People – The Largest Source of Cleanroom Contamination | Cleanroom HVAC Design & M&E Design Dublin, Ireland
- MTS DNC ENERGY CONSULTANTS LIMITED
- 6 days ago
- 4 min read
When designing pharmaceutical cleanrooms, hospitals, biotechnology facilities and medical device manufacturing plants, most engineers focus on HVAC design, HEPA filtration, pressure cascades and airflow patterns. However, decades of industry research consistently show that people are responsible for approximately 75% of all cleanroom contamination.
At MTS DNC Energy Consultants, we specialise in M&E design in Dublin, Ireland, delivering cleanroom HVAC design, mechanical ventilation systems, pharmaceutical building services engineering and GMP-compliant cleanroom solutions. Understanding contamination sources is fundamental to designing HVAC systems that maintain product quality, regulatory compliance and patient safety.
Why Are People the Largest Source of Cleanroom Contamination?
Every person continuously releases particles into the surrounding environment, even when standing still. These particles include:
Dead skin cells
Hair
Textile fibres
Respiratory droplets
Saliva
Microorganisms
A healthy adult sheds approximately one million skin particles every 24 hours, and particle generation increases significantly with movement.
For engineers involved in cleanroom HVAC design, this highlights the importance of airflow management, air changes per hour (ACH), HEPA filtration and contamination control strategies.
Sources of Cleanroom Contamination
Industry data shows the following typical sources of contamination:
Source | Typical Contribution |
People | 75% |
Ventilation Systems | 15% |
Room Structure | 5% |
Equipment | 5% |
Although HVAC systems remove airborne contaminants, the majority of particles originate from personnel. This is why cleanroom HVAC design must work alongside proper gowning procedures, operator training and GMP compliance.
How Human Movement Increases Particle Generation
Human activity has a direct impact on airborne particle generation.
Activity | Approximate Particles Generated |
Motionless (standing or sitting) | 100,000 |
Head, neck and arm movement | 500,000 |
Arms, trunk and leg movement | 1,000,000 |
Sitting down or standing up | 2,500,000 |
Walking at 2 mph (3.2 km/h) | 5,000,000 |
Walking at 3.5 mph (5.6 km/h) | 7,500,000 |
Walking at 5 mph (8 km/h) | 10,000,000 |
This demonstrates why unnecessary movement should always be minimised in ISO-classified cleanrooms and GMP pharmaceutical facilities.
Non-Viable Contamination
Non-viable contamination consists of particles that are not living organisms.
Typical examples include:
Dust
Skin flakes
Clothing fibres
Plastic particles
Packaging debris
Although these particles are not biological contaminants, they frequently carry microorganisms and can compromise pharmaceutical manufacturing processes.
Proper HVAC design uses HEPA filters, carefully designed airflow patterns and appropriate air change rates to remove these particles before they settle on critical products or equipment.
Viable Contamination
Viable contamination refers to living microorganisms such as:
Bacteria
Yeasts
Fungi
Mould spores
Humans naturally host more than 200 species of bacteria.
These microorganisms are found on:
Skin
Hair
Eyes
Nose
Mouth
Intestinal tract
Dry skin alone may contain thousands of microorganisms per square millimetre.
For this reason, cleanroom HVAC design must maintain controlled airflow, pressure differentials and high-efficiency filtration to minimise microbial contamination.
How Microorganisms Spread Inside a Cleanroom
Personnel continuously release microorganisms through everyday activities, including:
Walking
Speaking
Breathing
Touching surfaces
Scratching
More significant contamination occurs when personnel:
Cough
Sneeze
Blow their nose
A single sneeze can generate hundreds of thousands of aerosol droplets, which may attach to dust particles and remain suspended in the air until removed by HEPA filtration.
This is why pharmaceutical HVAC design carefully controls airflow direction, air velocities and room pressurisation.
Personal Health Conditions That Increase Contamination
Certain medical conditions increase contamination risks considerably.
Skin Conditions
Examples include:
Dermatitis
Dry skin
Sunburn
Dandruff
Cuts
Grazes
These conditions significantly increase particle shedding.
Respiratory Conditions
Personnel experiencing:
Coughing
Sneezing
Colds
Influenza
should be assessed before entering controlled manufacturing environments.
Allergies
Allergic reactions may lead to:
Frequent sneezing
Scratching
Itching
Running nose
Personnel may also react to:
Polyester garments
Latex gloves
Cleaning chemicals
Disinfectants
Solvents
Pharmaceutical compounds
These behaviours increase the likelihood of contamination events.
Characteristics of Cleanroom Personnel
Successful cleanroom operation depends on personnel who demonstrate:
Excellent attention to detail
High standards of personal hygiene
Self-motivation
Strong teamwork
Ability to follow Standard Operating Procedures (SOPs)
Good GMP awareness
Human behaviour remains one of the most important contamination control measures.
Human Factors That Increase Contamination Risk
Many contamination incidents result from behavioural rather than engineering failures.
Common causes include:
Unrealistic production targets
Fatigue
Poor planning
Inadequate training
Operator stress
Lack of motivation
Familiarity with repetitive tasks
Complacency
Even the most advanced cleanroom HVAC design cannot compensate for poor operator behaviour.
Why HVAC Design Is Critical for Cleanrooms
Modern pharmaceutical facilities rely on sophisticated HVAC systems to maintain controlled environments.
Key design considerations include:
HEPA filtration
Air change rates (ACH)
Pressure cascades
Temperature control
Humidity control
Airflow visualisation
Smoke testing
ISO 14644 compliance
EU GMP Annex 1 compliance
A properly designed HVAC system continuously removes airborne contamination while maintaining appropriate pressure differentials between cleanroom grades.
The Role of M&E Design in Pharmaceutical Cleanrooms
Successful contamination control requires more than HVAC alone.
Professional M&E design in Dublin, Ireland integrates:
Mechanical ventilation systems
Heating and cooling systems
Chilled water systems
Clean steam
Building Management Systems (BMS)
Electrical services
Lighting
Life safety systems
Energy efficiency
Sustainability
An integrated design approach ensures both GMP compliance and operational efficiency throughout the facility lifecycle.
Key Takeaways
People contribute approximately 75% of all cleanroom contamination.
Human movement dramatically increases airborne particle generation.
Skin cells are the largest source of non-viable contamination.
Humans naturally carry more than 200 bacterial species, making them the primary source of viable contamination.
Proper operator behaviour is just as important as engineering controls.
Cleanroom HVAC design plays a critical role in removing airborne contaminants and maintaining GMP-compliant environments.
Integrated M&E design in Dublin, Ireland, combining HVAC, mechanical and electrical engineering, is essential for pharmaceutical, biotechnology and medical device manufacturing facilities.
How Our Consultants Can Help
At MTS DNC Energy Consultants, we provide:
Heat pump assessments
Part L compliance reports
Building energy modelling
Through NEXUS M&E Design, we also deliver:
Heat loss calculations
Heat pump sizing
Radiator and underfloor heating design
Mechanical ventilation design
We ensure every system is designed for maximum efficiency, compliance, and long-term performance.
Disclaimer
The content shared in these posts is intended for informational purposes only and should not be interpreted as design advice, specifications, or a calculation template. For professional guidance or design services, please contact us through our contact form.
