Rules to be followed in the Cleanrooms

Within a cleanroom, many rules-of-conduct must be followed to ensure that products are not contaminated. The management must produce a set of written procedures suitable for their room. It may be useful to have these 'does and don'ts' posted in the change or production area. Commonly used procedures that may be adopted are given below. These procedures do not consider the choice of cleanroom garments, masks, gloves and similar clothing items.

Air Transfers with in the Cleanrooms To ensure that air is not transferred from an area of high contamination to one of lower contamination (e.g. the outside corridor to the production room) the following disciplines should be adhered to:

Personnel must always come in and out of the cleanroom through change areas. The change area is used not only to change clothing, but as a buffer zone between the outer dirty corridor and the inner clean production area. Personnel should not use any entrance, such as an emergency exit, which leads directly from the production area to the corridor; this will allow contamination to enter directly into the cleanroom, and their garments may also become contaminated.

Doors should not be left open. If they are, air will be transferred between the two adjoining areas because of general air turbulence as well as air transfer caused by a temperature difference between the two areas

Doors should not be opened or closed quickly, or air will be pumped from one area to the other.

Doors usually open inwards into the production room and are held shut by the higher pressure. However, to aid the movement of personnel who are carrying materials, some doors open outwards. Doors should then be fitted with door-closing devices to ensure that the doors are kept closed, and shut slowly to reduce the air transfer. Doors without handles will assist in preventing contamination of gloves.

When passing through the doors in an airlock, personnel should ensure the first door is closed before going through the Next one. Electrical interlocks between entry and exit doors achieve this, but care must be taken to ensure that there is no danger in the case of fire. Indicator lights, which show if the doors are shut, are also used. Pass-through hatches should be used in a similar way.

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Cleanroom Particle Generations and Average Particle Generations by Human Activity and Clothings

What is Particle Concentration?
The number of particles detected per unit volume of air 

Particle Concentration in Different Locations

Place                Number of Particles per cubic foot 
                         (greater than or equal to 0.5µm)

Town                1000000
Mountain          100000
Moon                100
Industrial          10000000

Particles Generated by Clothing Activities

Activity                     Normal Street Clothing  Laboratory Clothing   Cleanroom Garments

Sitting Still                448000                             142000                        14920

Sitting and
 Moving Arms          4450000                            462000                        48600

Standing 
and Rotating             2240000                            390000                        31700

Walking Rapidly      5380000                            1285000                       15700


Particles Generated from Human Activity

Activity                                 Number of Particles released

Sitting                                   100000

Sitting awith 
Rotating Arm 
Movements                          500000

Rising Up 
and Sitting Down                 2500000

Running and 
Walking Up                          10000000


Particles Generated From Human Beings

Human skin can produce upto 1 x 106 microorganisms per cm2

Human saliva can contain upto 1 x 109 microorganisms per ml

Nasal Wash (from healthy person) can obtain 1 x 106 microorganisms per ml

The aerosol produced by sneezing (if no barrier is used) can contain 100000 microorganisms

Human excrement can contain 1x1012 microorganisms per g. This figure correspondance to approximately 50% of the dry weight of the excrement

Major and Minor Sources of Cleanroom Contamination in Cleanrooms

Major Source of Cleanroom Contamination  Sources

* Personnel
* Incoming Air
* Machineries
* Raw Material
* Packing Material
* Chemicals Used for Cleaning
* Office Equipment and Material
* Visitors
* Maintenance Personnel

General Source of Indoor Environment Cleanroom Contaminations
People
skin scales, microorganisms, tobacco, smoke, hair, textile fibres
Cleaning Activities
choice of material and chemicals
Machineries
painting, welding and grinding
Construction Material
fibrous insulation material, microorganisms in wet wood

General Source of Outdoor Environment Cleanroom Contaminations

Natural Processes

wind, fire and natural cycle of plants
Manmade Processes
fossil material waste disposal

Types of Cleanroom Based on Operational Conditions and Air Flow Directions

Cleanroom Types as Based on Operational Conditions

as-built Cleanroom Facility
A cleanroom facility that is complete and ready for operation, with all services connected and functional, but without equipment or operating personnel in the facility

as-rest Cleanroom Facility
A cleanroom facility that is complete, with all services functioning and with equipment installed and operable or operating as specified, but without operating personnel in the facility

Operational Cleanroom Facility 
A cleanroom facility in normal operation, with all services functioning and with equipment and personnel, if applicable, present and performing their mormal work functions in the facility

Cleanroom Types Based on Air Flow Direction

Mixed Airflow Cleanrooms 
A hybrid cleanroom containing both unidirectional and nonunidirectional types of airflow within the same enclosure

Nonunidirectional Airflow Cleanrooms

A cleanroom in which the filtered air entering the room or passing through the work zone is characterized by nonuniform velocity or turbulent flow. Such rooms exhibit nonuniform, random airflow patterns throughout the enclosure

Unidirectional Aiflow Cleanrooms / Laminar airflow Cleanrooms

A Cleanroom in which the filtered air entering the room makes a single pass through the work area in parallel flow pattern, with a minimum of turbulent flow areas. Unidirectional airflow rooms typically have HEPA or ULPA filter coverage of 80% or more of the ceiling (vertical flow) or one wall (horizontal flow)

DFT TECH Vertical Laminar Flow Cabeints Specifications

DFT TECH Cleanroom Horizontal Laminar Flow Cabinets Specifications

What are Cleanroom Equipments?

The equipments that protects or maintains the sterility of product being prepared / manufactured in the process flow with air filtration system.

DFT TECH Manufacturing , Exporting and Supplying all these equipment to india, chennai, bangalore, hyderabad, coimbatore, madurai, trichy and etc..

Here are the list of some cleanroom equipments used in the industry.

1. Laminar Air Flow Cabinets ( Vertical / Horizontal )

 

2. Biosafety Cabints ( Class i / Class ii, Class iii) provides protection for product, personnel and environment

 


3. HEPA filtered Vial Filling Stations

4. Powder Dispensing / Sampling Booths ( Used in Chemical Weighing and Mixing in production )

 

5. Pass Through Boxes ( Static Pass Boxes / Dynamic Pass Boxes )

6. Softwall Cleanrooms

7. Prefabricated Cleanrooms

Applications of Cleanrooms in Various Industry

Now a days cleanrooms are more common in all range of industries where the products require controlled environment for their manufacturing.

Cleanrooms are widely used in industries like

Application of CleanroomsBiotechnology Industries

Semicondutor Manufacturers

Medical Device Manufacturers

Food and Beverages

Hospitals and Health Care Centres

Research Institutes

Microelectronics

Pharmaceutical Manufacturing

Optical lense Manufacturing Industries

Aerospace Engineering

Lense Manufacturing

Valve Manufacturers

Automobile Industries

AND MANY MORE ...

What is Cleanrooms?

 an environment free from dust and other contaminants, used chiefly for the manufacture of electronic components.

OR 

Typically used in manufacturing or scientific research, a cleanroom is a controlled environment that has a low level of pollutants such as dust, airborne microbes, aerosol particles, and chemical vapors. To be exact, a cleanroom has a controlled level of contamination that is specified by the number of particles per cubic meter at a specified particle size. The ambient air outside in a typical city environment contains 35,000,000 particles per cubic meter, 0.5 mm and larger in diameter, corresponding to an ISO 9 cleanroom which is at the lowest level of cleanroom standards.

Cleanroom Overview

Cleanrooms are used in practically every industry where small particles can adversely affect the manufacturing process. They vary in size and complexity, and are used extensively in industries such as semiconductor manufacturing, pharmaceuticals, biotech, medical device and life sciences, as well as critical process manufacturing common in aerospace, optics, military and Department of Energy.

A cleanroom is any given contained space where provisions are made to reduce particulate contamination and control other environmental parameters such as temperature, humidity and pressure. The key component is the High Efficiency Particulate Air (HEPA) filter that is used to trap particles that are 0.3 micron and larger in size. All of the air delivered to a cleanroom passes through HEPA filters, and in some cases where stringent cleanliness performance is necessary, Ultra Low Particulate Air (ULPA) filters are used.

Personnel selected to work in cleanrooms undergo extensive training in contamination control theory. They enter and exit the cleanroom through airlocks, air showers and/or gowning rooms, and they must wear special clothing designed to trap contaminants that are naturally generated by skin and the body.

Depending on the room classification or function, personnel gowning may be as limited as lab coats and hairnets, or as extensive as fully enveloped in multiple layered bunny suits with self contained breathing apparatus.

Cleanroom clothing is used to prevent substances from being released off the wearer’s body and contaminating the environment. The cleanroom clothing itself must not release particles or fibers to prevent contamination of the environment by personnel. This type of personnel contamination can degrade product performance in the semiconductor and pharmaceutical industries and it can cause cross-infection between medical staff and patients in the healthcare industry for example.

Cleanroom garments include boots, shoes, aprons, beard covers, bouffant caps, coveralls, face masks, frocks/lab coats, gowns, glove and finger cots, hairnets, hoods, sleeves and shoe covers. The type of cleanroom garments used should reflect the cleanroom and product specifications. Low-level cleanrooms may only require special shoes having completely smooth soles that do not track in dust or dirt. However, shoe bottoms must not create slipping hazards since safety always takes precedence. 

A cleanroom suit is usually required for entering a cleanroom. Class 10,000 cleanrooms may use simple smocks, head covers, and booties. For Class 10 cleanrooms, careful gown wearing procedures with a zipped cover all, boots, gloves and complete respirator enclosure are required.