Exploring the Differences: Negative and Positive Pressure Cleanroom

Differences Between Positive and Negative Pressure Cleanroom

  Air naturally flows from high-pressure areas to low-pressure areas (pressure cascade), so the pressure levels determine how the air flows within the space.

  In positive pressure cleanroom, the indoor air pressure is higher than the surrounding environment, causing the indoor air to flow outwards. This effectively prevents external particles, bacteria, and other contaminants from entering the cleanroom, thus ensuring the cleanliness of the internal environment.

  In negative pressure cleanroom, the indoor air pressure is lower than the surrounding environment, causing the outside air to flow inwards. This effectively prevents harmful substances and contaminants inside the cleanroom from leaking out.

How to Achieve Positive and Negative Pressure in Cleanroom:
  Cleanroom pressure cascade is achieved by controlling the amount of air entering and being extracted from the cleanroom.

Positive Pressure Cleanroom: 
  Filtered air is continuously pumped into the room through HEPA filters and the cleanroom HVAC system. If a door or window is opened in the cleanroom, the air will rush out to the external environment. This positive pressure ensures that products and processes inside the cleanroom are protected in case of breaches or leaks. Since the cleanroom has positive pressure, the air is forced out, preventing contaminated or unfiltered air from seeping in.

Negative Pressure Cleanroom: 
  External exhaust systems extract air from the cleanroom at a faster rate than air is introduced in a period of time. This creates a negative pressure, meaning that air tends to flow into the cleanroom to fill the low-pressure area, effectively preventing contaminants from escaping against the natural airflow.

  To maintain positive or negative pressure in cleanroom, adjacent spaces must be maintained at a lower or higher pressure than the cleanroom. If you implement a cleanroom pressurization system, a pressure monitoring system is crucial for ensuring balance and consistency, which will check and maintain consistent pressure and can be adjusted manually or automatically.

Applications of Positive and Negative Pressure Cleanroom:
  In practical applications, the choice between positive or negative pressure control methods depends on the required cleanliness level and the actual working environment.
  If the cleanliness requirements are high and the external environment poses a significant contamination risk, negative pressure cleanroom are required. They are widely used in medical cleanroom for research, experiments, and developing treatments using sensitive materials, such as pharmaceutical plants, laboratories, hospitals, and hazardous chemical handling rooms, etc.

  If the external environment poses less contamination risk, positive pressure cleanroom can be used. They are normally applied in production and manufacturing areas that require cleanliness, such as electronic component production lines, cleanrooms, and laboratories.

  In summary, both positive and negative pressure are methods to ensure the sanitary conditions of cleanroom environments. Choosing the appropriate pressure control method for different scenarios can effectively guarantee the internal air quality of the workshop. Regardless of the method adopted, it is essential to enhance management and monitoring to maintain the indoor cleanliness and employee health.