AIR VELOCITY TEST BY USING VELOCITY MATRIX
ISO 14644 is a standard that provides guidelines for the classification of airborne particles in cleanrooms and controlled environments. While ISO 14644 specifies air cleanliness levels based on particle concentration, it does not explicitly provide guidelines for conducting air velocity tests using velocity matrices.
However, air velocity testing is an essential part of cleanroom qualification and monitoring. It helps ensure that the airflow within the cleanroom is adequate to maintain the desired particle cleanliness levels. The following general steps can be followed to conduct an air velocity test in accordance with ISO standards:
- Equipment: Obtain a suitable air velocity measuring instrument, such as an anemometer or thermal anemometer, capable of measuring air velocities within the desired range and accuracy specified by ISO 14644.
- Test Points: Identify the locations within the cleanroom where air velocity measurements need to be taken. These points are typically predetermined based on the cleanroom design and should cover critical areas, such as the workstations, laminar flow benches, and return air grilles.
- Calibration: Calibrate the air velocity measuring instrument as per the manufacturer’s instructions or using a traceable calibration standard. This ensures the accuracy of the measurements.
- Measurement Procedure: Follow the specified measurement procedure for air velocity testing. ISO 14644 does not provide specific guidelines for this procedure, so you may refer to other industry standards or internal protocols. The procedure generally involves positioning the instrument probe at each test point and recording the air velocity measurement.
- Velocity Matrix: If you want to create a velocity matrix to visualize the airflow patterns, you can use a grid system overlaid on the cleanroom floor plan or ceiling plan. The grid should have regularly spaced points where air velocity measurements are taken.
- Data Analysis: After collecting the air velocity measurements, analyze the data to ensure compliance with the required velocity criteria specified in ISO 14644 or other applicable standards. Calculate averages, maximums, and minimums as needed. Compare the results against the specified velocity ranges for each classification level.
- Reporting: Prepare a comprehensive report documenting the test procedure, test points, measured velocities, and the compliance status. Include any deviations or areas that require corrective actions.
It’s important to note that ISO 14644 focuses primarily on particle cleanliness levels rather than air velocity testing. Therefore, while air velocity measurements are crucial, you may need to refer to other industry guidelines, local regulations, or internal cleanroom standards for more detailed instructions on conducting air velocity tests and establishing acceptable velocity ranges.