FAQ

Cleanrooms

What is a cleanroom?

A cleanroom is an environment specifically designed, constructed, and maintained to control the concentration of airborne particles within a defined volume. The design and management of such spaces aim to minimize the introduction and retention of airborne particulate matter in order to ensure a contaminant-free working environment that is as clean and isolated as possible.

The main characteristics of a cleanroom are:

Air control and filtration.
Air is a carrier of particles—and therefore of dust, microbes, and aerosol suspensions—and represents a potential risk factor in controlled environments. For this reason, it is essential to manage the ventilation system using an HVAC (Heating, Ventilation, and Air Conditioning) system that allows the maintenance of a constant temperature regardless of external climatic variations and reduces the risk of contamination due to humidity. To ensure clean and particle-free air, the ventilation system must also be equipped with suitable filtration using HEPA (High Efficiency Particulate Air) filters, which are designed to capture up to 99.999% of particles larger than 0.3 microns.
Airflow types.
In unidirectional (laminar flow) cleanrooms, filtered air is distributed evenly across the room through parallel lines to avoid particle recirculation and to direct them towards extraction zones. In turbulent flow rooms, on the other hand, air is mixed inside the room, creating a swirling movement. This second type is less expensive to build and maintain, suitable for larger and more complex configurations, but provides a lower cleanliness level (ISO Class 8–9) compared to laminar flow rooms.
Environmental parameter control. Temperature, humidity, pressure, and airflow velocity must be maintained within precise ranges to ensure stable and safe operating conditions.
Materials and finishes.
Materials used in cleanrooms must be easy to clean, disinfect, and sterilize. Commonly used materials include high-pressure laminate (HPL), PVC, stainless steel, aluminum, epoxy resins, and linoleum.
Gowning and access.
Authorized personnel must wear specific clothing and protective equipment (coveralls, caps, goggles, masks, shoe covers) and follow strict gowning and access procedures to minimize the introduction of contaminants.
Monitoring and control.
The cleanroom is equipped with a continuous monitoring system for environmental parameters and operational conditions, enabling the detection of any anomalies and timely intervention.

How are cleanrooms classified?

The most widely used classification system globally is defined by the ISO 14644-1 standard, which classifies cleanrooms according to air cleanliness—that is, the concentration of particles per cubic meter of air—specifically based on the number of particles larger than 0.5 microns.

The cleanest class (ISO 1) has an extremely low particle concentration, while the least clean (ISO 9) has a higher concentration.

Measurements are carried out under three different conditions:

“as built” (completed environment with no equipment or personnel),
“at rest” (equipment installed and operating, but no personnel present),
“in operation” (equipment operating and personnel present).

Another classification system, primarily used in the medical and pharmaceutical sectors, is defined by the EU-GMP (Good Manufacturing Practice) Guidelines. This document identifies four classes of cleanrooms, from A to D, and provides recommended limits for airborne particle concentration for each class.

What are the main applications of cleanrooms?

Cleanrooms are used in a wide range of industrial and scientific sectors, where the presence of airborne contaminants could compromise product quality or process success:

Pharmaceutical and Biotechnology Industries

Sterile drug production: antibiotics, vaccines, injectable solutions
Medical device manufacturing: catheters, prostheses, contact lenses
Drug Research & Development: molecular and cellular biology labs

Electronics Industry

Semiconductor production: chips, microprocessors, sensors
Assembly of electronic devices: motherboards, displays, smartphones
Research & Development of electronic components: nanotechnology laboratories

Scientific Research

Basic research labs: physics, chemistry, biology
Medical research centers: virology, bacteriology labs

Aerospace Industry

Satellite and spacecraft assembly: electronic, optical, and mechanical components
Jet engine production: combustion chambers and turbines

Food Industry

Food production, packaging, storage, and preservation
R&D of new food products: food microbiology labs

Optics
Lens production

Assembly of optical instruments: microscopes, telescopes

Automotive Industry

Electronic components
Driver assistance systems and sensors
Optical components: LED headlights, cameras, LiDAR sensors for autonomous vehicles
Paintwork

What are the phases of cleanroom construction?

1. Design

Defining requirements: determine the necessary cleanliness class, room dimensions, type of activity to be carried out, and applicable regulations
Material selection: choose suitable materials for walls, floors, and ceilings based on their corrosion resistance, cleanability, and ability to reduce particle generation
Filtration system design: design the air filtration system, choosing the appropriate HEPA (High Efficiency Particulate Air) or ULPA (Ultra Low Penetration Air) filters to achieve the desired purity level
Ventilation system design: ensure proper airflow and air exchange
Service design: plan electrical, water, and lighting systems based on cleanroom needs

2. Construction

Site preparation: ensure the area is level and free of irregularities
Wall installation: modular or panel walls made of cleanroom-suitable materials
Floor installation: typically made of epoxy resin or PVC for a smooth, easy-to-clean surface
Ceiling installation: includes a plenum for filtered air distribution
System installation: filtration, ventilation, lighting, and environmental control systems
Sealing: seal joints and gaps to prevent air leaks and dead zones

3. Validation

Parameter measurement: check particle concentration, temperature, humidity, and differential pressure to ensure compliance
Filter integrity check: test HEPA and ULPA filter performance
Certification issuance: if all parameters are compliant, a certification is issued to validate the cleanroom

4. Qualification

Operator qualification: personnel must be properly trained and qualified to perform their tasks safely and correctly
Process qualification: processes within the cleanroom must be qualified to ensure product quality

How is cleanroom maintenance carried out?

Cleanroom maintenance is carried out by specialized personnel, often from companies involved in cleanroom design and construction or industrial cleaning service providers. These operators must have thorough knowledge of industry regulations and protocols, as well as proper training in cleaning and disinfection procedures.

Maintenance includes a series of activities:

Regular cleaning to remove impurities and contaminants from surfaces using specific detergents and disinfectants
Sanitization, a deeper process than cleaning, involving stronger disinfectants to eliminate pathogenic microorganisms. It is performed periodically or after events that may have compromised environmental purity, such as an incident or prolonged shutdown
System checks to periodically verify the proper functioning of systems such as filtration, ventilation, temperature and humidity control, and monitoring
Validation, carried out regularly to verify that all environmental parameters meet the required standards. This includes measuring particle concentration, temperature, humidity, pressure, and other relevant factors

The frequency of maintenance depends on several factors, including the cleanroom class, the type of activity performed, general regulations, and internal company procedures

Regulations

What are the standards and regulations for cleanrooms?

Controlled contamination environments are subject to strict standards and regulations to ensure that air and surface cleanliness levels are appropriate for specific applications.

The international ISO 14644 standard is the main technical reference for measuring and classifying the concentration of airborne particles inside a cleanroom. Specifically, it provides methods and criteria for:

classifying air cleanliness sampling air and counting the number of particles monitoring environmental parameters (such as humidity, temperature, and pressure)
verifying compliance by defining procedures for initial and periodic qualification of cleanrooms

In addition to ISO 14644, other standards and guidelines are applied based on the sector and specific application:

GMP (Good Manufacturing Practices): In the pharmaceutical and biotechnology sectors, GMP defines the requirements for the production, control, and distribution of pharmaceutical products
FDA (Food and Drug Administration): In the United States, the FDA establishes specific regulations for the manufacturing of medical devices and pharmaceuticals
EN ISO 13485: Specifies quality management system requirements for medical devices
European ATEX Directives: Regulate safety in environments at risk of explosion (e.g., due to production of flammable powders and gases)
European PED Directives: Apply to pressure equipment used in cleanrooms, such as ventilation systems, piping, and valves

Who can access a cleanroom and with what precautions?

Even minimal contamination can compromise cleanroom cleanliness and affect product or process quality.

For this reason, access is strictly regulated and limited to specially trained and authorized personnel.

Personnel must follow a series of procedures regarding personal hygiene and health, clothing, PPE (Personal Protective Equipment), and access methods. In some controlled contamination environments, entry occurs through a transitional area called an airlock, which minimizes air exchange between environments with different characteristics, thereby preventing cross-contamination.

Additional precautions may include behavioral rules (e.g., not touching surfaces) and movement restrictions (e.g., moving slowly and deliberately to avoid stirring up dust or particles).