SOPs for Facility Maintenance, Cleaning and Sanitization

Cleanrooms demand a meticulously defined and executed cleaning regimen. SOPs for cleaning and sanitizing controlled environments are essential to ensure the continuous removal of viable and non-viable particulates while maintaining regulatory compliance and operational consistency.

By the end of this chapter, readers will understand how to:

• Define cleaning frequencies and task sequences based on ISO classification

• Select compatible cleanroom wipers, mops, and chemistries for various surfaces

• Write clear, step-by-step SOPs that standardize procedures and minimize contamination risks

• Incorporate validation, auditing, and visual inspection techniques to verify outcomes

“Having documented and scheduled cleaning that is conducted according to the SOP maintains the integrity of the controlled environment and decreases the risk of product contamination.”

Cleaning Frequency and Task Structure

Cleaning SOPs must account for surface-specific and time-based frequencies. For example:

• Daily: Work surfaces and equipment

• Weekly: Floors, tacky mats

• Monthly: Walls, ceilings

• Quarterly/Semi-Annually: Full facility deep cleaning

These tasks must follow a top-to-bottom and clean-to-dirty progression, always ending at the exit. SOPs should specify the direction of wiping/mopping and techniques such as pull-lift and crisscross patterns.

Selecting Materials and Chemistries

Only cleanroom-compatible tools and solutions should be used. SOPs must identify approved:

• Wiper materials (e.g., polyester, microfiber, poly-cellulose)

• Mops and swabs (pre-saturated or dry with spray)

• Cleaning agents like 70% IPA, sterile DI water, or application-specific disinfectants

Material compatibility with surfaces and chemistries must be documented to prevent corrosion or residue buildup.

SOP Detail and Validation Methods

Effective SOPs include:

• Specific stroke directions and overlap percentages

• Identification of zones and cleaning order

• Chemical handling protocols and safety requirements

• Instructions for removing gross contamination before disinfection

Validation includes visual inspections, particle probes, white/UV light examination, and viable residue testing via swabs.

“The SOP should specify the exact cleaning sequences, down to the stroke and direction of mopping and wiping.”

Implementation Principles for Cleanroom Cleaning SOPs

• SOPs should establish task-specific cleaning frequencies and validated techniques

• Only approved materials and chemistries should be used to avoid surface degradation

• Cleaning steps must be ordered and directional, ensuring clean-to-dirty progression

• SOPs should include auditable processes with defined checkpoints and change history

Explore More Resources

Continue deepening your understanding of SOPs for controlled environments:

• Chapter 1: Introduction to Writing Internal SOPs for Controlled Environments

• Chapter 2: Optimizing Cleanroom Operations – SOPs for Gowning Protocols

• Chapter 3: SOPs for Cleanroom Operator Requirements and Training

• Chapter 5: SOPs for Critical Cleaning