GW 30 SPRING 2025

Air expands to fill a greater space as _____.

• relative humidity increases

• pressure drops

• temperature rises

• All of the above.

Return air inlets should be placed _____.

• always near the ceiling

• always along the floor

• the minimum distance from the supply duct outlets

• the maximum distance from the supply duct outlets

To bring fresh air into a building’s conditioned space and minimize how much it might affect indoor temperature, use a(n) _____.

• barometric damper

• HRV or ERV

• motorized damper

• soffit vent and ridge vent

Negative pressure in a building _____.

• enhances the efficiency of exhaust fans

• helps keep out airborne pollen

• makes a fuel-fired furnace more efficient

• tends to bring in outside contaminants

A system in cooling mode should provide at least _____ cfm of air per person.

• 5

• 15

• 50

• 100

How long would an air-conditioning system take to complete one air exchange in a 12,000 ft3 space occupied by 25 people?

• 0.0315 min.

• 1.88 min.

• 32 min.

• 64 min.

Which shape of ducts provides the least resistance to airflow?

• Hexagonal

• Square

• Rectangular

• Round

Which of the following statements about sheet metal ducts is false?

• They are used for warm air distribution.

• They are usually coated with zinc.

• They expand and contract as they heat and cool.

• They are susceptible to only a small amount of corrosion.

The ratio of a duct’s wide side to its narrow side is called the _____.

• effective length

• aspect ratio

• throw

• length ratio

A rectangular duct with a _____ aspect ratio can hold the maximum amount of air using the minimum amount of material.

• 1:2

• 2:1

• 1:1

• 3:1