308A HVAC Ductwork Systems 2

Question 1

What is the equal friction method of duct sizing?

Accepted Answer

A design method that maintains a constant friction loss rate per unit of duct length throughout the system

Answer

Making all ducts the same size

Answer

Using equal numbers of fittings in each branch

Answer

Installing equal amounts of insulation on all ducts

Question 2

What is the function of a fire damper in a duct system?

Accepted Answer

To automatically close and prevent the spread of fire and smoke through duct penetrations in fire-rated walls and floors

Answer

To regulate temperature

Answer

To control airflow volume

Answer

To reduce noise

Question 3

What is the recommended maximum air velocity in a main supply duct for a commercial HVAC system to minimize noise?

Accepted Answer

1,200 to 1,500 FPM

Answer

500 FPM

Answer

3,000 FPM

Answer

5,000 FPM

Question 4

What is the purpose of a balancing damper in an HVAC duct system?

Accepted Answer

To adjust airflow to individual branches or outlets to achieve the designed air distribution

Answer

To prevent backdraft

Answer

To filter the air

Answer

To reduce vibration

Question 5

What is a 'flexible duct' commonly used for in HVAC systems?

Accepted Answer

To connect rigid duct branches to diffusers and registers in locations where rigid duct is impractical

Answer

As the main trunk line

Answer

As exhaust duct for kitchen hoods

Answer

As underground ductwork

Question 6

What SMACNA duct pressure class is typically specified for a standard commercial supply air system?

Accepted Answer

2 inch WG

Answer

1/2 inch WG

Answer

6 inch WG

Answer

10 inch WG