308A HVAC Ductwork Systems 3

Question 1

What is the purpose of a 'smoke damper' and how does it differ from a fire damper?

Accepted Answer

A smoke damper is motor-operated and controlled by smoke detectors, while a fire damper uses a fusible link activated by heat

Answer

They are the same device

Answer

A smoke damper is only used outdoors

Answer

A fire damper handles smoke while a smoke damper handles fire

Question 2

What is the primary reason for insulating supply air ductwork?

Accepted Answer

To prevent heat gain or loss and control condensation on cold duct surfaces

Answer

To make the duct stronger

Answer

To reduce the weight of the duct

Answer

To make the duct easier to install

Question 3

What is an 'air handling unit' (AHU) and what components does it typically contain?

Accepted Answer

A factory-assembled unit containing fans, heating/cooling coils, filters, and dampers for conditioning and distributing air

Answer

A single fan mounted in a duct

Answer

An outdoor condenser unit only

Answer

A thermostat and controller assembly

Question 4

What is the purpose of an 'economizer' in an HVAC system?

Accepted Answer

To use cool outdoor air for free cooling when outside conditions are favorable, reducing mechanical cooling load

Answer

To reduce the cost of ductwork materials

Answer

To speed up the fan

Answer

To recirculate air without conditioning

Question 5

What is the code-required clearance between uninsulated HVAC ductwork and combustible materials?

Accepted Answer

A minimum of 1 inch clearance from combustible materials

Answer

No clearance is required

Answer

6 inches clearance

Answer

24 inches clearance

Question 6

What is the difference between a 'diffuser' and a 'register' in HVAC terminology?

Accepted Answer

A diffuser distributes air in a spreading pattern and typically has no damper, while a register has a built-in damper for flow adjustment

Answer

They are the same device

Answer

A diffuser is for exhaust only

Answer

A register is only used with return air