Cleanroom pressure differential is a crucial factor that directly impacts the effectiveness of contamination control in a cleanroom environment. Therefore, it is essential to regularly measure and verify the pressure differential to ensure it remains within the specified range. In this article, let’s explore the cleanroom pressure differential and the methods for measuring it with INTECH Service!
What is Cleanroom Pressure Differential?
Cleanroom pressure is the measurement of the air pressure inside the cleanroom compared to the air pressure outside the cleanroom. It is measured in Pascals (Pa) (or inches of water gauge – in. w.g) and is detected using a pressure sensor.
Cleanroom pressure differential is the difference in pressure between one area and an adjacent area, typically measured in Pascals. For example, if point A has a pressure of 100 Pa and point B has a pressure of 70 Pa, the pressure differential between points A and B is 100 – 70 = 30 Pa.
Standards and Regulations on cleanroom Pressure Differential
Cleanroom pressure differential standards are defined by various international and national organizations, depending on the industry and specific applications.
General Regulations
According to cleanroom design rules, the pressure differential between cleanrooms of different levels must not be less than 5 Pa.
The pressure differential between a clean area and a non-clean area must not be less than 5 Pa.
The pressure differential between a clean area and the outside environment must not be less than 10 Pa.
GMP (Good Manufacturing Practice) Regulations
The pressure differential must not be less than 10 Pascals between different levels of clean areas or between clean and non-clean areas.
Adherence to appropriate pressure must be maintained depending on the clean area to prevent contamination and cross-contamination within the clean area.
Pressure differential gauges must be installed between adjacent areas where pressure differential is common.
Other Standards
Institute of Environmental Sciences and Technology (IEST): Establishes pressure standards based on air filtration levels and cleanroom types.
World Health Organization (WHO): Sets pressure standards for operating rooms and emergency rooms.
U.S. Food and Drug Administration (FDA): Establishes pressure standards for cleanrooms in the production of pharmaceuticals, medical devices, and food-related products.
Principles of Measuring Differential Pressure in cleanroom
To measure differential pressure, we must use differential pressure measurement devices. These devices need to have two ports to measure the pressure at each end, and then subtract one from the other to determine the differential pressure.
The differential pressure measurement device will be installed between two different environments to measure the differential pressure between these environments. For example, if environment A has higher pressure, we can call it the high-pressure end. Environment B, with lower pressure, can be called the low-pressure end. The differential pressure between these two environments will be equal to the pressure at end A minus the pressure at end B.
To measure differential pressure accurately, we need to identify the correct measurement points to choose the necessary differential pressure to measure. Selecting incorrect measurement locations will lead to inaccuracies in the differential pressure measurement process.
The formula to calculate differential pressure:
The differential pressure between two ends A and B is calculated using the formula:
dP = pA – pB
where:
pA is the high-pressure end
pB is the low-pressure end
Common Methods for Measuring cleanroom Pressure Differential
Using Specialized Pressure Measuring Devices
Measure the pressure directly inside and outside the cleanroom to calculate the pressure differential. The pressure measuring devices must be placed in two different locations: one inside the cleanroom and one outside. Ensure that the installation points are sealed and free of air leaks.
Advantages:
High Accuracy: This is the most accurate method for measuring cleanroom pressure differential.
Ease of Use: Specialized pressure measuring devices are usually easy to use and come with clear instructions.
Versatility: These devices can be installed in various locations within the cleanroom to measure pressure differentials in different areas.
Disadvantages:
Cost: Specialized pressure measuring devices can be expensive.
Training Required: Proper training is needed to use the devices accurately.
Using an Automatic Monitoring System
This system uses pressure sensors to measure the pressure inside and outside the cleanroom. It can also be set up to alert when the pressure differential exceeds the permissible limit.
How to Use the Automatic Monitoring System:
Install the System:
Install pressure sensors in two different locations: one inside the cleanroom and one outside.
Connect the pressure sensors to the data collection unit.
Install monitoring software on a computer.
Configure the System:
Configure the system to set parameters such as the allowable pressure differential limits.
Monitor the System:
Observe the measurement data displayed on the monitoring software.
Respond to alerts when the pressure differential exceeds the permissible limit.
Advantages:
Continuous Monitoring: The automatic monitoring system can continuously monitor the cleanroom pressure differential 24/7.
Timely Alerts: The system can be configured to alert when the pressure differential exceeds the permissible limit, allowing operators to respond promptly.
Easy Data Collection and Storage: The system can automatically collect and store measurement data, making it easy to track and analyze data over time.
Increased Operational Efficiency: The automatic monitoring system helps ensure the pressure differential is maintained at an appropriate level, improving cleanroom operational efficiency.
Disadvantages:
High Investment Cost: The automatic monitoring system can be more expensive than manual pressure differential measurement methods.
Expertise Required: Specialized knowledge is needed to install and operate the automatic monitoring system.
Maintenance: The automatic monitoring system requires regular maintenance to ensure accurate operation.
Notes:
Adhere to Pressure Standards: Ensure compliance with cleanroom pressure standards and maintain proper airflow in and out.
Adjustments: If the cleanroom pressure differential does not meet requirements, adjust the exhaust airflow to either increase or decrease pressure to achieve the desired differential.
Pressure Gauge Installation: Install pressure gauges in appropriate locations to measure the pressure differential between the two areas to be checked. Ensure the gauges are properly installed and highly accurate.
Connecting Gauges: Use standby pipes to connect the gauges to ventilation valves if the gauges are not fixed.
Seal Doors: Ensure all doors are tightly sealed to prevent pressure leakage and ensure that airflow is maintained along the floor near the doors.
The above information provides insights into cleanroom pressure differentials and common methods for measuring them. INTECH Service specializes in providing reliable pressure differential measurement and pressure balancing services, with a team of highly skilled specialists and advanced, modern equipment. Contact us today for the earliest consultation.