Clean Room Quiz 5

Clean Room Quiz 5

Question: What is recommended for measuring the supply air volume flow rate in cases where there is local airflow turbulence and jet velocities issuing from an outlet?

Answer: It is recommended to use an airflow capture hood that captures all of the air issuing from each final filter or supply diffuser.

Question: How should the opening of the airflow capture hood be positioned when measuring the supply air volume flow rate?

Answer: The opening of the airflow capture hood should be placed completely over the entire filter or diffuser, and the face of the hood should be seated against a flat surface to prevent air bypass and inaccurate readings.

Question: What should be done if the accuracy of the airflow capture hood is not verified?

Answer: If the accuracy of the airflow capture hood is not verified, a correction factor should be applied. This correction factor is related to the flow and corresponds to an in situ check based on the difference between the reference measurement in air ducts and the air outlet.

Question: How can the supply air volume flow rate be evaluated without using an airflow capture hood?

Answer: The supply air volume flow rate can be evaluated by using an anemometer downstream of each final filter. The flow rate is determined by multiplying the airflow velocity by the corrected (free) area of exit.

Question: What should be considered when determining the number of measuring points (grid cells) and calculating the supply air volume flow rate?

Answer: When determining the number of measuring points and calculating the supply air volume flow rate, factors such as the inability to divide the plane into equal areas for measuring points should be considered. In such cases, the average air velocity weighted by area may be substituted.

Question: What factors can influence the accuracy of the air volume flow rate when calculated using this method?

Answer: The accuracy of the air volume flow rate can be influenced by factors such as the choice of test apparatus, selection of measuring locations, number of measuring points, distance from the filter face, and calculation of open cell area. These variations should be considered when performing the test.

Question: What types of apparatus are recommended for airflow velocity measurements?

Answer: For airflow velocity measurements, ultrasonic anemometers, thermal anemometers, vane-type anemometers, or their equivalent, can be used.

Question: Which apparatus can be used for supply air volume flow rate measurements?

Answer: For supply air volume flow rate measurements, airflow capture hood, orifice meters, Venturi meters, pitot static tubes, averaging tube array and manometers, or their equivalent, can be used.

Question: What should be considered when selecting apparatus for airflow velocity measurements?

Answer: When selecting apparatus for airflow velocity measurements, it’s important to choose equipment that is not affected by point-to-point velocity variation over small distances. For example, a thermal anemometer can be used if small grid divisions are selected and additional measuring points (grid cells) are used. Conversely, a vane anemometer can be used if it is sensitive enough and large enough to measure average air velocity over a range of variation.

Question: What requirement should the chosen apparatus meet?

Answer: The chosen apparatus should have a valid calibration certificate.

Question: What information and data should be recorded in test reports for airflow tests?

Answer: Test reports for airflow tests should include the following information and data:

1. a) Type of tests and measurements, along with the measuring conditions.
2. b) Type designations of each measuring apparatus used and their calibration status.
3. c) Measuring locations and the distance from the filter face.
4. d) Occupancy state(s) during the test.
5. e) Results of the measurements.
6. f) Any other relevant data pertaining to the measurement.

Question: Why is it important to record the type of tests and measurements in airflow test reports?

Answer: Recording the type of tests and measurements provides clarity on the specific parameters being evaluated and the methods used for measurement, ensuring transparency and reproducibility of the results.

Question: What significance does the calibration status of measuring apparatus hold in airflow test reports?

Answer: Including the calibration status of measuring apparatus ensures the reliability and accuracy of the measurements recorded in the test reports, as calibrated equipment provides trustworthy data.

Question: How does recording the occupancy state(s) contribute to airflow test reports?

Answer: Noting the occupancy state(s) during the test helps contextualize the airflow conditions and allows for comparisons between different states, such as during operation and at rest, providing valuable insights into the performance of the airflow system.

Clean Room Quiz 6