semiconductor fabs at $15–$40/sq ft annually — reflecting specialized labor, validated materials, and documentation overhead
Source: IEST Cleanroom Operations Resource Center, 2024
| Requirement | ISO 7–8 | ISO 5–6 |
|---|---|---|
| Staff Gowning Training | Required; smock/hair cover | Required; full bunny suit certification |
| Validated Cleaning Materials | Low-linting certified materials | Particle-tested; ISO class-certified |
| Chemical Qualification | Cleanroom-approved product list | Semiconductor-grade IPA/DI water only |
| Particle Count Verification | Periodic (quarterly typical) | Post-clean verification standard |
| Written SOPs | Required | Required; audited by client |
| Insurance Minimums | $2M GL; E&O recommended | $5M GL; errors & omissions required |
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Frequently Asked Questions
How much contamination does a cleaning tech generate?
A person standing perfectly still sheds roughly 100,000 particles per minute. Once that same person is moving and working, the count climbs to 5-10 million. Cleaning staff end up among the highest particle generators in the room, meaning the crew sent in to remove contamination is also one of its largest sources. Gowning, not scheduling, is the primary control for that.
Which gowning does each ISO class require?
ISO 5 calls for the full bunny suit, double gloves, and a full-face respirator or PAPR. ISO 6 steps down to a bunny suit or coverall with a face mask. ISO 7 requires a coverall, hair cover, gloves, and mask. ISO 8 is satisfied by a smock or coat with hair cover and gloves.
What does the ISO class number actually mean?
Each class sets the maximum allowable airborne particle concentration per cubic meter under ISO 14644-1, so a lower number means tighter air. ISO 5, the old FED 209E Class 100, allows 100,000 particles at 0.1 micron or larger per cubic meter. ISO 8 is the old Class 100,000. The number is a ceiling on the air, which is why the gowning tightens in step with it.
Where does semiconductor work sit versus packaging?
Semiconductor and biotech operations sit at ISO 5, the tightest class here and the one carrying the full bunny suit, double gloves, and full-face respirator or PAPR. Electronics assembly and packaging generally sit at ISO 8, the old Class 100,000, where a smock or coat, hair cover, and gloves cover the requirement. Knowing which class a space is rated to tells you the gowning bill before you price the labor.
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Opora editorial sources from BLS OEWS wage tables, ISSA-447 production rates, NCCI workers' compensation classifications, EPA List N, OSHA 29 CFR standards, and primary state regulatory filings. We don't recycle blog posts — we audit primary documents.
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