If we understand Contamination, why to stop??? let's move toward the Key Elements for Control of Contaminations...
- 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 an 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 make 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).
- Humans in Cleanrooms-There are both physical and psychological concerns when humans are present in cleanrooms. Physical behaviour like fast motion and horseplay can increase contamination. Psychological concerns like room temperature, humidity, claustrophobia, odors and workplace attitude are important.
- 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.
- Cosmetics-Many cosmetics contain sodium, magnesium, silicon, calcium, potassium or iron. These chemicals can create damaging particles. 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.
- 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 tribo electric charge. Special care is taken to use ESD protective materials to prevent damage from ESD.
It's time to proceed to have action our next Blog will brief you with the Procedure to achieve the Cleanroom Guidelines.
