Using the Right Tools Effectively

Understanding Wiper Types and Their Applications

The presenter outlines multiple wipe categories:

Non-Wovens

• Creped: Added texture increases sorbency.
• Apertured: Texture creates spaces to trap contaminants.
• Flat goods: Cleaner (less contaminative) but less sorbent.

There is always a trade-off: adding features (e.g., sorbency) may increase contamination risk.

Knitted Wipes

• Made from continuous threads, generally cleaner than non-wovens.
• Commonly used in ISO 5 and more critical environments.
• Laminated knits improve sorbency by increasing internal spacing.

Specialty Wipes

• Sealed borders (common in semiconductor).
• Electrostatic dissipative wipes (typically not needed in pharma).

The key takeaway: wipe selection must match room classification and application.

Mop Systems and Hardware Considerations

Mops vary widely:

• Flat mops (often for walls)
• String mops (common for floors)
• Knitted mop covers
• Different colors (though color can leach into solutions)

Hardware selection (handles, frames, carts) must align with:

• Chemical compatibility
• Autoclavability (for aseptic pharma)
• Sterility requirements
• Operator ergonomics

Key Tool Selection Criteria Before Purchasing

Before engaging vendors, facilities should evaluate:

• Chemical compatibility with disinfectants/sporicides
• Autoclavability or sterile availability
• Room height and surface area
• Frequency of cleaning (ceilings, walls, floors)
• Tool weight and ergonomic impact
• Risk of repetitive stress injuries
• Durability and resistance to corrosion
• Flexibility for future facility growth
• Storage space within the cleanroom
• Maintenance requirements

Storage is frequently overlooked—new cleanrooms often lack dedicated storage space for cleaning tools.

Writing SOPs That Support Effective Tool Use

Tool selection must align with existing SOPs.

Rewriting SOPs can be burdensome, so:

• Avoid writing specific part numbers into SOPs.
• Use generic descriptors (e.g., “flat cleanroom mop”).
• Allow flexibility for substitutions if products are discontinued.

The presenter emphasizes that FDA inspectors will compare practice to written SOPs. Deviations may result in observations (e.g., 483s).

General Rules for Effective Wiping Techniques

Several core principles are emphasized repeatedly:

• Change solutions more frequently than expected.
• Never wipe in circular motions.
• Use overlapping, unidirectional strokes.
• Lift at the end of each pass to avoid redepositing contamination.
• Be methodical and consistent.

Circular wiping only redistributes contamination instead of removing it.

Proper Use of Wipers: Folding, Strokes, and Coverage

Quarter-folding a wipe creates multiple clean surfaces:

1. Fold in half
2. Fold again to create four usable sections
3. Use folded edges only
4. Rotate to a new surface for each pass
5. Discard after four passes

Pre-wetted wipes were previously demonstrated as most effective for particle removal.

Unidirectional, slightly overlapping strokes ensure full coverage. Operators must avoid reverting to back-and-forth or circular habits.

Cleaning Order: From Cleanest to Dirtiest

Cleaning should follow logical contamination flow:

• From highest to lowest
• From cleanest to dirtiest
• From driest to wettest
• From farthest point toward the exit

Examples of logical contamination flow:

• In fume hoods: wipe away from filters.
• In isolators: wipe from ceiling downward.
• In rooms: walls before floors.

Difficult areas (edges, protrusions, door frames, alarm switches) should be cleaned first—similar to “cutting in” when painting.

Floor Cleaning Methods: Place-and-Pull vs. S-Curve

Place-and-Pull Method

• Straight, unidirectional strokes.
• Start at the farthest corner and exit without rewalking cleaned areas.

S-Curve Method

• Ergonomically easier.
• Must include a clean pass along the wall first to ensure 100% coverage.

Both methods require maintaining a leading edge to capture contaminants.

Single-bucket systems are discouraged due to redeposition risk. Multi-bucket systems reduce contamination carryover.

Wall Cleaning Methods: Vertical, Horizontal, and Hybrid

Three wall-cleaning techniques are described:

Vertical

• Ceiling to floor.
• Risk: next stroke may bring floor contaminants upward.

Horizontal

• Across the wall in bands.
• Reduces contamination reversal.

Hybrid (Preferred)

• Vertical from ceiling to mid-height.
• Horizontal below.
• Minimizes risk of moving floor contaminants upward.

Solution Management and Dwell Time

Proper disinfectant use requires:

• Leaving surfaces visibly wet for the full labeled dwell time.
• Recognizing that cleanroom airflow and low humidity make long dwell times difficult.
• Reapplying disinfectant when necessary.

Excess liquid is only beneficial when using disinfectants. With solvents (e.g., IPA), excess liquid can increase particle adhesion via hygroscopic forces.

Multi-Bucket Systems and Contamination Control

Single-bucket systems can redeposit contamination into solution.

Multi-bucket systems:

• Separate clean solution from contaminated rinse
• Reduce cross-contamination
• Improve overall room cleanliness

Solution clarity is a simple indicator: if visibly dirty, change it.

Disinfectant Rotation Practices

Modern disinfectant rotation typically includes:

• Daily intermediate disinfectant (often with TB claim)
• Weekly sporicidal application
• Additional sporicide use triggered by environmental monitoring results

Older high-pH/low-pH rotation strategies are less common today.