A technician needs to measure the actual volumetric airflow delivered through a supply diffuser. A suitable calibrated capture hood can completely cover the opening. Which method directly measures that airflow?
- AInspect the diffuser visually without taking measurements.
- BUse only the pressure drop predicted in the design documents.
- Measure with the capture hood, following its manufacturer instructions.
- DAssume the installed airflow equals the design airflow.
Where to look it up
https://19january2017snapshot.epa.gov/indoor-air-quality-iaq/iaq-building-education-and-assessment-model-ibeam-diagnosing-and-solving_.html
Why C is correct
A capture hood measures airflow through the opening it covers. Follow the instrument instructions and account for its measurement limitations. Visual inspection and design calculations alone do not measure the installed airflow. A single diffuser reading also does not map air movement throughout the room.