Considerations When Building a Clean Room
Building a Clean Room
A clean room design requires careful consideration of its intended use, permissible particle concentration, location, manufacturing process and of course cost. The design and specification of a clean room require close coordination between the many departments impacted by it and the design team. Certain products, such as pharmaceuticals and medical devices, must be built in a sealed and sterile environment to avoid contamination and ruin.
ISO 14644-4 specifies the requirements for the design and construction of the clean room facilities (to be referred to as clean room installations) but does not prescribe specific technological nor contractual means to meet the requirements.
Federal Standard 209E defines a clean room as a room in which the concentration of airborne particles is controlled to specified limits.
Clean Room: Contamination Control
These are the things that need to be considered when building an effective contamination control room.
- 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.
- Clean Room Architecture - Clean rooms 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 airflow the more turbulence. Turbulence can cause particle movement.
- Measurement and Instrumentation - Some important measurements related to contamination control are particle count, air flow & velocity, humidity, temperature and surface cleanliness. Clean room 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 turbo-electric 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
- Ventilation and Makeup Air- Ventilation and makeup air volumes are dictated by the amount required to maintain indoor air quality, replace process exhaust and for building pressurization.
- Pressurization- Rooms in a clean facility should be maintained at static pressures higher than atmospheric to prevent infiltration by wind. The only exception to using a positive differential pressure is when dealing with specific hazardous materials where governmental agencies require the room to be at a negative pressure.
- Temperature and Humidity- Temperature control is required to provide stable conditions for materials, instruments, and personnel comfort. Humidity control is necessary to prevent corrosion, condensation on work surfaces, eliminate static electricity, and provide personnel comfort.