IAQ Testing, Adjusting, and Balancing

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.