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NEXUS

M&E DESIGN

Understanding Contamination in Cleanrooms: Key Risks and How to Control Them

  • Writer: MTS DNC ENERGY CONSULTANTS LIMITED
    MTS DNC ENERGY CONSULTANTS LIMITED
  • Dec 6
  • 3 min read

Cleanroom technician wearing full PPE to minimise contamination risk in a controlled environment.

Cleanrooms are essential in pharmaceutical, medical device, biotech, and high-end manufacturing environments. Their purpose is simple but critical: protecting the product from contamination. Even a small lapse in contamination control can lead to product failure, recalls, rework, compromised patient safety, and damage to a company’s reputation.

At NEXUS M&E Design, we support clients in designing and maintaining cleanroom environments that minimise risk and ensure compliance. Below is a clear overview of what contamination is, where it comes from, and how it can be controlled.


🔬 What Is Contamination?

Contamination refers to the unintended introduction of impurities, whether chemical, microbiological, or particulate, during:

  • Production

  • Sampling

  • Packaging / repackaging

  • Storage or transport

Common contaminant types include:

  • Micro-organisms (bacteria, moulds, yeast, fungi, viruses)

  • Chemical residues

  • Foreign particulates (fibres, dust, flakes, equipment debris)

  • Endotoxins (residues of degraded microorganisms)

Cross-contamination — contamination from one product to another — is a specific and highly critical subset.


👤 People: The Biggest Source of Contamination

It may be surprising, but up to 75% of contamination in cleanrooms originates from people.

Humans shed:

  • Skin flakes

  • Hair

  • Clothing fibres

  • Moisture droplets

  • Cosmetics and aerosol residues

  • Microorganisms from skin, nose, hair, and mouth

Even simple movement—walking, turning, or stretching—creates millions of particles.


Mindset Matters

Personnel mindset directly influences contamination risk. Cleanroom workers must be:

  • Conscientious

  • Detail-oriented

  • Hygienic

  • Calm and consistent

  • Highly trained

  • Fully aware of the impact of their actions on product safety

Fatigue, stress, poor training, or complacency can all result in contamination incidents.


🏢 Facilities & Buildings

Poorly maintained facilities contribute significantly to contamination. Issues include:

  • Flaking paint

  • Cracked surfaces

  • Accumulated dust

  • Dirty containers or packaging

  • Leaking pipework or flanges

  • Poorly designed airflow or pressure cascades

Any deterioration in a cleanroom environment increases the risk of microbial or particulate ingress.


📦 Materials & Raw Inputs

Materials can bring both viable (microbial) and non-viable (particulate) contamination.Examples include:

  • Dust from powders

  • Fibres from cardboard, paper, or packaging

  • Raw material contamination due to inadequate handling

  • Incorrect materials introduced due to operator error

Proper sanitisation and controlled transfer procedures are essential.


⚙️ Equipment & Tools

Equipment may introduce contamination through:

  • Dirty surfaces or product residues

  • Moving parts and belt drives generating particulates

  • Lubricant leaks and emissions

  • Chemical residues from cleaning agents

Inadequate cleaning between product batches is a major cross-contamination risk.


💧 Water & Fluids

Any wet surface can harbour micro-organisms. Risks include:

  • Damp containers

  • Wet floors

  • Equipment not fully dried after sanitisation

  • Residual moisture inside vessels, tubing, or components

Ensuring everything is dried, drained, and monitored is essential.


🌫️ Environment

Environmental contamination includes:

  • Airborne particles

  • Dust on floors and surfaces

  • External contaminants entering due to pressure imbalance

  • Poor ventilation or HEPA filtration performance

A compromised HVAC system is one of the leading sources of cross-contamination during operations.


🔁 Cross-Contamination

Cross-contamination arises when foreign product or material enters a process stream. Common causes include:

  • Poorly designed or maintained AHU/dust extraction systems

  • Inadequate cleaning procedures

  • Incorrect pressure cascades

  • Faulty segregation between areas

  • Misuse of equipment or poor material flow design

Proper room classification, pressure control, zoning, and validated cleaning procedures are central to its prevention.


🛡️ How Cleanrooms Control and Prevent Contamination

A well-designed contamination control strategy includes:


1. Proper Cleanroom Design & Maintenance

  • Correct airflow and pressure cascades

  • Well-maintained surfaces and finishes

  • Minimised particle traps


2. Controlled Access

  • Restricted entry

  • Full gowning procedures

  • Sanitisation of all materials entering the room


3. Cleaning & Sanitisation

  • Effective detergents and disinfectants

  • Regular scheduled cleaning

  • Removal of residues and dirt


4. Sterilisation

  • Validated sterilisation of components, equipment, and product contact surfaces


5. Aseptic Techniques

  • Slow, deliberate movements

  • Minimising turbulence

  • Contact only with sterile tools

  • Zero-touch mindset


✨ Final Thought

Cleanroom contamination is not a single issue — it is the result of people, equipment, environment, materials, and processes interacting.With the right design, training, and operational controls, contamination risks can be minimised, ensuring product safety and regulatory compliance.

At NEXUS M&E Design, we support clients with:

  • Cleanroom HVAC design

  • Pressure cascade strategies

  • Contamination control consulting

  • Process flow optimisation

  • Compliance with GMP and regulatory standards

If you want help improving or designing your cleanroom systems, we’re here to support you.


Disclaimer: This post is meant to share general information only. It’s not a substitute for engineering design, specifications, or calculations. If you need expert advice or design help, feel free to contact us through our contact page.


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