Clean room humidity control is essential to provide a conducive environment for the research, development, and manufacturing of equipment or processes, ensuring a low level of environmental pollutants such as dust, airborne microbes, aerosol particles, and chemical vapours. These rooms are designed to maintain stringent environmental standards, which are critical for various high-precision industries.
With the growing emphasis on quality checks & controls, zero tolerance on defects and stringent manufacturing practices, the demand of clean rooms has increased manifold. The Clean rooms are now being designed as specially constructed enclosed areas, environmentally controlled with respect to airborne particles, temperature, humidity, air pressure flow patterns, air motion, vibration, noise and viable organisms.
Major application areas of clean rooms are in the electronic industry, pharmaceuticals, aerospace, automotive, information technology and many others requiring more stringent manufacturing conditions. The Clean Room applications range from the fabrication of microscopically small sub-assemblies, electronic devices and instruments, to the increasing demand for more sterility and purity in drugs, foods and a germ-free atmosphere for medical and biological applications.
Contaminants can come from a wide variety of sources: air (the cleanliness of which is defined according to the classes of clean rooms and classes of dust), water, chemicals, the physical plant itself, and personnel.
Importance of Clean Room Humidity Control
Effective clean room humidity control or using a clean room dehumidifier is crucial for maintaining the integrity and quality of sensitive processes and products. Here are key reasons why controlling humidity in clean rooms is so important:
Microbial Growth and Corrosion: High humidity levels can foster the growth of microbes and bacteria, which can compromise sterile environments and contaminate products. Additionally, excessive moisture can lead to the corrosion of equipment and materials, reducing their lifespan and reliability.
Condensation on Work Surfaces: When humidity is not properly controlled, condensation can form on work surfaces and equipment. This not only causes delays in production schedules due to the need for additional cleaning and drying but also can lead to inferior product quality if moisture interferes with manufacturing processes.
Contamination Leading to Product Spoilage: Uncontrolled humidity can introduce contaminants that spoil products, particularly in industries like pharmaceuticals and biotechnology, where even minor contamination can render a batch unusable. This can lead to significant financial losses and regulatory issues.
Material Stability: Many materials used in clean room environments, such as certain polymers and chemicals, are sensitive to humidity levels. Proper clean room humidity control measure ensures these materials maintain their stability and performance.
Compliance with Standards: Industries that utilise clean rooms, such as pharmaceuticals, electronics, and aerospace, must adhere to strict regulatory standards. Effective humidity control is a key component in meeting these standards and ensuring the safe and effective production of goods.
Causes of Uncontrolled Humidity
- Semiconductor Clean Rooms
Microcircuits and microchips manufacturing requires hygroscopic polymers called photo resists to mask circuit lines for etching process. Because of their hygroscopic nature, they absorb moisture and, therefore, microscopic circuit lines are cut or bridged, resulting in circuit failures.
In addition, in semiconductor manufacturing, when the humidity level fluctuates in a wafer fabrication area, a multitude of problems can occur. Bake-out times typically increase, and the entire process generally becomes harder to control. Humidity levels above 35% RH make the components vulnerable to corrosion.
Additionally, as developer solvents are sprayed onto the wafer, the solvents evaporate rapidly, cooling the wafer enough to condense moisture from the air. This extra water can change the developer characteristics and be absorbed onto the semiconductor layers. This can cause swelling and further product quality problems, necessitating additional process control.
- Pharmaceutical Clean Rooms
In Pharmaceutical manufacturing facilities, high humidity causes fine powders to absorb moisture, clogging the powder feed to the tableting press. Powder inconsistency caused by moisture absorption results in crumbling tablets and clogged tablet dies. Variation in humidity means difficult adjustments in bed temperature and spraying rates, resulting in heat damage and moisture intrusion. Also, humidity in air duct-work creates moist places for bacterial colonies to grow and causes process contamination.
General Recommendation
Relative Humidity in Clean Rooms should be controlled between 35-40% RH (this is a function of the process requirement) for year-round operation. These RH levels are generally maintained in a narrow band ±2 % RH at temperatures below 20°C (70°F).
Bry-Air Solution
Bry-Air Desiccant Dehumidifiers or clean room humidity control systems can maintain dew points at very low levels consistently, such as (-) 60°C, a manifold reduction in the air moisture, way beyond what can be achieved by a standard HVAC grade refrigeration system.
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