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Cleanrooms

Recommended Practices for Cleanrooms

Laminar Airflow assures full product protection such as basic microbial culture and not recommended for operator / environment protection. Continuous flushing of working area by a unidirectional and ultra-filtered airflow allows operation in sterile and particle free conditions. The Airflow pattern will be 100% supply and 0% exhaust.
Procedures To Be Followed To Maintain Cleanliness Level

CGMP Requirement

Selection of airborne particulate cleanliness classes for cleanrooms and zones
Air Classification Maximum Concentration limits ( Particle/m3) for particles equal to and larger than the considered sizes
Static – (At rest) Dynamic – (At Operation)
0.5µm 5 µm 0.5 µm 5 µm
Class A 3500 0 3500 0
Class B 3500 0 35000 2000
Class C 350000 2000 3500000 20000
Class D 350000 20000 NOT DEFINED NOT DEFINED
The average of particles concentrations measured at each of the locations do not exceed the concentration limits mentioned in the above table (EU GMP Standards)

Federal standard 209 E Class Limits

Class Limits
Class Name ≥0.1µm ≥0.2µm ≥0.3µm ≥0.5µm ≥5µm
Volume Units Volume Units Volume Units Volume Units Volume Units
SI English (m3) (ft3) (m^3) (ft^3) (m^3) (ft^3) (m^3) (ft^3) (m^3) (ft^3)
M1 350 9.91 75.7 2.14 30.9 0.875 10.0 0.283
M1.5 1 1240 35.0 265 7.50 106 3.00 35.3 1.00
M2 3500 99.1 757 21.4 309 8.75 100 2.83
M2.5 10 12400 350 2650 75.0 1060 30.0 353 10.0
M3 35000 991 7570 214 3090 87.5 1000 28.3
M3.5 100 26500 750 10600 300 3530 100
M4 75700 2140 30900 875 10000 283
M4.5 1000 35300 1000 247 7.00
M5 100000 2830 618 17.5
M5.5 10000 353000 10000 2470 70.0
M6 1000000 28300 6180 175
M6.5 100000 3350000 100000 24700 700
M7 10000000 283000 61800 1750

Selection ISO 14644-1 airborne particulate cleanliness classes for cleanrooms and clean zones

ISO Classification  number Maximum concentration limits (particles/m^3 of air ) for particles equal to and larger than the considered sizes shown below:
≥0.1µm ≥0.2µm ≥0.3µm ≥0.5µm ≥1µm ≥5.0µm
ISO Class 1 10 2
ISO Class 2 100 24 10 4
ISO Class 3 1000 237 102 35 8
ISO Class 4 10000 2370 1020 352 83
ISO Class 5 100000 23700 10200 3520 832 29
ISO Class 6 1000000 237000 102000 35200 8320 293
ISO Class 7 352000 83200 2930
ISO Class 8 3520000 832000 29300
ISO Class 9 35200000 8320000 293000

The Meanings of the Cleanrooms Classification

Class 1 : This Cleanrooms class is mainly used within the microelectronic industry when manufacturing integrated circuits which requires submicron resolution.
Class 10: This Cleanroom class is mainly used within the semiconductor industry using band widths below 2micrometer.
Class 100: This cleanroom class is, according to many, the most useful critical cleanliness class. Cleanrooms class 100 are often, incorrectly, known as sterile rooms and are used when >bacterial free < and /or >particle free< environments are required. Cleanroom class 100 is used in aseptic manufacturing within the pharmaceutical industry, for example .This cleanroom class is frequently used during the manufacture of integrated circuits; and also during isolation and treatment of patients who are especially sensitive to bacterial infections, e.g. after bone marrow transplantation.
Class 1000: This cleanroom class is mainly used when producing high quality optics; When carrying out mounting work and testing of gyroscopes for aircrafts; and also when mounting high quality miniature bearings.
Class 10000: Cleanrooms of class 10000 are used for mounting procedures in hydraulic or pneumatic equipment and on some occasions are also used within the food and beverage industry. Class 10000 cleanrooms are also commonly used within the pharmaceutical industry.
Class 100000: This classroom class is used by many industries, for example when working with optical products, when building large electronic systems based on smaller components, when building hydraulic and pneumatic systems and also within the food and beverage industry. The pharmaceutical industry also makes frequent use of this class of cleanrooms.

The Scope of the various currently available standards is presented below:

ISO 14644-1 Classification of air cleanliness

This standard covers the classification of air cleanliness in cleanrooms and associated controlled environments. This classification is in accordance with the standard as specified and is only concerned with the concentration of airborne particles. It must be stressed that this standard cannot be used to characterize the physical, chemical, radiological, or viable nature of airborne particle.

ISO 14644-2 Specification for testing and monitoring to prove continued compliance

This part of the overall standard specifies requirements for periodic testing of cleanrooms and associated controlled environments to prove their continued compliance with ISO14644-1, and for the designated class of environmental cleanliness.

ISO 14644-3 Metrology and test methods

This standard specifies the various methods and techniques which can be used to characterize and monitor various parameters in cleanrooms and other controlled environments.

ISO 14644-4 Design, Construction, and start-up:

ISO 14644-5 Cleanroom operations

This international standard specifies the basic requirements for operating cleanrooms and other controlled environments. It is primarily intended for those who are planning to carry out work in a cleanroom or any other controlled environment.

ISO 14698-1 General principles

This standard describes the principles and basic methodology for a formal system to assess and control bio-contamination where cleanroom technology is applied. The standard is used in order to allow reproducible monitoring of bio-contamination and also to allow selection of appropriate protective measures.

ISO 14698-2 Evaluation and interpretation of bio-contamination data

This part of the standard concerning cleanroom technology and bio-contamination control describes basic principles and methodological requirements for all microbiological data evaluation. The standard also covers the estimation of bio-contamination data obtained from sampling for viable particles in zone at risks, as specification by the selected system.

ISO 14698-3 Methodology for measuring the efficiency

This standard concerns the efficiency of various processes that incorporated one or more of the following actions: rinsing, cleaning, disinfection, combined cleaning and disinfection by either biochemical or mechanical means. Methods of measuring the efficiency of the processes of rinsing and/ or cleaning and /or disinfection and/or combined cleaning and disinfection of wet soiled surfaces on which microorganisms may be present either with or without the formation of a bio-film, is explained in relation to the application of cleanroom technology.

Air Velocities & Air Changes in Cleanrooms

Class of Cleanroom Airflow type Average velocity(ft/min) Air Changes /hr
ISO 8 (100,000) N/M 1-8 5-48
ISO 7 (10,000) N/M 10-15 60-90
ISO 6 (1,000) N/M 25-40 150-240
ISO 5 (100) U/N/M 40-80 240-480
ISO 4 (10) U 50-90 300-540
ISO 3 (1) U 60-90 360-540
Better Than ISO 3 U 60-100 360-600
Air Changes per hour= Average airflow velocity* x room area x 60 min/hr
Room Volume
N=non unidirectional; M= mixed flow room; U= Unidirectional flow.

Classification of filters according to the EN 1822

Filter Class Overall Value Efficiency (%) Overall Value Penetration (%) Leak test Efficiency (%)Leak test Penetration (%)
H 10 85 15
H 11 95 5
H 12 99.5 0.5
H 13 99.95 0.05 99.75 0.25
H 14 99.995 0.005 99.975 0.025
U 15 99.999 5 0.000 5 99.997 5 0.002 5
U 16 99.999 95 0.000 05 99.999 75 0.000 25
U 17 99.999 995 0.000 005 99.999 9 0.000 1

Schedule of tests to demonstrate continuing compliance

Test Parameter Class Maximum Time Interval
To Demonstrate compliance by Particle Counting ≤ISO 5  6 months
>ISO 5 12 months
Schedule of additional All Classes 12 months
Air flow Velocity or Volume
Air Pressure difference All Classes 12 months
Schedule of Optional tests All Classes 24* months
Installed filter leakage
Airflow Visualisation All Classes 24* months
Recovery All Classes 24* months
Containment Leakage All Classes 24* months

Sources, route of transfer and control and monitoring methods used in classrooms

Hazard Route Control methods Monitoring Methods
Supply air Airborne Air filters Filter integrity test
Areas adjacent to the cleanroom Airborne   Contact Overpressure; air movement control Cleanroom mats Room pressure differential  Mat inspection
Various airborne dispersions Airborne Ventilation Air supply rate or velocity Counts of airborne particles Counts of airborne micro-organisms Control of airflow
Floors, Walls and other Surfaces Contact Cleaning (and ,where required, disinfection) Surface Counting of Particles, and micro-organisms
People Airborne   Contact Cleanroom garments   Gloves Surface counts; inspection for tears; particle penetration testing Inspection for punctures Surface contamination counts
Machines Airborne   Contact Ventilation Design of machine cleaning or disinfection Air extract rates and airflow patterns   Surface contamination
Raw materials Mainly contact Control of manufacturing of raw materials Cleaning if solids, or filtration if fluids sterilization Particle and bacterial counts within, or on,  the materials   Filtration systems Sterilisation system
Containers and packaging Mainly Contact Control of their composition and manufacturing environment sterilization Particles and microbial Counts on surface Sterilisation Systems
R=recommended
NR=not recommended
AS=application specific
NR*=not recommended in non directional flow

Garments Systems for different classes of cleanrooms according to IEST-RP-CC-003.2

Apparel Type ISO 7&8(100K &10k) ISO 6(1000) ISO 5(100) ISO 4&3 (10 & 1)
Frock R AS AS(NR*) NR
2 piece suit AS AS AS AS
Coverall AS R R R
Shoe Cover R AS AS(NR*) NR
Boot AS R R R
Special Footwear AS AS AS AS
Hair Cover R R R R
Hood AS AS R R
Facial Cover AS AS R R
Powered headgear AS AS AS AS
Woven gloves AS AS AS NR
Barrier gloves AS AS AS R
Inner suit AS AS AS R

Garments Systems for Aseptic Cleanrooms (IEST RP CC-003.2

Apparel Type ISO Class 7 Class(10 000) ISO Class 6& 5 Class(1000&100) ISO Class 4&3 (10 & 1)
Frock NR NR NR
2 piece suit NR NR NR
Coverall R R R
Shoe Cover NR NR NR
Boot R R R
Special Footwear AS AS AS
Hair Cover(bouffant) R R R
Hood AS R R
Facial Cover R** R** R**
Powered headgear AS AS AS
Woven gloves NR NR NR
Barrier gloves R R R
Inner suit AS AS R
R=recommended
NR=not recommended
AS=application specific
R**=Surgical mask recommended

Recommended frequency of change of garment according to the IEST RP-CC-003

Class Of Room ISO 7 & 8 Class 1000 &100000 ISO 6 (Class 1000) ISO 5 (Class 100) ISO 4 (Class 10) ISO 3 ( Class1)
Frequency 2 per week 2 to 3 per week daily Per entry to 2 per day On each entry