Quiz Air Distribution Systems by DP

Radial perimeter system

A duct system commonly used in small homes in areas with cold climates is the

Perimeter loop system

A duct system installed in a concrete slab that helps keep the entire floor warm is the ______.

Static, Velocity & Total Pressure.

A duct system is pressurized by what three pressures?

Free air Delivery

A fan moving air with no effective restrictions to airflow at its inlet or outlet is called ______.

The fusible link melts

A fire damper will close when​

Psychrometric chart

A graphic representation of the relationship between air properties is known as ___

pressure

A manometer is used to measure

Pitot tube

A tool that is inserted into a duct to capture pressure values is a ___

Remember

An air distribution system must deliver draft free quantities of conditioned air and return the air the air handler without excessive power consumption and with minimal maintenance.

Register

An air outlet device that directs air in a concentrated non-spreading stream is a _______.

Wet-bulb and​ dry-bulb temperature

An electronic psychrometer is used to measur

1,000 rpm

An existing air distribution system has an airflow of​ 6,000 cfm created by a blower operating at a speed of​ 1,200 rpm. If you wanted to change the airflow to​ 5,000 cfm, what is the required new blower​ speed

Hygrometer.

An instrument that gives a direct reading of relative humidity is called a?

14.7 psi

At sea level, every inch of Earth as an absolute pressure of?

Takeoffs

Branch ducts need ______ so they can be connected to the main duct.

Make minor adjustments in airflow

Dampers built into supply diffusers and registers are used to​

Total pressure loss in an air distribution system excluding the blower itself

External static pressure loss is the​

A friction loss equal to some length of the same size straight duct

Fitting and transition used in a duct system have

Cooling when used with​ room-by-room returns

High sidewall registers work best in​

decreases slightly

If the resistance against a centrifugal bloweris doubled, the cfm output decreases, and theamperage draw of the motor ____.

increases

If the resistance against a propeller fan isdoubled, the cfm output decreases, but the amperage draw of the motor ____.

Class 1

In order to minimize the spread of smoke within a building, select smoke damper with a leakage?

Remember 2`

Incline meter is more accurate then u tube meter

Wet-bulb temperature

Temperature taken with a thermometer that has a saturated wick wrapped around its sensing bulb before taking a reading is called a(n) ____

Ak Factor

The _____ reflects the free area of a grille, register, or diffuser in relation to one square foot.

Blower door

The device containing a fan that is used to depressurize a building for air leak testing is the ____

Sheet metal

The duct material that has the least friction loss is​

Dry-bulb temperature

The temperature measureed using a standard thermometer is called ____

Backward inclined centrifugal blower

The type of blower or fan that is best suited to applications with a high resistance to airflow is the

Propeller fan

The type of fan usually housed in a short venturi is the ____.

Remember 1

The volume in cubic feet per minute cfm is calculated by multiplying the area of the duct by the velocity of the air moving through it

Cubic feet per minute (cfm)

The volume of air flowing past a point in one minute is measured in ____

Boots

To transition from branch ducts to the grille and registers, ________ are typically required.

When the opening exceeds 1/4" 6-7mm.

Under what conditions would it be necessary to seal a duct with fiberglass tape and​ mastic

static pressure in a duct system

Which of the following is typically measuredwith an inclined water manometer?

A higher pressure measured in the duct than in the home during a test indicates a leak.

Which of the following statements about pressure testing residential duct systems is true?

Ceiling

Which supply air diffuser or register location offers the best cooling performance?

Outlet of the blower

Within an air distribution​ system, the highest pressure level is found at the

R-value

the effectiveness of insulation is reflected in its ______.

Relative humidity RH

the ratio of the amount of moisture present in a given sample of air compared to the amount it can hold at saturation defines _______.

total pressure

the sum of the static pressure and the velocity pressure in an air duct provides the ______.

the perimeter is where most of the heat gain or loss occurs

the supply-air grilles in a residential system are often placed around the perimeter of the structure because ____.

Velocity

usually measured in feet per minute, reflects how fast air is moving in a duct

forward curved centrifugal

which type of blower is commonly used in residential system?

Reducing extended plenum

A 24 ft. x 37 ft. single story house with abasement has the heating unit in one end of the basement. What type of supply duct system would be used in this application?

Transfer Grille

A _______ allows air to move freely out of an enclosed are.

Damper

A device use to control and balance airflow in forced air systens is a?

External Static Pressure ESP

Adding up the total friction loss of the ducts and all other objects in the air distribution system beyond the blower itself will result in the ____

3.5 in W.C.

Air distribution air systems considered to be high-pressure systems have pressure greater than?

Stratify

Air masses at different temperatures will _____ unless an outside force encourages it to move and mix.

Less airflow than.

Air systems used only for heating usually require_______ systems used for both heating and cooling.

2,000 cfm

An air distribution system for a light commercial building is designed to work with a​ 5-ton cooling system. About how many cfm of airflow should the system blower be capable of​ supplying

This is where the heat exchange occurs, placed next to the outside wall to accomplish the load cancelling effect. cold air kept in & hot air kept out. depending on the season.

Floor diffusers along the outer wall of the room are the best way to introduce treated air into a room. Why?

400 cfm +_50

Forced-air systems designed for cooling require about_______ of airflow per ton of cooling.

air volume

Multiplying the cross sectional are of a duct by the air velocity is used to calculate _____.

Build on concrete slabs.

Overhead trunk and radial systems are typically used in homes?

Air pressure and velocity

Pitot tubes are used in measuring​

sheet metal screw

Round metal duct sections are normally connected using ______.

takeoff

The ideal location for a balancing damper in a branch duct is at the _____.

Vapor barrier

The material installed over insulation to prevent moisture from entering is referred to as a ______.

Static pressure s.p.

The pressure exerted uniformly in all directions within a duct system is called ____.

Velocity pressure

The pressure in a duct due to the forward movement of the air is referred to as the ______.

maintain a more even pressure throughout the entire length of the trunk duct

The reason for using a reducing extended plenum system is to ____,

Venturi

The ring or panel surrounding the blades of a propeller fan that increases the fan's performance is called a(n) ___.

Plenum

The sealed enclosure at the inlet or outlet of an air handler is called a(n) ____

Revolutions per minute rpm

The speed at which the shaft of an air-moving device is rotating over a period of time is reported in ______.

Inches of water column or centimeters of water

The static​ pressure, velocity​ pressure, and total pressure measured in a duct system are measured in

Dew Point

The temperature at which the air becomes saturated with water, causing it to condense into water droplets and fall out, is called the ___.