FC FC Ductwork & Air Distribution 2

Question 1

What type of duct leakage test measures the total leakage of a duct system at a reference pressure of 25 Pa?

Accepted Answer

Duct blaster (duct pressurization) test

Answer

A duct blaster test pressurizes the duct system to 25 Pa and measures airflow required to maintain pressure, quantifying total duct leakage.

Question 2

Flex duct installed with excessive sag will cause which problem?

Accepted Answer

Increased airflow restriction due to liner compression and tight bends

Answer

Sagging flex duct compresses the inner liner, dramatically increasing airflow resistance and reducing delivered CFM to registers.

Question 3

When sealing duct joints and seams, which material is approved by most building codes and SMACNA standards?

Accepted Answer

UL 181-rated mastic or foil tape

Answer

UL 181-rated mastic sealant or pressure-sensitive foil tape are code-approved for sealing rigid and flex duct connections.

Question 4

What is the purpose of balancing dampers in a forced-air distribution system?

Accepted Answer

To adjust airflow to individual zones or rooms to achieve comfort balance

Answer

Balancing dampers allow technicians to restrict airflow to over-supplied areas and redirect it to under-supplied rooms.

Question 5

Supply registers in a forced-air system are typically located near which area for best comfort in heating climates?

Accepted Answer

Low on exterior walls under windows

Answer

Placing supply registers low on exterior walls under windows counteracts cold downdrafts and creates an even floor-to-ceiling temperature.

(FC) Furnace Installation and Maintenance Certification Practice Test