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Chapter 7

Chapter 7. IAQ Testing, Adjusting, and Balancing. Testing, Adjusting, and Balancing of Air-Handling Systems • Air-Handling System Duct Measurements • Air-Handling System Test Instruments • Outdoor Air Quantities . Chapter 7. IAQ Testing, Adjusting, and Balancing.

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Chapter 7

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  1. Chapter 7 IAQ Testing, Adjusting, and Balancing Testing, Adjusting, and Balancing of Air-Handling Systems • Air-Handling System Duct Measurements • Air-Handling System Test Instruments • Outdoor Air Quantities

  2. Chapter 7 IAQ Testing, Adjusting, and Balancing Testing, Adjusting, and Balancing of Air-Handling Systems • Air-Handling System Duct Measurements • Air-Handling System Test Instruments • Outdoor Air Quantities

  3. Proper verification of air-handling systems is necessary to prevent poor IAQ.

  4. Test instruments can measure various aspects of air-handling systems including air temperature, humidity, and airflow rate.

  5. Test instruments must be properly calibrated before performing tests.

  6. Measurement readings often undergo unit conversions. Some instruments can perform conversions electronically.

  7. When beginning the TAB process, the HVAC system design should be checked to ensure it is compatible with the building configuration.

  8. A detailed equipment check is performed after confirming that all components of an air-handling system are installed to design specifications.

  9. Total pressure is static pressure and velocity pressure added together.

  10. Once the average velocity pressure of a duct is known, the velocity of air can be calculated.

  11. Duct diameter is the distance from side-to-side across the middle of a rectangular or round duct.

  12. When traversing a duct, the number of test positions is determined by the size of the duct.

  13. Traversing a round duct requires dividing the duct into circles, each containing an equal area.

  14. Inclined-tube manometers are mainly used in applications where the manometer is permanently attached.

  15. Inclined-tube manometer procedures for measuring the pressure differential in a duct include several steps.

  16. Digital manometers are portable test instruments used to measure pressure and pressure differential in air systems.

  17. Using a digital manometer to measure the pressure in a space requires several steps.

  18. Thermoanemometers are permanently installed instruments that measure air velocity in a duct.

  19. The proper procedure must be followed when using a thermo-anemometer to measure air velocity.

  20. To calculate the airflow rate of a duct, first find the duct area then solve for the airflow rate.

  21. Rotating-vane anemometers are similar in design to a propeller or windmill.

  22. The airflow rate in a grill can be measured with a rotating-vane anemometer.

  23. Deflecting-vane anemometers are used because of their portability, direct readings, and ease of use.

  24. Deflecting-vane anemometers can be used to measure airflow rate in a particular space.

  25. Capture hoods may be used for airflow measurements from a diffuser or grill.

  26. Analog capture hoods use a mechanical selector to force air over a sensing manifold.

  27. Measuring the airflow rate from a diffuser with an analog capture hood requires several steps.

  28. Digital capture hoods have many of the same features as analog capture hoods.

  29. Digital capture hoods can measure airflow rate to a space using a few procedural steps.

  30. A velometer provides direct cubic feet per minute readings, while anemometers and pitot tubes require a stationary engineer to convert readings into cubic feet per minute.

  31. One technique for determining outdoor air quantities involves traversing the outside air duct.

  32. Calculating the outdoor air percentage of a facility can be done if the outdoor-air, mixed-air, and return-air temperatures are known.

  33. The outdoor air percentage is often calculated using an air meter that measures carbon dioxide.

  34. Connecting a capture hood (capture hood has reverse flow switch) to a return-air grill can be done to measure airflow in a reverse manner.

  35. ASHRAE publishes standards concerning ventilation air requirements.

  36. Air should circulate completely through occupied zone of a building to flush out contaminants.

  37. Open area measurements may be used for purposes such as measuring drafts.

  38. Motor current and voltage measurements of a fan are necessary to ensure the fan is operating properly.

  39. Fan capacity readings are checked against a curve to ensure the fan operating point is correct.

  40. A mechanical fan drive consists of belts and pulleys.

  41. Fans that use electric motor drives offer more flexibility than mechanical fan drives.

  42. After a system supply fan is adjusted, return and exhaust fans are tested as well.

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