Cleanroom Cleaning and Sanitisation Programme: Practical Guide to ISO 14644-5:2025 (with an inspector’s mindset)

If you want a real reality check:
in a very large number of inspections, cleaning is the area where credibility is lost the fastest.

Why?

• It is visible.
• It is performed daily.
• It has a direct impact on particles and (in GMP environments) microbiology.
• And above all: mistakes are often basic (ignored high surfaces, incomplete logs, residues, wrong tools).

ISO 14644-5:2025 pushes a clear concept: 👉 cleaning is not a generic activity, it is a governed programme.

What a “defensible” cleaning & sanitisation programme must include

A robust programme answers six key questions:

• What do you clean (complete list of surfaces)?
• When do you clean (frequencies + timing: before/after production)?
• How do you clean (method, direction, sequence)?
• With what do you clean (agents, concentrations, contact times, rinses)?
• Who cleans (roles, training, supervision)?
• How do you demonstrate effectiveness (trends, verifications, investigations, CAPAs)?

1) Surface list: where findings are born

Many programmes are strong on floors and benches, but weak on:

• ceilings
• light fixtures
• supply/return air grilles
• surfaces above equipment
• behind equipment / under structures
• carts and trolleys
• waste bins
• sticky mats (if present)

If any of these areas accumulate dust, the auditor will see it—or worse, prove it.

Best practice:
a matrix “surface → frequency → method → agent → record”.

2) Frequencies: how to justify them without inventing numbers

There is no “magic” frequency. There are only frequencies that are:

• consistent with cleanroom class and criticality
• consistent with operational load (people, processes, materials)
• sustainable and actually performed
• defensible through risk assessment and data

Classic mistake:
defining overly ambitious frequencies that are not executed → audit misalignment.

3) Method: the difference between “cleaning” and “not contaminating while cleaning”

Typical operational expectations include:

• cleaning from top to bottom
• controlled movements (no random scrubbing)
• defined change frequency for wipes/mops
• controlled handling of dirty wipes (closed containers)
• prevention of recontamination (e.g. two-bucket method, pre-impregnated single-use wipes)

Training plays a major role here—especially since cleaning staff are often contractors.
👉 Standardisation is critical.

4) Chemical agents: effectiveness, residues and compatibility

ISO 14644-5:2025 increases attention on two often underestimated topics:

Residues (films) from detergents and disinfectants

• Visible or sticky residues are red flags.
• If agents leave films, you must manage:
• rinsing (which water? how often?)
• alternation between detergent and disinfectant
• verification that residues do not accumulate

Compatibility with surfaces and equipment

A disinfectant must not only “work”—it must also not damage:

• stainless steel
• coatings
• seals
• plastic materials

In GMP environments, there is often an additional expectation of disinfectant rotation, particularly where microbiological control is required.

5) Special cleaning (the actions that save trends)

A mature programme includes defined special cleaning after high-impact events:

• after maintenance (drilling, plant work, replacements)
• after shutdown or prolonged inactivity
• after environmental OOS/OOT
• after contamination events (spills, breakages)
• after significant changes

In audits: 👉 a particle peak after maintenance without special cleaning = high finding risk.

6) Evidence: complete, legible, consistent logs (data integrity)

In GMP, cleaning logs are critical documents. Typical issues include:

• missing days
• signatures not attributable
• cleaning agents not specified
• untracked corrections
• “all OK” statements without verification

Pragmatic advice:
design logs that are easy to complete and hard to complete incorrectly
(checklists + mandatory fields + comment sections).

How to demonstrate effectiveness (without overcomplicating)

Three simple, highly defensible levers:

1. Stable EM trends (particles/microbiology) aligned with cleaning activities
2. Structured visual inspections (routine + internal audits)
3. Effective investigations when signals appear (not just “we cleaned again”)

At a higher maturity level:
integrate indicators such as “post-maintenance events” or “repeated alerts at the same location”.

Common mistakes (that inspectors notice immediately)

• Dust on high surfaces or diffusers
• Cardboard/paper or non-cleanroom materials used or present
• Disinfectants used without respecting contact time
• Unmanaged residues (streaks, films)
• Inadequate post-maintenance cleaning
• Contaminating cleaning tools (lint-shedding wipes, non-HEPA vacuum cleaners)

Mini “anti-finding” checklist for the cleaning programme

• Complete surface list (including high and hidden surfaces)?
• Frequencies realistic and actually respected?
• SOPs describing method and sequence (not just “clean”)?
• Agents defined: concentration, contact time, expiry, rotation (if applicable)?
• Residue management: rinsing/controls defined?
• Special cleaning codified (post-maintenance, post-shutdown)?
• Suitable tools (low-lint, HEPA for vacuuming)?
• Training and supervision of cleaning staff (including contractors)?
• Logs complete and consistent with reality?
• Correlation with EM data and actions taken on trends?

If you want a complete checklist and an audit-ready structure
(including special cleaning, residues, evidence and typical finding points),

👉 you’ll find everything in the guide “ISO 14644-5:2025 – Operational Guide to Cleanroom Operations” on guidegxp.com.