Mediclean - Systems for your clean rooms
A cleanroom is a controlled environment where products are manufactured. It is a room in which the concentration of airborne particles is controlled to specified limits. Eliminating sub-micron airborne contamination is really a process of control.
These contaminants are generated by people, process, facilities and equipment. They must be continually removed from the air. The level to which these particles need to be removed depends upon the standards required. The most frequently used standard is the Federal Standard 209E.
The 209E is a document that establishes standard classes of air cleanliness for airborne particulate levels in cleanrooms and clean zones. Strict rules and procedures are followed to prevent contamination of the product.
The only way to control contamination is to control the total environment. Air flow rates and direction, pressurization, temperature, humidity and specialized filtration all need to be tightly controlled. And the sources of these particles need to controlled or eliminated whenever possible. There is more to a clean room than air filters. Cleanrooms are planned and manufactured using strict protocol and methods.
What is Contamination
Contamination is a process or act that causes materials or surfaces to be soiled with contaminating substances. There are two broad categories of surface contaminants: film type and particulates. These contaminants can produce a "killer defect" in a miniature circuit. Film contaminants of only 10 nm (nanometers) can drastically reduce coating adhesion on a wafer or chip. It is widely accepted that particles of 0.5 microns or larger are the target. However, some industries are now targeting smaller particles.
They are frequently found in electronics, pharmaceutical, biopharmaceutical, medical device industries and other critical manufacturing environments. It only takes a quick monitor of the air in a cleanroom compared to a typical office building to see the difference. Typical office building air contains from 500,000 to 1,000,000 particles (0.5 microns or larger) per cubic foot of air. A Class 100 cleanroom is designed to never allow more than 100 particles (0.5 microns or larger) per cubic foot of air. Class 1000 and Class 10,000 cleanrooms are designed to limit particles to 1000 and 10,000 respectively.
A human hair is about 75-100 microns in diameter. A particle 200 times smaller (0.5 micron) than the human hair can cause major disaster in a cleanroom. Contamination can lead to expensive downtime and increased production costs.
Preventing these contaminants from entering the cleanroom environment is the objective. It requires a commitment by everyone entering the cleanroom to make it happen. Mediclean understands the need to be aware of the importance of controlling contaminants. Strict procedures should be followed whenever entering or cleaning a cleanroom. Compromise is not acceptable when cleaning in a cleanroom.
Key Elements of Contamination Control
HEPA(High Efficiency Particulate Air Filter) - These filters are extremely important for maintaining contamination control. They filter particles as small as 0.3 microns with a 99.97% minimum particle-collective efficiency.
CLEANROOM ARCHITECTURE - Cleanrooms are designed to achieve and maintain a airflow in which essentially the entire body of air within a confined area moves with uniform velocity along parallel flow lines. This air flow is called laminar flow. The more restriction of air flow the more turbulence. Turbulence can cause particle movement.
FILTRATION - In addition to the HEPA filters commonly used in cleanrooms, there are a number of other filtration mechanisms used to remove particles from gases and liquids. These filters are essential for providing effective contamination control.
CLEANING - Cleaning is an essential element of contamination control. Decisions need to be made about the details of cleanroom maintenance and cleaning. Applications and procedures need to be written and agreed upon by cleanroom management and contractors (if used). There are many problems associated with cleaning. Managers need to answer the following questions before proceeding with any cleanroom cleaning program:
- What is clean?
- How is clean measured?
- What cleaning materials can be used in the cleanroom?
- When can the cleanroom be cleaned?
- How frequent does it need to be cleaned?
CLEANROOM GARMENTS - The requirements for cleanroom garments will vary from location to location. It is important to know the local garment requirements of the cleanroom management. Gloves, face masks and head covers are standard in nearly every cleanroom environment. Smocks are being used more and more. Jump suits are required in very clean environments.
HUMANS IN CLEANROOMS - There are both physical and psychological concerns when humans are present in cleanrooms. Physical behavior like fast motion and horseplay can increase contamination. Psychological concerns like room temperature, humidity, claustrophobia, odors and workplace attitude are important. Below are several ways people produce contamination:
- Body Regenerative Processes-- Skin flakes, oils, perspiration and hair.
- Behavior-- Rate of movement, sneezing and coughing.
- Attitude-- Work habits and communciation between workers.
People are a major source of contamination in the cleanroom. Look at the people activies listed below. Notice the number of particles produced per minute during these activities.
|PEOPLE ACTIVITY||PARTICLES/MINUTE (0.3 microns and larger)|
|Motionless (Standing or Seated)||100,000|
|Walking about 2 mph||5,000,000|
|Walking about 3.5 mph||7,000,000|
|Walking about 5 mph||10,000,000|
COMMODITIES - Care is taken when selecting and using commodity items in cleanrooms. Wipers, cleanroom paper and pencils and other supplies that service the cleanroom should be carefully screened and selected. Review of the local cleanroom requirements for approving and taking these items into the cleanroom are essential. In fact, many cleanroom managers will have approval lists of these types of items.
COSMETICS - Many cosmetics contain sodium, magnesium, silicon, calcium, potassium or iron. These chemicals can create damaging particles. Cleanroom managers may ban or restrict cosmetics in the cleanroom. This is usually dependent upon the threat to the product being made in the cleanroom. A recent mirror on a space telescope was fogged up from the cologne that was present in the cleanroom.
MEASUREMENT AND INSTRUMENTATION - Some important measurements related to contamination control are particle count, air flow & velocity, humidity, temperature and surface cleanliness. Cleanroom managers usually have specific standards and/or instruments to measure these factors.
ELECTROSTATIC DISCHARGE (ESD) - When two surfaces rub together an electrical charge can be created. Moving air creates a charge. People touching surfaces or walking across the floor can create a triboelectric charge. Special care is taken to use ESD protective materials to prevent damage from ESD. Cleaning managers should work with their personnel to understand where these conditions may be present and how to prevent them.
Cleaning Procedures for clean rooms:
Housekeeping maintenance of the cleanroom and restricted areas is essential to assure quality. Cleaning of a cleanroom should be performed on a daily basis. Improper cleaning of the cleanroom can lead to contamination and a loss in end user product quality.
Proper selection of equipment and materials is important for proper cleaning. Only products that have proven cleanroom performance records should be considered for use in cleanrooms.
Mediclean understands the need for correct procedures and equipment for cleaning clean rooms. Our products have been designed to assist in maintaining high standards throughout these environments.
Mediclean has outlined some guidelines for preparing work procedures and schedules. Local requirements must be included in any cleaning program.
List of Equipment and Supplies Mediclean will provide to clean your cleanroom
||Cleaning and disinfecting solutions:
Mediclean will provide chemicals which will be able to reduce bacteria and assist in mainaining low levels of bacteria levels
||Cleanroom mops - mops to be laundried or washed and dried.
||Cleanroom vacuum cleaner A Karacher or equivalent vacuum cleaner with a HEPA filter will be provided to vac all floor surcaes within the cleanroom.
||Cleanroom wipers - Disposable wipes to be used in the cleaning program.
||Cleanroom mop bucket and wringer will be designated for the cleanroom environment only and not be used in any other area.
Cleaning Procedures for a Class 1000 Cleanroom
Below is a sample of a cleaning program in a Class 1000 Cleanroom. This is only a sample of a program. Local standards and requirements must be followed.
|Area||Description of Work||Frequency|
|101||Change tacky mats||Every 2 hours|
|102||Wet mop with approved mop, cleaner & DI water||2 times per shift|
|103||Dust mop (if allowed)||2 times per shift|
|104||Remove trash, sweep, mop with appropriate cleaner wipe down tables and coffee area, clean walls and recycle cans||1 time per shift|
|105||Vacuum entry mats, sweep and mop floors||1 time per shift|
|106||Mop floor with pre-burnish cleaner and tap water||1 time per shift|
|107||Remove trash. Always wear gloves. Never take waste containers inside cleanrooms.||1 time per shift|
|108||Wet mop floors||1 time per shift|
|109||Remove acid and solvent trash||1 time per shift|
|110||Clean and replenish dispenser in all restrooms||3 times per week|
|111||Vacuum floor (if allowed)||2 times per week|
|112||Clean stainless steel pass throughs with s/s cleaner and appropriate wipes||1 time per week|
The list above is a sample of some of the common tasks that need to be performed in a Class 100 cleanroom. The list is not exhaustive. But gives some ideas of how to prepare work schedules and procedures. An assessment of the cleanroom in conjunction with cleanroom management will help define these tasks and frequencies.
General Cleanroom Regulations
Below is a list of general regulations recommended as a minimum for the successful operation of a cleanroom. All professional cleaning personnel should be aware and follow these regulations at all times.
- All personal items such as keys, watches, rings, matches, lighters and cigarettes should be stored in the personal locker outside the gowning room.
- Valuable personal Items such as wallets may be permitted in the cleanroom provided they are NEVER removed from beneath the cleanroom garments.
- NO eating, smoking or gum chewing allowed inside the cleanroom.
- Only garments approved for the cleanroom should be worn when entering.
- NO cosmetics shall be worn in the cleanrooms. This includes: rouge, lipstick, eye shadow, eyebrow pencil, mascara, eye liner, false eye lashes, fingernail polish, hair spray, mousse, or the heavy use of aerosols, after shaves and perfumes.
- Only approved cleanroom paper shall be allowed in the cleanroom.
- Approved ball point pens shall be the only writing tool used.
- Use of paper or fabric towels are prohibited. Use of hand dryers equipped with HEPA filters are suggested.
- Gloves or finger cots should not be allowed to touch any item or surface that has not been thoroughly cleaned.
- Only approved gloves, finger cots (powder-free), pliers, tweezers should be used to
handle product. Finger prints can be a major source of contamination on some products.
- Solvent contact with the bare skin should be avoided. They can remove skin oils and increase skin flaking.
- Approved skin lotions or lanolin based soaps are sometimes allowed. These can reduce skin flaking.
- All tools, containers and fixtures used in the cleaning process should be cleaned to the same degree as the cleanroom surfaces. All of these items are a source of contamination.
- NO tool should be allowed to rest on the surface of a bench or table. It should be place on a cleanroom wiper.
- Only cleanroom approved wipers are allowed to be used. The wipers must be approved for the Class of cleanroom being cleaned.
- ALL equipment, materials and containers introduced into a sterile facility must be subjected to stringent sterilization prior to entrance.
- NO ONE who is physically ill, especially with respiratory or stomach disorders, may enter a sterile room. This is a good practice in any cleanroom environment.
Personal Actions Typically Prohibited in Cleanrooms
- Fast motions such as running, walking fast or horseplay.
- Sitting or leaning on equipment or work surfaces.
- Writing on equipment or garments.
- Removal of items from beneath the cleanroom garments.
- Wearing the cleanroom garment outside the cleanroom.
- Wearing torn or soiled garments.